FDA approves Mesoblast’s drug for chronic low back pain, sending shares on a rollercoaster

Stem cell-focused biotech Mesoblast is gaining traction in the US after the Food and Drug Administration granted regenerative medicine advanced therapy designation for its new drug.

Mesoblast chief executive Silviu Itescu. Picture: Stuart McEvoy

The US Food and Drug Administration has approved Mesoblast’s opioid-free treatment for chronic low back pain, sending shares in stem cell-focused biotech on a wild ride, reaching one-year highs before finishing in negative territory.

The US Food and Drug Administration has granted Mesoblast regenerative medicine advanced therapy (RMAT) designation for its drug rexlemestrocel-L, which is injected into a lumbar disc.

The $881m company is awaiting a decision from the FDA for another of its drugs, remestemcel-L, to treat children with acute graft versus host disease, after successful phase three trials.

Chief executive Silviu Itescu said the RMAT designation on rexlemestrocel-L provided “all the benefits of breakthrough and fast-track designations, including rolling review and eligibility for priority review on filing of a biologics licence application.

He said there was a significant need for a safe, effective, and “durable opioid-sparing treatment” in patients with chronic low back pain (CLBP) associated with degenerative disc disease.

“We are pleased to receive RMAT designation for our cellular therapy to treat CLBP due to disc degeneration” Dr Itescu said.

“We look forward to working closely with the FDA to efficiently generate the additional data needed to support marketing approval of rexlemestrocel-L for the treatment of this serious and debilitating condition.”

Mesoblast shares vaulted 9 per cent to $1.30 in morning trade on Thursday – the highest level since January last year. They later lost steam, closing down 1.3 per cent at $1.18. This compared with the broader share market shedding 0.5 per cent.

Phase three trials found that a single injection of rexlemestrocel-L into the lumbar disc resulted in a significant reduction in pain compared with saline control at 12 and 24 months across all of the 404 patients who participated.

Among patients on opioids at baseline, despite instructions to maintain existing therapies

throughout the trial, at 36 months 28 per cent who received rexlemestrocel-L were not taking an opioid compared with 8 per cent of saline treated controls.

Chronic low back pain is the fifth most common reason for visiting a doctor in the US. It affects about 10 to 30 per cent of America’s adult population in a lifetime and is the leading cause of disability in those under 45 years old.

Mesoblast has been on a rollercoaster ride with US regulators. In August 2020, the US Oncologic Drugs Advisory Committee (ODAC) voted nine to one in favour of the remestemcel-L therapy for acute graft versus host disease (aGVHG) – a decision that sent Mesoblast shares soaring to a six-year high at $5.22.

But 12 months later, the FDA recommended that Mesoblast conduct at least one additional randomised, controlled study in adults and/or children to provide further evidence of the effectiveness of remestemcel-L for aGVHD, sending the company’s shares into a nosedive.

Mesoblast has since provided new phase three clinical data – the final step before regulatory approval and commercialisation – which shows that remestemcel-L remains effective at least four years after initial treatment, improving life expectancy rates.

The FDA is expected to make a decision on remestemcel-L within six months.