medwireNews: Sacituzumab govitecan offers a significant progression-free survival (PFS) benefit over standard treatment in patients with endocrine-resistant, hormone receptor-positive, HER2-negative (HR+, HER2–) advanced breast cancer, according to phase 3 trial data.
The risk for progression or death was a significant 34% lower with the anti-Trop-2 antibody–drug conjugate than physician’s choice of single-agent chemotherapy in this heavily pretreated population, presenter Hope Rugo, from the University of California San Francisco in the USA, told the audience at the 2022 ASCO Annual Meeting in Chicago, Illinois, USA.
Commenting on the findings in a press release, ASCO Expert Jane Lowe Meisel, from the Winship Cancer Institute of Emory University in Atlanta, Georgia, USA, said “[t]his trial shows that sacituzumab govitecan, which is already approved for the treatment of metastatic triple-negative breast cancer, may represent an important new option” for this patient population.
“This would address a critical unmet medical need, given the limited number of effective treatment options currently available for these patients,” she added.
TROPiCS-02 included 543 patients who had received two to four chemotherapy regimens (median, three) for unresectable locally advanced or metastatic disease, and at least one endocrine therapy, taxane, and CDK4/6 inhibitor in any setting.
After a median follow-up of 10.2 months, the independently assessed median PFS was 5.5 months for the 272 participants who were randomly assigned to receive sacituzumab govitecan 10 mg/kg on days 1 and 8 of each 21-day cycle. This was significantly longer than the median duration of 4.0 months for their 271 counterparts who instead received physician’s choice of capecitabine, vinorelbine, gemcitabine, or eribulin.
And in landmark analyses, a higher proportion of sacituzumab govitecan- than chemotherapy-treated patients were alive and progression-free at all timepoints. Specifically, the PFS rates were 46.1% versus 30.3% at 6 months, 32.5% versus 17.3% at 9 months, and 21.3% versus 7.1% at 12 months.
Rugo also presented the first interim analysis for overall survival (OS), which showed a numeric, but not statistically significant, improvement in favor of sacituzumab govitecan, at a median of 13.9 months compared with 12.3 months for chemotherapy.
However, the “results are not yet mature, and further follow-up for OS is ongoing,” she noted.
Moving onto the safety data, Rugo said that the toxicity profile of sacituzumab govitecan “was consistent with that observed in previous studies,” and “no new safety concerns were identified.”
The incidence of treatment-emergent adverse events (TEAEs) of at least grade 3 was higher in the sacituzumab govitecan than chemotherapy group, at 74% versus 60%, but the rate of discontinuation due to TEAEs was low in both arms, at 6% and 4%.
There were six deaths as a result of TEAEs among sacituzumab govitecan-treated patients and none among those given chemotherapy, but Rugo pointed out that just one – septic shock due to neutropenic colitis – was considered related to study treatment by the investigator.
Session discussant Véronique Dieras (Centre Eugène Marquis, Rennes, France) said that TROPiCS-02 is a “well-designed” trial that addresses a medical need in a heavily pretreated population with a high burden of disease.
However, she questioned how clinically meaningful the magnitude of benefit was given the between-group difference in median PFS of just 1.5 months, and said that additional data, including further follow-up of OS, are needed before considering sacituzumab govitecan as an option for this population.
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