I haven't read the NEJM article yet - all I know is what is outlined here:
Results - Phase II chronic hepatitis C-associated thrombocytopenia
After four weeks of treatment in chronic HCV patients, once-daily doses of PROMACTA at 30mg, 50mg and 75mg resulted in elevated platelet counts >=100,000/microliter in 75% (9/12), 79% (15/19) and 95% (20/21) of patients respectively compared to no platelet elevations >=100,000/microliter in patients receiving placebo (p<0.001). Treatment with PROMACTA enabled 71% (30mg dose) to 91% (75mg dose) of patients to initiate antiviral therapy. Up to 12 weeks of antiviral therapy were completed by 36% (5/14), 53% (10/19) and 65% (15/23) of patients in the 30mg, 50mg and 75mg PROMACTA groups, respectively, versus 6% in the placebo group.
(EDIT: - I now note that this was in a population with pre-existing thrombocytopenia)