The results from the confirmatory Phase 3 ASCENT study have been announced showing that sacituzumab govitecan-hziy extended overall survival (OS) and improved overall response rate (ORR) and clinical benefit rate (CBR), compared to treatment of choice (TPC) standard single-agent chemotherapy in brain metastases-negative patients with mTNBC who had previously received at least two prior therapies for metastatic disease.

These results were presented as a late-breaking abstract at the European Society for Medical Oncology (ESMO) Virtual Congress 2020.

“The randomised Phase 3 study results confirm that sacituzumab govitecan should be considered as a new standard of care in patients with third-line mTNBC,” stated Aditya Bardia, MD, MPH, Director of Precision Medicine at the Center for Breast Cancer, Mass General Cancer Center and Assistant Professor of Medicine at Harvard Medical School, who will give an oral presentation of the study at the ESMO Congress.

“We wish to express our gratitude to the patients and their caregivers for their valuable contribution, as well as the dedicated clinical trial investigators and their devoted team members for making the ASCENT trial possible. Ongoing studies are evaluating sacituzumab govitecan in earlier lines of therapy, including the neoadjuvant and adjuvant settings, in combination with other targeted agents, and in patients with hormone receptor-positive, human epidermal growth factor 2-negative metastatic breast cancer, which will help accelerate our efforts to further improve outcomes for patients with breast cancer.”

Despite having received a median of four prioranticancer regimens, patients treated with sacituzumab govitecan-hziy in the ASCENT study showed a statistically significant and clinically meaningful improvement in OS with a median of 12.1 months (95% confidence interval (CI), 10.7-14.0) versus 6.7 months (95% CI, 5.8-7.7) for chemotherapy, with a hazard ratio of 0.48 (95% CI, 0.38-0.59; p<0.0001).

Sacituzumab govitecan-hziy also demonstrated a statistically significant improvement in ORR (35%) and CBR (45%) compared to chemotherapy (5% and 9%, respectively).

Ten complete responses were observed (4%) in the sacituzumab govitecan-hziy arm compared with two (1%) in the control group.

As of data cutoff on March 11, 2020, 15 patients continued to receive sacituzumab govitecan-hziy treatment while no patient remained on study in the TPC control arm.

“We believe these remarkable results should facilitate the establishment of sacituzumab govitecan-hziy as a new standard of care in patients with third-line mTNBC,” said Dr. Loretta M. Itri, Chief Medical Officer of Immunomedics.

“We are working very collaboratively with FDA under the RTOR program to submit a supplemental Biologics License Application to have sacituzumab govitecan-hziy’s label expanded to include these confirmatory new data. Additionally, we plan to submit a Marketing Authorization Application to the European Medicines Agency in the first half of 2021 in order to make this this important new treatment available to mTNBC patients in Europe.”

Ssacituzumab govitecan-hziy was well tolerated by patients in the ASCENT study, with a manageable safety profile consistent with the U.S. Food and Drug Administration (FDA)-approved label; no new safety signals were observed in the ASCENT study.

Adverse events leading to treatment discontinuation were low and similar (sacituzumab govitecan-hziy 4.7% vs TPC 5.4%) in both arms of the study.

“We are delighted to witness the clinically meaningful survival benefit sacituzumab govitecan-hziy is bringing to mTNBC patients. These outstanding results have inspired us to fully demonstrate the potential of this valuable new treatment to improve the outlook of cancer patients worldwide,” commented Dr. Behzad Aghazadeh, Executive Chairman of Immunomedics. 

Source: ESMO

See related video.