Sonrotoclax (BEQALZI) is a next-generation, highly selective B-cell lymphoma 2 (BCL2) inhibitor developed and commercialized by BeOne Medicines (formerly BeiGene) for the treatment of B-cell malignancies. As a potent BH3 mimetic, sonrotoclax is designed to induce apoptosis in malignant B cells by selectively inhibiting the anti-apoptotic BCL2 protein. Compared with the first-generation BCL2 inhibitor venetoclax, sonrotoclax has been engineered to deliver greater potency and selectivity, with the potential for improved tolerability and a more favorable pharmacokinetic profile. The drug achieved its first global regulatory approval in China in early 2026 for adults with relapsed/refractory mantle cell lymphoma (MCL) and relapsed/refractory CLL/SLL previously treated with systemic therapy, including a Bruton tyrosine kinase (BTK) inhibitor. Supported by a strong intellectual property portfolio extending to 2039 across the United States, Europe, Japan, and China, sonrotoclax is positioned as a foundational therapy within BeOne’s hematology franchise. The agent is being evaluated across multiple B-cell malignancies, both as monotherapy and in combination regimens, particularly with the BTK inhibitor zanubrutinib, to achieve deep, durable, and treatment-free remissions.

In May 2026, the drug received an accelerated approval by the US FDA for relapsed/refractory MCL after at least two prior lines of therapy, including a BTK inhibitor.

At EHA 2026, BeOne Medicines presented updated results from the frontline CLL/SLL study evaluating fixed-duration sonrotoclax plus zanubrutinib. 

Key Efficacy Highlights:

• ORR was 100%, with 55% achieving CR. Median time to response was 2.6 months

• CR rates were 51.0% in the 160-mg cohort and 59.5% in the 320-mg RP2D cohort, yielding an overall CR rate of 56.3%

• In the 320-mg cohort, blood undetectable minimal residual disease at a sensitivity of 10⁻⁴ (uMRD4) rates improved over time, reaching 81.2% at week 24, 91.8% at week 48, and 98.2% at week 96; the best uMRD5 rate was 87.3%

• No patients converted from uMRD4 to detectable MRD at the data cutoff

• High uMRD4 rates at week 96 were maintained across high-risk subgroups, including IGHV-mutated (91.7%) vs IGHV-unmutated (96.8%) and TP53-mutated/del(17p) (92.9%) vs TP53 wild-type (97.7%) patients 

• Median time to uMRD4 in the 320-mg cohort was rapid and comparable, irrespective of IGHV status (4.5 months for IGHV-mutated vs 5.2 months for IGHV-unmutated patients)

• No disease progression was observed in the 320-mg RP2D cohort, resulting in a 24-month PFS rate of 100%; one progression event (Richter transformation) occurred in the 160-mg cohort

• Among 69 patients who electively discontinued sonrotoclax, the median time off treatment was 9.2 months, with no progression events reported in the 320-mg cohort during treatment-free follow-up

Key Safety Highlights:

• Most treatment-emergent adverse events (TEAEs) were grade 1–2 and transient

• TEAEs were reported in 99.3% of patients; Grade ≥3 TEAEs occurred in 63.5% of patients; serious TEAEs in 34.3%

• Most common TEAEs: neutropenia (38%), contusion (38%), COVID-19 (33%), and upper respiratory tract infection (30%)

• In the 320-mg cohort, neutropenia occurred in 39% of patients, including 31% grade ≥3 events

• No tumor lysis syndrome (TLS) events were reported

• No treatment-emergent adverse events led to death

• Only 3.6% of patients discontinued sonrotoclax due to TEAEs

KOL insights

“The depths and kinetics of undetectable MRD achieved with sonrotoclax plus zanubrutinib highlight the improved potency and differentiated profile of this combination vs available combination therapies in first-line CLL.”– Expert Opinion

“Early clinical data suggest sonrotoclax may provide a more potent BCL2 inhibition strategy with encouraging responses and no significant tumor lysis syndrome observed to date; however, longer follow-up and comparative studies with venetoclax are needed to define its efficacy–safety balance, particularly regarding class-related toxicities.”– Expert Opinion

Conclusion 

CLL/SLL is a slow-growing but ultimately incurable B-cell malignancy, with disease driven by abnormal proliferation and survival of clonal B lymphocytes that accumulate in blood, bone marrow, and lymphoid tissues. In the UK, approximately 4,700 new cases are diagnosed annually. Despite substantial advances with targeted therapies, there remains a need for fixed-duration treatment approaches capable of achieving deeper remissions, minimizing long-term toxicity, and enabling treatment-free intervals. Sonrotoclax represents an important evolution of the BCL2 inhibitor class, offering enhanced potency, selectivity, and the potential for improved tolerability compared with earlier-generation agents. In an increasingly competitive landscape that includes lisaftoclax and mesutoclax, sonrotoclax has emerged as the first next-generation BCL2 inhibitor to achieve regulatory approval, supported by compelling clinical activity across multiple B-cell malignancies. Sonrotoclax plus zanubrutinib delivered deep MRD-negative remissions and durable disease control, including in high-risk CLL/SLL populations. These results reinforce its potential to become a best-in-class BCL2 inhibitor and a cornerstone of fixed-duration therapy.