Study summary

Gene therapy with lighter chemotherapy worked in a first small trial

Gentler gene therapy trial · 7 people, phase 1/2 · Published May 2025, Nature Medicine

What was tested

Lentiviral gene therapy using reduced-intensity conditioning, a milder chemotherapy, to make gene therapy safer and more tolerable.

What they found

• All 7 patients had an 80% or greater reduction in severe pain crises.
• Low blood counts lasted days, not weeks (median 8 days of severe neutropenia).

What it means

A step toward gene therapy without the harshest chemotherapy; still very early.