Adempas: Bayer is first off the starting block in a crowded race

Adempas
Project name: riociguat
Diseases: Pulmonary arterial hypertension, chronic thromboembolic pulmonary hypertension
Peak sales estimate: $679 million
Approved: Oct. 8
Company: Bayer

The Scoop:
The FDA set priority review status for riociguat, helping make it the first of a new generation of drugs for pulmonary arterial hypertension (PAH), giving Bayer a very small head start in a crowded field.

Just 10 days after it announced its Adempas approval, the FDA gave the green light to rival Actelion's ($ATLN) Opsumit (macitentan). Opsumit is an oral version of Tracleer (bosentan), which brought in $1.6 billion last year as an injectable treatment for PAH. A third entrant, United Therapeutics ($UTHR), is joining the game a little late after a surprise approval in late 2013 for its oral version of Remodulin.

Adempas and Opsumit will also face off against Gilead Sciences' ($GILD) Letairis (ambrisentan), an existing oral treatment for PAH. Letairis brought in $410 million last year. A fourth pill, Pfizer's ($PFE) Revatio, contains the same active ingredient as the erectile dysfunction drug Viagra.

Where Adempas stands alone is as a treatment for chronic thromboembolic pulmonary hypertension (CTEPH). Once considered a rare condition, CTEPH was recently shown to complicate 3.8% of acute pulmonary embolic events.

Thomson Reuters Pharma put analysts' average sales projection for Adempas at $679 million by 2017. The drug joins Stivarga for metastatic colorectal cancer (2012) and Xofigo for advanced prostate cancer (2013) among Bayer's recent new drug approvals.

PAH causes elevated pressure in the pulmonary arteries, which carry blood from the heart to the lungs. Symptoms include shortness of breath, fatigue, chest pain and racing heartbeat, according to the NIH. Heart failure is the most common cause of death in PAH patients.

A 12-week clinical trial of Adempas for PAH included 443 participants taking 1.5 mg or 2.5 mg of Adempas, or placebo, three times daily. Adempas patients' 6-minute walk distance improved by an average of 36 meters (about 118 feet) more than that of placebo patients.

Adempas' safety and effectiveness in patients with CTEPH were established in a 16-week clinical trial with 261 participants randomized between placebo and Adempas, with the dose gradually increased up to 2.5 mg three times daily. Adempas patients' 6-minute walk distance improved 46 meters (about 150 feet) over placebo. -- Galen Moore (email | Twitter)

For more:
Bayer's now-approved Adempas girds for market-share battle in PAH
Bayer bolsters campaign for PAH drug riociguat with positive long-term data
Actelion wins crucial FDA approval for next-gen lung-disease drug Opsumit
Strike two: FDA hands United Therapeutics another snub on oral Remodulin

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Adempas: Bayer is first off the starting block in a crowded race