Teva has received a jolt with the news that regulators in the USA are going to review Momenta Pharmaceuticals and Novartis unit Sandoz’ copycat version of the Israeli drugmaker’s blockbuster multiple sclerosis drug Copaxone.

The US Food and Drug Administration news has accepted for review an Abbreviated New Drug Application for a generic version of Copaxone (glatiramer acetate) submitted by Sandoz, a move that has pushed down Teva’s share price. The drug had US sales of $1.1 billion last year.

The Sandoz application comes on the tails of Mylan saying that it had signed a licensing and supply deal with India's Natco Pharma for another generic version of Copaxone. However Teva is ready to defend its patents on the drug vigorously, which run up to 2014.

The Petah Tikva-headquartered firm responded by saying that it intends to file a lawsuit for patent infringement against Momenta and Sandoz within the 45-day period provided under the Hatch-Waxman legislation. The suit will trigger a stay of the FDA approval of the ANDA until the earlier of the expiration of a period of 30 months or a district court decision in its favour, Teva added.

Hard copy to make
The company added that Copaxone is “a complex mixture of the acetate salts of synthetic polypeptides, non-uniform with respect to molecular weight and sequence”. Due “to the variability of the composition of the polymers”, it believes that “replicating this formulation would be extremely difficult and presents a significant challenge”.

Teva added that once subcutaneously injected, it is rapidly hydrolyzed locally and no level of the intact drug can be measured in the blood, “rendering a bioequivalence study comparing two formulations extremely difficult”. Therefore, evidence supporting the effectiveness of a generic copy “cannot be derived from bioequivalence studies but from a full-fledged clinical study using clinical outcomes”.

Analysts tend to agree with Teva that approval for a generic of Copaxone is a long way off. In a research note, Ken Cacciatore at Cowen & Co wrote that he believes the FDA will treat the drug as a biologic (though it was originally approved with a New Drug Application) so will fall under new generic biologic legislation due to come into force in the USA by the end of 2009.

"For Copaxone generic challengers, this likely will cause an extended delay,” he says, of at least five years, “and the resulting products would not be interchangeable." Credit Suisse analyst Marc Goodman noted that a filing “is just the start of a long and arduous process” and is no indication that a generic will or will not be approved anytime soon".