Staff Writer

Privately held Paratek Pharmaceuticals Inc. has found another partner to help develop its antibiotic PTK 0796 for life-threatening infections, this time joining with Swiss drugmaker Novartis AG in a deal valued at up to $485 million.

PTK 0796, now in late-stage development, previously was licensed to Merck & Co. Inc. until the arrangement ended in 2007 due to "a difference of opinion" on how the product should be developed, Thomas Bigger, Paratek president and CEO, told BioWorld Today.

Prior to the Merck collaboration, Boston-based Paratek partnered with Bayer AG in 2003, but that relationship dissolved in 2005 as Bayer turned its focus to other indications.

Both an oral and intravenous antibiotic, PTK 0796 is aimed at infections caused by drug-resistant bacteria such as methicillin-resistant Staphylococcus aureus. Patients could start with an I.V. while in the hospital and then take the pill form when they are discharged.

Studies have estimated there were nearly 100,000 deaths from hospital-acquired infections in the U.S. in 2002, and around 50,000 deaths a year in the European Union, according to Novartis.

Paratek's product could be more convenient than current options that are given strictly through I.V.

Another potential advantage, according to Novartis, is that it could be used as a single agent against a range of bacteria, unlike other antibiotics that may have to be used in combination.

A Phase II study in complicated skin and skin structure infections found that clinical success rates were 98 percent for PTK 0796 and 93 percent for linezolid (Zyvox, Pfizer Inc.). In the study, PTK 0796 was used as a single agent, while Zyvox was used for Gram-positive infections only and an additional antibiotic had to be given for Gram-negative cases.

The Phase II study met its primary safety and tolerability endpoints by showing no relevant difference between PTK 0796 and linezolid in terms of adverse events.

With relatively few antibiotics in the pipeline for resistant strains of bacteria, there was a "quite a bit of interest" in Paratek's product, Bigger said. But as Paratek considered potential partners, it realized that some company pipelines could potentially compete for resources with its antibiotic.

Novartis, on the other hand, had a pipeline that was "truly complementary," Bigger said. He also noted that Novartis' approach to developing the product was similar to what Paratek had in mind.

Last year, Novartis acquired Protez Pharmaceuticals, gaining North American and European rights to PTZ601 (razupenem), which currently is in Phase II development as the first injectable broad-spectrum antibiotic in the carbapenem class to cover MRSA. (See BioWorld Today, June 5, 2008.)

The Novartis portfolio for hospital-based infections includes Cubicin (daptomycin), marketed by Novartis in the European Union and other countries. Cubicin, developed by Lexington, Mass.-based Cubist Pharmaceuticals Inc., is the first of a new class of antibiotics called cyclic lipopeptides.

Joe Jimenez, CEO of the Novartis Pharmaceuticals Division, said in a statement that PTK 0796 "will potentially benefit patients by offering a flexible and highly effective approach to the treatment of a number of critical infections, and should form an important addition to our growing portfolio of antibiotic medicines."

Under the PTK 0796 deal, both companies will share the development costs of the antibiotic, but they have not divulged what the percentage will be for each party. They currently are working to hash out the timeline for a Phase III study of the drug that is currently under way in patients with cSSSI.

Paratek hopes to conduct another Phase III next year in patients with community-acquired bacterial pneumonia. Two Phase III studies would be needed in each of the indications pursued to file for regulatory approval.

The potential value of the deal includes an undisclosed up-front payment, as well as future milestone payments from Novartis, plus royalties on net sales if PTK 0796 is approved. Basel, Switzerland-based Novartis will gain the exclusive right to commercialize PTK 0796 on a worldwide basis.

Published  October 9, 2009