CSL shares plunge on medical trial disappointment

Biotechnology manufacturer CSL has failed to prove the efficacy of one of its most promising drugs under development – CSL112 (apolipoprotein A-I [human]).

As recently as last year the Melbourne company was testing the drug in reducing the risk of follow on adverse cardiovascular events (MACE) in patients following an acute myocardial infarction (AMI) or heart attack.

The company’s view that the drug could be a blockbuster was punctured in an announcement of top-line results from the Phase 3 AEGIS-II trial evaluating the efficacy and safety of CSL112 compared to placebo.

CSL told investors: “The study did not meet its primary efficacy endpoint of MACE reduction at 90 days.

“As a result, there are no plans for a near-term regulatory filing. There were no major safety or tolerability concerns with CSL112.”

CSL shares fell on the ASX yesterday by $14.76 or 4.84 percent following the announcement.

The drug works by speeding the first step in the removal of cholesterol from the system, a process known as cholesterol efflux.

CSL said that further analysis and primary results of the study would be presented at the American College of Cardiology Scientific Sessions to be held on April 6, 2024, and published in a peer-reviewed journal.

Executive Vice President and Head of R&D for CSL Dr. Bill Mezzanotte said: “Substantial work remains to fully analyse and understand the complete data and then to determine any development path ahead for this asset.

“AEGIS-II is the most ambitious study in our company’s history and we are proud of the quality of the study we delivered and the enhanced capabilities we developed to do so.

“We plan to apply these capabilities as well as our plasma protein platform to future unmet medical need in cardiovascular and metabolic conditions as well as those in our other strategic therapeutic areas.”

CSL112 was developed using a novel formulation of human plasma or blood-derived apoA-I, the primary functional component of high-density lipoproteins (HDL).

Picture: Dr. Bill Mezzanotte