Sanofi has released phase 3 data from the LUNA 3 trial of rilzabrutinib that should spark some buyer’s delight.
The drug, which the French pharma giant acquired through a $3.7 billion buyout of Principia Biopharma in 2020, raised and sustained platelet levels in 23% of immune thrombocytopenia (ITP) patients who received it, compared to none in the placebo arm. The results were shared Nov. 5 in advance of being presented at the American Society of Hematology (ASH) meeting on Dec. 8.
Patients receiving the drug also saw meaningful improvements in physical fatigue and bleeding, as measured by the Immune Thrombocytopenic Purpura-Patient Assessment Questionnaire and the ITP Bleeding Scale, respectively.
Patients in the treatment and placebo arms experienced similar overall numbers of adverse events, with patients receiving rilzabrutinib more likely to experience low-grade diarrhea, nausea, headache and abdominal pain than patients receiving placebo, according to the ASH abstract.
In April, Sanofi revealed that the study had hit its primary endpoint.
As of March 2024, the trial enrolled 202 adults with ITP who had not responded to prior treatments. A durable rise in platelet levels was mainly assessed as a platelet count greater than 50,000 microliters for at least eight of the last 12 weeks of the 24-week treatment period. This is the trial’s primary endpoint, while secondary endpoints include improvements in fatigue and bleeding.
The LUNA-3 trial is set to fully wrap up in November 2026.
ITP is characterized by low platelet levels in blood, which can interfere with clotting. Symptoms include bruising easily, bleeding into the skin (which looks like a rash) and bleeding from the gums, nose or in urine and feces.
Rilzabrutinib is an oral inhibitor of Bruton’s tyrosine kinase (BTK), a protein that controls the development of B cells. In ITP, the patient’s own immune system—like B cells—are responsible for targeting and destroying platelets. By slowing down B-cell activity, BTK inhibitors could treat ITP and other autoimmune conditions.
Sanofi’s bet on has paid off in other indications as well. Earlier this year, the drug reduced disease severity in a phase 2 trial of patients with the skin condition chronic spontaneous urticaria.
And the Big Pharma plans to seek FDA approval for another BTK inhibitor, tolebrutinib, in multiple sclerosis. That drug delayed time to onset of confirmed disability progression in a phase 3 trial but was also put in a partial clinical hold by the FDA in 2022 due to reports of liver injury.