INTRODUCTION

Pembrolizumab is a PD-1 inhibitor with confirmed activity in metastatic melanoma. Response rates in published trials range from 26-34%, with superior toxicity profile comparing to other available agents.

We analyzed the results of patients treated with pembrolizumab under named access program with focus on efficacy.

METHODS

Patient records from two hospitals participating in the program were reviewed retrospectively for a period between 01 May 2014 and 30 June 2015. Pembrolizumab was administered every three weeks at 2mg/kg dose.

Patients were treated until disease progression or unacceptable toxicity.  Tumour responses were assessed every three months and were evaluated according to the Response Evaluation Criteria in Solid Tumours (RECIST) version 1.1.

RESULTS

During the above period, 81 patients were enrolled onto the program.

Median age was 62 (22-82). 61% of patients had stage IVc disease and 16% had brain metastases prior to treatment commencement. 72 patients received at least one cycle of treatment.

Response rate in the treated group was 39%, with 8% complete responses and 31% partial responses. Rate of stable disease was 21%, and 35% of patients had progressive disease.

Median number of cycles was 8.1 (95%CI 6.9-9.4). 57% of patients were still on treatment at the time of data cutoff.

There were no grade III or above toxicity and no treatment discontinuation due to toxicity. The most common toxicity were diarrhea and pruritus, each reported by 5% of patients.

CONCLUSION

Pembrolizumab was well tolerated with no unexpected toxicity. Early efficacy results were not dissimilar to the ones described in literature.