Background:
In germ cell tumors (GCTs), even if the disease relapsed after initial chemotherapy, patients have a chance of cure with second-line standard dose chemotherapy or high dose chemotherapy (HDCT). But, there is no established treatment for patients relapsed after second-line chemotherapy. We conducted the present phase II multi-institute trial to elucidate the efficacy and safety of nivolumab monotherapy for refractory GCT patients.
Patients and methods:
Patients aged 18 years or older with relapsed or refractory primary GCTS after 2-lines or more previous chemotherapies were eligible for the study. Both gonadal (testis or ovary primary) and extragonadal primary GCT could be included, but intracranial GCT was excluded. Nivolumab was administrated at 240 mg/body every 2 weeks. The primary endpoint was overall response rate.
Results:
In total, 17 patients were enrolled. Median age was 34 years. All but one patient was male. Tumor histology were nonseminoma in 14 patients and seminoma in 3 patients. Primary sites were gonadal in 12 patients, the remaining 5 patients had extragonadal GCT. Patients were pretreated with a median of 3 (range 2-5) previous chemotherapy lines including HDCT in 3 patients. One patient achieved partial response (PR). The response continued for 58 weeks in this patient. The best response was stable disease (SD) in 4 patients with median duration of 9 weeks (range 5-68 weeks). One patient achieved durable SD of 68 weeks. The remaining 12 patients showed progressive disease. There were 2 grade 3 adverse events.
Conclusion:
Nivolumab was tolerated by heavily pretreated GCT patients. The objective response rate was limited to 6% (1PR). But, response was durable in 2 patients (1PR and 1SD).