Mesoblast shares plunge after US FDA questions COVID-19 treatment

Shares in Mesoblast sank over 20pc after US authorities raised concerns about the effectiveness of its COVID-19 treatment.

Shares in Stem-cell focused biotech Mesoblast dived more than 30 per cent after the US Food and Drug Administration raised questions about the effectiveness of its new treatment to combat COVID-19.

Mesoblast’s shares have had a stellar run in past months, rising more than 323 per cent, largely due to the success of its drug remestemcel-L, which has been trialled in the US on patients with serious COVID-19 complications.

But a discussion paper the FDA released ahead of an advisory committee meeting on Thursday has rattled investors, sending Mesoblast shares down 31 per cent to $3.36.

“FDA’s position is that the product attributes the applicant has identified as related to potency and activity, however, do not have a demonstrated relationship to the clinical performance of specific DP (drug product) lots, and that the product’s proposed immunomodulators mechanism of action has not been demonstrated in vivo in study subjects receiving remestemcel-L,” the FDA said in its discussion paper.

“Without a demonstrated relationship with clinical effectiveness and/or in vivo potency/activity, controlling these CQAs (critical quality attributes) may not be sufficient to ensure the manufacturing process consistently produces remestemcel-L lots of acceptable quality.”

But analysts from Cantor Fitzgerald believed Mesoblast had sufficient data to allay the FDA’s concerns.

“MESO has potency assays and experience from clinical trials to correlate this potency to measurable clinical outcomes,” the analysts said in a note to investors.

“We think MESO will be able to address the concerns that were raised in the briefing materials. The topics of discussion were already anticipated by the company, and MESO has been preparing for the AdCom (advisory committee).”

Equity markets have been sensitive to developments on COVID-19 treatments. Earlier this year, the Dow Jones Industrial Average gave up most of a 400-point rally after Gilead Science’s much-hyped COVID-19 busting drug “flopped” in its first randomised clinical trial.

Shares in Gilead, which is currently seeking FDA approval for its COVID-19 treatment remdesivir, have fallen 18.4 per cent from a high of $US84 ($117.31) on April 30 to $US68.51.

Last month Mesoblast chief executive Dr Silviu Itescu stated: “Remestemcel-L has two imminent major milestones, the interim analysis in the ongoing phase 3 trial of remestemcel-L in COVID-19 patients with acute respiratory distress syndrome and the FDA advisory committee panel review of our submission for potential approval of RYONCIL™ (remestemcel-L) in children with steroid-refractory acute graft versus host disease.

“Together with the upcoming phase 3 readouts in chronic heart failure and back pain, these key milestones will take the company into the most significant period in its history,” Dr Itescu said.

Remestemcel-L was initially developed as a drug to treat children with steroid-refractory acute graft versus host disease, which has a similar immune response in coronavirus-infected patients who have developed acute respiratory distress syndrome (ARDS). Remestemcel-L aims to suppress that response.