RedHill Announces Orphan Drug Designation for NTM Infection Treatment

RedHill Biopharma announced that the U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation to RHB-204 for the treatment of nontuberculous mycobacteria (NTM) disease.

“NTM infections are resistant to most antibiotics and are extremely challenging to treat. With no FDA-approved first-line therapy available to patients today, there is a tremendous urgent need for new treatments for this debilitating and potentially fatal infectious disease,” said Patricia Anderson, RedHill’s VP Regulatory Affairs. “Along with the QIDP designation already granted to RHB-204 by the FDA, the Orphan Drug Designation extends potential market exclusivity to a total of 12 years.”

A Phase 3 study to evaluate the safety and efficacy of RHB-204 in patients with pulmonary NTM infections caused by Mycobacterium avium Complex (MAC) is planned to be initiated in the coming weeks in the U.S.

The multi-center, randomized, double-blind, placebo-controlled, parallel-group Phase 3 study, under ongoing discussion with the FDA, is planned to be conducted at up to 40 sites across the U.S. and aims to enroll 125 patients, randomized at a 3:2 ratio to receive either RHB-204 or placebo. The study is planned to evaluate the safety and efficacy of RHB-204, evaluating patient-reported outcomes and sputum culture conversion (SCC) by Month 6 of treatment with RHB-204, compared to placebo, and patients will continue to receive treatment for 12 months from SCC.

The FDA grants orphan status to drugs intended to treat rare disorders that affect fewer than 200,000 people in the U.S. The designation provides various development incentives to the drug developer, including extended market exclusivity upon FDA approval, prescription drug user fee (PDUFA) waivers and tax credits for qualified clinical testing.

RHB-204 was previously granted a Qualified Infectious Disease Product (QIDP) designation by the FDA, providing for eligibility for Fast-Track development, NDA priority review and a five-year extension of U.S. market exclusivity, if approved. The Orphan Drug Designation extends U.S. market exclusivity for RHB-204 by an additional seven years, for a potential total of 12 years upon FDA approval.

Pulmonary nontuberculous mycobacteria (NTM) disease is a chronic and debilitating lung disease caused by ubiquitous environmental bacteria, found in soil as well as natural and engineered water systems. The most common NTM symptoms include fever, weight loss, chest pain, and blood in sputum. NTM infections can lead to recurring cases of bronchitis and pneumonia and can, in some cases, lead to respiratory failure. Although rare, the incidence and prevalence of pulmonary NTM disease are increasing in many areas of the world. There were an estimated 110,000 pulmonary NTM disease patients in the U.S. in 2017. Pulmonary manifestations account for 80-90% of all NTM-associated diseases5, and approximately 80% of pulmonary NTM infections are caused by Mycobacterium avium Complex (MAC).

Treatment of NTM infection can be difficult, with no FDA-approved first-line standard-of-care therapy. It requires multiple antibiotics and an extended treatment course due to the risk of development of resistance. Many patients fail these types of therapies and more than half will have either recurring disease or a new infection after completing treatment. Thus, new treatment options for NTM are urgently needed.

RHB-204 is a proprietary, fixed-dose oral capsule containing a combination of clarithromycin, rifabutin, and clofazimine, developed for the treatment of pulmonary NTM infections caused by Mycobacterium avium Complex (MAC). RHB-204 was granted both FDA Orphan Drug Designation for the treatment of NTM disease and QIDP Designation under the Generating Antibiotic Incentives Now Act (GAIN Act), extending U.S. market exclusivity for RHB-204 to a potential total of 12 years to be granted at the time of FDA approval. RHB-204 is also covered by U.S. patents which extend patent protection until 2029 and a pending U.S. patent application which, if allowed, could extend RHB-204 patent protection until 2041.