Table 2.

Comparison of characteristics of romiplostim and eltrombopag

	Romiplostim	Eltrombopag
Route of administration	Once weekly subcutaneous injection	Once daily oral
Starting dose	1 μg/kg/week	50–75 mg/day
Efficacy	Platelet count increases seen at 5 days; peak at day12–15	Platelet count increases seen at 7 days; peak at day 15
Response rates:
Phase II	79%	70% 50 mg
		81% 75 mg
Phase III	79% Splenectomized	66%* 50–75 mg**
	88% Nonsplenectomized
Extension studies	87% Transient response	79% transient response
Duration of platelet response after treatment discontinuation	Platelets return to baseline within 2 weeks	Platelets return to baseline within 2 weeks
Effect of previous splenectomy on durable platelet response	Slightly more effective if nonsplenectomized (51% vs 31%)	No difference
Common reported adverse events	Headache, contusion, fatigue, expistaxis, arthralgia	Headache, contusion, nausea, nasopharyngitis
Other adverse events	Transient bone marrow reticulin deposition	Elevated liver enzymes, possible bone marrow reticulin deposition
Presence of cross-reactive antibodies	No	No

Notes:

^*59% response with 50 mg and additional 29% response when dose increased to 75 mg.

^**No statistical difference between splenectomized and nonsplenectomized patients. Characteristics of romiplostim and eltrombopag derived from clinical trials.⁵⁰,⁵¹,⁶⁶,⁶⁷