Real-World efficiency of pembrolizumab in metastatic melanoma patients following adjuvant anti-PD1 treatment

Abstract

Background: Postoperative treatment of patients with either BRAF/MEK inhibitors or anti-PD1 antibodies in the adjuvant setting results in improved recurrence free survival and has therefore become a standard of care for most patients with resected stage III melanoma. For patients who need systemic treatment after failure of adjuvant immune checkpoint inhibitors, there is insufficient evidence regarding efficacy of a retreatment with anti-PD1 antibodies. Methods: From the European Melanoma Treatment Registry (EUMelaReg) we have identified 74 patients and evaluated the clinical characteristics and outcome of anti-PD1 retreatment with pembrolizumab in these patients. The primary objectives were overall response rate and progression-free survival stratified by type of recurrence, i.e. whether recurrence occurred while on adjuvant anti-PD1, or later during follow up. In addition, the analysis was stratified for patients, who terminated adjuvant treatment early due to side effects. Results: The ORR of pembrolizumab retreatment in 1st line after recurrence (n=51) was 37.3 %, which did not differ significantly between type of recurrence (40.9 % in early vs. 34.5 % in late recurrence). Patients who discontinued adjuvant anti-PD1 for toxicity had a higher ORR (52.9 %) compared to patients who completed the treatment (37.5 %) or discontinued due to disease progression (23.1 %). PFS in 1st line retreatment was comparable between the groups with a median PFS (95 % CI) of 7.4 (2.3-NR) months and 6.1 (3.4–13.1) months in early and late recurrence, respectively. Conclusion: Retreatment with pembrolizumab may be a valuable treatment option after failure of adjuvant immunotherapy, in particular in patients who have stopped adjuvant treatment for side effects.

Keywords

• Melanoma
• Immunotherapy
• Adjuvant treatment
• Skin Cancer
• Immune Checkpoint Inhibitor