Low-Dose Anti-PD(L)1 for the Treatment of Solid Malignancies

Mounting data suggest that lower doses of anti-PD(L)1 agents can be as efficacious as label-approved doses at a fraction of its cost. We compare the outcomes of patients treated with low-dose (LD) and with conventional-dose (CD) anti-PD(L)1 agents.

This observational study evaluates the outcomes of patients with solid malignancies treated with anti-PD(L)1 agents (LD or CD) at Hospital de Base, Brazil. Patients were classified as receiving LD if the dose administered in the first cycle was below the label-approved dose. Efficacy outcomes, including best clinical overall response rate (cORR), clinical progression-free survival (cPFS), and overall survival (OS), were evaluated.

From January 2020 to May 2023, 71 patients were included: 49 (69%) with LD and 22 (31%) with CD agents. The most frequent tumor sites were the lung (41% LD, 22.9% CD) and skin (melanoma; 24.6% LD, 50% CD). Most of the patients were treated with pembrolizumab (65% LD and 72% CD). The mean dose of pembrolizumab was 95.3 mg (1.5 mg/kg) in LD and 168.7 mg (2.12 mg/kg) in CD groups, once a day, q21d (every 21 days). After a median follow-up of 10.9 months, there were no significant differences between LD versus CD in cORR (38.1% v 35.2%, P = .31), cPFS (5.3 m v 7 m, P = .36), and OS (12.8 m v not reached, P = .17). A subgroup analysis with patients receiving pembrolizumab was performed, and similar results were obtained.

Our study found no differences in cORR, cPFS, and OS between patients treated with LD and CD anti-PD(L)1. LD anti-PD(L)1 could be an alternative to promote accessibility, which warrants further investigation in randomized trials.