The FDA's approval of Genzyme Corp.'s Lemtrada (alemtuzumab) for relapsing forms of multiple sclerosis (MS) Friday brought good news for patients who've had trouble with other therapies, not to mention its parent company, Sanofi SA, which received a complete response letter last year questioning the drug's benefits in light of its risks.

But with biosimilar versions of Campath – a therapy with the same active ingredient that has been used off-label to treat MS – in the pipelines of at least four competitors, solid long-term profits from the therapy may be diminished.

Fully aware of the threat that off-label prescribing of Campath might have held for Lemtrada, Sanofi in 2012 pulled Campath from the market. It's still available, free-of-charge, to patients who need it through a special access program. But for all intents and purposes it's gone, except in the biosimilars world, where work to revive it continues.

Harvest Moon Pharmaceuticals USA Inc. and Panpharmaceuticals Inc. are together planning a European Union filing for its biosimilar alemtuzumab this year, while Biosavita Inc., Bioxpress Therapeutics SA and Zhejiang Hisun Pharmaceuticals Co. Ltd., all have their own versions of the CD52 antagonist and clusterin stimulator in the works. If anyone reaches the finish line, it could reintroduce off-label usage of the drug for MS, potentially threatening Lemtrada sales, which analysts on average have pegged at $141 million next year and about $461 million by 2019, according to Thomson Reuters Cortellis.

Campath, approved by the FDA in 2007, faces patent expiration in 2015. With the reference biologic off the market, biosimilar Campath from any one of the four challengers would have a potentially clear path to market. Doctors upset at Sanofi's strategy or patients focused on saving money could even end up seeking out the biosimilars, which could be even cheaper than Campath, off-label for MS.

Campath was approved for chronic lymphocytic leukemia (CLL), an indication for which it was given in a different dosage than Lemtrada. Before Sanofi discontinued marketing it, the CLL therapy sold for $60,000 per year, according to Datamonitor. "But MS patients require just a fraction of the dosage used for CLL, equating to $6,000 per year if priced relatively," the independent market analyst wrote, suggesting that would be too low a price to charge in the MS market.

While Lemtrada was approved in the European Union in September 2013, its arrival in the U.S. was slowed by a 2013 year-end complete response letter from the FDA.

A less-than-glowing Peripheral and Central Nervous System Drugs Advisory Committee meeting drove the value of contingent value rights (NASDAQ:GCVRZ) attached to alemtuzumab's performance off a cliff in November last year, sending them tumbling to 77 cents on Nov. 8, 2013, from an earlier close of $2 each. With Friday's approval, shares recovered somewhat, rising 74.8 percent to 90 cents. (See BioWorld Today, Nov. 13, 2013, and Dec. 31, 2013.)

OPTIONS NEEDED

Regardless of what form relief comes in, MS patients across the country have made clear to the FDA that new treatment options were needed, even when they carry risks.

"The approval of Lemtrada provides an important and immunologically powerful new therapeutic option for people with relapsing MS," said Bruce Cohen, a professor at Northwestern University's Feinberg School of Medicine and chair of the National MS Society's National Medical Advisory Committee. "Its long-lasting effects may profoundly influence the course of relapsing MS, but will require careful and sustained monitoring for side effects which people receiving the medicine must follow."

Among the labeled risks MS patients will need to consider are sometimes fatal autoimmune conditions, serious and life-threatening infusion reactions and a potentially increased risk of malignancies. Accordingly, the FDA said, the drug should generally be reserved for patients who have had an inadequate response to two or more drugs indicated for the treatment of MS.

A comprehensive risk evaluation and mitigation strategy will be instituted in order to help detect and manage the serious risks identified with treatment.

Lemtrada is given as intravenous infusion, for five consecutive days initially and for three consecutive days one year later.