NIH Trial Confirms Bone Marrow Cancer Drug Efficacy

Breakthrough in Rare Blood Disorder Treatment

A clinical trial supported by the National Institutes of Health (NIH) has shown promising results for pomalidomide, a drug typically used to treat bone marrow cancer and Kaposi sarcoma, in the treatment of hereditary hemorrhagic telangiectasia (HHT). The trial, which was halted early due to compelling evidence of the drug's effectiveness and safety, marks a significant advancement in treating this rare bleeding disorder that affects approximately 1 in 5,000 individuals worldwide. The findings, published in the *New England Journal of Medicine*, reveal that patients receiving pomalidomide experienced a notable decrease in nosebleed severity, reduced reliance on blood transfusions and iron infusions, and an overall improvement in quality of life. Dr. Andrei Kindzelski of the NIH’s National Heart, Lung, and Blood Institute emphasized the rarity of discovering an effective treatment for a condition like HHT, stating, “This discovery will give people who suffer with this disease a positive outlook and better quality of life.”

Understanding Hereditary Hemorrhagic Telangiectasia

HHT, also referred to as Osler-Weber-Rendu Syndrome, is characterized by abnormal blood vessel formation, leading to fragile, tangled vessels prone to leakage. This condition can result in severe nosebleeds and bleeding from other mucosal surfaces, significantly impairing quality of life and potentially causing life-threatening complications. Currently, treatment options are limited, often involving procedures to close malformed blood vessels or off-label medications for temporary relief. The mechanism by which pomalidomide operates is believed to involve the inhibition of abnormal blood vessel growth, potentially leading to improved vessel structure and strength. Dr. Keith McCrae of the Cleveland Clinic, who led the research, noted that further studies are needed to confirm these effects.

Study Details and Future Implications

The trial enrolled 144 adults diagnosed with HHT across 11 medical centers in the U.S. from November 2019 to June 2023. Participants were given either a daily dosage of pomalidomide or a placebo. The trial's interim analysis in June 2023 demonstrated that pomalidomide met the predetermined efficacy criteria, prompting the closure of further enrollment. Dr. Kindzelski highlighted the broader implications of these findings, especially for patients with severe HHT manifestations that could lead to critical complications, such as hemorrhagic strokes. Some patients reported extended periods without nosebleeds even after discontinuing the medication, suggesting potential for long-term therapeutic benefits.

Highlights

• NIH-supported trial shows pomalidomide effective for treating HHT.
• Significant reduction in nosebleeds and improved patient quality of life.
• Current treatments for HHT are limited and often ineffective long-term.
• Pomalidomide may offer hope as a long-term treatment option.