Tarsa Completes Phase III For Oral Calcitonin In Osteoporosis, Plans 2011 NDA

Initially, biotech will pursue a treatment indication but also has its recombinant oral formulation in Phase II for osteoporosis prevention.

Tarsa Therapeutics has completed Phase III testing of recombinant oral salmon calcitonin in the treatment of post-menopausal osteoporosis and plans to file an NDA by the end of this year.

As it gears up for an FDA decision, the company is considering its business development options, including partnering opportunities. The company could announce its partnering plans by the end of the year, said CEO David Brand in an interview, indicating a partner would be necessary to market the drug effectively.

"I think it would be feasible to market the product along with a partner if that particular option was chosen," Brand said. "Because of the broad use of osteoporotic products, you would have to have a fairly broad reach with respect to marketing this product appropriately.

That said, partners may be hard to come by, given difficulties of the osteoporosis market, which is heavily genericized (Also see "Warner Chilcott’s Launch Of Atelvia Hits Headwinds" - Pink Sheet, 27 Jun, 2011.). Because of pricing pressure and concerns about the safety of a key class of drugs, bisphosphonates, for osteoporosis, sales and volume are declining in the U.S.

Meanwhile, the company also announced on July 12 that it has raised $24.5 million from existing investors to fund the drug's clinical development and other expenses.

The privately held, Philadelphia-based firm announced positive Phase II top-line data in March from the pivotal ORACAL study, in which its once-daily oral formulation was tested against both placebo and a nasally inhaled version of calcitonin. Marketed by Novartis as Miacalcin (chemically derived calcitonin) and Upsher-Smith as Fortical (recombinant calcitonin), nasal calcitonin has been approved by FDA as a treatment for osteoporosis since the middle of the last decade.

In ORACAL, the oral formulation demonstrated superiority to placebo and non-inferiority to Fortical as measured by a primary endpoint of percent improvement in lumbar spine bone mineral density following one year of treatment. The study also found the oral version had similar tolerability to nasal spray calcitonin and to placebo.

Brand said safety would be one of the key differentiators between its product and other osteoporosis drugs already on the market. "Calcitonin has been utilized for over 30 years, with nasal spray [use] now close to seven years, and has over 1 million years of patient use with a pretty well-defined safety record," he said. "You don't hear reports of similar bone events with calcitonin products as you do with bisphosphonates."

Full data of the completed ORACAL study will be presented at the 2011 American Society for Bone and Mineral Research meeting in San Diego in September, Tarsa said on July 12. Details of the full data package will not be revealed until then.

Meanwhile, the company also has fully enrolled the 120-patient TAR01-201 Phase II trial to test oral calcitonin for prevention of osteoporosis and maintenance of bone mass in post-menopausal women with low bone mass (osteopenia) and increased risk of fracture. Six-month data from the proof-of-concept trial should be available in early 2012, Tarsa says.

$24.5 Million To Back Prevention Trials

The trial will be financed through a $24.5 million multi-tranche private financing with individual investors. Brand said each of the company's original investors, who backed Tarsa with a $24 million Series A round in 2009, participated ([See Deal]). They include MVM Life Science Partners, Novo AS, Quaker BioVentures and Unigene Laboratories.

Unigene, which licensed the rights to recombinant oral calcitonin to Tarsa in 2009, is a 25% owner of Tarsa ([See Deal]). Under that deal, Unigene, which out-licensed the program so it could focus on peptide development and manufacturing activities, also could qualify for sales milestones and royalties.

Those milestones and royalties could be significant if oral calcitonin finds the market Brand expects. Market research with private and public payers indicates that they are eager for an oral osteoporosis drug that would be easier to use than nasal spray and safer than bisphosphonates.

"In comparison to bisphosphonates and other agents in the physician's potential armamentarium, the managed care organizations seem quite positive and open to listing oral calcitonin initially as a replacement for nasal calcitonin," Brand said. "And also as a use for patients who cannot take bisphosphonates or estrogens. And then lastly as a product that would be utilized in a younger, earlier population - first-time osteoporosis patients who are looking for a safer agent."

Brand wouldn't speculate whether prevention would be a more lucrative market for the product, although he indicated that a prevention indication - which currently available formulations of calcitonin do not have - would find an audience that would use the product for a long period of time and be attracted by a strong safety profile.

"I could see [oral] calcitonin being utilized in the existing patient population first and then moving into prevention treatment," he said. "That is, while not a larger treatment population, a much larger diagnosed and epidemiologic-sized population."

Tarsa, which has a Special Protocol Assessment with FDA for the treatment indication, expects to file an NDA later this year backed by the single Phase III trial. The company also expects to file in Europe next year with data from the one pivotal trial.

-Joseph Haas ([email protected])