RedHill Biopharma has launched a Phase 3 clinical trial to evaluate the safety and effectiveness of its investigational oral therapy RHB-204 in adults with bronchiectasis who have lung infections caused by Mycobacterium avium complex (MAC), a type of non-tuberculous mycobacteria (NTM).
Eligible patients include those without cystic fibrosis (CF) and who have not yet received treatment for MAC, or at least not within the six months prior to enrollment.
“NTM is notoriously resistant to most antibiotics and challenging to treat, and there is no [U.S. Food and Drug Administration]-approved first-line therapy for the approximately 110,000 cases of NTM infection in the U.S.,” Kevin Winthrop, MD, the study’s principal investigator, said in a press release.
“If successful, [this study] represents an opportunity to make a breakthrough in managing NTM infections,” added Winthrop, also a professor of infectious diseases at Oregon Health & Science University.
People with bronchiectasis are at a particularly high risk of lung infections by NTM, a set of more than 160 species of bacteria found naturally in the environment. Such infections are associated with worsened lung function and more hospitalizations, and are considered therapeutically challenging, often becoming chronic.
In fact, “treatment of NTM disease requires multiple antibiotics and an extended treatment course due to the risk of development of resistance,” said Aida Bibliowicz, the vice president of RedHill’s clinical affairs.
“Many patients fail these types of therapies and more than half will have either recurring disease or a new infection after completing treatment, making new treatment options for NTM an urgent need,” Bibliowicz added.
RHB-204, an oral capsule containing a combination of clarithromycin, rifabutin, and clofazimine, is being developed as a potential first-line, stand-alone treatment for NTM lung disease caused by MAC — its most common cause.
According to RedHill, the investigational therapy has potent intracellular, anti-mycobacterial, and anti-inflammatory properties.
RHB-204 was granted qualified infectious disease product (QIDP) designation from the FDA, providing eligibility for fast-track designation, priority review, and a five-year extension of U.S. market exclusivity, if approved. This was granted under the FDA’s Generating Antibiotic Incentives Now Act, which is intended to promote the development of new therapies for serious or life-threatening infections that can pose a serious threat to public health.
The therapy also recently received the FDA’s orphan drug designation, providing further regulatory support and financial benefits, as well as extending its period of U.S. market exclusivity by an additional seven years, for a potential total of 12 years upon approval.
The upcoming two-part Phase 3 trial, called CleaR-MAC (NCT04616924), will evaluate RHB-204’s safety and effectiveness in up to 125 adults with non-CF bronchiectasis and MAC lung infection.
Participants, to be recruited at up to 40 sites across the U.S., will be randomly assigned to receive an oral capsule of either RHB-204 or a placebo for up to 16 months. More information on contacts and locations, as well as updates on enrollment, can be found here.
In the study’s first part, researchers will assess whether RHB-204 is superior to a placebo at clearing MAC from patients’ sputum after six months of treatment. MAC clearance will be defined as at least three consecutive, monthly, negative sputum results.
Time to first negative sputum result for the presence of MAC, and changes in patient-reported outcomes, including physical functioning, respiratory symptoms and fatigue, also will be evaluated.
In part two, eligible participants will continue on RHB-204 or placebo for up to month 16. The durability of clinical benefit and of microbiological response will be evaluated at month 16 and again three months after treatment completion.
RedHill also holds patent rights on RHB-204’s formulation at least until 2029, with a pending decision that could extend the protection until 2041.