Efficacy and Safety of Low-Dose Nivolumab in Treatment of Advanced Solid Tumors: A Retrospective Audit from Resource-Constrained Settings.

Background: Immunotherapy has improved outcomes in many advanced solid tumors. In resource-constrained settings, less than 2% of patients can afford standard dose immunotherapy. A recent phase II study showed the efficacy of low-dose immunotherapy in this setting. We used low-dose immunotherapy on a compassionate basis in patients who had progressed on available standard treatment options and standard dose immunotherapy was not feasible. Patients and Methods: We retrospectively collected data from the medical oncology department for consecutive patients who had initially received standard lines of therapy followed by low-dose immunotherapy (nivolumab 40 mg) on a compassionate basis. The demographic details, histology, prior treatment, clinical and radiological response, date of disease progression, date of death, and toxicity data were collected. Results: A total of 54 consecutive patients, who received low-dose immunotherapy with nivolumab from January 1, 2018 to February 14, 2020, were included in this analysis; 4 patients were not radiologically evaluable. The median age was 50.4 years (range 35-74 years), male:female ratio was 6:1. The most common comorbidities were hypertension and diabetes seen in 12 (22.2%) and 6 (11.1%) patients, respectively. The majority of the patients (70.4%) were of head and neck cancer. The median follow-up was 4.5 months (range 0.5-11.7). Clinical benefit was observed in 18 (33.3%) patients. Partial response and stable disease were achieved in 9 (16.7%) and 5 (9.3%) patients, respectively. Median survival was not reached for these patients. Six months progression-free survival and overall survival were 100 versus 8.7% (hazard ratio [HR] 0.05, 95% confidence interval [CI]: 0.01-0.36; Conclusion: In resource-constrained settings, low-dose immunotherapy with nivolumab seems to be an effective treatment option. Further studies are warranted to evaluate this approach.