Where essential thrombocythemia treatment is heading

Essential thrombocythemia (ET) is a slow-growing blood cancer in which the bone marrow makes too many platelets, raising the risk of clots and sometimes bleeding; several thousand Americans are diagnosed each year, and most live a normal lifespan. It is driven by JAK2, CALR or MPL gene changes. Treatment is aspirin and, for higher-risk people, hydroxyurea, anagrelide or interferon. New drugs aim to change the disease itself, including the first antibody that targets mutant CALR.

• 56studies open or running
• 9phase 3 trials
• 217papers published this year
• 16NIH-funded projects

1. Now

   Nov 2026

   An LSD1 pill controls plateletsHappened 77% platelet response

   Bomedemstat controlled platelets in 77% at 24 weeks and lowered mutation levels in 85%.

   77%: platelet response at 24 weeks.

   • Bomedemstat phase 2 study

   Interferon works across mutation typesHappened 60.2% durable response

   Ropeginterferon gave durable responses in 60.2% of North American patients.

   60.2%: durable blood-count response.

   • EXCEED-ET trial (ropeginterferon)

   Targeting the mutation itselfHappened

   In mice, CAR T cells against mutant CALR eliminated disease-starting stem cells while sparing normal ones.

   • Mutant-CALR CAR T-cell study (laboratory)

2. 6 months

   by May 2027

   Interferon for ET in the USPossible 60.2% durable response

   PharmaEssentia sought an added FDA indication for ropeginterferon in ET in 2026.

   60.2%: durable blood-count response.

   • EXCEED-ET trial (ropeginterferon)

3. 12 months

   by Nov 2027

   Bomedemstat phase 3 resultsPossible

   Merck's trials against best available therapy (340 people, due July 2027) and hydroxyurea (300 people, due September 2027).

   • Bomedemstat phase 2 study
   • Bomedemstat vs BAT
   • Bomedemstat vs hydroxyurea

   Blood thinners vs aspirinPossible

   AVAJAK (1,308 people) tests whether apixaban or rivaroxaban prevents clots better than aspirin; due July 2027.

   • AVAJAK

4. 3 years

   by late 2029

   The first mutant-CALR antibody in phase 3Possible

   Incyte's EXCALIBUR-ET2 (426 people) tests INCA033989 against best available therapy; due June 2029.

   • Mutant-CALR CAR T-cell study (laboratory)
   • EXCALIBUR-ET2

5. 5 years

   by late 2031

   Toward a cure for CALR-mutant diseaseLong shot

   If antibodies and CAR T cells against mutant CALR clear the disease-starting cells, a transplant-free cure may become possible.

   • Mutant-CALR CAR T-cell study (laboratory)

The research paths

Borrowed from other conditions

Open to join now

• CALR-mutant ET

  INCA033989 (mutant-CALR antibody)

  Phase 3 · 196 sites

  Locations and eligibility →

• ET

  Bomedemstat

  Phase 3 · 21 sites

  Locations and eligibility →

• JAK2-positive MPN

  Blood thinners vs aspirin

  Phase 3 · 42 sites

  Locations and eligibility →

• ET

  JBI-802

  Phase 1/2 · 7 sites

  Locations and eligibility →

See every recruiting ET trial →

When the trials finish

Completion dates the trials registered. Results usually follow 3 to 12 months later.

What just happened

Standard treatment today

• Very low or low riskAspirin or observation.
• High risk (age over 60 or past clot)Hydroxyurea or interferon, plus aspirin.
• Not responding or intolerantAnagrelide, interferon, or a clinical trial (bomedemstat, CALR antibodies).
• Progression to myelofibrosisTreated as myelofibrosis.

See ET trials recruiting now →