Manufacturing Problems at Pfizer
Can anything else go wrong at Pfizer? Unfortunately for Pfizer employees, the answer is yes. Pfizer and FDA announced late last week that they found detectable levels of the mutagen/carcinogen ethyl methanesulfonate (EMS) in Viracept, the company’s flagship anti-HIV medication. EMS has long been known to be a potent mutagen and carcinogen. I can attest to the mutagenic potential of EMS, because in my former life as a bench scientist I routinely used it to generate point mutations in the bacteria that I was working with. Pfizer and FDA agreed not to recall the drug in the US because the quantity of EMS found was “low”. However, Roche, the company that sells Viracept in Europe, did recall the drug (slightly higher levels of EMS were found in the European version of Viracept). Predictably, FDA cautioned that although there are no human data, EMS has been shown to cause mutations, tumors and birth defects in animals and is a "potential human carcinogen. Not surprisingly, Pfizer advises children and pregnant women not to start the drug, although children already taking it may continue (really?).
How EMS got into both the US and European versions of the drug remains a mystery. If I had to guess, it is likely that there are significant quality control and quality assurance issues at the manufacturing plant(s) that produces Viracept. Alternatively, the EMS may have always been present in Viracept (as a contaminant or chemical by product) but nobody thought to look for it until recently. According to one report, “Pfizer is working with the FDA to prospectively limit EMS levels in Viracept, while still considering the immediate needs of patients on therapy. This is nonsense. There are other protease inhibitors that HIV-infected patients can try before they continue to take EMS-tainted Viracept. I think that Pfizer should voluntarily recall Viracept and eliminate all traces of EMS before it is reintroduced to the US and European markets!
Until next time….
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