Nektar pulls NDA for pain drug after unanimous AdComm rejection

Nektar Therapeutics
Shares in Nektar fell 15% following news of the rejection of its opioid oxycodegol. (Nektar Therapeutics)

Nektar Therapeutics has withdrawn the new drug application for its opioid oxycodegol after an advisory committee unanimously recommended against approval. The 27-0 vote against approval followed questioning of Nektar’s decision to run one pivotal trial and the extent to which it assessed the risk of abuse. 

In oxycodegol, formerly known as NKTR-181, Nektar thought it had a mu opioid receptor agonist that is less addictive and less likely to be abused because it enters the brain more slowly and has reduced binding affinity. To make its case, Nektar ran a single pivotal study in patients with chronic non-cancer pain that linked oxycodegol to improvements comparable to those achieved by other opioids.

That proved to be woefully insufficient to win over the advisory committee members, all 27 of whom recommended against approval of the drug. The unanimous rejection followed the publication of a FDA briefing document that questioned the reliance on a single pivotal trial.

While the FDA approves drugs in some indications based on one study, two pivotal trials remains the standard. Nektar’s belief it could get oxycodegol, which failed a midphase study in 2013, to market on the strength of one pivotal trial raised eyebrows even before the unanimous rejection.  

“We never quite understood why the company did not pursue two pivotal studies which has always been the standard requirement for approval,” analysts at Jefferies wrote in a note to investors. 

Nektar responded swiftly and decisively to the advisory committee rejection, withdrawing its filing for approval and stopping further investment in the program. The decision is expected to save Nektar up to $125 million in spending on commercialization and post-approval studies in 2020. 

While the rare unanimous rejection is embarrassing and raises questions about the oxycodegol R&D strategy, the financial impact of the setback may be relatively mild. Analysts had low hopes for the drug, with the team at Jefferies predicting peak sales of less than $200 million, and the closing off of that opportunity is offset by lower spending on oxycodegol.