. 2020 Dec 29;5(1):e516. doi: 10.1097/HS9.0000000000000516

Table 1.

Selected Clinical Studies With JAK Inhibitors in MPN.

JAK Inhibitors	Clinical Trial	Design	Clinical Impact	Main Side Effects
Ruxolitinib	MF: COMFORT-I phase 3^24,27	vs Placebo	Spleen volume reduction Reduction of constitutional symptoms Survival benefit	Anemia, thrombocytopenia
	MF: COMFORT-II phase 3^35,37	vs BAT
	PV: RESPONSE phase 3^25,36	vs BAT	Spleen volume reduction Hematocrit control Reduction of constitutional symptoms
	PV: RESPONSE-2 phase 3³⁸	vs BAT
	ET: MAJIC-ET phase 2²⁶	vs BAT	Nonsignificant benefit (complete hematologic response)
Fedratinib	MF: JAKARTA phase 3³⁹	vs Placebo	Spleen volume reduction	Anemia, gastrointestinal, encephalopathy (black box warning!)
	MF: JAKARTA phase 3³⁹	Rux naive	Spleen volume reduction
	MF: JAKARTA-2 phase 2⁴⁰	vs Placebo	Reduction of constitutional symptoms
	MF: JAKARTA-2 phase 2⁴⁰	Rux refractory	Reduction of constitutional symptoms
Momelotinib	MF: SIMPLIFY-1 phase 3⁴¹	vs Rux	Spleen volume reduction (n.s.) Reduction of constitutional symptoms (n.s.) Decreased transfusion dependence	Peripheral neuropathy, anemia, thrombocytopenia
	MF: SIMPLIFY-1 phase 3⁴¹	Rux naive
	MF: SIMPLIFY-2 phase 2⁴²	vs BAT
	MF: SIMPLIFY-2 phase 2⁴²	Rux refractory
Pacritinib	MF: PERSIST-1 phase 3⁴³	vs BAT	Spleen volume reduction Reduction of constitutional symptoms Decreased transfusion dependence	Anemia, thrombocytopenia, gastrointestinal
Pacritinib	MF: PERSIST-2 phase 3⁴⁴	vs BAT, in thrombocytopenia		Anemia, thrombocytopenia, gastrointestinal

Key studies on JAK2 inhibitors in clinical development are indicated including design, main clinical impact, and most important side effects.

BAT = best available therapy; ET = essential thrombocythemia; JAK = Janus kinase; MF = myelofibrosis; MPNs = myeloproliferative neoplasms; n.s. = non significant; PV = polycythemia vera; Rux = ruxolitinib.