A recent study found that more than half of patients receiving the experimental monoclonal antibody ianalumab for primary immune thrombocytopenia (ITP) were able to maintain safe platelet counts without experiencing serious bleeding episodes for at least one year. Conducted as a Phase III clinical trial, the findings were published in the New England Journal of Medicine and presented at the 67th American Society of Hematology Annual Meeting in Orlando, Florida.
ITP is an autoimmune disorder in which the immune system mistakenly attacks platelets, the cells responsible for blood clotting. It affects approximately 50,000 people in the United States and can present at any age. Symptoms may include abnormal bleeding from skin and mucous membranes, such as nosebleeds and heavy menstruation, along with easy bruising and fatigue. While some individuals may not require treatment, those with low platelet counts or severe bleeding typically start with steroids. However, these treatments are not effective for everyone, leading to the need for alternative therapies.
Currently, three FDA-approved second-line therapies exist for ITP, but they generally require lifelong treatment, often in the form of daily pills or weekly injections. These approaches can introduce various side effects and substantial costs. Dr. Adam Cuker, the study’s lead author and section chief for Hematology at the Perelman School of Medicine, expressed hope about the study’s findings. “This study shows that prolonged, durable responses to ITP treatment, without the need for ongoing therapy, are possible—and that’s a huge advantage for patients,” he stated.
Clinical Trial Findings
The double-blind, multicenter clinical trial, known as the VAYHIT2 study, involved 152 adult patients with ITP, who were randomized into three groups: a higher-dose of ianalumab (50 patients), a lower-dose of ianalumab (51 patients), and a placebo (51 patients). Ianalumab operates by targeting the B-cell-activating factor (BAFF) receptor, which depletes the autoreactive B cells responsible for producing anti-platelet antibodies.
Patients were eligible for the trial if they had previously relapsed after steroid treatment or if their ITP did not respond to such therapies. Participants received ianalumab intravenously once a month for four months. Due to the treatment’s gradual onset, all patients also received eltrombopag, a currently approved oral medication for ITP. In this study, the objective was to taper off eltrombopag, which is typically taken indefinitely.
The primary endpoint measured was “time to treatment failure,” defined as experiencing low platelet counts, needing additional ITP therapy, failing to taper or discontinue eltrombopag, or death. Results indicated that the estimated probability of avoiding treatment failure at 12 months was 54.2% in the high-dose group and 50.5% in the low-dose group, compared to only 30% in the placebo group. Furthermore, at the six-month mark—two months after the last dose of ianalumab—62% of patients in the high-dose group maintained stable platelet counts, while only 39.2% of the placebo group did.
Future Implications and Research
While the results are promising, ianalumab is not yet approved by the FDA, and additional clinical trials are underway to assess its efficacy in other autoimmune conditions. The research team plans to continue monitoring the patients from this study to evaluate long-term responses to the treatment.
“We’re looking forward to seeing if the treatment-free responses in this study extend out even further,” Dr. Cuker added. “Improving the long-term reality of living with ITP is not something we’ve been able to think about before. The goal has always been to improve platelet counts or reduce the risk of bleeding, but this research is ushering in a new era of hope for patients with ITP.”
The study was funded by Novartis. More information on the study can be found in the publication titled “Ianalumab plus Eltrombopag versus Placebo plus Eltrombopag in Immune Thrombocytopenia” in the New England Journal of Medicine (2025). DOI: 10.1056/NEJMoa2515168.
