FDA requests more data for toremifene 80 mg

According to a media release from GTx and other reports, the US Food and Drug Administration (FDA) has requested additional information about the effectiveness and safety of toremifene 80 mg before they will be willing to approve a New Drug Application (NDA) for this drug as a treatment to reduce fractures in men with prostate cancer receiving androgen deprivation therapy (ADT).

The FDA has suggested that the following information will be needed to allow an appropriate assessment of the risks and benefits of toremifene 80 mg for this specific clinical use:

  • Results of a second adequate and well controlled Phase III trial demonstrating the safety and efficacy of toremifene citrate 80mg to reduce fractures in men with prostate cancer on ADT
  • Results from an adequate and well-controlled clinical trial demonstrating that toremifene treatment to reduce fractures in men with prostate cancer on ADT does not have a detrimental effect on either time-to-disease progression or overall survival.

The “New” Prostate Cancer InfoLink assumes that it would be possible to meet both these needs through implementation of a single, well-designed trial. Whether GTx has the resources to develop and implement such a trial is a rather different question. There is also the question of how long it would take to complete such a trial.

GTx has apparently requested a meeting with the FDA to determine appropriate next steps.

The bottom line to all of this is that the FDA is concerned that certain side effects of toremifene, most particularly its known risk for “venous thromboembolic events” (blood clots) and its impact on prolongation of the QTc interval, have not been adequately investigated yet. (The QTc interval is a measure of the heart rate-corrected time between the start of the Q wave and the end of the T wave in the heart’s electrical cycle.)

The FDA is responsible for ensuring that the benefits of any form of drug therapy outweigh the risks associated with the use of the drug, and while some people will undoubtedly be upset by this decision, it is equally possible to see why the FDA has come to this conclusion.

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