ASCO GU 2019: Patients with Previously Treated Metastatic Urothelial Cancer Treated with Sacituzumab Govitecan (IMMU-132)

San Francisco, CA ( Patients with metastatic urothelial carcinoma (mUC) have a poor prognosis, and those who progress after platinum chemotherapy and immunotherapy with programmed death ligand 1 (PD-1)/(PD-L1) inhibitors have limited treatment options. Sacituzumab govitecan (SG) is a novel antibody-drug conjugate. The antibody is humanized anti-Trop2 and it is attached to the active metabolite of irinotecan, a cytotoxic chemotherapy agent. The combination drug targets Trop-2 which is overexpressed in aggressive epithelial cancers including up to 83% of UC.

Presented is an international, multi-center, open-label, phase 1/2 study in patients with mUC after the failure of anti-PD-1/PD-L1. All patients in the study will receive SG on day 1 and 8 of 21-day cycles until progression or unacceptable toxicity. Cohort 1 includes patients in third-line therapy after platinum-based chemotherapy and anti-PD-1/anti-PD-L1 immunotherapy. Cohort 2 includes patients in second-line therapy, ineligible for cisplatin-based therapy and after anti-PD-1/anti-PD-L1 immunotherapy. CT/MRI scans were obtained at 8-week intervals to assess treatment response.

The primary outcome measures were safety and objective response rate (ORR) by RECIST 1.1. Secondary outcome measures included the duration of response (DOR), progression-free survival (PFS) and overall survival (OS).

The study start date was 2018 and the estimated completion date is 2020; a total of 140 participants are estimated to enroll. The ORR was 14/45 (31%), with 2 complete and 12 partial responses. In patients with visceral involvement, the ORR was 9/33 (27%). The ORR in immunotherapy-treated patients was 4/17 (23%). Median PFS and OS were 7.3 months and 18.9 months respectively. The adverse events profile was consistent with prior reports as summarized below.
UroTodayASCOGU2019 IMMU 132

In conclusion, in preliminary studies, SG demonstrated clinical activity in patients with relapsed/refractory mUC including those previously treated with immunotherapy (check-point inhibitors) and those with visceral metastases.

Presented by: Scott T. Tagawa, MD, MS, Weill Cornell Medicine, New York, New York

Written by: Selma Masic, MD, Urologic Oncology Fellow (SUO), Fox Chase Cancer Center, @selmasic at the 2019 American Society of Clinical Oncology Genitourinary Cancers Symposium, (ASCO GU) #GU19, February 14-16, 2019 - San Francisco, CA
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