# Nemtabrutinib

Source: https://onco.cc/drugs/nemtabrutinib/  
OnCo record `nemtabrutinib` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Nemtabrutinib is Merck's reversible BTK blocker, active against the C481S escape mutation, being tested against ibrutinib and acalabrutinib in first-line CLL.

## Summary

BELLWAVE-001 (phase 1/2): ORR 53% (including partial response with lymphocytosis) at the 65 mg dose in relapsed CLL/SLL. Phase 3 BELLWAVE-011 (vs ibrutinib or acalabrutinib, untreated CLL) and BELLWAVE-008 (vs chemoimmunotherapy) are recruiting. Also inhibits other kinases (ERK pathway), which may add activity in Richter transformation.

## Fields

- Kind: Treatment
- Status: phase-3
- Last checked: 2026-09-07
- Code: MK-1026, ARQ-531
- Modality: Small-molecule non-covalent BTK inhibitor
- Mechanism: Reversible ATP-competitive inhibitor of wild-type and C481S BTK, with off-target activity on ERK-pathway kinases.
- Dosing: Oral; 65 mg once daily (RP2D)
- Toxicity (grade 3+): Neutropenia 17%

## Sources

- ClinicalTrials.gov NCT06136559 (BELLWAVE-011): https://clinicaltrials.gov/study/NCT06136559

## Connected records

- cancers: [Chronic lymphocytic leukaemia](https://onco.cc/cancers/cll/), [Chronic lymphocytic leukaemia, first treatment](https://onco.cc/cancers/cll-treatment-naive/), [Mantle cell lymphoma](https://onco.cc/cancers/mantle-cell-lymphoma/), [Relapsed or refractory chronic lymphocytic leukaemia](https://onco.cc/cancers/cll-relapsed/)
- technologies: [Small-molecule kinase inhibitors](https://onco.cc/technologies/kinase-inhibitors/)
- targets: [BTK (Bruton tyrosine kinase)](https://onco.cc/targets/btk/)
- companies: [Merck & Co. (MSD)](https://onco.cc/companies/merck/)
- trials: [A Study of Nemtabrutinib (MK-1026) in Participants With Relapsed or Refractory Hematologic Malignancies (ARQ 531-101/MK-1026-001)](https://onco.cc/trials/nct03162536/), [A Study of Nemtabrutinib Plus Venetoclax vs Venetoclax + Rituximab (VR) in Second-line (2L) + Relapsed/Refractory (R/R) Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (CLL/SLL) (MK-1026-010/BELLWAVE-010).](https://onco.cc/trials/nct05947851/), [A Study of Nemtabrutinib vs Chemoimmunotherapy for Participants With Previously Untreated Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (CLL/SLL) Without TP53 Aberrations (MK-1026-008, BELLWAVE-008)](https://onco.cc/trials/nct05624554/), [A Study of Zilovertamab Vedotin (MK-2140) as Monotherapy and in Combination in Participants With Aggressive and Indolent B-cell Malignancies (MK-2140-](https://onco.cc/trials/nct05458297/), [BELLWAVE-011](https://onco.cc/trials/bellwave-011/), [Efficacy and Safety of Nemtabrutinib (MK-1026) in Participants With Hematologic Malignancies (MK-1026-003)](https://onco.cc/trials/nct04728893/)

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