Indevus Pharmaceuticals Inc. filed with the FDA seeking approval of Nebido, an injectable three-month formulation of testosterone for treating primary and secondary hypogonadism.

The move follows positive data in June from a Phase III pharmacokinetic study of Nebido (testosterone undecanoate), which requires injections every 12 weeks instead of every few weeks like existing approved products. Nebido already is approved in about 75 countries.

The new drug application filing continues a busy regulatory month for Lexington, Mass.-based Indevus, which on Aug. 3 gained FDA approval of Sanctura XR (trospium chloride extended-release capsules) for treating overactive bladder and last week received an approvable letter from the agency on Valstar for BCG-refractory carcinoma in situ of the urinary bladder.

Indevus already has a testosterone product on the market for male hypogonadism, Delatestryl (testosterone enanthate), which is designed for injection once every two to four weeks. The company said Nebido would be the first three-month testosterone preparation approved in the U.S., where it estimated the testosterone therapy market at more than $550 million. Indevus said about 130,000 of the 340,000 men in the U.S. receiving such therapy are using injectable products. The others use topical treatments.

Indevus acquired rights to Nebido in July 2005 in a deal with Schering AG, now Bayer Schering Pharma AG. That deal called for payments to Schering of up to $30 million, including $7.5 million up front and $5 million upon FDA approval. Schering also is entitled to receive an undisclosed percentage of sales.

Male hypogonadism is characterized by a reduced or absent secretion of testosterone from the testes, which can lead to health and quality-of-life problems, Indevus said. It estimated there are 4 million to 5 million men in the U.S. who suffer from the condition, with fewer than 10 percent of them receiving treatment with testosterone therapy.

The Nebido NDA filing contains data from six studies in which more than 400 patients received at least one dose of Nebido, with more than 300 of them treated for more than one year. It also includes post-marketing data from safety reporting through June, data that includes information on more than 260,000 injections of the product.

The 237-patient Phase III trial reported in June met its primary endpoints related to testosterone concentrations. Data showed 94 percent of patients receiving 1,000 mg of Nebido and 86 percent of patients receiving 750 mg ended up with a normal testosterone level, both surpassing the FDA's 75 percent response criteria.

Both treatment arms also demonstrated improvements from baseline in secondary clinical outcome variables, Indevus said.

Indevus reported cash and equivalents of $42.1 million as of June 30, the end of its third quarter. That figure did not include a $49.9 million milestone payment from Esprit Pharma Inc., its U.S. partner on the overactive bladder products Sanctura and Sanctura XR. For the nine-month period, it had revenues of $12.2 million, and a net loss of $95.1 million. The nine-month loss was $48.1 million excluding $53.3 million in charges related to its acquisition of Valera Pharmaceuticals Inc., of Cranbury, N.J., which was completed in April.

Robin DeCarlo, director of corporate communications at Indevus, said the current plan is that the company would market Nebido with its own sales force, which now totals about 100 people. She told BioWorld Today the acquisition of the hypogonadism product Delatestryl in January 2006 from Savient Pharmaceuticals Inc. was done with Nebido in mind.

"Delatestryl was a strategic move," DeCarlo said. "It opened the door to endocrinologist offices prior to" the planned launch of Nebido. "It helped build those relationships."

She said Indevus would determine later whether it would add sales reps upon approval and launch of Nebido.

In addition to Sanctura and Delatestryl, Indevus markets two implant products: Vantas, a 12-month hydrogel implant that provides histrelin, a luteinizing hormone-releasing hormone agonist, for the palliative treatment of advanced prostate cancer; and Supprelin LA, a 12-month implant for treating central precocious puberty.

Indevus' stock (NASDAQ:IDEV) fell 21 cents Tuesday to close at $6.89.