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The past decade has brought rapid advancements in treatment with immune checkpoint inhibitors and molecularly targeted agents, which have significantly improved objective response rates (ORRs), progression-free survival (PFS), and overall survival (OS) for patients with metastatic melanoma. This article reviews current evidence for immune checkpoint blockade and molecularly targeted agents in the treatment of metastatic melanoma after progression on first-line therapy. The selection of first-line therapy for metastatic melanoma is reviewed in a separate article.
Case Presentation
A 62-year-old man was diagnosed with stage IIA melanoma after undergoing wide local excision of a right scalp lesion (final staging was consistent with pT3aN0M0). After 3.5 years of follow-up, he developed symptoms of vertigo, diplopia, and recurrent falls prompting medical attention. Magnetic resonance imaging (MRI) brain revealed multiple supratentorial and infratentorial lesions concerning for intracranial metastases and computed tomography (CT) chest/abdomen/pelvis revealed a right lower lobe pulmonary mass with right hilar and subcarinal lymphadenopathy. He was treated with intravenous dexamethasone and further evaluation with an endobronchial ultrasound-guided fine-needle aspiration of the right lower lobe mass revealed metastatic melanoma. The patient underwent whole brain radiation therapy for symptomatic relief prior to initiating systemic therapy. Testing showed the melanoma was positive for a BRAF V600K mutation. He was started on combination molecularly targeted therapy with dabrafenib and trametinib. He initially did well, with a partial response noted by resolution of symptoms and decreased size of his intracranial metastases and decreased size of the right lower lobe mass.
After 3 months of therapy, surveillance PET-CT notes increasing size and FDG avidity of the right lower lobe mass. MRI brain reveals resolution of several previously noted metastases, but with interval development of a new left frontal lobe mass concerning for progressive disease.
What is the general approach to treatment of metastatic melanoma after progression on first-line therapy?
Based on the current evidence, there is no definitive algorithm for the treatment of metastatic melanoma after progression on first-line therapy. Enrollment in clinical trials is encouraged to further elucidate the best sequencing of treatment. The current practice is to typically switch class of agents after progression on front-line therapy to either immunotherapy that has not yet been tried or to molecularly targeted therapy in patients harboring a BRAF V600 mutation. After further progression of disease, retreatment with a previously received agent is possible, and this may be combined with investigational therapies.
Immune Checkpoint Inhibitors in Progressive Disease
The 2 major populations of patients to consider are those with BRAF wild-type melanomas who progress on first-line immunotherapy and those with BRAF V600 mutation–positive melanoma who progress on molecularly targeted therapy with BRAF and MEK inhibitors. There is relatively limited data on the efficacy of immune checkpoint inhibition after progression on anti-programmed cell death 1 (PD-1) monotherapy. A small retrospective study of patients who progressed on anti-PD-1 monotherapy were treated with ipilimumab, with a 10% ORR and another 8% having stable disease for more than 6 months; however, 35% of patients experienced grade 3 to 5 immune-related adverse events.1 The only prospective data supports the efficacy of anti-PD-1 therapy after progression on ipilimumab, as supported by the CheckMate 037 trial (nivolumab versus chemotherapy)2 and KEYNOTE-002 trial (pembrolizumab versus chemotherapy)3,4; however, this is no longer applicable as ipilimumab is no longer given in the first-line setting and has been replaced by anti-PD-1 monotherapy or combination immunotherapy.
Another interesting facet of PD-1 monotherapy is the idea of treatment beyond progression. The concept of pseudoprogression—whereby patients receiving PD-1 inhibitors initially meet Response Evaluation Criteria in Solid Tumors (RECIST) criteria for progression, but then later go on to demonstrate significant decreases in tumor burden on subsequent imaging studies—has been described in melanoma patients receiving such immunotherapies. It is thought that pseudoprogression occurs due to either an initial delay in anti-tumor response to the immunotherapy or from the measured target lesion appearing larger due to surrounding immune/inflammatory infiltrate. In an analysis of individual patient data pooled from 8 multicenter clinical trials, 19% of patients were treated beyond initially documented RECIST progression and had subsequent imaging to evaluate the tumor burden; in these patients, the same target lesion later met RECIST criteria for response, with a greater than 30% reduction in tumor size. Furthermore, of the evaluable cohort, the median OS in patients who did receive treatment beyond progression was 24.4 months compared to 11.2 months in those who did not receive treatment beyond progression.5 While further randomized studies are warranted to characterize the potential benefit, the existing data suggests that selected patients who are doing well clinically despite evidence of radiographic progressive disease may benefit from continued treatment with PD-1 inhibitors.
Combination immunotherapy with both PD-1 and CTLA-4 blockade has been studied retrospectively in the second-line setting. A retrospective analysis of patients who had progressive disease on PD-1 inhibitor monotherapy compared the outcomes of patients who received just ipilimumab to those of patients who received both ipilimumab and nivolumab. The ORR (16% ipilimumab vs 21% combination group) and 1-year OS (54% vs 55%) were similar in both groups,6 and this demonstrated significantly less efficacy with combination therapy when compared to use in the first-line setting, albeit in a separate prospective trial.7 A multicenter, retrospective study by Tétu and colleagues compared outcomes with ipilimumab plus nivolumab across 3 groups that included previously untreated patients, patients who had progressed on single-agent immunotherapy, and patients who had progressed on prior molecularly targeted therapy.8 Despite clearly inferior efficacy in previously treated patients, the results support combination immunotherapy as a viable treatment option in the second-line setting. Outcomes are reported in Table 1 below. Of note, there is an ongoing phase 2 trial to assess the use of combined PD-1 and CTLA-4 inhibitors versus CTLA-4 inhibition alone after progression on first-line PD-1 inhibitor monotherapy (NCT03033576).
For patients with BRAF V600–mutation positive melanoma who progress on front-line molecularly targeted therapy, immune checkpoint inhibitor therapy with either anti-PD-1 monotherapy or combination anti-PD-1 and ipilimumab should be considered. The KEYNOTE-006 trial that demonstrated superiority of pembrolizumab compared to ipilimumab included patients who had received up to 1 prior systemic therapy that was not a PD-1 or CTLA-4 inhibitor, and subgroup analysis demonstrated efficacy with pembrolizumab in patients who had received prior treatment with a BRAF inhibitor.9 The retrospective analysis by Tétu et al (Table 1) noted efficacy of combination nivolumab and ipilimumab in patients treated with prior molecularly targeted therapy, as evidenced by an ORR of 35% and median OS of 16.5 months.8
A retrospective trial by Ackerman et al analyzed ORR, median PFS, and median OS from the time of commencement of BRAF inhibitor therapy (with or without a MEK inhibitor), and the comparison was made between those who received ipilimumab before or after molecularly targeted therapy. While ipilimumab is no longer the first-line immunotherapy agent used in advanced melanoma, the study did highlight some important concepts. First, ORRs to BRAF inhibitors were similar between the 2 treatment groups. The conclusions of the analysis were that there was no significant difference in median PFS or OS in regard to which therapy was given first, but median OS after BRAF inhibitors were discontinued was very short and patients had poor responses to ipilimumab after stopping a BRAF inhibitor. This highlights the concern that patients who have progressive disease on molecularly targeted therapy often have a poor performance status and undergo too rapid of a clinical decline to derive benefit from immunotherapy, which can often take weeks to months to take effect.10
A more recent retrospective study by Johnson et al compared efficacy outcomes in patients who received single-agent anti-PD-1 therapy prior to molecularly targeted therapy (BRAF inhibitor with or without MEK inhibitor) to those who received molecularly targeted therapy prior to anti-PD-1 therapy. The difference in median OS was not statistically significant (27.5 months with PD-1 inhibitor first vs 40.3 months with molecularly targeted therapy first). Both treatments demonstrated second-line efficacy, but outcomes were inferior to those reported when either type of therapy was used in the first-line setting. Interestingly, patients who were maintained on molecularly targeted therapy for more than 6 months prior to progression demonstrated an improved ORR to subsequent anti-PD-1 therapy (34% vs 15%).11
Molecularly Targeted Therapy in Progressive Disease
When melanoma patients with a BRAF V600 mutation are treated initially with immunotherapy and demonstrate progressive disease, molecularly targeted therapy with combined BRAF and MEK inhibition should be considered for second-line therapy. While there are no dedicated prospective trial results with BRAF/MEK inhibitors after progression on immune checkpoint inhibitors, for practical purposes, it may be reasonable to extrapolate outcomes from the currently available first-line studies.12-16 An ongoing study (NCT02224781) in which patients are randomized to receive ipilimumab/nivolumab followed by dabrafenib/trametinib at progression versus the reverse order is designed to help answer the question of optimal sequencing and timing of therapy. Johnson et al’s retrospective analysis of patients receiving single-agent anti-PD-1 therapy prior to molecularly targeted therapy compared to the reverse order concluded that there was no statistically significant difference in median OS.11 Ackerman et al’s retrospective study of patients who had received ipilimumab before or after molecularly targeted therapy noted similar response rates to molecularly targeted therapy in each treatment group.10
The issue of re-treatment with a BRAF/MEK inhibitor in a patient already progressing on targeted therapy is a more challenging situation, and currently available data suggests there is limited benefit. However, select patients may be considered for this approach. The combination of dabrafenib/trametinib demonstrated an ORR of approximately 15% in a cohort of patients who progressed on single-agent BRAF inhibitor therapy, with a suggestion that those patients who had previously derived benefit for more than 6 months may have a more favorable outcome.17
Based on the hypothesis that acquired resistance to BRAF/MEK inhibition may be reversible if the selective pressure of the medication is held for a period of time, a phase 2 trial analyzed outcomes with retreatment. The study included patients with BRAF V600–mutant melanoma who had progressed on prior BRAF inhibition (with or without MEK inhibitor) and required that they had been off of therapy for at least 12 weeks. Of the 25 patients who received dabrafenib plus trametinib as retreatment, 32% demonstrated a partial response and 40% had stable disease.18 While further studies are warranted, retreatment with molecularly targeted therapy may be a viable option, especially in light of the multiple approved BRAF and MEK inhibitor combinations.
Another concept that has been studied is treatment beyond disease progression with molecularly targeted therapy. In a retrospective analysis of patients who had progressed on a single-agent BRAF inhibitor, 39% of those patients were continued on the same BRAF inhibitor and compared to patients who received no subsequent therapy or changed to an alternative systemic therapy. In the multivariable analysis adjusting for other prognostic factors, continued treatment with the BRAF inhibitor was associated with prolonged OS.19
Case Conclusion
The patient is started on second-line therapy with nivolumab and ipilimumab and demonstrates a partial response. One year later he continues to feel well with decreased size of the intracranial and right lower lobe lesions, and without any interval development of new areas of metastatic disease.
Special Considerations
Intralesional Therapies
Talimogene laherparepvec (T-VEC) is a genetically modified herpesvirus-1 oncolytic virus that is injected into melanoma skin lesions and leads to the expression of granulocyte-macrophage colony-stimulating factor. While T-VEC is currently approved for local treatment of unresectable cutaneous, subcutaneous, or nodal recurrences,20 it has also been investigated in combination with other therapies for patients with advanced disease. In patients with previously treated melanoma, T-VEC plus ipilimumab demonstrated superior ORR to ipilimumab alone (39% vs 18%), and the tumor response was not limited to the injected lesions. The observation of systemic response suggests synergy between T-VEC and immune checkpoint blockade in enhancing the anti-tumor immune response.21 The phase 1b MASTERKEY-265 trial combining pembrolizumab and T-VEC led to an ORR of 62% and CR of 33%.22 A phase 3 trial comparing pembrolizumab plus T-VEC to pembrolizumab alone is ongoing (NCT02263508).
Melanoma Brain Metastases
The presence of brain metastases is a common event in patients with metastatic melanoma, and often confers a poor prognosis.23 The approach to the management of brain metastases should be multidisciplinary among medical oncology, neurosurgery, and radiation oncology providers, as treatment algorithms continue to rapidly evolve. Historically, there has been little prospective clinical trial data regarding optimal systemic therapy, and local therapies such as surgery or stereotactic radiation have long been the mainstay of therapy for intracranial disease.24 However, recent data with both immunotherapy and molecularly targeted therapy has demonstrated efficacy with intracranial metastases.
A recent trial of combined nivolumab and ipilimumab as frontline therapy in patients with asymptomatic melanoma brain metastases demonstrated a complete response rate of 26% and partial response rate of 30% in patients with a median follow-up of 14 months.25 In a separate study, ipilimumab plus nivolumab demonstrated better intracranial ORR when compared to nivolumab alone in asymptomatic, previously untreated patients. Outcomes were better in patients presenting with asymptomatic versus symptomatic brain metastases.26 Collectively, these results suggest that systemic immunotherapy alone may be adequate for patients with asymptomatic, previously untreated brain metastases.
For molecularly targeted therapy in patients with BRAF mutations and brain metastases, the BREAK-MB trial demonstrated that an intracranial response was attainable with dabrafenib regardless of whether the patient had previously received local therapy in the form of surgery or radiation.27 The COMBI-MB trial enhanced the preexisting data by testing the intracranial efficacy of dabrafenib plus trametinib in 4 different cohorts of patients, further supporting that systemic molecularly targeted therapy can provide significant intracranial activity in patients with both symptomatic and asymptomatic brain lesions and regardless of prior local therapy (Table 2).28
Conclusion
The treatment of advanced melanoma has been drastically improved over the past decade by the development and study of immune checkpoint inhibitors and molecularly targeted agents. There is still much to learn regarding the optimal combination and sequencing of therapies. Many of these trials are ongoing and will provide additional evidence to guide treatment decisions moving forward.
1. Bowyer S, Prithviraj P, Lorigan P, et al. Efficacy and toxicity of treatment with the anti-CTLA-4 antibody ipilimumab in patients with metastatic melanoma after prior anti-PD-1 therapy. Br J Cancer. 2016;114:1084-1089.
2. Weber JS, D’Angelo SP, Minor D, et al. Nivolumab versus chemotherapy in patients with advanced melanoma who progressed after anti-CTLA-4 treatment (CheckMate 037): a randomised, controlled, open-label, phase 3 trial. Lancet Oncol. 2015;16:375-384.
3. Ribas A, Puzanov I, Dummer R, et al. Pembrolizumab versus investigator-choice chemotherapy for ipilimumab-refractory melanoma (KEYNOTE-002): a randomised, controlled, phase 2 trial. Lancet Oncol. 2015;16:908-918.
4. Hamid O, Puzanov I, Dummer R, et al. Final analysis of a randomised trial comparing pembrolizumab versus investigator-choice chemotherapy for ipilimumab-refractory advanced melanoma. Eur J Cancer. 2017;86:37-45.
5. Beaver JA, Hazarika M, Mulkey F, et al. Patients with melanoma treated with an anti-PD-1 antibody beyond RECIST progression: a US Food and Drug Administration pooled analysis. Lancet Oncol. 2018;19:229-239.
6. Zimmer L, Apuri S, Eroglu Z, et al. Ipilimumab alone or in combination with nivolumab after progression on anti-PD-1 therapy in advanced melanoma. Eur J Cancer. 2017;75:47-55.
7. Larkin J, Chiarion-Sileni V, Gonazalez R, et al. Combined nivolumab and ipilimumab or monotherapy in untreated melanoma. N Engl J Med. 2015;373:23-34.
8. Tétu P, Mangana J, Dummer R, et al. Benefit of the nivolumab and ipilimumab combination in pretreated advanced melanoma. Eur J Cancer. 2018;93:147-149.
9. Robert C, Schachter J, Long GV, et al. Pembrolizumab versus ipilimumab in advanced melanoma. N Engl J Med. 2015;372:2522-2532.
10. Ackerman A, Klein O, McDermott D, et al. Outcomes of patients with metastatic melanoma treated with immunotherapy prior to or after BRAF inhibitors. Cancer. 2014;120:1695-1701.
11. Johnson DB, Pectasides E, Feld E, et al. Sequencing treatment in BRAFV600 mutant melanoma: anti-pd-1 before and after BRAF inhibition. J Immunother. 2017;40:31-35.
12. Long GV, Stroyakovskiy D, Gogas H, et al. Dabrafenib and trametinib versus dabrafenib and placebo for Val600 BRAF-mutant melanoma: a multicenter, double-blind, phase 3 randomised controlled trial. Lancet Oncol. 2015;386:444-451.
13. Long GV, Flaherty KT, Stroyakovskiy D, et al. Dabrafenib plus trametinib versus dabrafenib monotherapy in patients with metastatic BRAF V600E/K-mutant melanoma: long-term survival and safety analysis of a phase 3 study. Ann Oncol. 2017;28:1631-1639.
14. Ascierto PA, McArthur GA, Dréno B, et al. Cobimetinib combined with vemurafenib in advanced BRAFV600-mutant melanoma (coBRIM): updated efficacy results from a randomised, double-blind, phase 3 trial. Lancet Oncol. 2016;17:1248-1260.
15. Dummer R, Ascierto PA, Gogas HJ, et al. Encorafenib plus binimetinib versus vemurafenib or encorafenib in patients with BRAF-mutant melanoma (COLUMBUS): a multicenter, open-label, randomised phase 3 trial. Lancet Oncol. 2018;19:603-615.
16. Dummer R, Ascierto PA, Gogas HJ, et al. Overall survival in patients with BRAF-mutant melanoma receiving encorafenib plus binimetinib versus vemurafenib or encorafenib (COLUMBUS): a multicenter, open-label, randomised, phase 3 trial. Lancet Oncol. 2018;19:1315-1327.
17. Johnson DB, Flaherty KT, Weber, JS et al. Combined BRAF (Dabrafenib) and MEK inhibition (Trametinib) in patients with BRAFV600-mutant melanoma experiencing progression with single-agent BRAF inhibitor. J Clin Oncol. 2014;32:3697-3704.
18. Schreuer M, Jansen Y, Planken S, et al. Combination of dabrafenib plus trametinib for BRAF and MEK inhibitor pretreated patients with advanced BRAFV600-mutant melanoma: an open-label, single arm, dual-centre, phase 2 clinical trial. Lancet Oncol. 2017;18:464-472.
19. Chan MM, Haydu LE, Azer MW, et al. The nature and management of metastatic melanoma after progression on BRAF inhibitors: effects of extended BRAF inhibition. Cancer. 2014;120:3142-3153.
20. Imlygic (talimogene laherparepvec) suspension for intralesional injection [package insert]. Thousand Oaks, CA: BioVex; 2015.
21. Chesney J, Puzanov I, Collichio F, et al. Randomized, open-label phase ii study evaluating the efficacy and safety of talimogene laherparepvec in combination with ipilimumab versus ipilimumab alone in patients with advanced, unresectable melanoma. J Clin Oncol. 2018;36:1658-1667.
22. Ribas A, Dummer R, Puzanov I, et al. Oncolytic virotherapy promotes intratumoral t cell infiltration and improves anti-PD-1 immunotherapy. Cell. 2018;174:1031-1032.
23. Sampson JH, Carter Jr. JH, Friedman AH, Seigler HF. Demographics, prognosis, and therapy in 702 patients with brain metastases from malignant melanoma. J Neurosurg. 1998;88:11-20.
24. Yamamoto M, Serizawa T, Shuto T, et al. Stereotactic radiosurgery for patients with multiple brain metastases (JLGK0901): a multi-institutional prospective observational study. Lancet Oncol. 2014;15:387-395.
25. Tawbi HA, Forsyth PA, Hamid O, et al. Combined nivolumab and ipilimumab in melanoma metastatic to the brain. N Engl J Med. 2018;379:722-730.
26. Long GV, Atkinson V, La S, et al. Combination nivolumab and ipilimumab or nivolumab alone in melanoma brain metastases: a multicenter randomised phase 2 study. Lancet Oncol. 2018;19:672-681.
27. Long GV, Trefzer U, Davies MA, et al. Dabrafenib in patients with Val600Glu or Val600Lys BRAF-mutant melanoma metastatic to the brain (BREAK-MB): a multicenter, open-label, phase 2 trial. Lancet Oncol. 2012;13:1087-1095.
28. Davies MA, Saiag P, Robert C, et al. Dabrafenib plus trametinib in patients with BRAFV600-mutant melanoma brain metastases (COMBI-MB): a multicenter, multicohort, open-label, phase 2 trial. Lancet Oncol. 2017;18:863-873.
The past decade has brought rapid advancements in treatment with immune checkpoint inhibitors and molecularly targeted agents, which have significantly improved objective response rates (ORRs), progression-free survival (PFS), and overall survival (OS) for patients with metastatic melanoma. This article reviews current evidence for immune checkpoint blockade and molecularly targeted agents in the treatment of metastatic melanoma after progression on first-line therapy. The selection of first-line therapy for metastatic melanoma is reviewed in a separate article.
Case Presentation
A 62-year-old man was diagnosed with stage IIA melanoma after undergoing wide local excision of a right scalp lesion (final staging was consistent with pT3aN0M0). After 3.5 years of follow-up, he developed symptoms of vertigo, diplopia, and recurrent falls prompting medical attention. Magnetic resonance imaging (MRI) brain revealed multiple supratentorial and infratentorial lesions concerning for intracranial metastases and computed tomography (CT) chest/abdomen/pelvis revealed a right lower lobe pulmonary mass with right hilar and subcarinal lymphadenopathy. He was treated with intravenous dexamethasone and further evaluation with an endobronchial ultrasound-guided fine-needle aspiration of the right lower lobe mass revealed metastatic melanoma. The patient underwent whole brain radiation therapy for symptomatic relief prior to initiating systemic therapy. Testing showed the melanoma was positive for a BRAF V600K mutation. He was started on combination molecularly targeted therapy with dabrafenib and trametinib. He initially did well, with a partial response noted by resolution of symptoms and decreased size of his intracranial metastases and decreased size of the right lower lobe mass.
After 3 months of therapy, surveillance PET-CT notes increasing size and FDG avidity of the right lower lobe mass. MRI brain reveals resolution of several previously noted metastases, but with interval development of a new left frontal lobe mass concerning for progressive disease.
What is the general approach to treatment of metastatic melanoma after progression on first-line therapy?
Based on the current evidence, there is no definitive algorithm for the treatment of metastatic melanoma after progression on first-line therapy. Enrollment in clinical trials is encouraged to further elucidate the best sequencing of treatment. The current practice is to typically switch class of agents after progression on front-line therapy to either immunotherapy that has not yet been tried or to molecularly targeted therapy in patients harboring a BRAF V600 mutation. After further progression of disease, retreatment with a previously received agent is possible, and this may be combined with investigational therapies.
Immune Checkpoint Inhibitors in Progressive Disease
The 2 major populations of patients to consider are those with BRAF wild-type melanomas who progress on first-line immunotherapy and those with BRAF V600 mutation–positive melanoma who progress on molecularly targeted therapy with BRAF and MEK inhibitors. There is relatively limited data on the efficacy of immune checkpoint inhibition after progression on anti-programmed cell death 1 (PD-1) monotherapy. A small retrospective study of patients who progressed on anti-PD-1 monotherapy were treated with ipilimumab, with a 10% ORR and another 8% having stable disease for more than 6 months; however, 35% of patients experienced grade 3 to 5 immune-related adverse events.1 The only prospective data supports the efficacy of anti-PD-1 therapy after progression on ipilimumab, as supported by the CheckMate 037 trial (nivolumab versus chemotherapy)2 and KEYNOTE-002 trial (pembrolizumab versus chemotherapy)3,4; however, this is no longer applicable as ipilimumab is no longer given in the first-line setting and has been replaced by anti-PD-1 monotherapy or combination immunotherapy.
Another interesting facet of PD-1 monotherapy is the idea of treatment beyond progression. The concept of pseudoprogression—whereby patients receiving PD-1 inhibitors initially meet Response Evaluation Criteria in Solid Tumors (RECIST) criteria for progression, but then later go on to demonstrate significant decreases in tumor burden on subsequent imaging studies—has been described in melanoma patients receiving such immunotherapies. It is thought that pseudoprogression occurs due to either an initial delay in anti-tumor response to the immunotherapy or from the measured target lesion appearing larger due to surrounding immune/inflammatory infiltrate. In an analysis of individual patient data pooled from 8 multicenter clinical trials, 19% of patients were treated beyond initially documented RECIST progression and had subsequent imaging to evaluate the tumor burden; in these patients, the same target lesion later met RECIST criteria for response, with a greater than 30% reduction in tumor size. Furthermore, of the evaluable cohort, the median OS in patients who did receive treatment beyond progression was 24.4 months compared to 11.2 months in those who did not receive treatment beyond progression.5 While further randomized studies are warranted to characterize the potential benefit, the existing data suggests that selected patients who are doing well clinically despite evidence of radiographic progressive disease may benefit from continued treatment with PD-1 inhibitors.
Combination immunotherapy with both PD-1 and CTLA-4 blockade has been studied retrospectively in the second-line setting. A retrospective analysis of patients who had progressive disease on PD-1 inhibitor monotherapy compared the outcomes of patients who received just ipilimumab to those of patients who received both ipilimumab and nivolumab. The ORR (16% ipilimumab vs 21% combination group) and 1-year OS (54% vs 55%) were similar in both groups,6 and this demonstrated significantly less efficacy with combination therapy when compared to use in the first-line setting, albeit in a separate prospective trial.7 A multicenter, retrospective study by Tétu and colleagues compared outcomes with ipilimumab plus nivolumab across 3 groups that included previously untreated patients, patients who had progressed on single-agent immunotherapy, and patients who had progressed on prior molecularly targeted therapy.8 Despite clearly inferior efficacy in previously treated patients, the results support combination immunotherapy as a viable treatment option in the second-line setting. Outcomes are reported in Table 1 below. Of note, there is an ongoing phase 2 trial to assess the use of combined PD-1 and CTLA-4 inhibitors versus CTLA-4 inhibition alone after progression on first-line PD-1 inhibitor monotherapy (NCT03033576).
For patients with BRAF V600–mutation positive melanoma who progress on front-line molecularly targeted therapy, immune checkpoint inhibitor therapy with either anti-PD-1 monotherapy or combination anti-PD-1 and ipilimumab should be considered. The KEYNOTE-006 trial that demonstrated superiority of pembrolizumab compared to ipilimumab included patients who had received up to 1 prior systemic therapy that was not a PD-1 or CTLA-4 inhibitor, and subgroup analysis demonstrated efficacy with pembrolizumab in patients who had received prior treatment with a BRAF inhibitor.9 The retrospective analysis by Tétu et al (Table 1) noted efficacy of combination nivolumab and ipilimumab in patients treated with prior molecularly targeted therapy, as evidenced by an ORR of 35% and median OS of 16.5 months.8
A retrospective trial by Ackerman et al analyzed ORR, median PFS, and median OS from the time of commencement of BRAF inhibitor therapy (with or without a MEK inhibitor), and the comparison was made between those who received ipilimumab before or after molecularly targeted therapy. While ipilimumab is no longer the first-line immunotherapy agent used in advanced melanoma, the study did highlight some important concepts. First, ORRs to BRAF inhibitors were similar between the 2 treatment groups. The conclusions of the analysis were that there was no significant difference in median PFS or OS in regard to which therapy was given first, but median OS after BRAF inhibitors were discontinued was very short and patients had poor responses to ipilimumab after stopping a BRAF inhibitor. This highlights the concern that patients who have progressive disease on molecularly targeted therapy often have a poor performance status and undergo too rapid of a clinical decline to derive benefit from immunotherapy, which can often take weeks to months to take effect.10
A more recent retrospective study by Johnson et al compared efficacy outcomes in patients who received single-agent anti-PD-1 therapy prior to molecularly targeted therapy (BRAF inhibitor with or without MEK inhibitor) to those who received molecularly targeted therapy prior to anti-PD-1 therapy. The difference in median OS was not statistically significant (27.5 months with PD-1 inhibitor first vs 40.3 months with molecularly targeted therapy first). Both treatments demonstrated second-line efficacy, but outcomes were inferior to those reported when either type of therapy was used in the first-line setting. Interestingly, patients who were maintained on molecularly targeted therapy for more than 6 months prior to progression demonstrated an improved ORR to subsequent anti-PD-1 therapy (34% vs 15%).11
Molecularly Targeted Therapy in Progressive Disease
When melanoma patients with a BRAF V600 mutation are treated initially with immunotherapy and demonstrate progressive disease, molecularly targeted therapy with combined BRAF and MEK inhibition should be considered for second-line therapy. While there are no dedicated prospective trial results with BRAF/MEK inhibitors after progression on immune checkpoint inhibitors, for practical purposes, it may be reasonable to extrapolate outcomes from the currently available first-line studies.12-16 An ongoing study (NCT02224781) in which patients are randomized to receive ipilimumab/nivolumab followed by dabrafenib/trametinib at progression versus the reverse order is designed to help answer the question of optimal sequencing and timing of therapy. Johnson et al’s retrospective analysis of patients receiving single-agent anti-PD-1 therapy prior to molecularly targeted therapy compared to the reverse order concluded that there was no statistically significant difference in median OS.11 Ackerman et al’s retrospective study of patients who had received ipilimumab before or after molecularly targeted therapy noted similar response rates to molecularly targeted therapy in each treatment group.10
The issue of re-treatment with a BRAF/MEK inhibitor in a patient already progressing on targeted therapy is a more challenging situation, and currently available data suggests there is limited benefit. However, select patients may be considered for this approach. The combination of dabrafenib/trametinib demonstrated an ORR of approximately 15% in a cohort of patients who progressed on single-agent BRAF inhibitor therapy, with a suggestion that those patients who had previously derived benefit for more than 6 months may have a more favorable outcome.17
Based on the hypothesis that acquired resistance to BRAF/MEK inhibition may be reversible if the selective pressure of the medication is held for a period of time, a phase 2 trial analyzed outcomes with retreatment. The study included patients with BRAF V600–mutant melanoma who had progressed on prior BRAF inhibition (with or without MEK inhibitor) and required that they had been off of therapy for at least 12 weeks. Of the 25 patients who received dabrafenib plus trametinib as retreatment, 32% demonstrated a partial response and 40% had stable disease.18 While further studies are warranted, retreatment with molecularly targeted therapy may be a viable option, especially in light of the multiple approved BRAF and MEK inhibitor combinations.
Another concept that has been studied is treatment beyond disease progression with molecularly targeted therapy. In a retrospective analysis of patients who had progressed on a single-agent BRAF inhibitor, 39% of those patients were continued on the same BRAF inhibitor and compared to patients who received no subsequent therapy or changed to an alternative systemic therapy. In the multivariable analysis adjusting for other prognostic factors, continued treatment with the BRAF inhibitor was associated with prolonged OS.19
Case Conclusion
The patient is started on second-line therapy with nivolumab and ipilimumab and demonstrates a partial response. One year later he continues to feel well with decreased size of the intracranial and right lower lobe lesions, and without any interval development of new areas of metastatic disease.
Special Considerations
Intralesional Therapies
Talimogene laherparepvec (T-VEC) is a genetically modified herpesvirus-1 oncolytic virus that is injected into melanoma skin lesions and leads to the expression of granulocyte-macrophage colony-stimulating factor. While T-VEC is currently approved for local treatment of unresectable cutaneous, subcutaneous, or nodal recurrences,20 it has also been investigated in combination with other therapies for patients with advanced disease. In patients with previously treated melanoma, T-VEC plus ipilimumab demonstrated superior ORR to ipilimumab alone (39% vs 18%), and the tumor response was not limited to the injected lesions. The observation of systemic response suggests synergy between T-VEC and immune checkpoint blockade in enhancing the anti-tumor immune response.21 The phase 1b MASTERKEY-265 trial combining pembrolizumab and T-VEC led to an ORR of 62% and CR of 33%.22 A phase 3 trial comparing pembrolizumab plus T-VEC to pembrolizumab alone is ongoing (NCT02263508).
Melanoma Brain Metastases
The presence of brain metastases is a common event in patients with metastatic melanoma, and often confers a poor prognosis.23 The approach to the management of brain metastases should be multidisciplinary among medical oncology, neurosurgery, and radiation oncology providers, as treatment algorithms continue to rapidly evolve. Historically, there has been little prospective clinical trial data regarding optimal systemic therapy, and local therapies such as surgery or stereotactic radiation have long been the mainstay of therapy for intracranial disease.24 However, recent data with both immunotherapy and molecularly targeted therapy has demonstrated efficacy with intracranial metastases.
A recent trial of combined nivolumab and ipilimumab as frontline therapy in patients with asymptomatic melanoma brain metastases demonstrated a complete response rate of 26% and partial response rate of 30% in patients with a median follow-up of 14 months.25 In a separate study, ipilimumab plus nivolumab demonstrated better intracranial ORR when compared to nivolumab alone in asymptomatic, previously untreated patients. Outcomes were better in patients presenting with asymptomatic versus symptomatic brain metastases.26 Collectively, these results suggest that systemic immunotherapy alone may be adequate for patients with asymptomatic, previously untreated brain metastases.
For molecularly targeted therapy in patients with BRAF mutations and brain metastases, the BREAK-MB trial demonstrated that an intracranial response was attainable with dabrafenib regardless of whether the patient had previously received local therapy in the form of surgery or radiation.27 The COMBI-MB trial enhanced the preexisting data by testing the intracranial efficacy of dabrafenib plus trametinib in 4 different cohorts of patients, further supporting that systemic molecularly targeted therapy can provide significant intracranial activity in patients with both symptomatic and asymptomatic brain lesions and regardless of prior local therapy (Table 2).28
Conclusion
The treatment of advanced melanoma has been drastically improved over the past decade by the development and study of immune checkpoint inhibitors and molecularly targeted agents. There is still much to learn regarding the optimal combination and sequencing of therapies. Many of these trials are ongoing and will provide additional evidence to guide treatment decisions moving forward.
The past decade has brought rapid advancements in treatment with immune checkpoint inhibitors and molecularly targeted agents, which have significantly improved objective response rates (ORRs), progression-free survival (PFS), and overall survival (OS) for patients with metastatic melanoma. This article reviews current evidence for immune checkpoint blockade and molecularly targeted agents in the treatment of metastatic melanoma after progression on first-line therapy. The selection of first-line therapy for metastatic melanoma is reviewed in a separate article.
Case Presentation
A 62-year-old man was diagnosed with stage IIA melanoma after undergoing wide local excision of a right scalp lesion (final staging was consistent with pT3aN0M0). After 3.5 years of follow-up, he developed symptoms of vertigo, diplopia, and recurrent falls prompting medical attention. Magnetic resonance imaging (MRI) brain revealed multiple supratentorial and infratentorial lesions concerning for intracranial metastases and computed tomography (CT) chest/abdomen/pelvis revealed a right lower lobe pulmonary mass with right hilar and subcarinal lymphadenopathy. He was treated with intravenous dexamethasone and further evaluation with an endobronchial ultrasound-guided fine-needle aspiration of the right lower lobe mass revealed metastatic melanoma. The patient underwent whole brain radiation therapy for symptomatic relief prior to initiating systemic therapy. Testing showed the melanoma was positive for a BRAF V600K mutation. He was started on combination molecularly targeted therapy with dabrafenib and trametinib. He initially did well, with a partial response noted by resolution of symptoms and decreased size of his intracranial metastases and decreased size of the right lower lobe mass.
After 3 months of therapy, surveillance PET-CT notes increasing size and FDG avidity of the right lower lobe mass. MRI brain reveals resolution of several previously noted metastases, but with interval development of a new left frontal lobe mass concerning for progressive disease.
What is the general approach to treatment of metastatic melanoma after progression on first-line therapy?
Based on the current evidence, there is no definitive algorithm for the treatment of metastatic melanoma after progression on first-line therapy. Enrollment in clinical trials is encouraged to further elucidate the best sequencing of treatment. The current practice is to typically switch class of agents after progression on front-line therapy to either immunotherapy that has not yet been tried or to molecularly targeted therapy in patients harboring a BRAF V600 mutation. After further progression of disease, retreatment with a previously received agent is possible, and this may be combined with investigational therapies.
Immune Checkpoint Inhibitors in Progressive Disease
The 2 major populations of patients to consider are those with BRAF wild-type melanomas who progress on first-line immunotherapy and those with BRAF V600 mutation–positive melanoma who progress on molecularly targeted therapy with BRAF and MEK inhibitors. There is relatively limited data on the efficacy of immune checkpoint inhibition after progression on anti-programmed cell death 1 (PD-1) monotherapy. A small retrospective study of patients who progressed on anti-PD-1 monotherapy were treated with ipilimumab, with a 10% ORR and another 8% having stable disease for more than 6 months; however, 35% of patients experienced grade 3 to 5 immune-related adverse events.1 The only prospective data supports the efficacy of anti-PD-1 therapy after progression on ipilimumab, as supported by the CheckMate 037 trial (nivolumab versus chemotherapy)2 and KEYNOTE-002 trial (pembrolizumab versus chemotherapy)3,4; however, this is no longer applicable as ipilimumab is no longer given in the first-line setting and has been replaced by anti-PD-1 monotherapy or combination immunotherapy.
Another interesting facet of PD-1 monotherapy is the idea of treatment beyond progression. The concept of pseudoprogression—whereby patients receiving PD-1 inhibitors initially meet Response Evaluation Criteria in Solid Tumors (RECIST) criteria for progression, but then later go on to demonstrate significant decreases in tumor burden on subsequent imaging studies—has been described in melanoma patients receiving such immunotherapies. It is thought that pseudoprogression occurs due to either an initial delay in anti-tumor response to the immunotherapy or from the measured target lesion appearing larger due to surrounding immune/inflammatory infiltrate. In an analysis of individual patient data pooled from 8 multicenter clinical trials, 19% of patients were treated beyond initially documented RECIST progression and had subsequent imaging to evaluate the tumor burden; in these patients, the same target lesion later met RECIST criteria for response, with a greater than 30% reduction in tumor size. Furthermore, of the evaluable cohort, the median OS in patients who did receive treatment beyond progression was 24.4 months compared to 11.2 months in those who did not receive treatment beyond progression.5 While further randomized studies are warranted to characterize the potential benefit, the existing data suggests that selected patients who are doing well clinically despite evidence of radiographic progressive disease may benefit from continued treatment with PD-1 inhibitors.
Combination immunotherapy with both PD-1 and CTLA-4 blockade has been studied retrospectively in the second-line setting. A retrospective analysis of patients who had progressive disease on PD-1 inhibitor monotherapy compared the outcomes of patients who received just ipilimumab to those of patients who received both ipilimumab and nivolumab. The ORR (16% ipilimumab vs 21% combination group) and 1-year OS (54% vs 55%) were similar in both groups,6 and this demonstrated significantly less efficacy with combination therapy when compared to use in the first-line setting, albeit in a separate prospective trial.7 A multicenter, retrospective study by Tétu and colleagues compared outcomes with ipilimumab plus nivolumab across 3 groups that included previously untreated patients, patients who had progressed on single-agent immunotherapy, and patients who had progressed on prior molecularly targeted therapy.8 Despite clearly inferior efficacy in previously treated patients, the results support combination immunotherapy as a viable treatment option in the second-line setting. Outcomes are reported in Table 1 below. Of note, there is an ongoing phase 2 trial to assess the use of combined PD-1 and CTLA-4 inhibitors versus CTLA-4 inhibition alone after progression on first-line PD-1 inhibitor monotherapy (NCT03033576).
For patients with BRAF V600–mutation positive melanoma who progress on front-line molecularly targeted therapy, immune checkpoint inhibitor therapy with either anti-PD-1 monotherapy or combination anti-PD-1 and ipilimumab should be considered. The KEYNOTE-006 trial that demonstrated superiority of pembrolizumab compared to ipilimumab included patients who had received up to 1 prior systemic therapy that was not a PD-1 or CTLA-4 inhibitor, and subgroup analysis demonstrated efficacy with pembrolizumab in patients who had received prior treatment with a BRAF inhibitor.9 The retrospective analysis by Tétu et al (Table 1) noted efficacy of combination nivolumab and ipilimumab in patients treated with prior molecularly targeted therapy, as evidenced by an ORR of 35% and median OS of 16.5 months.8
A retrospective trial by Ackerman et al analyzed ORR, median PFS, and median OS from the time of commencement of BRAF inhibitor therapy (with or without a MEK inhibitor), and the comparison was made between those who received ipilimumab before or after molecularly targeted therapy. While ipilimumab is no longer the first-line immunotherapy agent used in advanced melanoma, the study did highlight some important concepts. First, ORRs to BRAF inhibitors were similar between the 2 treatment groups. The conclusions of the analysis were that there was no significant difference in median PFS or OS in regard to which therapy was given first, but median OS after BRAF inhibitors were discontinued was very short and patients had poor responses to ipilimumab after stopping a BRAF inhibitor. This highlights the concern that patients who have progressive disease on molecularly targeted therapy often have a poor performance status and undergo too rapid of a clinical decline to derive benefit from immunotherapy, which can often take weeks to months to take effect.10
A more recent retrospective study by Johnson et al compared efficacy outcomes in patients who received single-agent anti-PD-1 therapy prior to molecularly targeted therapy (BRAF inhibitor with or without MEK inhibitor) to those who received molecularly targeted therapy prior to anti-PD-1 therapy. The difference in median OS was not statistically significant (27.5 months with PD-1 inhibitor first vs 40.3 months with molecularly targeted therapy first). Both treatments demonstrated second-line efficacy, but outcomes were inferior to those reported when either type of therapy was used in the first-line setting. Interestingly, patients who were maintained on molecularly targeted therapy for more than 6 months prior to progression demonstrated an improved ORR to subsequent anti-PD-1 therapy (34% vs 15%).11
Molecularly Targeted Therapy in Progressive Disease
When melanoma patients with a BRAF V600 mutation are treated initially with immunotherapy and demonstrate progressive disease, molecularly targeted therapy with combined BRAF and MEK inhibition should be considered for second-line therapy. While there are no dedicated prospective trial results with BRAF/MEK inhibitors after progression on immune checkpoint inhibitors, for practical purposes, it may be reasonable to extrapolate outcomes from the currently available first-line studies.12-16 An ongoing study (NCT02224781) in which patients are randomized to receive ipilimumab/nivolumab followed by dabrafenib/trametinib at progression versus the reverse order is designed to help answer the question of optimal sequencing and timing of therapy. Johnson et al’s retrospective analysis of patients receiving single-agent anti-PD-1 therapy prior to molecularly targeted therapy compared to the reverse order concluded that there was no statistically significant difference in median OS.11 Ackerman et al’s retrospective study of patients who had received ipilimumab before or after molecularly targeted therapy noted similar response rates to molecularly targeted therapy in each treatment group.10
The issue of re-treatment with a BRAF/MEK inhibitor in a patient already progressing on targeted therapy is a more challenging situation, and currently available data suggests there is limited benefit. However, select patients may be considered for this approach. The combination of dabrafenib/trametinib demonstrated an ORR of approximately 15% in a cohort of patients who progressed on single-agent BRAF inhibitor therapy, with a suggestion that those patients who had previously derived benefit for more than 6 months may have a more favorable outcome.17
Based on the hypothesis that acquired resistance to BRAF/MEK inhibition may be reversible if the selective pressure of the medication is held for a period of time, a phase 2 trial analyzed outcomes with retreatment. The study included patients with BRAF V600–mutant melanoma who had progressed on prior BRAF inhibition (with or without MEK inhibitor) and required that they had been off of therapy for at least 12 weeks. Of the 25 patients who received dabrafenib plus trametinib as retreatment, 32% demonstrated a partial response and 40% had stable disease.18 While further studies are warranted, retreatment with molecularly targeted therapy may be a viable option, especially in light of the multiple approved BRAF and MEK inhibitor combinations.
Another concept that has been studied is treatment beyond disease progression with molecularly targeted therapy. In a retrospective analysis of patients who had progressed on a single-agent BRAF inhibitor, 39% of those patients were continued on the same BRAF inhibitor and compared to patients who received no subsequent therapy or changed to an alternative systemic therapy. In the multivariable analysis adjusting for other prognostic factors, continued treatment with the BRAF inhibitor was associated with prolonged OS.19
Case Conclusion
The patient is started on second-line therapy with nivolumab and ipilimumab and demonstrates a partial response. One year later he continues to feel well with decreased size of the intracranial and right lower lobe lesions, and without any interval development of new areas of metastatic disease.
Special Considerations
Intralesional Therapies
Talimogene laherparepvec (T-VEC) is a genetically modified herpesvirus-1 oncolytic virus that is injected into melanoma skin lesions and leads to the expression of granulocyte-macrophage colony-stimulating factor. While T-VEC is currently approved for local treatment of unresectable cutaneous, subcutaneous, or nodal recurrences,20 it has also been investigated in combination with other therapies for patients with advanced disease. In patients with previously treated melanoma, T-VEC plus ipilimumab demonstrated superior ORR to ipilimumab alone (39% vs 18%), and the tumor response was not limited to the injected lesions. The observation of systemic response suggests synergy between T-VEC and immune checkpoint blockade in enhancing the anti-tumor immune response.21 The phase 1b MASTERKEY-265 trial combining pembrolizumab and T-VEC led to an ORR of 62% and CR of 33%.22 A phase 3 trial comparing pembrolizumab plus T-VEC to pembrolizumab alone is ongoing (NCT02263508).
Melanoma Brain Metastases
The presence of brain metastases is a common event in patients with metastatic melanoma, and often confers a poor prognosis.23 The approach to the management of brain metastases should be multidisciplinary among medical oncology, neurosurgery, and radiation oncology providers, as treatment algorithms continue to rapidly evolve. Historically, there has been little prospective clinical trial data regarding optimal systemic therapy, and local therapies such as surgery or stereotactic radiation have long been the mainstay of therapy for intracranial disease.24 However, recent data with both immunotherapy and molecularly targeted therapy has demonstrated efficacy with intracranial metastases.
A recent trial of combined nivolumab and ipilimumab as frontline therapy in patients with asymptomatic melanoma brain metastases demonstrated a complete response rate of 26% and partial response rate of 30% in patients with a median follow-up of 14 months.25 In a separate study, ipilimumab plus nivolumab demonstrated better intracranial ORR when compared to nivolumab alone in asymptomatic, previously untreated patients. Outcomes were better in patients presenting with asymptomatic versus symptomatic brain metastases.26 Collectively, these results suggest that systemic immunotherapy alone may be adequate for patients with asymptomatic, previously untreated brain metastases.
For molecularly targeted therapy in patients with BRAF mutations and brain metastases, the BREAK-MB trial demonstrated that an intracranial response was attainable with dabrafenib regardless of whether the patient had previously received local therapy in the form of surgery or radiation.27 The COMBI-MB trial enhanced the preexisting data by testing the intracranial efficacy of dabrafenib plus trametinib in 4 different cohorts of patients, further supporting that systemic molecularly targeted therapy can provide significant intracranial activity in patients with both symptomatic and asymptomatic brain lesions and regardless of prior local therapy (Table 2).28
Conclusion
The treatment of advanced melanoma has been drastically improved over the past decade by the development and study of immune checkpoint inhibitors and molecularly targeted agents. There is still much to learn regarding the optimal combination and sequencing of therapies. Many of these trials are ongoing and will provide additional evidence to guide treatment decisions moving forward.
1. Bowyer S, Prithviraj P, Lorigan P, et al. Efficacy and toxicity of treatment with the anti-CTLA-4 antibody ipilimumab in patients with metastatic melanoma after prior anti-PD-1 therapy. Br J Cancer. 2016;114:1084-1089.
2. Weber JS, D’Angelo SP, Minor D, et al. Nivolumab versus chemotherapy in patients with advanced melanoma who progressed after anti-CTLA-4 treatment (CheckMate 037): a randomised, controlled, open-label, phase 3 trial. Lancet Oncol. 2015;16:375-384.
3. Ribas A, Puzanov I, Dummer R, et al. Pembrolizumab versus investigator-choice chemotherapy for ipilimumab-refractory melanoma (KEYNOTE-002): a randomised, controlled, phase 2 trial. Lancet Oncol. 2015;16:908-918.
4. Hamid O, Puzanov I, Dummer R, et al. Final analysis of a randomised trial comparing pembrolizumab versus investigator-choice chemotherapy for ipilimumab-refractory advanced melanoma. Eur J Cancer. 2017;86:37-45.
5. Beaver JA, Hazarika M, Mulkey F, et al. Patients with melanoma treated with an anti-PD-1 antibody beyond RECIST progression: a US Food and Drug Administration pooled analysis. Lancet Oncol. 2018;19:229-239.
6. Zimmer L, Apuri S, Eroglu Z, et al. Ipilimumab alone or in combination with nivolumab after progression on anti-PD-1 therapy in advanced melanoma. Eur J Cancer. 2017;75:47-55.
7. Larkin J, Chiarion-Sileni V, Gonazalez R, et al. Combined nivolumab and ipilimumab or monotherapy in untreated melanoma. N Engl J Med. 2015;373:23-34.
8. Tétu P, Mangana J, Dummer R, et al. Benefit of the nivolumab and ipilimumab combination in pretreated advanced melanoma. Eur J Cancer. 2018;93:147-149.
9. Robert C, Schachter J, Long GV, et al. Pembrolizumab versus ipilimumab in advanced melanoma. N Engl J Med. 2015;372:2522-2532.
10. Ackerman A, Klein O, McDermott D, et al. Outcomes of patients with metastatic melanoma treated with immunotherapy prior to or after BRAF inhibitors. Cancer. 2014;120:1695-1701.
11. Johnson DB, Pectasides E, Feld E, et al. Sequencing treatment in BRAFV600 mutant melanoma: anti-pd-1 before and after BRAF inhibition. J Immunother. 2017;40:31-35.
12. Long GV, Stroyakovskiy D, Gogas H, et al. Dabrafenib and trametinib versus dabrafenib and placebo for Val600 BRAF-mutant melanoma: a multicenter, double-blind, phase 3 randomised controlled trial. Lancet Oncol. 2015;386:444-451.
13. Long GV, Flaherty KT, Stroyakovskiy D, et al. Dabrafenib plus trametinib versus dabrafenib monotherapy in patients with metastatic BRAF V600E/K-mutant melanoma: long-term survival and safety analysis of a phase 3 study. Ann Oncol. 2017;28:1631-1639.
14. Ascierto PA, McArthur GA, Dréno B, et al. Cobimetinib combined with vemurafenib in advanced BRAFV600-mutant melanoma (coBRIM): updated efficacy results from a randomised, double-blind, phase 3 trial. Lancet Oncol. 2016;17:1248-1260.
15. Dummer R, Ascierto PA, Gogas HJ, et al. Encorafenib plus binimetinib versus vemurafenib or encorafenib in patients with BRAF-mutant melanoma (COLUMBUS): a multicenter, open-label, randomised phase 3 trial. Lancet Oncol. 2018;19:603-615.
16. Dummer R, Ascierto PA, Gogas HJ, et al. Overall survival in patients with BRAF-mutant melanoma receiving encorafenib plus binimetinib versus vemurafenib or encorafenib (COLUMBUS): a multicenter, open-label, randomised, phase 3 trial. Lancet Oncol. 2018;19:1315-1327.
17. Johnson DB, Flaherty KT, Weber, JS et al. Combined BRAF (Dabrafenib) and MEK inhibition (Trametinib) in patients with BRAFV600-mutant melanoma experiencing progression with single-agent BRAF inhibitor. J Clin Oncol. 2014;32:3697-3704.
18. Schreuer M, Jansen Y, Planken S, et al. Combination of dabrafenib plus trametinib for BRAF and MEK inhibitor pretreated patients with advanced BRAFV600-mutant melanoma: an open-label, single arm, dual-centre, phase 2 clinical trial. Lancet Oncol. 2017;18:464-472.
19. Chan MM, Haydu LE, Azer MW, et al. The nature and management of metastatic melanoma after progression on BRAF inhibitors: effects of extended BRAF inhibition. Cancer. 2014;120:3142-3153.
20. Imlygic (talimogene laherparepvec) suspension for intralesional injection [package insert]. Thousand Oaks, CA: BioVex; 2015.
21. Chesney J, Puzanov I, Collichio F, et al. Randomized, open-label phase ii study evaluating the efficacy and safety of talimogene laherparepvec in combination with ipilimumab versus ipilimumab alone in patients with advanced, unresectable melanoma. J Clin Oncol. 2018;36:1658-1667.
22. Ribas A, Dummer R, Puzanov I, et al. Oncolytic virotherapy promotes intratumoral t cell infiltration and improves anti-PD-1 immunotherapy. Cell. 2018;174:1031-1032.
23. Sampson JH, Carter Jr. JH, Friedman AH, Seigler HF. Demographics, prognosis, and therapy in 702 patients with brain metastases from malignant melanoma. J Neurosurg. 1998;88:11-20.
24. Yamamoto M, Serizawa T, Shuto T, et al. Stereotactic radiosurgery for patients with multiple brain metastases (JLGK0901): a multi-institutional prospective observational study. Lancet Oncol. 2014;15:387-395.
25. Tawbi HA, Forsyth PA, Hamid O, et al. Combined nivolumab and ipilimumab in melanoma metastatic to the brain. N Engl J Med. 2018;379:722-730.
26. Long GV, Atkinson V, La S, et al. Combination nivolumab and ipilimumab or nivolumab alone in melanoma brain metastases: a multicenter randomised phase 2 study. Lancet Oncol. 2018;19:672-681.
27. Long GV, Trefzer U, Davies MA, et al. Dabrafenib in patients with Val600Glu or Val600Lys BRAF-mutant melanoma metastatic to the brain (BREAK-MB): a multicenter, open-label, phase 2 trial. Lancet Oncol. 2012;13:1087-1095.
28. Davies MA, Saiag P, Robert C, et al. Dabrafenib plus trametinib in patients with BRAFV600-mutant melanoma brain metastases (COMBI-MB): a multicenter, multicohort, open-label, phase 2 trial. Lancet Oncol. 2017;18:863-873.
1. Bowyer S, Prithviraj P, Lorigan P, et al. Efficacy and toxicity of treatment with the anti-CTLA-4 antibody ipilimumab in patients with metastatic melanoma after prior anti-PD-1 therapy. Br J Cancer. 2016;114:1084-1089.
2. Weber JS, D’Angelo SP, Minor D, et al. Nivolumab versus chemotherapy in patients with advanced melanoma who progressed after anti-CTLA-4 treatment (CheckMate 037): a randomised, controlled, open-label, phase 3 trial. Lancet Oncol. 2015;16:375-384.
3. Ribas A, Puzanov I, Dummer R, et al. Pembrolizumab versus investigator-choice chemotherapy for ipilimumab-refractory melanoma (KEYNOTE-002): a randomised, controlled, phase 2 trial. Lancet Oncol. 2015;16:908-918.
4. Hamid O, Puzanov I, Dummer R, et al. Final analysis of a randomised trial comparing pembrolizumab versus investigator-choice chemotherapy for ipilimumab-refractory advanced melanoma. Eur J Cancer. 2017;86:37-45.
5. Beaver JA, Hazarika M, Mulkey F, et al. Patients with melanoma treated with an anti-PD-1 antibody beyond RECIST progression: a US Food and Drug Administration pooled analysis. Lancet Oncol. 2018;19:229-239.
6. Zimmer L, Apuri S, Eroglu Z, et al. Ipilimumab alone or in combination with nivolumab after progression on anti-PD-1 therapy in advanced melanoma. Eur J Cancer. 2017;75:47-55.
7. Larkin J, Chiarion-Sileni V, Gonazalez R, et al. Combined nivolumab and ipilimumab or monotherapy in untreated melanoma. N Engl J Med. 2015;373:23-34.
8. Tétu P, Mangana J, Dummer R, et al. Benefit of the nivolumab and ipilimumab combination in pretreated advanced melanoma. Eur J Cancer. 2018;93:147-149.
9. Robert C, Schachter J, Long GV, et al. Pembrolizumab versus ipilimumab in advanced melanoma. N Engl J Med. 2015;372:2522-2532.
10. Ackerman A, Klein O, McDermott D, et al. Outcomes of patients with metastatic melanoma treated with immunotherapy prior to or after BRAF inhibitors. Cancer. 2014;120:1695-1701.
11. Johnson DB, Pectasides E, Feld E, et al. Sequencing treatment in BRAFV600 mutant melanoma: anti-pd-1 before and after BRAF inhibition. J Immunother. 2017;40:31-35.
12. Long GV, Stroyakovskiy D, Gogas H, et al. Dabrafenib and trametinib versus dabrafenib and placebo for Val600 BRAF-mutant melanoma: a multicenter, double-blind, phase 3 randomised controlled trial. Lancet Oncol. 2015;386:444-451.
13. Long GV, Flaherty KT, Stroyakovskiy D, et al. Dabrafenib plus trametinib versus dabrafenib monotherapy in patients with metastatic BRAF V600E/K-mutant melanoma: long-term survival and safety analysis of a phase 3 study. Ann Oncol. 2017;28:1631-1639.
14. Ascierto PA, McArthur GA, Dréno B, et al. Cobimetinib combined with vemurafenib in advanced BRAFV600-mutant melanoma (coBRIM): updated efficacy results from a randomised, double-blind, phase 3 trial. Lancet Oncol. 2016;17:1248-1260.
15. Dummer R, Ascierto PA, Gogas HJ, et al. Encorafenib plus binimetinib versus vemurafenib or encorafenib in patients with BRAF-mutant melanoma (COLUMBUS): a multicenter, open-label, randomised phase 3 trial. Lancet Oncol. 2018;19:603-615.
16. Dummer R, Ascierto PA, Gogas HJ, et al. Overall survival in patients with BRAF-mutant melanoma receiving encorafenib plus binimetinib versus vemurafenib or encorafenib (COLUMBUS): a multicenter, open-label, randomised, phase 3 trial. Lancet Oncol. 2018;19:1315-1327.
17. Johnson DB, Flaherty KT, Weber, JS et al. Combined BRAF (Dabrafenib) and MEK inhibition (Trametinib) in patients with BRAFV600-mutant melanoma experiencing progression with single-agent BRAF inhibitor. J Clin Oncol. 2014;32:3697-3704.
18. Schreuer M, Jansen Y, Planken S, et al. Combination of dabrafenib plus trametinib for BRAF and MEK inhibitor pretreated patients with advanced BRAFV600-mutant melanoma: an open-label, single arm, dual-centre, phase 2 clinical trial. Lancet Oncol. 2017;18:464-472.
19. Chan MM, Haydu LE, Azer MW, et al. The nature and management of metastatic melanoma after progression on BRAF inhibitors: effects of extended BRAF inhibition. Cancer. 2014;120:3142-3153.
20. Imlygic (talimogene laherparepvec) suspension for intralesional injection [package insert]. Thousand Oaks, CA: BioVex; 2015.
21. Chesney J, Puzanov I, Collichio F, et al. Randomized, open-label phase ii study evaluating the efficacy and safety of talimogene laherparepvec in combination with ipilimumab versus ipilimumab alone in patients with advanced, unresectable melanoma. J Clin Oncol. 2018;36:1658-1667.
22. Ribas A, Dummer R, Puzanov I, et al. Oncolytic virotherapy promotes intratumoral t cell infiltration and improves anti-PD-1 immunotherapy. Cell. 2018;174:1031-1032.
23. Sampson JH, Carter Jr. JH, Friedman AH, Seigler HF. Demographics, prognosis, and therapy in 702 patients with brain metastases from malignant melanoma. J Neurosurg. 1998;88:11-20.
24. Yamamoto M, Serizawa T, Shuto T, et al. Stereotactic radiosurgery for patients with multiple brain metastases (JLGK0901): a multi-institutional prospective observational study. Lancet Oncol. 2014;15:387-395.
25. Tawbi HA, Forsyth PA, Hamid O, et al. Combined nivolumab and ipilimumab in melanoma metastatic to the brain. N Engl J Med. 2018;379:722-730.
26. Long GV, Atkinson V, La S, et al. Combination nivolumab and ipilimumab or nivolumab alone in melanoma brain metastases: a multicenter randomised phase 2 study. Lancet Oncol. 2018;19:672-681.
27. Long GV, Trefzer U, Davies MA, et al. Dabrafenib in patients with Val600Glu or Val600Lys BRAF-mutant melanoma metastatic to the brain (BREAK-MB): a multicenter, open-label, phase 2 trial. Lancet Oncol. 2012;13:1087-1095.
28. Davies MA, Saiag P, Robert C, et al. Dabrafenib plus trametinib in patients with BRAFV600-mutant melanoma brain metastases (COMBI-MB): a multicenter, multicohort, open-label, phase 2 trial. Lancet Oncol. 2017;18:863-873.