Erin Roesch, MD
The phase 3 KEYNOTE-355 trial established the role of chemotherapy in combination with pembrolizumab in the first-line setting for programmed death-ligand 1 (PD-L1)–positive advanced triple-negative breast cancer (TNBC). Patients unselected for PD-L1 status in this trial who received platinum- or taxane-based chemotherapy with placebo had a median progression-free survival of 5.6 months.[3] Strategies to improve upon efficacy and tolerability are desired in this space, and various trials have evaluated "switch maintenance" that involves receipt of an intensive induction regimen followed by a switch to an alternative/more tolerable regimen after response is achieved.[4] The phase II DORA trial randomized 45 patients with advanced TNBC and ongoing stable disease or complete or partial response from first- or second-line platinum-based chemotherapy to a maintenance regimen of olaparib (300 mg orally twice daily) with or without durvalumab (1500 mg on day 1 and every 4 weeks) (Tan et al). At a median follow-up of 9.8 months, median progression-free survival was 4.0 months (95% CI 2.6-6.1) with olaparib and 6.1 months (95% CI 3.7-10.1) with the combination; both were significantly longer than the historical control of continued platinum-based therapy (P = .0023 and P < .0001, respectively). Durable disease control appeared more pronounced in patients with complete or partial response to prior platinum therapy, and no new safety signals were observed. Future efforts to study this approach include the phase 2/3 KEYLYNK-009 trial, which is evaluating olaparib plus pembrolizumab maintenance therapy after first-line chemotherapy plus pembrolizumab for TNBC.[5]
TNBC is a heterogenous subtype, characterized by aggressive biology, and it benefits from chemotherapy and immunotherapy treatment approaches. Presently, the management of early-stage TNBC often involves neoadjuvant systemic therapy; however, a proportion of patients receive treatment in the postoperative setting, highlighting the relevance of time to initiation of adjuvant therapy as well.[6] Various prior studies have showed that delayed administration of adjuvant chemotherapy for EBC can lead to adverse survival outcomes. Furthermore, this effect is subtype-dependent, with more aggressive tumors (luminal B, triple-negative, human epidermal growth factor receptor 2 [HER2]-positive) exhibiting inferior outcomes with delayed chemotherapy.[7] A retrospective cohort study that included 245 patients with early TNBC who received adjuvant chemotherapy after surgery evaluated the impact of time to initiation of adjuvant therapy in this population (Hatzipanagiotou et al). Superior survival outcomes were observed for the group receiving systemic therapy 22-28 days after surgery (median overall survival 10.2 years) compared with those receiving adjuvant chemotherapy at later time points (29-35 days, 36-42 days, and >6 weeks after surgery; median overall survival 8.3 years, 7.8 years, and 6.9 years, respectively). Patients receiving chemotherapy 22-28 days after surgery had significantly better survival than those receiving chemotherapy 29-35 days (P = .043) and >6 weeks (P = 0.033) postoperatively. This study emphasizes the importance of timely administration of adjuvant chemotherapy for early TNBC, and efforts aimed to identify potential challenges and propose solutions to optimize outcomes in this space are valuable.
Additional References
- Gnant M, Frantal S, Pfeiler G, et al, for the Austrian Breast & Colorectal Cancer Study Group. Long-term outcomes of adjuvant denosumab in breast cancer. NEJM Evid. 2022;1:EVIDoa2200162. doi: 10.1056/EVIDoa2200162 Source
- Fassio A, Idolazzi L, Rossini M, et al. The obesity paradox and osteoporosis. Eating and Weight Disorders - Studies on Anorexia, Bulimia and Obesity. 2018;23:293-30 doi: 10.1007/s40519-018-0505-2 Source
- Cortes J, Cescon DW, Rugo HS, et al, for the KEYNOTE-355 Investigators. Pembrolizumab plus chemotherapy versus placebo plus chemotherapy for previously untreated locally recurrent inoperable or metastatic triple-negative breast cancer (KEYNOTE-355): A randomised, placebo-controlled, double-blind, phase 3 clinical trial. Lancet. 2020;396:1817-1828. doi: 10.1016/S0140-6736(20)32531-9 Source
- Bachelot T, Filleron T, Bieche I, et al. Durvalumab compared to maintenance chemotherapy in metastatic breast cancer: The randomized phase II SAFIR02-BREAST IMMUNO trial. Nat Med. 2021;27:250-255. doi: 10.1038/s41591-020-01189-2 Source
- Saji S, Cussac AL, Andre F, et al. 68TiP KEYLYNK-009: a phase II/III, open-label, randomized study of pembrolizumab (pembro) + olaparib (ola) vs pembro + chemotherapy after induction with first-line (1L) pembro + chemo in patients (pts) with locally recurrent inoperable or metastatic TNBC (abstract). Ann Oncol. 2020;31(Suppl 6):S1268. doi: 10.1016/j.annonc.2020.10.088 Source
- Ortmann O, Blohmer JU, Sibert NT, et al for 55 breast cancer centers certified by the German Cancer Society. Current clinical practice and outcome of neoadjuvant chemotherapy for early breast cancer: Analysis of individual data from 94,638 patients treated in 55 breast cancer centers. J Cancer Res Clin Oncol. 2023;149:1195-1209. doi: 10.1007/s00432-022-03938-x Source
- Yu KD, Fan L, Qiu LX, et al. Influence of delayed initiation of adjuvant chemotherapy on breast cancer survival is subtype-dependent. Oncotarget. 2017;8:46549-46556. doi: 10.18632/oncotarget.10551 Source