In December of last year the FDA denied approval of Sanofi’s new MS drug Lemtrada. John Marler, a drug reviewer for the FDA, sited unclear benefits of Lemtrada and potential side effects as the reason for the denial. According to the FDA it was not clear from the clinical trials if the risks associated with Lemtrada outweighed the potential side effects. They also added that the benefits of Lemtrada would have to be “substantial” in order to justify exposing patients to the potential side effects. Lemtrada’s developers argue that side effects that occurred in clinical trials were all non life-threatening, treatable conditions. During clinical trials two deaths occurred, one from sepsis and one from accidental causes.
Two Phase III clinical trials were done comparing Lemtrada to interferon injections. The FDA was concerned about the design of these studies, citing that they were not blind studies which can potentially bias the results. This means that the patients and the doctors knew if Lemtrada or interferon was being given. Blind studies mean that neither the patient or the doctor knows which treatment is being given. This is the preferred design of a clinical trial because the attitudes of the doctor and the patient, whether it be skepticism or enthusiasm, has been shown to skew data. However, in the case of these studies a blind comparison would be almost impossible because one drug is an injection given three times a week and one is an IV infusion given one year apart. The only way I see a blind study happening is if they compare Lemtrada infusions to placebo infusions. Unfortunately doing a placebo study would mean that half of the MS patients in the trial would be going without any treatment for at least two years.
Since the denial I have been waiting to hear what Sanofi, who acquired Genzyme, is going to do next. The FDA asked Sanofi to do another Phase III study with a different design. However last month Sanofi’s CEO Chris Viehbacher publicly stated that paying for and carrying out a new study is out of the question. Instead Lemtrada’s development team is working on a report that they will be submitting to the FDA later this quarter. In it they are extending the data from the existing trials to show results over a longer period of time, and to hopefully convince the FDA of Lemtrada’s potential benefits. They are hoping this is enough to get FDA approval.
Lemtrada is given via IV infusion, and its dosing is unique compared to current treatments. The first treatment is given IV once a day for five days, then another round lasting three days is given one year later. Researchers think that most patients will only require two doses in order to gain a long term benefit. Like other infusion medications already on the market it would be used on patients for whom other treatments have failed. It would also have to be given under the care of a specialist and, similar to other MS drugs, side effects would have to be monitored closely.
Campath, which is the same drug as Lemtrada, is used to treat leukemia. It has been taken off of the market in the US by Genzyme Sanofi while they have been attempting to gain FDA approval for Lemtrada. This has been to prevent doctors from prescribing Campath off label for MS patients. So currently patients who have progressive disease and are desperate for another option to try, have no way of gaining access to this potentially effective treatment. Taking Campath off of the market and rebranding it as Lemtrada, an MS drug, would mean that Genzyme Sanofi would go from making almost no profit to making roughly $60,000 per treatment.
So clearly Genzyme Sanofi stands to make a significant financial gain from Lemtrada, and patients gain the opportunity to try another treatment. After reading the clinical studies it is clear that Lemtrada is not without risks, but I don’t see how this is so different from every other disease modifying drug on the market. It will be interesting to see what happens next.