A couple of comments in response to this and previous posts:
1) While it is possible that the FDA may try to flex its muscle vis-a-vis Redux as putative protector of the public good, especially with FDA Reform legislation hitting the front burner in Congress through September, it will not color their view of other IPIC drugs under development. This information regarding valvular disease is all recent, and the FDA would only punish IPIC if they believed IPIC had withheld information. Furthermore, no IPIC drugs under development are going to be reviewed by the same FDA Division and Advisory Panel that dealt with Redux; they will face the CNS and Cardiovascular divisions in the next couple of years, but not Endocrine.
2) I believe that the comment citing such dramatic differences between dexfenfluramine and more common SSRI's overstates the case. Since Redux, like Prozac, Paxil, Zoloft, reduces serotonin reuptake, it increases synaptic serotonin levels. The concern regarding valvular disease is that it is believed caused by excess serotonin in the blood. However, both Redux and Pondimin are known to reduce serotonin in the blood (even as it increases in the brain). Thus the causal model is lacking substance. Remember also that Prozac was going to be marketed by Lilly as Lovan for obesity, but failed to show maintained weight loss, and thus was withdrawn from FDA consideration.It was however approved for bulimia, which has as its core symptom, episodic overeating. I keep wondering why those researchers basking in the media glow brought about by their claims of Redux-induced neurotoxicity and valvular heart disease have not expressed any worries about the far more common usage of these other SSRI's. The fact that one of the major figures in the neurotoxicity camp was a consultant to Lilly when Lilly was trying to advance Lovan, certainly gives a possible hint.
A side note: Redux is not to be combined with other SSRI's for the same reason that other SSRI's are not to be combined with each other; one runs the risk of a Serotonergic Malignant Syndrome, a rare adverse event which can be quite serious, similar to the Neuroleptic Malignant Syndrome seen in patients taking neuroleptics in high doses or combinations.
In any event, one has now anecdotal, unconfirmed reports of 4 possible cases of valvular disease in patients using Redux alone, out of a US population of 2 million who have used it. I do not know the absolute base rate for valvular disease in the general population, or in the obese population per se, but this seems to be an enormous hue-and-cry about a degree of association which thus far appears microscopic. I agree fully that this issue requires further evaluation, but the NEJM editorial describing Redux users as "succumbing to the allure of diet pills as a quick fix" was an overstatement both demeaning and intimidating to patients who might have genuinely been in need of obesity treatment.
Redux sales will continue to drop unless and until AHP more stenuously defends itself and Redux. IPIC will languish somewhat until citicoline and/or bucindolol capture the spotlight. NeuroInvestment |
