Study summary

An LSD1-blocking pill controlled platelets and lowered mutation levels in most patients

Bomedemstat phase 2 study · 73 people, phase 2 · Published May 2026, Blood Advances

What was tested

Bomedemstat, a once-daily pill that blocks the LSD1 enzyme needed by the cells that make platelets, for essential thrombocythemia not controlled by, or intolerant of, standard drugs.

What they found

• 77% had platelets controlled at 24 weeks; 72% had durable control.
• Driver-mutation levels (JAK2, CALR or MPL) fell in 85% of evaluable people.
• Bleeding events occurred in 21%; 15% stopped because of side effects.

What it means

Signs of disease modification, not just platelet control; now in phase 3 against hydroxyurea and other drugs.