FDA Grants Regular Approval to Sacituzumab Govitecan for TNBC

The FDA has granted a regular approval to sacituzumab govitecan-hziy (Trodelvy) for the treatment of patients with unresectable locally advanced or metastatic triple-negative breast cancer (TNBC) who have previously received 2 or more systemic therapies, at least 1 of them for metastatic disease.¹

The Trop2-directed antibody and topoisomerase inhibitor drug conjugate was previously granted an accelerated approval in April 2020 for use in patients with metastatic TNBC who had received at least 2 prior therapies for metastatic disease based on data from a phase 1/2 trial of the agent. At a median follow-up of 9.7 months, sacituzumab govitecan elicited an objective response rate (ORR) of 33.3% (95% CI, 24.6%-43.1%) per local assessment, with a median duration of response (DOR) of 7.7 months (95% CI, 4.9-10.8).² The clinical benefit rate with the agent was 45.4%. Additionally, the ORR was 34.3% (95% CI, 25.4%-44.0%) per blinded independent central review, and the median DOR was 9.1 months (95% CI, 4.6-11.3).

Data from the confirmatory phase 3 ASCENT trial (NCT02574455) supported the decision for the full approval. Among all randomized patients, the median progression-free survival (PFS) with sacituzumab govitecan was 4.8 months (95% CI, 4.1-5.8) vs 1.7 months (95% CI, 1.5-2.5) with chemotherapy (HR 0.43; 95% CI, 0.35-0.54; P <.0001); this translated to a 57% reduction in th risk of disease worsening or death. Moreover, the median overall survival (OS) was 11.8 months (95% CI, 10.5-13.8) and 6.9 months (95% CI, 5.9-7.6) in the investigative and control arms, respectively (HR 0.51; 95% CI, 0.41-0.62; P <.0001); this translated to a 49% reduction in the risk of death.

"Women with TNBC have historically had very few effective treatment options and faced a poor prognosis,” said Aditya Bardia, MD, MPH, director of Breast Cancer Research Program, Massachusetts General Cancer Center, assistant professor of medicine at Harvard Medical School, and global principal investigator of the ASCENT study, stated in a press release.³ “Today’s FDA approval reflects the statistically significant survival benefit seen in the landmark ASCENT study and positions sacituzumab govitecan as a potential standard of care for pretreated TNBC.”

ASCENT enrolled a total of 529 patients with unresectable locally advanced or metastatic TNBC who had relapsed following at least 2 previous chemotherapies, 1 of which could have been received in either the neoadjuvant or adjuvant setting, if progression occurred within 12 months.

Study participants were randomized 1:1 to receive either sacituzumab govitecan at 10 mg/kg as an intravenous infusion on days 1 and 8 of a 21-day cycle (n = 267) or physician’s choice of single-agent chemotherapy (n = 262).

The primary end point of the trial was PFS in patients who did not have brain metastases at baseline per blinded independent centralized review and RECIST v1.1 criteria. Additional efficacy end points comprised PFS for the full population, as well as OS.

Of the 482 patients evaluable for safety, sacituzumab govitecan was found to have a toxicity profile that proved to be consistent with what was indicated on the prior approved FDA label. The most commonly experienced grade 3 or higher toxicities with sacituzumab govitecan vs chemotherapy included neutropenia (52% vs 34%, respectively), diarrhea (11% vs 1%), leukopenia (11% vs 6%), and anemia (9% vs 6%). Five percent of patients who were treated with sacituzumab govitecan experienced toxicities that resulted in treatment discontinuation.

“Today’s approval is the culmination of a multi-year development program and validates the clinical benefit of this important treatment in metastatic TNBC,” said Merdad Parsey, MD, PhD, chief medical officer of Gilead Sciences, added in the release. “Building upon this milestone, we are committed to advancing [sacituzumab govitecan] with worldwide regulatory authorities so that, pending their decision, [sacituzumab govitecan] may become available to many more people around the world who are facing this difficult-to-treat cancer.”

References

1. FDA grants regular approval to sacituzumab govitecan for triple-negative breast cancer. News release. FDA. April 7, 2021. Accessed April 7, 2021. https://bit.ly/3fOWhUD
2. Immunomedics announces ASCENT study to be stopped for compelling efficacy. News release. Immunomedics, Inc. April 6, 2020. Accessed April 7, 2021. https://bit.ly/2Q66hOe
3. FDA approves Trodelvy, the first treatment for metastatic triple-negative breast cancer shown to improve progression-free survival and overall survival. News release. Gilead Sciences, Inc. April 7, 2021. Accessed April 7, 2021. https://bwnews.pr/39RHwfL