Effect of body mass index on immune checkpoint inhibitor efficacy in patients with advanced cancer

The need for predictive factors regarding the response to immune checkpoint inhibitors (ICIs) is increasing. Recent research indicates that an enhanced response to ICIs is associated with a higher body mass index (BMI). This study aims to evaluate the relationship between response to ICIs and BMI in solid tumors.

We retrospectively analyzed patients with advanced cancer treated with ICIs at one academic center. We compared the treatment responses of patients classified as underweight/normal weight (BMI <25) and overweight/obese (BMI ⩾ 25) according to their BMI at the initiation of ICI treatment. After excluding underweight patients, we also compared the progression-free survival (PFS) and overall survival (OS) of normal-weight, overweight, and obese patients.

Overall, 113 patients were evaluated. Forty-seven (41.6%) patients had BMI <25 and 66 (58.4%) patients had a BMI ⩾ 25. In underweight/normal patients, median PFS was 7.7 months (95% CI: 4.7-10.6) while it was 8.0 months (95% CI: 4.1-11.9) in overweight/obese patients (HR 1.16, 95% CI: (0.76-1.75), p=0.477). In underweight/normal patients, the median OS was 21.7 months (95% CI: 11.6-31.7) compared to 18.7 months (95% CI: 12.7-24.6) in overweight/obese patients (HR 1.06, 95% CI: (0.69-1.64), p=0.774). The objective response rate (ORR) was 38.3% in underweight/normal patients and 34.8% in overweight/obese patients (p = 0.707). After excluding underweight patients, there were also no significant differences in PFS (p = 0.914), OS (p = 0.642), and ORR (p = 0.909) between patients of normal weight, overweight, and obesity.

Our research found no correlation between BMI and response to ICIs. Additional prospective studies are necessary to assess the effect of BMI on the response to ICIs.