Study of Mirasol®-Based Pathogen Reduction in Platelets Fails to Meet Primary Endpoint

A study evaluating a Mirasol®-based pathogen-reduction strategy for platelets did not meet its primary end point and was terminated early.

In a recent study, treatment of platelet products using the Mirasol® Pathogen Reduction Technology System did not demonstrate noninferiority over the control method based on the study’s primary endpoint. Study results were presented at the 2022 Association for the Advancement of Blood and Biotherapies (AABB) Virtual Annual Meeting by Scott A. Koepsell, MD, PhD, of the University of Nebraska Medical Center in Omaha, Nebraska, and colleagues.

Platelet products may be treated to reduce the occurrence of potentially infectious pathogens. However, it has been unclear whether clinical efficacy of platelet products is reduced by this approach. Mirasol is intended to reduce the load of pathogens in a platelet sample through the use of ultraviolet light and riboflavin.

The prospective, multicenter, noninferiority MIPLATE study included patients who had a hematologic malignancy with hypoproliferative thrombocytopenia, with expected platelet counts of 10,000/mL or below and 2 or more platelet transfusions. Patients were given either Mirasol-treated platelets (Mirasol arm) or platelets prepared through conventional apheresis (control arm).

The primary end point of the study was the number of days with grade 2 or higher bleeding, as defined by the World Health Organization, within the first 28 days after a first platelet transfusion, or transfusion dependence (10 days without a platelet transfusion). Several secondary and safety-related endpoints were also evaluated.

The study had a planned enrollment of 620 patients, and Dr Koepsell and colleagues presented results for the 330 enrolled patients. The trial had terminated early based on futility following its planned interim analysis. The modified intent-to-treat population included 145 patients in the Mirasol arm and 152 patients in the control arm.

Among these patients, those in the Mirasol arm had a mean age of 55.1 years (SD, 16.26), and the control arm had a mean age of 54.3 years (SD, 17.65). The most common primary diagnoses were leukemia, lymphoma, and plasma cell dyscrasias in both groups.

In the modified intent-to-treat population, the Mirasol arm had a mean of 4.3 days (SD, 5.38) with grade ≥2 bleeding, compared with 2.1 days (SD, 2.15) for the control arm. The relative rate of days of grade ≥2 bleeding for those in the Mirasol arm was 2.79 (95% CI, 1.67-4.67), compared with the control arm, and the primary study end point was not met.

The rate of grade ≥2 bleeding among patients in the Mirasol arm was 40.0%, compared with 30.3% in the control arm (P =.08). Primary bleeding sites were in genitourinary and pulmonary areas. Patients in the Mirasol arm had a mean number of platelet transfusions per patient of 6.23, compared with 4.76 for the control arm (relative rate, 1.22; 95% CI, 1.05-1.41).

Treatment-related adverse events were reported in 84.4% of patients in the Mirasol arm and in 82.6% of patients in the control arm. This did not reflect a significant difference.

Dr Koepsell and colleagues concluded that the Mirasol approach did not show noninferiority for the primary end point of this study. The treatment arms demonstrated similar safety profiles.

Disclosures: Some authors have declared affiliations with or received grant support from the pharmaceutical industry. Please refer to the original study for a full list of disclosures.

This article originally appeared on Hematology Advisor

References:

Koepsell SA, Ness PM, Stolla M, et al. Clinical efficacy of Mirasol-treated apheresis platelets in patients with hypoproliferative thrombocytopenia (MIPLATE) trial. Presented at the 2022 AABB Virtual Annual Meeting; November 6-7, 2022; Abstract PL2-SN24.