LUNA 3: Rilzabrutinib meets primary endpoint in ITP

In the phase 3 LUNA 3 trial, rilzabrutinib, compared with placebo, improved efficacy and quality-of-life outcomes with an accompanying favourable safety profile among heavily pre-treated adult patients with immune thrombocytopenia (ITP).

The phase 3 LUNA 3 trial (NCT04562766) randomised 202 adult patients with previously treated ITP 2:1 to the BTK inhibitor rilzabrutinib twice daily or a placebo [1]. “Participants had qualifying platelet counts <30x10⁹/L and were allowed stable concomitant corticosteroids and/or TPO receptor agonists,” said Prof. David Kuter (Massachusetts General Hospital, MA, USA). The primary endpoint was a durable response at week 25, which was defined as a platelet count ≥50x10⁹/L for more than two-thirds of the last 12 weekly visits in the absence of rescue therapy.

The primary endpoint was achieved by 23% of the participants on rilzabrutinib and by 0% of those on placebo (Δ23%; 95% CI 16–30%; P<0.0001). Secondary endpoints, such as the use of rescue therapy, bleeding score, and fatigue, also significantly favoured rilzabrutinib over placebo. “We observed 2 important rilzabrutinib-related adverse events [AEs]: a grade 4 neutropenia and a grade 3 peripheral embolism,” expressed Prof. Kuter. Otherwise, AEs were mostly of grade 1 or 2, and there was no documented BTK class effect.

“Rilzabrutinib was associated with quick and durable platelet responses, improved quality-of-life outcomes, and was well-tolerated in a heavily pre-treated population of patients with ITP,” concluded Prof. Kuter.

1. Kuter DJ, et al. Efficacy and safety of oral Bruton tyrosine kinase inhibitor rilzabrutinib in adults with previously treated immune thrombocytopenia: a phase 3, placebo-controlled, parallel-group, multicenter study (LUNA 3). Plenary Scientific Session, 66^th ASH Annual Meeting, 7–10 December 2024, San Diego, CA, USA.

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Posted on 29 January 202529 January 2025