FDA Approves Next-Gen BCL2 Inhibitor Sonrotoclax for R/R Mantle Cell Lymphoma

The FDA has approved sonrotoclax (Beqalzi; formerly BGB-11417), a next-generation B-cell lymphoma 2 (BCL2) inhibitor, for the treatment of patients with relapsed or refractory (R/R) mantle cell lymphoma (MCL), following treatment with a Bruton tyrosine kinase (BTK) inhibitor.¹

In November 2025, the FDA accepted and granted priority review to a new drug application (NDA) for sonrotoclax.² The NDA was supported by data from the global, multicenter, single-arm, open-label phase 1/2 trial (NCT05471843).³

The study had a total enrollment of 125 patients with R/R MCL. Sonrotoclax achieved its primary end point of overall response rate (ORR) and showed promising results across secondary efficacy end points including complete response (CR), duration of response, and progression-free survival. Sonrotoclax had a tolerable safety profile.

At a median follow-up of 14.2 months, the ORR among patients treated in part 2 of the study at the recommended phase 2 dose of 320 mg once daily (n = 103) was 52.4% (95% CI, 42.4%-62.4%; 1-sided P <.0001). The CR rate was 15.5% (95% CI, 9.1%-24.0%), and the median time to response was 1.9 months (range, 1.6-6.2 months).

The full results were presented at the 67th American Society of Hematology (ASH) Annual Meeting and Exposition in December 2025.

Mechanism of Action

Sonrotoclax is a highly selective, small-molecule inhibitor of the BCL2 anti-apoptotic protein. In B-cell malignancies—including MCL—overexpression of BCL2 facilitates survival and chemotherapy resistance by sequestering pro-apoptotic proteins. Sonrotoclax disrupts this sequestration, lowering the threshold for mitochondrial outer membrane permeabilization and restoring the intrinsic apoptotic pathway.

Pharmacokinetic and Pharmacodynamic Profile

Preclinical and early-phase data suggest a "best-in-class" profile characterized by high binding potency and favorable pharmacokinetic (PK) parameters:

• Rapid clearance: A short terminal half-life prevents significant drug accumulation.
• Safety implications: These PK advantages may improve the manageability of on-target toxicities, such as tumor lysis syndrome (TLS), and allow for more precise dosing titration compared with first-generation inhibitors.

Clinical Development and Combination Strategies

The global development program for sonrotoclax currently exceeds 2,200 enrolled patients across the spectrum of hematologic malignancies, evaluating the agent as both monotherapy and in rational combinations.

Current investigations emphasize the synergy between BCL2 and BTK inhibition. In treatment-naive chronic lymphocytic leukemia (CLL), the combination of sonrotoclax plus zanubrutinib (Brukinsa) demonstrated rapid, deep molecular responses, achieved high rates of undetectable minimal residual disease, and thereby supports the agent's potential as a backbone for fixed-duration, chemotherapy-free frontline regimens.

Beyond CLL and R/R MCL, ongoing trials are exploring the efficacy of sonrotoclax across diverse B-cell histologies, positioning it as a potentially more potent and manageable alternative to venetoclax (Venclexta).

REFERENCES

1. FDA grants accelerated approval to sonrotoclax for relapsed or refractory mantle cell lymphoma. News release. US FDA. May 13, 2026. Accessed May 13, 2026. https://tinyurl.com/bdcrcrtb

2.U.S. FDA grants priority review to sonrotoclax for the treatment of relapsed or refractory mantel cell lymphoma. News release. BeOne Medicines. Published November 26, 2025. Accessed January 26, 2026. https://tinyurl.com/46x9sa73

3.Study of BGB-11417 monotherapy in participants with relapsed or refractory mantle cell lymphoma. ClinicalTrials.gov. Updated September 9, 2025. Accessed January 26, 2026. https://clinicaltrials.gov/study/NCT05471843