Immunomedics Acquisition Transfers Development of Sacituzumab Govitecan to Gilead Sciences

Sara M. Tolaney, MD, MPH

Gilead Sciences’ acquisition of Immunomedics, the manufacturer of sacituzumab govitecan-hziy (Trodelvy), is expected to advance the development of the antibody-drug conjugate (ADC) not only across additional types of breast cancer beyond triple-negative disease, but also in other solid tumors.¹

“The acquirement of Immunomedics will be very meaningful for further development of this agent. With Gilead’s resources, there will be many opportunities to move sacituzumab govitecan into larger studies in earlier disease settings,” said Sara M. Tolaney, MD, MPH, an author on the phase 1/2 IMMU-132-01 trial (NCT01631552) that led to the conditional approval of the ADC,² in an interview with OncLive.

On April 22, 2020, the FDA granted sacituzumab govitecan accelerated approval for use in adults with metastatic triple-negative breast cancer (TNBC) who received at least 2 prior therapies for metastatic disease.² Results of the phase 3 ASCENT trial recently presented at the 2020 ESMO Virtual Congress validated the benefit of the agent in this patient population, demonstrating a 59% reduction in the risk of disease progression or death compared with physician’s choice of single-agent chemotherapy.³

Sacituzumab govitecan is specifically approved for third-line metastatic TNBC, but has shown promise in earlier stages of disease,¹ supporting further study of the Trop-2–directed intervention in more immediate lines of treatment.

“There is so much potential for this agent to be able to move earlier in the metastatic setting and have a bigger role in the early-disease setting, and I think having Gilead develop this agent and move it into these settings is incredible,” said Tolaney, who is also the director of Clinical Trials in Breast Oncology and the associate director of the Susan F. Smith Center for Women’s Cancers at Dana-Farber Cancer Institute.

After closing on Immunomedics, Gilead will initiate several mid- and late-stage studies examining the efficacy of sacituzumab govitecan as a single agent and in combination with other therapies. Gilead has yet to disclose the disease settings in which these investigations will proceed.¹ When initiated, these trials will broaden the portfolio of studies examining the safety of the ADC and its anticancer activity in various malignancies.

Ongoing research efforts include the phase 3 TROPICS-02 study (NCT03901339) of sacituzumab govitecan in third-line hormone receptor–positive, HER2-negative breast cancer and the phase 2 open-label TROPHY U-01 trial (NCT03547973) in metastatic urothelial carcinoma. Final results from the metastatic urothelial cancer cohort of the TROPHY U-01 trial were presented during the 2020 ESMO Virtual Congress and confirmed the clinical activity of sacituzumab govitecan in patients with heavily pretreated disease who progressed on platinum chemotherapy and

immunotherapy. The ADC is also the focus of the phase 3 TROPiCS-04 confirmatory trial (NCT04527991) that is being done in patients with urothelial carcinoma.⁴

Sacituzumab govitecan is also under investigation in non–small cell lung cancer, recurrent glioblastoma, endometrial carcinoma, and metastatic castration-resistant prostate cancer, among other solid tumors. The breadth of trials evaluating the ADC is a testament to Immunomedics’ efforts to advance the agent, according to Tolaney. “I think Immunomedics has done a great job developing sacituzumab govitecan from a first-in-human basket study,” Tolaney said.

The news of the acquisition comes after Immunomedics’ August 5, 2020 announcement that it planned to submit a supplemental biologics application for the full approval of sacituzumab govitecan in metastatic TNBC during the fourth quarter of 2020.⁵

Immunomedics is reportedly also on track to file for regulatory approval of the agent in Europe in the first half of 2021, according to Gilead. Under the acquisition, sacituzumab govitecan will join Gilead’s portfolio of approved and late-stage therapies for hematological malignancies, which currently includes axicabtagene ciloleucel (Yescarta), brexucabtagene autoleucel (Tecartus), and magrolimab.¹

References:

1. Gilead to acquire Immunomedics. News release. Gilead Sciences, Inc. September 13, 2020. Accessed October 8, 2020. https://bit.ly/34GW8eR.
2. FDA grants accelerated approval to sacituzumab govitecan-hziy for metastatic triple negative breast cancer. News release. FDA. April 22, 2020. Accessed October 8, 2020. https://bit.ly/33EFq0i.
3. Bardia A, Tolaney SM, Loirat D, et al. ASCENT: A randomized phase 3 study of sacituzumab govitecan (SG) vs treatment of physician’s choice (TPC) in patients (pts) with previously treated metastatic triple-negative breast cancer (mTNBC). Presented at: 2020 ESMO Virtual Congress; September 19-21, 2020; Virtual. Abstract LBA17.
4. Loriot Y, Balar AV, Petrylak DP, et al. Final results from TROPHY-U-01 cohort 1: a phase 2 open-label study of sacituzumab govitecan (SG) in patients with metastatic urothelial cancer (mUC) and disease progression after platinum (PLT)-based regimens and checkpoint inhibitors (CPI). Presented at 2020 ESMO Virtual Congress; Virtual. Abstract LBA24.
5. Immunomedics reports second quarter 2020 results and provides corporate update. News release. Immunomedics. August 5, 2020. Accessed October 8, 2020. https://bit.ly/3nwuyJK.