Activity and Safety of Geptanolimab (GB226) for patients with unresectable, recurrent or metastatic alveolar soft part sarcoma: a phase 2 single-arm study

Activity and Safety of Geptanolimab (GB226) for patients with unresectable, recurrent or metastatic alveolar soft part sarcoma: a phase 2 single-arm study:

Purpose: Patients with alveolar soft part sarcoma (ASPS) are rare and have few treatment options. We assessed the activity of geptanolimab (GB226), a fully humanized PD-1 antibody, for patients with unresectable, recurrent or metastatic ASPS. Patients and methods: We did this multicentre, single-arm, phase 2 study (Gxplore-005,NCT03623581) in patients aged 18-75 years who had unresectable, recurrent or metastatic ASPS at 11 sites in China. Patients received intravenous geptanolimab (3 mg/kg) every 2 weeks until disease progression or unacceptable toxicity. The primary endpoint was objective response rate assessed by independent review committee (IRC) per RECIST 1.1 in the full analysis set population. Results: Between September 6, 2018 and March 6, 2019, we enrolled and treated 37 patients with 23 (62.2%) having received prior systemic treatment. 14 (37.8%, 95% confidence interval [CI] 22.5-55.2) of 37 patients had an objective response assessed by IRC with a 6-month duration of response rate of 91.7%. Median progression-free survival was 6.9 months (95% CI 5.0-not reached) and disease control was achieved in 32 (86.5%, 95% CI 71.2-95.5) patients. Three of 37 patients reported grade 3 treatment-related adverse events (TRAEs), including anaemia, hypophysitis and proteinuria (one each [2.7%]). No grade 4 TRAEs were observed. Two (5.4%) patients discontinued treatment due to TRAE (one with hypophysitis and one with Mobitz type I atrioventricular block). The baseline percentage of CD4+ T cells was adversely associated with patient response (P=0.031). Conclusions: Geptanolimab has clinically meaningful activity and a manageable safety profile in unresectable, recurrent or metastatic ASPS.