Summary Background Patients with melanoma that progresses on ipilimumab and, if BRAFV600 mutant-positive, a BRAF or MEK inhibitor or both, have few treatment options. We assessed the efficacy and ...safety of two pembrolizumab doses versus investigator-choice chemotherapy in patients with ipilimumab-refractory melanoma. Methods We carried out a randomised phase 2 trial of patients aged 18 years or older from 73 hospitals, clinics, and academic medical centres in 12 countries who had confirmed progressive disease within 24 weeks after two or more ipilimumab doses and, if BRAFV600 mutant-positive, previous treatment with a BRAF or MEK inhibitor or both. Patients had to have resolution of all ipilimumab-related adverse events to grade 0–1 and prednisone 10 mg/day or less for at least 2 weeks, an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, and at least one measurable lesion to be eligible. Using a centralised interactive voice response system, we randomly assigned (1:1:1) patients in a block size of six to receive intravenous pembrolizumab 2 mg/kg or 10 mg/kg every 3 weeks or investigator-choice chemotherapy (paclitaxel plus carboplatin, paclitaxel, carboplatin, dacarbazine, or oral temozolomide). Randomisation was stratified by ECOG performance status, lactate dehydrogenase concentration, and BRAFV600 mutation status. Individual treatment assignment between pembrolizumab and chemotherapy was open label, but investigators and patients were masked to assignment of the dose of pembrolizumab. We present the primary endpoint at the prespecified second interim analysis of progression-free survival in the intention-to-treat population. This study is registered with ClinicalTrials.gov , number NCT01704287 . The study is closed to enrolment but continues to follow up and treat patients. Findings Between Nov 30, 2012, and Nov 13, 2013, we enrolled 540 patients: 180 patients were randomly assigned to receive pembrolizumab 2 mg/kg, 181 to receive pembrolizumab 10 mg/kg, and 179 to receive chemotherapy. Based on 410 progression-free survival events, progression-free survival was improved in patients assigned to pembrolizumab 2 mg/kg (HR 0·57, 95% CI 0·45–0·73; p<0·0001) and those assigned to pembrolizumab 10 mg/kg (0·50, 0·39–0·64; p<0·0001) compared with those assigned to chemotherapy. 6-month progression-free survival was 34% (95% CI 27–41) in the pembrolizumab 2 mg/kg group, 38% (31–45) in the 10 mg/kg group, and 16% (10–22) in the chemotherapy group. Treatment-related grade 3–4 adverse events occurred in 20 (11%) patients in the pembrolizumab 2 mg/kg group, 25 (14%) in the pembrolizumab 10 mg/kg group, and 45 (26%) in the chemotherapy group. The most common treatment-related grade 3–4 adverse event in the pembrolizumab groups was fatigue (two 1% of 178 patients in the 2 mg/kg group and one <1% of 179 patients in the 10 mg/kg group, compared with eight 5% of 171 in the chemotherapy group). Other treatment-related grade 3–4 adverse events include generalised oedema and myalgia (each in two 1% patients) in those given pembrolizumab 2 mg/kg; hypopituitarism, colitis, diarrhoea, decreased appetite, hyponatremia, and pneumonitis (each in two 1%) in those given pembrolizumab 10 mg/kg; and anaemia (nine 5%), fatigue (eight 5%), neutropenia (six 4%), and leucopenia (six 4%) in those assigned to chemotherapy. Interpretation These findings establish pembrolizumab as a new standard of care for the treatment of ipilimumab-refractory melanoma. Funding Merck Sharp & Dohme.
Summary Background The anti-programmed-death-receptor-1 (PD-1) antibody pembrolizumab has shown potent antitumour activity at different doses and schedules in patients with melanoma. We compared the ...efficacy and safety of pembrolizumab at doses of 2 mg/kg and 10 mg/kg every 3 weeks in patients with ipilimumab-refractory advanced melanoma. Methods In an open-label, international, multicentre expansion cohort of a phase 1 trial, patients (aged ≥18 years) with advanced melanoma whose disease had progressed after at least two ipilimumab doses were randomly assigned with a computer-generated allocation schedule (1:1 final ratio) to intravenous pembrolizumab at 2 mg/kg every 3 weeks or 10 mg/kg every 3 weeks until disease progression, intolerable toxicity, or consent withdrawal. Primary endpoint was overall response rate (ORR) assessed with the Response Evaluation Criteria In Solid Tumors (RECIST, version 1.1) by independent central review. Analysis was done on the full-analysis set (all treated patients with measurable disease at baseline). This study is registered with ClinicalTrials.gov , number NCT01295827. Findings 173 patients received pembrolizumab 2 mg/kg (n=89) or 10 mg/kg (n=84). Median follow-up duration was 8 months. ORR was 26% at both doses—21 of 81 patients in the 2 mg/kg group and 20 of 76 in the 10 mg/kg group (difference 0%, 95% CI −14 to 13; p=0·96). Treatment was well tolerated, with similar safety profiles in the 2 mg/kg and 10 mg/kg groups and no drug-related deaths. The most common drug-related adverse events of any grade in the 2 mg/kg and 10 mg/kg groups were fatigue (29 33% vs 31 37%), pruritus (23 26% vs 16 19%), and rash (16 18% vs 15 18%). Grade 3 fatigue, reported in five (3%) patients in the 2 mg/kg pembrolizumab group, was the only drug-related grade 3 to 4 adverse event reported in more than one patient. Interpretation The results suggest that pembrolizumab at a dose of 2 mg/kg or 10 mg/kg every 3 weeks might be an effective treatment in patients for whom there are few effective treatment options. Funding Merck Sharp and Dohme.
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