Sacituzumab govitecan confers survival benefit in Asian patients with mBC

Sacituzumab govitecan improved progression-free survival (PFS) and overall survival (OS) in Asian patients with HR+/HER2– metastatic breast cancer (mBC) compared with the treatment of physician’s choice (TPC*), according to the EVER-132-002 study presented at ESMO Asia 2023.

The trial met its primary endpoint, demonstrating a statistically significant improvement in BICR**-assessed PFS with sacituzumab govitecan vs TPC in the HR+/HER2– patient cohort, said Dr Shusen Wang from the Department of Medical Oncology at Sun Yat-sen University Cancer Center, Guangzhou, China.

“Based on the results of the global phase III TROPiCS-02 study that enrolled predominantly non-Asian patients, sacituzumab govitecan is now approved for pretreated HR+/HER2– mBC in the US and Europe,” he noted.

In the open-label, multicentre, phase III EVER-132-002 trial, Wang and colleagues assessed the efficacy and safety of sacituzumab govitecan in Asian patients (n=331; median age 52 years) with endocrine-resistant, pretreated HR+/HER2– mBC who have received 2–4 prior lines of chemotherapy. Participants were randomly assigned to receive either intravenous sacituzumab govitecan (10 mg/kg on days 1 and 8 of every 21-day cycle; n=166) or TPC (n=165).

At a median follow-up of 13.4 months, there was a 33-percent reduction in the risk of disease progression or death with sacituzumab govitecan vs TPC (hazard ratio [HR], 0.67; p=0.0028). [ESMO Asia 2023, abstract LBA4]

In addition, PFS rates were higher in the sacituzumab govitecan vs the TPC arm at 6 months (41.4 percent vs 24.2 percent), 9 months (26.2 percent vs 12.9 percent), and 12 months (17.2 percent vs 9.2 percent). “Nearly twice as many [sacituzumab govitecan-treated] patients were alive and progression-free at all landmark time points,” said Wang.

PFS per investigator (INV) assessment were generally consistent with the BICR-assessed PFS, Wang added.

Key secondary endpoints

Sacituzumab govitecan recipients achieved a clinically meaningful improvement in OS compared with those on TPC (median 21 vs 15.3 months; HR, 0.64; p=0.0061), translating to a 36-percent reduction in the risk of death.

OS rates were higher in the sacituzumab govitecan vs TPC arm, both at 12 months (76 percent vs 62.1 percent) and 18 months (58.6 percent vs 43.9 percent).

Objective response rates were numerically higher with sacituzumab govitecan than with TPC in both BICR (20 percent vs 15 percent) and INV assessments (19 percent vs 16 percent), as were clinical benefit rates (38 percent vs 22 percent [BICR] and 46 percent vs 29 percent [INV]).

The median duration of response was similar between the sacituzumab govitecan and TPC groups as per BICR assessment (5.3 vs 5.2 months) but longer with the former vs the latter in the INV assessment (8.2 vs 4.2 months).

Safety endpoints

There were more grade ≥3 treatment-emergent adverse events (TEAEs) in the sacituzumab govitecan arm vs TPC arm (82 percent vs 70 percent) but fewer TEAEs leading to treatment discontinuation (3 percent vs 4 percent).

The most common TEAEs reported with sacituzumab govitecan were neutropenia (88 percent), anaemia (71 percent), and leukopenia (68 percent). The corresponding rates in the TPC group were 78, 55, and 63 percent, respectively.

“The safety profile of sacituzumab govitecan was manageable and consistent with prior global studies; no new safety signals were identified,” said Wang.

New treatment option

“The statistically significant and clinically meaningful benefit of sacituzumab govitecan vs TPC in the EVER-132-002 study is consistent with the global TROPiCS-02 study,” said Wang.

Therefore, the current findings “support the use of sacituzumab govitecan as a new treatment option for Asian patients with endocrine-resistant, pretreated hormone HR+/HER2– mBC,” he added.