KEYNOTE-A17: First-Line Pembrolizumab Plus Cisplatin-Pemetrexed in Japanese Participants With Advanced Pleural...

Area of Science:

• Oncology
• Immunotherapy
• Clinical Trials

Background:

• Pleural mesothelioma (PM) is an asbestos-associated cancer with a poor prognosis.
• Effective first-line treatments for advanced PM are limited, necessitating novel therapeutic strategies.

Purpose of the Study:

• To evaluate the safety and preliminary efficacy of first-line pembrolizumab plus chemotherapy in Japanese participants with advanced pleural mesothelioma.
• To assess dose-limiting toxicities (DLTs), adverse events (AEs), and antitumor response in this patient cohort.

Main Methods:

• Phase 1b KEYNOTE-A17 study (NCT04153565) enrolled Japanese participants with previously untreated, advanced unresectable PM.
• Participants received pembrolizumab (200 mg Q3W) with cisplatin and pemetrexed (Q3W for 4-6 cycles).
• DLTs were assessed during cycle 1; AEs were graded per NCI CTCAE 5.0; tumor response was evaluated per modified RECIST.

Main Results:

• Of 19 participants, 2 (11%) experienced DLTs; 95% had treatment-related AEs, with 74% being grade 3-4.
• Treatment discontinuation due to AEs occurred in 26% of participants.
• The objective response rate was 74%, with a median duration of response of 16.8 months.

Conclusions:

• First-line pembrolizumab plus chemotherapy is tolerable and demonstrates acceptable safety in Japanese patients with advanced PM.
• The combination showed promising preliminary antitumor activity, supporting further investigation in this population.