Therapeutic Plasma Exchange (TPE) for Thrombotic Thrombocytopenic Purpura (TTP) Using Plasma Prepared with Photochemical Treatment (INTERCEPT Plasma).

INTERCEPT Plasma (I-FFP) uses amotosalen (S-59, 150μM ) and UVA light (3 J/cm² to inactivate pathogens in single plasma units. TPE is the mainstay therapy for TTP. Efficacy and safety of I-FFP for TPE of TTP were evaluated in a double-blinded, randomized, controlled trial. Eligible patients (pts) with TTP unrelated to cancer, cancer therapy, transplantation, AIDS, HUS, or SLE received daily TPE (1.0 to 1.5 blood volumes) with either I-FFP or conventional plasma (C-FFP) for up to 2 TPE cycles, each with a maximum of 35 days (d) of TPE. Treated pts were followed for 7 d after the last TPE to detect overall adverse events (AE) and for 60 d after achieving remission to detect relapse and serious adverse events (SAE). The primary endpoint was the proportion of pts in remission (platelet count ≥ 150,000/μL for 2 consecutive d without neurologic progression) within 30 d after the 1st TPE. Secondary endpoints were: time to 1st remission, volume of plasma used, number of TPEs, relapse rates after remission, vWF cleaving protease (vWF-CP) activity and inhibitor levels, antibodies to potential S-59 neoantigens, and safety. 35 pts (17 I-FFP, 18 C-FFP), mean age of 40 yr, 80% female were treated. TPE with I-FFP was comparable to C-FFP in remission rates (82% I-FFP, 89% C-FFP:p=0.66), median time to remission (6 d I-FFP, 6 d C-FFP:p=0.58), mean total volume of plasma exchanged (40.6 L I-FFP, 41.3 L C-FFP:p=0.86), mean number TPEs (11.3 I-FFP, 10.3 C-FFP:p=0.68), and relapse rates (36% I-FFP, 38% C-FFP:p=1.00). Baseline and post TPE vWF-CP activity and inhibitor levels were similar between groups. Overall AEs, serious AEs, deaths (1 I-FFP and 1 C-FFP: neither attributed to TPE), rates of discontinuation from study, laboratory abnormalities, and vital signs (VS) during TPE were comparable between groups. 1 C-FFP pt had TRALI. Five I-FFP pts had AEs coded to the cardiac system organ class compared to no C-FFP pts (p=0.02). In 4 of the I-FFP pts, these AEs were non-serious and did not interrupt TPE. One I-FFP pt with relapsing TTP had a serious AE after 12d of TPE, recovered without sequelae, was withdrawn from study, and continued on non-study FFP TPE with recurrent relapse. No antibodies to potential S-59 neoantigens were detected in any pts. In this trial, efficacy endpoints and safety profiles of TTP pts treated with I-FFP TPE were similar to those for TTP pts treated with C-FFP TPE.