FDA knocks back QRxPharma's MoxDuo again

Shares in QRxPharma (ASX:QRX) slumped nearly 25% after the company disclosed it has been issued a second complete response letter (CRL) from the US FDA over dual-opioid drug MoxDuo IR.

QRxPharma will now need to resubmit its New Drug Application (NDA) with more information and analysis, further delaying the approval process.

The FDA advised that the second CRL has been issued to allow more time to submit and evaluate data on the respiratory safety advantages of MoxDuo compared to equianalgesic doses of morphine or oxycodone.

The sticking point is data from one particular safety study, which QRxPharma said will require individual validation of over 30 million oxygen saturation data values from the 375 patients involved.

The FDA has already advised that existing data is adequate to demonstrate efficacy and that no safety issues were identified as part of the trials supporting the original application.

QRxPharma now expects to resubmit its NDA in the fourth quarter and anticipates a new PDUFA date - the deadline for the FDA’s decision on approval - sometime in Q2 2014.

Despite the setback, QRxPharma CEO John Holaday said the CRL does afford the company some certainty. “We now have clarity from the FDA as to next steps, and a six-month clock will begin upon refiling the NDA,” he said.

“We remain confident in MoxDuo as a potential therapeutic option for the millions of patients suffering from moderate to severe acute pain and will continue our efforts and work with the FDA and our partners to bring this therapy to market; the company believes we are on track to launch in 2014.”

MoxDuo IR is the immediate-release variant of MoxDuo, a proprietary formulation combining morphine and oxycodone.

The FDA’s original CRL for MoxDuo, issued in June 2012, came as a surprise given the positive results during trials and the long history of use of morphine and oxycodone in healthcare.

But QRxPharma was spared from the prospect of having to conduct more trials and the FDA accepted QRxPharma’s resubmitted application in March.

QRxPharma (ASX:QRX) shares were trading 22.58% lower at $0.84 as of around 1.30 pm on Tuesday.