Johnson & Johnson’s $30B buyout suffers setback as Actelion antibiotic fails in one phase 3, succeeds in another

Actelion's headquarters in Switzerland

Actelion has posted mixed late-phase data on its antibiotic cadazolid. The drug, which Johnson & Johnson is set to acquire in its $30 billion (€27 billion) takeover of Actelion, failed to match an old antibiotic in one study despite holding its own in another identical trial.

Investigators enrolled 1,263 patients with Clostridium difficile-associated diarrhea across the two studies and randomized them to receive either cadazolid or vancomycin. Patients randomized to receive cadazolid also took a placebo with the same dosage form and regimen as vancomycin. And patients in the vancomycin arm took a placebo version of cadazolid. The primary endpoint was the rate of clinical cure 10 days after starting treatment with the study drugs.

One of the phase 3 trials failed to show cadazolid is non-inferior to vancomycin. Cadazolid met the primary non-inferiority endpoint in the other study. Actelion is now working to analyze the data ahead of publishing a more detailed breakdown of the results.

The Swiss biopharma company designed the clinical trials to be identical. Both trials enrolled patients using the same inclusion-exclusion criteria and gave them the same regimens of cadazolid or active comparator.

There were some small differences between the trials, though. While both trials enrolled patients around the world, different sites and, to some extent, different countries were used in each study. Both trials activated sites in North America and Western Europe. But one study included more sites in Asia, Eastern Europe and South America. The study with sites in countries such as Argentina, Croatia, Israel and Hungary missed its primary endpoint.

Actelion isn’t the first company to get different results from identical clinical trials. Last year Roche reported lebrikizumab significantly reduced exacerbations in people with severe asthma in one trial but failed to do so in a second study.

The addition of cadazolid to the list of drugs to post such mixed data poses more of a headache for J&J than Actelion. While J&J agreed to spin out earlier-stage Actelion assets to create a new biotech, now called Idorsia, it included two phase 3 programs in its $30 billion buyout. J&J is due to take ownership of cadazolid and multiple sclerosis asset ponesimod when it completes its takeover of Actelion.

Cadazolid is a minor part of the deal compared to the pulmonary arterial hypertension assets J&J wants to build a new franchise around to drive sales growth in the coming years.