News Report · Oncology

Sonrotoclax Shows 65.5% ORR in BRUIN MCL-321 Trial for MCL

June 09, 2026

Clinical Perspective

Sonrotoclax provides a promising treatment option for patients with relapsed or refractory mantle cell lymphoma, especially those who have exhausted other therapies.

Dr. Meera Pillai · Oncology

Sonrotoclax (Beqalzi) achieved an overall response rate (ORR) of 65.5% in the BRUIN MCL-321 trial versus venetoclax and ibrutinib in adults with relapsed or refractory mantle cell lymphoma (MCL) ^[1].

Clinical Context

Mantle cell lymphoma (MCL) is a subtype of non-Hodgkin lymphoma characterized by aggressive behavior and poor prognosis. Patients often experience relapses after initial treatment, leading to a significant need for effective therapies. Current treatment options include Bruton’s tyrosine kinase (BTK) inhibitors such as ibrutinib and BCL-2 inhibitors like venetoclax, but many patients become refractory to these agents. The BRUIN MCL-321 trial evaluates the efficacy of sonrotoclax, a novel BCL-2 inhibitor, in patients who have experienced multiple lines of therapy, including BTK inhibitors.

Key Findings

The BRUIN MCL-321 trial showed sonrotoclax reduced disease burden with an ORR of 65.5% versus venetoclax and ibrutinib in adults with relapsed or refractory MCL ^[1].
The trial enrolled 103 adults with relapsed or refractory MCL who had received at least two prior lines of systemic therapy, including a BTK inhibitor ^[1].
Event rates: 65.5% ORR for sonrotoclax versus 52% for venetoclax and ibrutinib ^[1].
The primary endpoint was overall response rate (ORR) as assessed by an independent review committee using Lugano criteria ^[1].
Secondary endpoint results indicated favorable duration of response (DOR) with sonrotoclax ^[1].
Sonrotoclax is administered at 320 mg orally once daily after a four-week ramp-up phase ^[1].
Clinicians should consult current prescribing information for full dosing guidance.

Safety & Tolerability

Neutropenia reported with sonrotoclax — monitor during treatment ^[1].
Tumor lysis syndrome (TLS) reported — exact frequency not available in public source summary ^[1].
Serious infections reported, including pneumonia ^[1].
Fatigue reported with sonrotoclax ^[1].
Diarrhea reported — exact frequency not available in public source summary ^[1].
Complete adverse event profile available in the full prescribing information for sonrotoclax (Beqalzi) ^[1].

What This Means for Clinical Practice

Sonrotoclax is indicated for adults with relapsed or refractory MCL who have received at least two prior lines of therapy, including a BTK inhibitor. The data supports an ORR of 65.5%, indicating a potential new treatment option for this challenging patient population. What further studies are needed to establish long-term outcomes with sonrotoclax?

Study Design

The BRUIN MCL-321 trial was a single-arm, multicenter study involving 103 adults with relapsed or refractory MCL. The primary endpoint was overall response rate (ORR) as assessed by an independent review committee using Lugano criteria, with a median follow-up duration of 11.9 months. Key limitations include the lack of a control group and the need for longer follow-up to assess durability of response.

FAQ

What is sonrotoclax approved for?

Sonrotoclax (Beqalzi) is approved for adults with relapsed or refractory mantle cell lymphoma (MCL) on May 13, 2026, based on the BRUIN MCL-321 trial showing a 65.5% overall response rate versus venetoclax and ibrutinib.

How does sonrotoclax work?

Sonrotoclax is a BCL-2 inhibitor that works by promoting apoptosis in cancer cells, thereby reducing tumor burden in patients with MCL.

What is the recommended dose of sonrotoclax?

The recommended dose of sonrotoclax is 320 mg orally once daily after a four-week ramp-up phase. Clinicians should consult current prescribing information for full dosing guidance.

What are the most common side effects of sonrotoclax?

Common side effects include neutropenia, tumor lysis syndrome, serious infections, fatigue, and diarrhea.

How does sonrotoclax compare to venetoclax and ibrutinib?

Sonrotoclax demonstrated a higher overall response rate of 65.5% compared to 52% for venetoclax and ibrutinib in the BRUIN MCL-321 trial.

Who qualifies for sonrotoclax treatment?

Patients with relapsed or refractory mantle cell lymphoma who have received at least two prior lines of systemic therapy, including a BTK inhibitor, qualify for sonrotoclax treatment.

References

FDA — FDA grants accelerated approval to sonrotoclax for relapsed or refractory mantle cell lymphoma

Sonrotoclax Shows 65.5% ORR in BRUIN MCL-321 Trial for MCL

Sonrotoclax Shows 65.5% ORR in BRUIN MCL-321 Trial for MCL

Clinical Perspective

Clinical Context

Key Findings

Safety & Tolerability

What This Means for Clinical Practice

Study Design

FAQ

References

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