Report: Promacta safe and effective in repeated short term use for ITP
Repeated short-term use of eltrombopag in patients with chronic immune thrombocytopenia (ITP).
Bussel JB, Saleh MN, Vasey SY, Mayer B, Arning M, Stone NL.
Weill Medical College of Cornell University, New York, NY, USA.
Eltrombopag is a thrombopoietin-receptor agonist that stimulates platelet production and increases platelet counts in patients with chronic immune thrombocytopenia (ITP). This open-label, single-arm study evaluated consistency of response and safety following repeated intermittent dosing of eltrombopag 50 mg daily over 3 cycles (1 cycle = up to 6 weeks on therapy followed by up to 4 weeks off therapy). The primary endpoint was proportion of patients with a response (platelet count ≥50 × 10(9) /l and ≥2× baseline) in Cycle 1 who subsequently responded in Cycle 2 or 3. Fifty-two of 65 evaluable patients (80%) responded in Cycle 1; these responding patients comprised the primary analysis population. Of these, 45/52 (87%) responded in Cycle 2 or 3 [95% confidence interval (CI), 74-94%] and 34/48 (71%; 95% CI, 56-83%) responded in both Cycles 2 and 3. Time to response was consistent, with 50% of responders responding by Day 8 in each cycle. Bleeding rates relative to baseline decreased by approximately 50% during each treatment cycle. The frequency or severity of adverse events, most commonly headache, did not increase over successive cycles. If a chronic ITP patient not requiring consistent therapy responds to short-term eltrombopag, then subsequent courses of eltrombopag, as needed, are likely to be safe and effective.