Eli Lilly-Pfizer's Non-Opioid Painkiller Faces Safety, Efficacy Concerns

Eli Lilly And Co LLY faced a setback following the release of top-line results from a late-stage study of its pain medication candidate. 

What Happened

Lilly and partner Pfizer Inc. PFE said in a Thursday news release the Phase 3 study intended to evaluate tanezumab in 2.5mg and 5mg doses for its long-term safety and 16-week efficacy relative to nonsteroidal anti-inflammatory drugs, or NSAIDs, in patients with moderate-to-severe osteoarthritis of the hip or knee produced mixed results.

Tanezumab is an investigational monoclonal antibody that selectively targets, binds and inhibits nerve growth factor, or NGF, which increases as a result of injury, inflammation or in chronic pain states. Inhibition of NGF prevents pain signals from reaching the spinal cord or brain.

The non-opioid chronic pain medication was administered subcutaneously every eight weeks for a total of 56 weeks, with a 24-week safety follow-up period.

The trial results showed that the 5mg arm met two of the three co-primary endpoints, showing a statistically significant improvement in pain and physical function relative to NSAIDs at 16 weeks. Yet the patients' overall assessment of their osteoarthritis was not significantly different from the NSAIDs.

The 2.5mg treatment arm did not show a statistically significant improvement in pain, physical function or patient's overall assessment of osteoarthritis at 16 weeks relative to NSAIDs.

There was worrying news on the safety front, with the companies reporting a higher rate of joint safety events in the tanezumab arms compared to NSAIDs at 80 weeks.

The companies also noted higher discontinuations due to adverse events in the tanezumab treatment arm compared to NSAIDs during the 56-week treatment period.

Why It's Important

Lilly paid Pfizer $200 million upfront in 2013 and agreed to as much as $1.6 billion in potential milestone payments for the co-development of the asset.

With the murky data, many analysts foresee the shelving of the study.

"To us, the product is likely dead, if not from a regulatory standpoint (i.e. is it even approvable?) then from a commercial one (i.e. will it ever sell?" Wolfe Research analyst Tim Anderson said, according to Endpoints News.

What's Next

The companies said they plan to review the totality of data from the clinical program with regulatory authorities. They expect to present the full results from this study in a future scientific publication or at a presentation.

Lilly shares were trading up slightly at $115.24 at the time of publication Monday, while Pfizer shares were falling 0.23 percent to $39.29. 

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