Effectiveness of Immune Checkpoint Inhibitors in Various Tumor Types Treated by Low, Per-Weight, and Conventional Doses at a Tertiary Care Center in Mumbai.

Abstract

The cost of immune checkpoint inhibitors (ICIs) limits their accessibility to a small number of patients with cancer in low- and middle-income countries. Early-phase clinical trials have shown target inhibition and high activity at doses lower than those registered and evaluated in clinical trials. Here, we report everyday experience of using ICIs in 100 Indian patients, many of whom received lower doses of ICIs. Consecutive patients who received at least one dose of an ICI irrespective of tumor type at a tertiary care hospital in Mumbai, India, that was able to access ICIs for its patients were enrolled. The objectives were to study the doses used over a 3-year time period, and the effectiveness of therapy, assessed primarily by the overall response rate (ORR), overall survival (OS), and progression-free survival were secondary end points. Twenty-five patients were treated with conventional doses of ICIs, 29 patients received lower doses per body weight, and 46 patients received low-dose treatment. The median number of cycles received was 5 (range, 1-28). Seventy-eight patients received ICIs in a palliative setting. The median follow-up time was 10.2, 9.8, and 3.9 months for those receiving fixed approved dosing, per body weight dosing, and low-dose treatment, respectively. There was a trend with time to prescribe lower doses. Response evaluation was available for 92 patients. Twenty-one (five-adjuvant and 16-palliative) patients received ICIs only. The ORR did not differ statistically among different dosing groups, but comparisons are confounded by inclusion of different ICIs, different tumor sites, and concurrent treatments. The median OS was 6.8 (range, 4.6-9.0) months. Adoption of per-body weight and lower dosing of ICIs appears to give acceptable outcomes. Lower dosing can improve access and timely delivery of ICIs in low- and middle-income countries.