FDA panel gives thumbs down to Pfizer, Lilly's OA pain drug tanezumab

An FDA advisory committee on Thursday voted by a margin of 19 to 1 against Pfizer and Eli Lilly's experimental osteoarthritis (OA) drug tanezumab, saying they do not believe the risk evaluation and mitigation strategy (REMS) proposed by the companies will ensure that the benefits of the anti-NGF antibody outweigh its risks of potentially worsening joint damage faster. Pfizer and partner Eli Lilly are seeking FDA approval of tanezumab 2.5 mg, injected subcutaneously every eight weeks, to treat moderate-to-severe OA in adults unable to get pain relief from other analgesics.

The panel vote aligns with a largely negative FDA staff review released earlier this week that said tanezumab has shown only "modest" benefit in clinical testing against nonsteroidal anti-inflammatory drugs (NSAIDs), but is linked to a higher risk of joint destruction and neuropathy. They also questioned whether the companies' proposed REMS will do anything to balance the risk of rapidly progressing osteoarthritis (RPOA) that has been seen with tanezumab, and also whether the mitigation strategies are feasible in clinical practice.

Side effects not worth the risk

In explaining his "no" vote, panel member Edward Cheng said that "while another therapy is sorely needed for these patients, I don't think it's this drug." Other advisory committee members raised concerns about long-term use of tanezumab, noting that while only 3% of patients in clinical trials developed more severe arthritis after taking the drug, study participants were only followed for about a year in the longest trial, and the figure could grow over time with real-world use.

In order to spot signs of RPOA, Pfizer and Eli Lilly had suggested that patients undergo baseline X-rays followed by another set of scans a year later. Meanwhile, patients could be at higher risk for this side effect if they also take pain drugs such as ibuprofen and naloxone. However, panel members said it was unrealistic to ask patients to go to those efforts and prohibit them from using such common drugs.

Seeking non-opioid options

Ken Verburg, team leader for tanezumab at Pfizer's global product development unit, said that "while we are disappointed with today's outcome, we continue to believe that tanezumab has a positive benefit-risk profile" in this population of OA patients, many of whom "are eager for new, non-opioid options." Pfizer noted that tanezumab has so far not demonstrated a risk of addiction, misuse or dependence in clinical studies. "We will continue to work with the FDA as the agency continues its review of our application," Verburg added.

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