Study summary

Asciminib kept beating older pills as first treatment, with fewer side effects

ASC4FIRST trial, 2-year results · 405 people, phase 3 · Published March 2026, Blood; FDA approved for first-line use October 2024

What was tested

Asciminib, a pill that locks the BCR::ABL1 protein in an inactive shape (a different way of blocking it than older drugs), against the doctor's choice of imatinib or a second-generation pill, for newly diagnosed chronic-phase CML.

What they found

• Major molecular response at 96 weeks was 74.1% vs 52.0% with the other pills, and 76.2% vs 47.1% against imatinib.
• Dose reductions were far less common than with second-generation pills (18.5% vs 54.9%).
• Risk of stopping because of side effects was roughly halved compared with second-generation pills (hazard ratio 0.46).

What it means

Makes asciminib a leading first choice, combining deeper responses with better tolerability.