Genzyme, a subsidiary of Sanofi (NYSE:SNY), announced this morning that the FDA has returned the company’s supplemental Biologics License Application (sBLA) for Lemtrada on grounds that the presented data needs reorganization. Genzyme submitted the drug for review in June of this year and hoped for a Priority Review designation to allow for faster commercialization, as early as six months from the acceptance date if granted. The FDA’s Refusal to File (RTF) does not require new testing or data for the drug, which might have been required under a Complete Response Letter, but will delay approval and launch. Sanofi hopes Lemtrada (alemtuzumab) will be approved for the treatment of relapsing multiple sclerosis (MS), for which trials showed promising results when compared to an existing  treatment. In the recent Phase III CARE-MS study, Lemtrada was tested against Pfizer’s (NYSE:PFE) Rebif MS treatment and demonstrated that disability was significantly slowed by Lemtrada compared to Rebif. In fact, patients treated with the Genzyme drug were twice as likely to experience a reduction in disability. Revenue from Lemtrada is expected to reach $400-$600 million annually in six years if approved. Today’s setback, however, will delay the launch of Lemtrada. The company has been hoping for a late 2012 or early 2013 launch if the drug was granted a fast-track review process, but with time for presentation reorganization, the launch could be delayed by months. Investors should consider Lemtrada a late 2013 product unless the company gives strong evidence of a priority review by the FDA, plus a quick resubmission. Sanofi shares will be weak today given early guidance for a possible 2012 approval. Some investors may have already been factoring the approval into 2012 estimates.

Interestingly enough, Sanofi pulled the plug on another drug marketed by the company, Campath, just last week. Lemtrada is essentially a different dosage of Campath, which is approved as a leukemia treatment but only brought in about $75 million last year. Campath’s removal began in a few European countries this year and is expected to continue gradually until it remains in as few as 50 countries worldwide. With glaring similarity between Campath and Lemtrada, Sanofi hopes to avoid off-label use of Campath and increase Lemtrada’s price to closer resemble competitors like Tysabri and Gilenya, from Biogen Idec (NASDAQ:BIIB) and Novartis (NYSE:NVS) respectively, both of which cost around $50,000 annually for treatment. Campath, used off-label to treat MS instead of leukemia, would cost less than $10,000.

Genzyme and Sanofi’s other developmental multiple sclerosis treatment, Aubagio, is still in testing as a pipeline candidate and the companies released positive results in June comparing the drug to a placebo. Abagio, however, failed to beat Rebif in previous trials, and has yet to impress analysts.