Ipilimumab with stereotactic radiotherapy feasible for metastatic cancers

The use of ipilimumab with stereotactic radiotherapy, either concurrently or sequentially, yields satisfactory outcomes with low toxicities in patients with metastatic cancer, according to the results of a phase II trial.

The trial included 106 metastatic cancer patients (median age, 60 years; 47 percent male). All patients received ≥1 cycle of ipilimumab (every 3 weeks for four doses) with radiotherapy, which was administered during the first dose (concurrent) or 1 week after the second dose (sequential) and delivered at 50 Gy in four fractions or 60 Gy in 10 fractions to metastatic liver or lung lesions.

In the cohort, common primary tumour sites were lung (n=30), gastrointestinal tract (n=20), and head and neck (n=19). Ninety-seven patients (91 percent) had received prior systemic therapy, 66 (62 percent) had undergone prior radiotherapy for metastatic disease, and 17 (16 percent) had received prior immunotherapy.

Over a median follow-up of 10.5 months, median progression-free survival was 2.9 months (95 percent confidence interval, 2.45–3.40), while median overall survival time was not reached. Clinical benefit rates (defined as partial or complete response or stable disease lasting ≥6 months) were 26 percent overall, 28 percent with sequential vs 20 percent with concurrent therapy (p=0.250), and 31 percent for lung vs 14 percent for liver metastases (p=0.061). The highest clinical benefit rate was recorded in the sequential lung group (42 percent).

Treatment-related adverse events did not significantly differ across the treatment groups.