Toripalimab regimen delays progression of PD-L1-positive triple-negative breast cancer
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Key takeaways:
- Patients who received torpialimab in addition to nab-paclitaxel had longer median PFS (8.4 months vs. 5.6 months).
- Incidence of grade 3 or higher adverse events appeared similar between the groups.
CHICAGO — The addition of toripalimab to first-line nab-paclitaxel significantly prolonged PFS among patients with PD-L1-positive metastatic or recurrent triple-negative breast cancer, according to results of a phase 3 trial.
The findings, presented at ASCO Annual Meeting, also showed tolerability of the combination with no new safety signals.
Rationale and methods
“Approximately 46% of patients with triple-negative breast cancer will have distant metastasis, with median survival of only 13.3 months after metastasis,” Qiang Liu, MD, PhD, professor and deputy director in the department of experimental research at Sun Yat-sen Memorial Hospital in China, said during a presentation. “Checkpoint blockade combined with taxane-based chemotherapy produced mixed results as first-line treatment for triple-negative breast cancer. Toripalimab [Junshi Biosciences], a humanized IgG4K monoclonal antibody specific for PD-L1, exhibited promising antitumor activity as a monotherapy in advanced triple-negative breast cancer in the salvage setting.”
The randomized, double-blind TORCHLIGHT trial compared the efficacy and safety of toripalimab plus first-line nab-paclitaxel (Abraxane, Bristol Myers Squibb) vs. placebo and nab-paclitaxel among 531 patients with metastatic or recurrent inoperable triple-negative breast cancer.
Researchers assigned patients 2:1 to 240 mg toripalimab on day 1 of a 3-week cycle (n = 353; 200 with PD-L1-positive disease) or placebo (n = 178; 100 with PD-L1-positive disease), each with 125 mg/m² nab-paclitaxel on days 1 and 8 for 3-week cycles.
PFS assessed by blinded independent central review per RECIST v1.1 in the PD-L1-positive population and the intention-to-treat population served as the primary endpoint. Secondary endpoints included OS in the PD-L1-positive population and the intention-to-treat population, ORR and safety. Treatment continued until disease progression or intolerable toxicity.
During ASCO, Liu presented results of a prespecified interim analysis of PFS.
Median follow-up was 14 months.
Findings, next steps
Results of the interim analysis showed a significant improvement in PFS among patients with PD-L1-positive disease assigned toripalimab vs. placebo (median PFS, 8.4 months vs. 5.6 months; HR = 0.65; 95% CI, 0.47-0.91). Researchers observed a similar trend in the intention-to-treat population (median PFS, 8.4 months vs. 6.9 months; HR = 0.77; 95% CI, 0.6-0.99).
Results of descriptive analysis of OS showed improvement among patients with PD-L1-positive disease (median, 32.8 months vs. 19.5 months; HR = 0.62; 95% CI, 0.41-0.91), as well as in the intention-to-treat population (median, 33.1 months vs. 23.5 months; HR = 0.69; 95% CI, 0.51-0.93).
Researchers additionally observed significant improvements in OS with torpalimab among 170 patients with a PD-L1 combined positive score (CPS) of 1 or higher (median OS, 32.8 months vs. 19.5 months; HR = 0.67; 95% CI, 0.4-1.13), and 130 patients with a PD-L1 CPS of 10 or higher (median OS, not reached vs. 18.3 months; HR = 0.55; 95% CI, 0.3-0.98).
Incidence of grade 3 or higher adverse events appeared similar between the groups (56.4% with toripalimab vs. 54.3% with placebo). However, treatment discontinuation (8.5% vs. 3.4%) and immune-associated adverse events (40.8% vs. 24%) appeared more common with toripalimab.
PFS in the intention-to-treat population and OS among the PD-L1-positive and intention-to-treat populations will be statistically tested in hierarchy in the forthcoming final analysis, Liu said.
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Jiang ZF, et al. Abstract LBA1013. Presented at: ASCO Annual Meeting; June 2-6, 2023; Chicago.
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