Novartis’ Sandoz has received US approval for the first generic form of Teva's multiple sclerosis blockbuster Copaxone (glatiramer acetate).

Marketed as Glatopa, the copycat drug is indicated for the treatment of patients with relapsing forms of MS, including those who have experienced a first clinical episode and have magnetic resonance imaging features consistent with the disease.

Glatopa is produced entirely in the US, but according to media reports launch plans are being kept under wraps, as Teva and Sandoz remain embroiled in patent litigation regarding the drug. As it currently stands, Copaxone’s patent protection is valid until September, though this is still the subject of an ongoing court battle.

Any delay to launch could see more patients switch from Copaxone to Teva’s long-acting version of the drug, given three times a week, potentially softening the blow of generic erosion, if only somewhat. Analysts fear that as much as 50% of Copaxone’s sales could be lost by 2018 because of cheaper copycats.

The once-daily injection was developed in collaboration with Momenta; its FDA approval has triggered a $10-million milestone payment to the firm, and it can expect another $10 million on first commercial sale of the drug.