Asciminib — Drug Monograph

Brand names: Scemblix

Drug class: Tyrosine Kinase Inhibitor

Mechanism of Action

STAMP inhibitor (Specifically Targeting the ABL Myristoyl Pocket) — allosteric inhibitor that binds the myristoyl pocket of ABL1, locking the kinase in an inactive conformation. This mechanism is completely orthogonal to ATP-competitive TKIs, allowing activity against all BCR-ABL1 kinase domain mutations including T315I (at the 200 mg BID dose). At 200 mg BID, activity is extended to T315I mutation.

FDA Indications

• Ph+ CML in chronic phase (CML-CP) after ≥2 prior TKIs (FDA approved October 2021; ASCEMBL: superior major molecular response rate vs bosutinib at 12 months)
• Ph+ CML-CP with T315I mutation at 200 mg BID dose

Common Side Effects

• Musculoskeletal pain (28%)
• Fatigue (20%)
• Nausea (17%)
• Rash (14%)
• Thrombocytopenia
• Neutropenia
• Hypertension
• Abdominal pain
• Lipase elevation (pancreatitis risk)

Clinical Pearl

Asciminib is the only approved STAMP inhibitor, targeting the myristoyl pocket rather than the ATP-binding site. This makes it active against all ATP-competitive resistance mutations, including T315I at the 200 mg BID dose. Its pancreatitis risk (lipase elevation ~30%) requires routine monitoring and is thought to relate to off-target SH2 domain effects.

Related Therapies & Mechanisms

• Dasatinib (Sprycel) — Tyrosine Kinase Inhibitor · Leukemia
• Ibrutinib (Imbruvica) — Tyrosine Kinase Inhibitor · Leukemia
• Idelalisib (Zydelig) — Tyrosine Kinase Inhibitor · Leukemia
• Imatinib (Gleevec) — Tyrosine Kinase Inhibitor · Leukemia