Washington Editor

Santarus Inc. won FDA approval of Rapinex, an immediate-release formulation of the proton pump inhibitor omeprazole, for the treatment of heartburn and other symptoms associated with gastroesophageal reflux disease, treatment and maintenance of healing of erosive esophagitis, and treatment of duodenal ulcers.

The company's stock (NASDAQ:SNTS) Wednesday soared 26.4 percent, or $3.01, to close at $14.40.

Santarus, a San Diego-based firm, is completing preparations for commercial sale and manufacturing, and anticipates launching the drug in December with its 230-person sales force.

Company officials could not be reached for comment.

The FDA approval concerns the powder for the oral suspension, 20-mg version of the drug. In a conference call Wednesday, company officials said they are developing capsule and chewable versions, and do not expect government clearance to require additional trials beyond pharmacokinetics studies.

Gerald Proehl, the firm's president and CEO, said Rapinex, which was approved in 10 months, is the first of the company's immediate-release proton pump inhibitors (PPIs) to win approval in the $12.9 billion U.S. market currently dominated by five delayed-release drugs. The FDA has requested that Santarus pursue another name for Rapinex.

To the company, FDA clearance validates its regulatory approach pathway.

"We plan to follow [this pathway] as we seek to bring additional products through the regulatory process to commercialization," Proehl said during the conference call.

Indeed, in February, the firm submitted a new drug application for the 40-mg dose of the powder version for the treatment of gastric ulcers and the prevention of upper gastrointestinal bleeding in critically ill patients. The Prescription Drug User Fee Act (PDUFA), or FDA action date, is Dec. 26.

Also, company officials said that in 2005 they plan to run trials to evaluate Rapinex in pediatric populations in which a liquid, titratable-dosage form might provide particular benefit.

Rapinex is designed to beat the widely used PPIs - omeprazole is one of them - that block stomach acid production by inhibiting the hydrogen-potassium adenosine triphosphate enzyme system. PPIs are available for oral use only in the delayed-release, enteric-coated formulation, which delays the onset of action. The powder-for-suspension version is an immediate-release omeprazole that uses an antacid (sodium bicarbonate) instead of an enteric coating to protect the omeprazole from acid degradation.

The 20-mg NDA was based on a favorable 359-patient Phase III trial, which compared Rapinex with intravenous cimetidine, a histamine-2 receptor antagonist. The primary endpoint of the study, the occurrence of clinically significant bleeding, also was used in the cimetidine trial, which led to its approval. The pre-specified analysis of the primary endpoint was statistically significant (p<0.025) for both the protocol and intent-to-treat populations, the company said. (See BioWorld Today, Aug. 7, 2003.)

Meanwhile, the 40-mg application is based on a pivotal Phase III study, which demonstrated that two hours after the first dose, the median gastric pH was 7.8 for Rapinex-treated patients and 6.4 for cimetidine-treated patients (p<0.001). Using acid-reducing agents, the therapeutic goal in critically ill patients is to raise gastric pH above 4. Failure to control gastric pH (pH<4 on two successive measurements) occurred during the 14-day trial in 58 percent of cimetidine-treated patients and in 18 percent of Rapinex-treated patients, leading to an increase of the cimetidine dose in 53 percent of patients and the Rapinex dose in 15 percent (p<0.009).

Santarus likely will seek a co-promotion partner in the powder version. Initially, the firm did not expect to seek a partner for the powder because it was believed that sales would be limited to certain populations, including the elderly who may have difficulty swallowing. However, Proehl said feedback from physicians indicated that the powder could be broadly prescribed.

Proehl said the company would begin the trial and regulatory process in Europe after it receives certain patent approvals.

Outside the U.S., Santarus intends to license development, distribution and marketing rights to one or more pharmaceutical companies with established commercialization capabilities.

Santarus raised $54 million in its IPO conducted in early April. In the conference call, Proehl said the company might need to raise additional funds to bankroll its operations. While he indicated that Santarus has several options for funding, he would not elaborate.

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