Immunotherapy with PD1/PDL1 checkpoint inhibitors has made a dramatic change in the treatment of many cancers like melanoma, Renal cell cancer (RCC), lung cancer and head and neck cancer. Understanding the toxicity profile of immunotherapy is important, as they are different from chemotherapy and oral tyrosine kinase inhibitor side effects. Being new therapies, there is not much data about these immune related adverse events (irAEs) in Indian patients.
We retrospectively reviewed all patients who received treatment with PD1 inhibitors in our tertiary hospital from June 2016 to March 2018. The objective was to assess the various adverse events.
70 patients received treatment with immunotherapy- 65 received Nivolumab and 5 Pembrolizumab. The 70 patients were as follows - 20 lung cancers, 20 RCC, 10 melanomas, 8 head and neck cancers, 3 urinary bladder cancers, 2 MMR deficient colon cancers, 2 stomach cancers, 2 breast cancers, 2 sarcomas and 1 ovarian cancer. Patient age ranged from 31 to 87 years. Number of cycles ranged from 2 to 18 cycles. Thyroid abnormality were the most common side effect, and was seen in 19 patients (27%). 15 patients (21.4%) had hypothyroidism, 2 (2.8%) had hyperthyroidism, and 2 (2.8%) had hyperthyroidism followed by hypothyroidism. Hypothyroidism was managed with thyroid replacement. Grade 2 skin toxicity in the form of pruritis and rash was seen in 6 patients (8.5%), and was managed with topical steroids. Grade 2 diarrhoea was seen in 5 patients (7.1%). Grade 1 elevation in liver enzymes was seen in 4 patients (5.7%). Pneumonitis was seen in 2 patients (2.8%). This was grade 3, requiring treatment with steroids and permanent discontinuation of immunotherapy. Grade 2 Arthritis was seen in 1 patient (1.4%), requiring temporary interruption, and treatment with oral steroids, with good resolution.
Treatment with PD1 checkpoint inhibitors is very well tolerated. The most common adverse events in our patients were hypothyroidism, skin rash and diarrhoea. Very few patients had grade 3 toxicity and there was no treatment related death. Though very well tolerated, we would need to be vigilant and aware of these unique side effects, to enable early pickup and early treatment with steroids.
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A. Rauthan: Advisory board: Roche, Merck, Bayer, Pfizer. All other authors have declared no conflicts of interest.