Orexo announced Tuesday that the FDA has issued a complete response letter (CRL) for OX124, the company's high-dose naloxone nasal spray developed for opioid overdose reversal.The CRL, received in response to Orexo's filing submitted last September, highlights two main issues. The agency wants Orexo to conduct another "human factors" (HF) study, a request that aligns with earlier discussions. However, it is also asking to see more technical data on the final commercial product, something Orexa said was "unexpected." The agency has not indicated a need for additional clinical or non-clinical studies.Orexa had been aiming for a potential launch later this year or early 2025. Since receiving feedback from the FDA in April, the company says it has worked to revise the product's usage instructions and that a new HF study was successfully completed. "However, I am surprised with the agency's other requests with regards to additional technical data from final commercial product," stated CEO Nikolaj Sørensen.Orexo noted that its filing did include technical data from pilot-scale manufacturing, and it believed that this would be sufficient for approval. Still, Sørensen said he is "confident we can address this efficiently."The market did not react negatively to the news, with the Swedish company's shares ending the day up by almost 2%.OX124 is based on Orexo's amorphOX drug delivery platform and is designed to reverse the effects of the most powerful synthetic opioids, such as fentanyl. Other naloxone-based products already available in the US include Emergent BioSolutions' Narcan and Harm Reduction Therapeutics' RiVive, both of which are over-the-counter nasal sprays that were approved by the FDA last year.