Multi-institutional report on toxicities of concurrent nivolumab and radiation therapy.

PURPOSE

Radiation therapy (RT) and nivolumab are standard therapies for a wide range of advanced and metastatic cancers, yet little is known about the toxicity profile of their combined treatment. The rate of grade ≥3 toxicities from nivolumab monotherapy and radiation-only palliative treatments has been reported at 10% to 18% and 0% to 26%, respectively. We reviewed our experience to assess the acute toxicity profile of concurrent RT-nivolumab.

METHODS AND MATERIALS

A retrospective review of all consecutive patients from January 2015 to May 2017 who received concurrent RT-nivolumab was conducted at 4 separate centers. Concurrent RT-nivolumab was defined as RT completed between 3 days prior to initial nivolumab infusion and 28 days after the last nivolumab infusion.

RESULTS

Of the 261 patients who received nivolumab, 46 (17.6%) had concurrent RT to 67 treatment sites. The median follow-up was 3.3 months (interquartile range, 1.7-6.1 months) and the 1-year overall survival rate was 22%. For the 11 of 46 patients (24%) who were alive at last analysis, the median follow-up was 12.8 months (interquartile range, 8.3-14.9 months). The most common histology, RT prescription, and treatment site were non-small cell lung cancer (23 of 46 patients; 50%), 30 Gy in 10 fractions (24 of 67 patients; 35.8%), and abdomen/pelvis (16 of 67 patients; 24%), respectively. Four patients with melanoma had concurrent ipilimumab and were removed from the final toxicity analysis of RT-nivolumab. Within 3 months of treatment with RT-nivolumab, 4 of 42 patients (9.5%) experienced grade 3 toxicity and 2 of these patients' toxicities were attributed specifically to the addition of RT: grade 3 hearing loss after whole brain RT and grade 3 pancreatitis after stereotactic body RT to the left adrenal gland. One death from transaminitis was attributed to nivolumab alone because the RT field did not encompass the liver.

CONCLUSIONS

Concurrent RT-nivolumab did not appear to increase the toxicity profile from the previously reported toxicity rates from nivolumab or radiation alone.