The commercialisation of osteoarthritis treatment ZILOSUL® has hit a hiccup in the United States with the US Food and Drug Administration (FDA) raising fresh questions to late-stage drug development company, Paradigm Biopharmaceuticals (ASX: PAR).

The FDA response related to Paradigm’s application for Investigational New Drug status to be granted for their focus compound, Pentosan Polysulfate Sodium (PPS).

PPS is currently used to treat bladder pain and discomfort caused by cystitis but Paradigm is working to repurpose the compound by developing and commercialising it for treatment of pain associated with musculoskeletal disorders. The FDA’s questions primarily relate to Paradigm’s recently completed nonclinical studies with the Company intending to clarify existing data, and is on track to have their responses submitted within the 30 day timeframe.

Osteoarthritis is a common joint disorder affecting 4 million Australians. This is expected to rise to 5.4 million by 2030 due to an aging population. OA is expected to cost the health system $7.6 billion per year in 2030. The loss of productivity is significant too with OA being the second most common cause of early retirement, resulting in a lost GDP of $9.4 billion by 2030.

Within a clinical setting, Paradigm is progressing with their plans for a Phase 3 clinical trial to evaluate the use of PPS in osteoarthritis, which will take place in both Australia and the US. Use of the drug has so far yielded promising study data, resulting in a reduction of chronic pain responses by an averFage of 49.6%. Pain scores reduced from baseline 12 weeks after initial injection with PPS.

Paradigm is separately exploring the application of PPS for the treatment of bone marrow lesions (BML), chronic heart failure and alpha viral arthritis. The key characteristics of PPS that make it so attractive for repurposing are its anti-inflammatory and tissue regenerative properties.

Drug repurposing is an effective way to satisfy unmet needs in the market. De novo drug development has a low probability of success and can take anywhere between 7 to 11+ years to gain regulatory approval. Repurposing existing drugs with a known safety profile can see regulatory approval gained in as little as 3 years.

Paradigm is working with the proprietary manufacturer of PPS and benefits from knowledge and expertise learned from earlier regulatory findings.