Pembrolizumab leads to a durable complete response (CR) with low rates of relapse — even 2 years after discontinuation — and may cure a subset of patients with metastatic melanoma, according to a study published in the Journal of Clinical Oncology.1
Patients with metastatic melanoma have among the worst prognoses of patients with cancer, but response rates and outcomes have improved markedly with the introduction of PD-L1 inhibitors, including pembrolizumab. Predictors for treatment success have not, however, yet been explored.
For this analysis, researchers evaluated the outcomes of 105 patients enrolled in KEYNOTE-001 (ClinicalTrials.gov Identifier: NCT01295827) who had a CR with pembrolizumab after a median follow-up of 43 months. Patients were eligible to discontinue pembrolizumab if treatment lasted for 6 months or longer and for at least 2 treatments beyond confirmed CR. Tumor response was assessed every 12 weeks by RECIST criteria and investigator review.
At time of data cutoff, with a median follow-up of 30 months after first CR, 92 patients (87.6%) maintained CR. Ninety-one patients (86.7%) discontinued pembrolizumab, of whom 67 (63.8%) did not receive further anticancer therapy during the observation period.
The 2-year disease-free survival rate was 90.9% among the 105 patients who had a CR and 89.9% among the 67 patients who discontinued pembrolizumab without any additional therapy.
Baseline tumor size and PD-L1 status were independently associated with CR.
The authors concluded that “the prolonged CRs experienced with pembrolizumab provide hope for a cure for advanced melanoma without the need for additional treatment.”
- Robert C, Ribas A, Hamid O, et al. Durable complete response after discontinuation of pembrolizumab in patients with metastatic melanoma. J Clin Oncol. 2017 Dec 28. doi: 10.1200/JCO.2017.75.6270 [Epub ahead of print]