Vivus, Inc has received a Complete Response Letter (CRL) from the US Food and Drug Administration (FDA) regarding its New Drug Application (NDA) for the investigational new drug Qnexa (phentermine/topiramate) Controlled-Release Capsules. The FDA issued the CRL to communicate its decision that the NDA cannot be approved in its present form. The application seeks the approval to market Qnexa as an oral, once-a-day formulation for the treatment of obesity, including weight loss and maintenance of weight loss, in patients who are obese or overweight with co-morbidities such as hypertension, type 2 diabetes, dyslipidemia or central adiposity.
The CRL included the following areas: clinical, labelling, REMS, safety update, and drug scheduling.
In the clinical section of the CRL, the FDA requested a comprehensive assessment of topiramate's and phentermine/topiramate's teratogenic potential. This will include a detailed plan and strategy to evaluate and mitigate the potential teratogenic risks in women of childbearing potential taking the drug for the treatment of obesity. In addition, the US FDA asked Vivus to provide evidence that the elevation in heart rate associated with phentermine/topiramate does not increase the risk for major adverse cardiovascular events.
The US FDA requested that Vivus formally submit the results from the already completed Sequel study (OB-305), a 52-week extension study for a subset of 675 patients who completed the previously reported 56-week Conquer study. Top-line results from the two-year Sequel study were announced by Vivus on September 21, 2010 and a final study report is being prepared for submission to the NDA.
The US FDA reserved the right to comment further on proposed labelling. On REMS, the US FDA requested that a discussion of an already submitted REMS plan be continued after the written response from Vivus has been submitted. The agency also requested a safety update of any new adverse events be submitted to the NDA. Finally, the US FDA stated that if approved, phentermine/topiramate would be a Schedule IV drug due to the phentermine component.
As part of the written response, Vivus plans to compile analyses integrating existing nonclinical and clinical data to provide a comprehensive assessment of the teratogenic potential of topiramate. In addition, Vivus plans to provide several new analyses to demonstrate Qnexa does not increase the risk for major cardiovascular events, which would include data from our OB-305 and OB-204 studies. In the CRL, no new clinical studies were requested; however, in the event that any of the US FDA concerns are not alleviated, additional clinical studies may be required.
"We remain confident in the efficacy and safety profile of Qnexa demonstrated in the clinical development program and look forward to continue working with the FDA towards the approval for the treatment of obesity," said Leland Wilson, chief executive officer of Vivus. "We are preparing a comprehensive response to the CRL for submission to the US FDA in approximately six weeks."
Vivus is a biopharmaceutical company developing therapies to address obesity, sleep apnea, diabetes and male sexual health.