Rare Daily Staff
The U.S. Food and Drug Administration approved Celgene subsidiary Impact Biomedicines’ Inrebic to treat adult patients with certain types of myelofibrosis, a rare bone disorder.
Myelofibrosis is a chronic condition where scar tissue forms in the bone marrow and the production of the blood cells moves from the bone marrow to the spleen and liver, causing organ enlargement. It can cause extreme fatigue, shortness of breath, pain below the ribs, fever, night sweats, itching and bone pain.
The FDA approval is for Inrebic as a treatment for intermediate-2 or high-risk primary or secondary myelofibrosis, which occurs when there is excessive red blood cell production or excessive platelet production that evolves into myelofibrosis.
The approval of Inrebic follows the FDA’s approval of Jakafi (ruxolitinib) in 2011. It was based on the results of a clinical trial where 289 patients with myelofibrosis were randomized to receive two different doses of Inrebic or placebo.
The clinical trial showed that 35 of 96 patients treated with the Inrebic at the dose recommended in the approved label experienced a significant therapeutic effect (measured by greater than or equal to a 35 percent reduction from baseline in spleen volume at the end of week 24 as measured by an MRI or CT scan with a follow-up scan four weeks later). As a result of treatment with Inrebic, 36 patients experienced greater than or equal to a 50 percent reduction in myelofibrosis-related symptoms, such as night sweats, itching, abdominal discomfort, feeling full sooner than normal, pain under ribs on the left side, and bone or muscle pain.
The approval of Inrebic comes with Boxed Warning to advise about the risk of serious and fatal brain damage or malfunction, including Wernicke’s, which is a neurologic emergency related to a deficiency in thiamine.
Common side effects for patients taking Inrebic are diarrhea, nausea, vomiting, fatigue and muscle spasms. Patients may experience severe anemia, and low levels of platelets in the blood. Patients should be monitored for gastrointestinal toxicity and for liver damage.
The FDA granted Inrebic Priority Review and Orphan Drug designations. Inrebic also received Orphan Drug designation, which provides incentives to assist and encourage the development of drugs for rare diseases.