Novel Agent Ianalumab Added to Standard Therapy Extends Time to Treatment Failure in Patients with Previously Treated Immune Thrombocytopenia

LBA-2: Primary results from VAYHIT2, a randomized, double-blind, phase 3 trial of ianalumab plus eltrombopag versus placebo plus eltrombopag in patients with primary immune thrombocytopenia (ITP) who failed first-line corticosteroid treatment

ORLANDO, Fla., Dec. 9, 2025 /PRNewswire/ -- Patients with immune thrombocytopenia (ITP) who received a first-in-class investigational drug in addition to standard therapy went longer without a bleeding episode that needed urgent treatment or needing another treatment for their ITP, compared with patients who received a placebo in addition to standard therapy. The study is the first to test a novel drug for ITP early in the disease course and was presented at the 67th American Society of Hematology (ASH) Annual Meeting and Exposition.

"In patients for whom first-line therapy had stopped working, treatment with four once-monthly infusions of ianalumab on top of standard therapy provided long-term disease control with no need for chronic therapy and no increase in infection risk," said lead study author Hanny Al-Samkari, MD, the Peggy S. Blitz Endowed Chair in Hematology/Oncology at Mass General Brigham Cancer Institute and an associate professor of medicine at Harvard Medical School, both in Boston.

ITP is an autoimmune disease in which the immune system mistakenly destroys platelets, cells that help promote blood clotting. A normal platelet count is between 150,000 and 400,000 per microliter of blood; in patients with ITP, it's often less than 50,000. The disease is rare, affecting an estimated 50,000 people in the United States — women more frequently than men. Standard first-line treatment includes steroid medications with or without antibody infusions. However, long-term steroid use can cause side effects such as obesity, cataracts, and loss of bone density.

"The longer people have ITP, the more difficult it becomes to treat," Dr. Al-Samkari said. "One of the major unmet needs in ITP treatment is a therapy that truly changes the course of the disease."

Ianalumab acts against B cells, white blood cells in the immune system, when they overreact and mistakenly attack the patient's own body. By blocking signals that these B cells need to grow and activate, the drug helps rid the body of the problematic cells and prevent new ones from developing.

VAYHIT2 was a phase III randomized controlled trial conducted in the United States and 23 other countries. It enrolled 152 patients with ITP who had either not responded to or relapsed after standard first-line treatment. About two-thirds of the patients were women. All patients had a platelet count of less than 30,000 at study entry.

Eltrombopag is a once-daily pill approved by the U.S. Food and Drug Administration to treat ITP after first-line treatment has failed. It works by stimulating the bone marrow to produce more platelets. Each patient received eltrombopag for 16 to 24 weeks. In addition, patients were randomly assigned to receive four once-monthly infusions of a lower dose of ianalumab (3 mg per kilogram of body weight), a higher dose ianalumab (9 mg per kilogram), or a placebo.  

The study's primary endpoint was time to treatment failure, defined as elapsed time until patients had a bleeding episode necessitating "rescue therapy" (rapid-acting treatment with steroids or antibodies) or a new ITP treatment after discontinuing study therapy. The key secondary endpoint was stable response at six months, defined as at least 75% of platelet counts between weeks 19 and 25 measuring higher than 50,000 with no rescue therapy or new ITP treatment. Median follow-up was 12.9 months for the higher-dose ianalumab group, 13.6 months in the lower-dose group, and 11.6 months in the placebo group.

The time to treatment failure was 13 months for patients on the higher dose of ianalumab and "not estimable" for those on the lower dose, compared with 4.7 months for those in the placebo group. "Not estimable" means that the number of patients in the lower-dose group who had problematic bleeding episodes or other primary endpoint events was too small to calculate the time to treatment failure, Dr. Al-Samkari said. Sixty-two percent of patients on the higher dose of ianalumab and 56.9% of those on the lower dose achieved a stable response at six months, compared with 39.2% of those who received the placebo.

At 24 weeks, patients in both ianalumab groups reported lower scores for fatigue, the second most common symptom of ITP after bleeding, on a quality of life questionnaire, compared with those in the placebo group. Patients treated with ianalumab had higher rates of transient neutropenia (below-normal levels of a type of white blood cell that helps the body fight infection) than those in the placebo group. This neutropenia generally resolved within a few days. However, they did not contract infections at higher rates than those in the placebo group, nor were the infections contracted any worse in severity than patients in the placebo group.

One limitation of the study is that, because patients had received just one prior treatment for ITP, the results shed no light on whether ianalumab treatment would increase time to treatment failure for patients with multiple prior treatments. Additionally, patient follow-up is not yet long enough to show whether ianalumab treatment actually halts long-term disease progression. "We will follow the patients for 39 months to look at the long-term durability of ianalumab treatment," Dr. Al-Samkari said.

A randomized trial of ianalumab plus steroids or placebo in previously untreated patients with ITP, known as VAYHIT1, is now underway.

This study will be simultaneously published online in The New England Journal of Medicine at the time of presentation. It was funded by Novartis, the developer of ianalumab.

Hanny Al-Samkari, MD, of Mass General Brigham Cancer Institute and Harvard Medical School, will present this study on Tuesday, December 9, 2025, at 7:45 a.m. Eastern time during the Late-Breaking Abstracts Session in West Hall D2 of the Orange County Convention Center. 

The American Society of Hematology (ASH) (hematology.org) is the world's largest professional society of hematologists dedicated to furthering the understanding, diagnosis, treatment, and prevention of disorders affecting the blood. Since 1958, the Society has led the development of hematology as a discipline by promoting research, patient care, education, training, and advocacy in hematology. Join the #Fight4Hematology by visiting hematology.org/fight4hematology.

The Blood journals (https://ashpublications.org/journals) are the premier source for basic, translational, and clinical hematologic research. The Blood journals publish more peer-reviewed hematology research than any other academic journals worldwide.

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SOURCE American Society of Hematology