BCR-ABL1 STAMP Inhibitor (ABL Myristoyl Pocket Binder) Pregnancy: Based on findings from animal studies and its mechanism of action, asciminib can cause embryo-fetal harm when administered to a pregnant woman; there are no available data in pregnant women. Animal reproduction studies in rats and rabbits showed structural abnormalities, embryo-fetal mortality and alterations to growth. Advise pregnant women and females of reproductive potential of the potential risk to a fetus and to use effective contraception.

Asciminib

Brand names: Scemblix

Asciminib is an oral tyrosine kinase inhibitor used for chronic-phase chronic myeloid leukaemia in patients previously treated with other tyrosine kinase inhibitors.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 80 mg orally once daily, or 40 mg orally twice daily — for newly diagnosed or previously treated Philadelphia chromosome-positive chronic myeloid leukaemia in chronic phase (Ph+ CML-CP)

Route: Oral — swallow tablets whole, do not break, crush or chew. Take without food: avoid food for at least 2 hours before and 1 hour after the dose.

Frequency: Once daily at approximately the same time each day, or twice daily at approximately 12-hour intervals. Continue as long as clinical benefit is observed or until unacceptable toxicity occurs.

SEPARATE REGIMEN — Ph+ CML-CP WITH THE T315I MUTATION: 200 mg orally twice daily at approximately 12-hour intervals, also taken without food (avoid food for at least 2 hours before and 1 hour after). MISSED DOSE: on the once-daily regimen, if a dose is missed by more than approximately 12 hours, skip it and take the next dose as scheduled; on twice-daily regimens, if a dose is missed by more than approximately 6 hours, skip it and take the next dose as scheduled. DOSE REDUCTIONS FOR ADVERSE REACTIONS — first reduction: 40 mg once daily OR 20 mg twice daily (newly diagnosed or previously treated), or 160 mg twice daily (T315I mutation); permanently discontinue in patients unable to tolerate 40 mg once daily or 20 mg twice daily (or 160 mg twice daily for T315I). SPECIFIC MODIFICATIONS: for ANC less than 1 x 10^9/L and/or platelets less than 50 x 10^9/L, withhold until recovery — resume at the starting dose if resolved within 2 weeks, or at a reduced dose if it takes longer; for recurrent severe cytopenia, withhold then resume at a reduced dose. For asymptomatic amylase and/or lipase elevation greater than 2 x ULN, withhold until less than 1.5 x ULN then resume at a reduced dose; permanently discontinue if the event recurs at the reduced dose or does not resolve, and perform diagnostic tests to exclude pancreatitis. For Grade 3 or higher non-haematological adverse reactions, withhold until recovery to Grade 1 or less then resume at a reduced dose, or permanently discontinue if not resolved. PAEDIATRIC: safety and efficacy in paediatric patients have not been established. SOURCE: no UK SPC was fetched in this bundle — this draft is distilled from the US SCEMBLIX prescribing information and must be verified against the UK SPC.

Dose auto-extracted from US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

None stated — the US label section 4 Contraindications reads 'None'

Side effects

Musculoskeletal pain (at least 20%)
Rash (at least 20%)
Fatigue (at least 20%)
Upper respiratory tract infection and headache (at least 20%)
Abdominal pain, arthralgia and diarrhoea (at least 20%)
Laboratory abnormalities (at least 20%) including decreased lymphocyte, leukocyte, platelet and neutrophil counts, increased lipase and amylase, and increased ALT, ALP and AST. Labelled warnings: myelosuppression (thrombocytopenia in 156 of 556 patients, 28%), pancreatic toxicity, hypertension, hypersensitivity and cardiovascular toxicity.

Interactions

Strong CYP3A4 inhibitors — asciminib is a CYP3A4 substrate and concomitant use increases asciminib Cmax and AUC; closely monitor for adverse reactions during concomitant use of asciminib 200 mg twice daily
Itraconazole oral solution containing hydroxypropyl-beta-cyclodextrin — avoid concomitant use at all recommended asciminib doses
Certain CYP3A4 substrates — closely monitor for adverse reactions at an 80 mg total daily dose of asciminib; avoid use with asciminib 200 mg twice daily
CYP2C9 substrates — avoid concomitant use at all recommended doses; if unavoidable, reduce the CYP2C9 substrate dose at the 80 mg total daily dose, and consider a non-CYP2C9 alternative at 200 mg twice daily
Certain P-gp substrates — closely monitor for adverse reactions at all recommended asciminib doses; BCRP substrates — avoid concomitant rosuvastatin at all recommended doses and monitor closely for other BCRP substrates

Clinical monograph

How it works

It inhibits BCR-ABL1 by binding the myristoyl pocket of the ABL1 kinase rather than the ATP-binding site, allosterically locking the kinase in an inactive conformation.

Prescribing in practice

Myelosuppression including thrombocytopenia and neutropenia can occur and may require dose interruption.
Pancreatic enzyme elevations, pancreatitis and rises in blood pressure have been reported and should be monitored.
Its distinct binding site can retain activity against some mutations resistant to conventional tyrosine kinase inhibitors.

Monitoring

Monitor full blood count, pancreatic enzymes and blood pressure during treatment, alongside the haematological and molecular response.

Counselling the patient

Attend regular blood tests to check your blood counts and response.
Report severe abdominal pain, which could indicate pancreatic inflammation.
Take the medicine as directed and avoid food around the time of dosing if instructed.

Evidence & guidelines

Asciminib has a distinct mechanism as a STAMP inhibitor and is supported by trial evidence in previously treated chronic-phase chronic myeloid leukaemia.

Reference: ASCEMBL trial (Réa et al. NEJM 2021); NICE TA805; MHRA SPC Scemblix; CABL001B2201 T315I study (Hughes et al. NEJM 2019); Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways