(Reuters) - Momenta Pharmaceuticals Inc and Mylan NV plan to begin a pivotal clinical trial of a biosimilar to Regeneron Pharmaceuticals Inc's blockbuster eye drug Eylea in the first half of this year, the two companies said on Wednesday.
If successful, it would likely mark the first competition from a cheaper biosimilar of Eylea, although Regeneron says it has U.S. patent protection on the treatment until 2023.
Germany's Formycon AG is far along in testing a biosimilar to Eylea rival Lucentis from Roche. It lists an Eylea biosimilar at the preclinical stage on its pipeline chart, putting it behind the Momenta/Mylan candidate.
Eylea, which treats a leading cause of blindness in the elderly - wet age-related macular degeneration - and related eye conditions, accounts for most of Regeneron's revenue.
Regeneron shares fell 1.5 percent to $388 in extended trading. Momenta shares rose 6 percent to $15, while Mylan shares were unchanged from their Nasdaq close at $43.14.
U.S. Eylea sales rose 12 percent in the third quarter to $953 million. Sales outside the United States, which are booked by Bayer AG, rose 20 percent in the most recently reported quarter. Global sales in 2016 exceeded $5 billion.
Eylea is also approved to treat macular edema following retinal vein occlusion, diabetic macular edema and diabetic retinopathy in patients with diabetic macular edema.
The proposed trial of the biosimilar, currently called M710, will be in patients with diabetic macular edema and compare the safety, efficacy and immunogenicity with Eylea.
Unlike generic versions of traditional pills, it is not possible to produce exact copies of complex biotech medicines made from living cells, thus the term biosimilar. Proposed biosimilars must prove themselves to be close enough to the original drug to satisfy regulators.
(Reporting by Bill Berkrot; Editing by Susan Thomas)