A neoadjuvant strategy combining two immunostimulatory agents with differing mechanisms of action is efficacious and safe in patients with high-risk, resectable melanoma, according to final results of the phase 2 Neo-C-Nivo trial.
The two agents are the PD-1 inhibitor nivolumab and CMP-001, an investigational Toll-like receptor 9 agonist that activates tumor-associated plasmacytoid dendritic cells.
CMP-001 and nivolumab produced a major pathologic response in 60% of patients, and these patients had a 1-year relapse-free survival rate of 89%. About 23% of patients had grade 3 treatment-related adverse events, and there were no grade 4-5 treatment-related events.
These data were reported at the Society for Immunotherapy of Cancer’s 35th Anniversary Annual Meeting.
“Stage III melanoma is a very, very high risk disease. Despite appropriate management, which involves surgical resection followed by adjuvant immunotherapy, a large number of patients still relapse,” noted study author Diwakar Davar, MD, of the University of Pittsburgh Hillman Cancer Center.
“Neoadjuvant immunotherapy in this setting enhances the systemic T-cell response to tumor antigens,” he explained. “As a result, there is greater detection and killing of micrometastatic disease. And, indeed, neoadjuvant immunotherapy with anti–[programmed death–1] monotherapy or with anti-PD1 and anti-CTLA4 combination therapy produces high response rates, although the combination therapy is associated with significant toxicity.”
Patients, treatment, and response
The Neo-C-Nivo trial enrolled 31 patients with resectable stage IIIB/C/D melanoma having clinically apparent lymph node disease.
The patients were treated with three cycles of nivolumab given every 2 weeks. They also received seven weekly injections of CMP-001 subcutaneously and then intratumorally. After surgical resection, the patients received more of the same immunotherapy.
At a median follow-up of 15 months, 60% of patients had a major pathologic response, 50% had a complete response, and 10% had a major response. Some 70% of patients (after additionally including partial responders) had any pathologic response.
“More than half of the patients that we treated had more than one injectable lesion,” Dr. Davar noted. “I want to emphasize that only one lesion was injected, so the results we got illustrate that the rest of the patients who had more than one injectable lesion had regression in their injected and uninjected lesions.”
Biomarker analyses showed that response was associated with evidence of immune activation, both in the tumor and in the blood. With immunotherapy, the density of CD8 tumor-infiltrating lymphocytes increased by a median of 10.3-fold in pathologic responders as compared with only 0.8-fold in nonresponders (P < .05). In addition, responders had evidence of activated CD8-positive T cells peripherally, as well as presence of plasmacytoid dendritic cells within the tumor microenvironment.
Survival and safety
Patients had better median relapse-free survival if they attained a major pathologic response (not reached in either group, P = .0106) or any pathologic response (not reached vs. 5 months, P = .0001).
The landmark 1-year relapse-free survival rate was 89% for major pathologic responders and 90% for all pathologic responders.
Overall, 22.6% of patients experienced grade 3 treatment-related adverse events, the majority of which did not require medical intervention and none of which delayed planned surgery. There were no grade 4-5 treatment-related adverse events.
Cytokine release syndrome was uncommon, seen in 16.1% of patients, possibly because the cohort received prophylaxis, Dr. Davar proposed.
