Hypopituitarism in patients with metastatic renal cell carcinoma treated with ipilimumab and nivolumab combination therapy

Objective: We investigated the incidence of hypopituitarism in Japanese patients with metastatic renal cell carcinoma (mRCC) who received ipilimumab and nivolumab (I-P) therapy and compared patient characteristics and survival rates between patients with hypopituitarism and those without. Methods: Twenty-two patients with mRCC who received I-P therapy as first-line treatment were the subjects of this retrospective study. The diagnosis of hypopituitarism was based on the hormone loading test. Results: Hypopituitarism occurred in 41% (9/22) patients who received I-P therapy. Median time of diagnosis was 12 weeks (IQR: 9.5-20). Clinical symptoms, such as fatigue, weakness or fever, were observed in 7 patients, while 2 patients had no clinical presentation. The following deficiency patterns were observed: isolated ACTH in 4 patients, ACTH and GH in 2 patients, ACTH and TSH in 2 patients and triple deficiency (ACTH, GH and TSH) in 1 patient. All patients with hypopituitarism were in the IMDC intermediate group, while 46% of those without hypopituitarism were in the IMDC intermediate group. Other patient characteristics were not different between the two groups. Object response rate was 33% (3/9) in patients with hypopituitarism and 23% (3/13) in those without (P = 0.5954). Progression free survival (PFS) was significantly longer in those with hypopituitarism than those without (median: 24.7 vs. 4.5 months, P = 0.0008), while overall survival did not differ (P = 0.136). Conclusions: Compared with the clinical trial, the incidence of hypopituitarism was higher than expected. Patients with hypopituitarism tended to have longer PFS, which may suggest that optimal management of hypopituitarism results in better prognosis.