Washington Editor

InterMune Inc. and Inhale Therapeutic Systems Inc. signed an agreement to develop a PEGylated version of InterMune's chronic hepatitis C drug, Infergen.

The companies expect to begin clinical trials on the new compound during the first half of the next year and hope to launch it in 2007, John Donovan, director of strategic planning and investor relations for Brisbane, Calif.-based InterMune, told BioWorld Today.

"Our feeling is that Infergen is really the most potent interferon for treating hepatitis C and, as a result, we are going to aggressively develop a PEGylated version that will allow one- to two-week dosing," Scott Harkonen, president and CEO of InterMune, told BioWorld Today. The PEGylated version is referred to as PEG-Infergen.

Applying the PEGylation technology, developed by Inhale's subsidiary, Shearwater Corp., is designed to help improve the effectiveness of the drug by increasing the circulation time in the bloodstream, improving the drug's solubility and stability, and reducing its immunogenicity.

In a prepared statement, Ajit Gill, president and CEO of San Carlos, Calif.-based Inhale, said of the deal, "We, too, are pleased to be collaborating with InterMune to improve the performance and delivery of its Infergen product and to address a significant medical need for hepatitis C patients. This collaboration is another validation of the use of PEGylation as the industry standard method for enabling improved performance of macromolecules."

When asked about specific financial terms of the deal, Harkonen referred to a prepared statement that said Inhale will provide expertise and exclusive manufacturing for the reagent used in the PEGylation of Infergen, while InterMune will be responsible for preclinical and clinical development as well as commercialization in North America. Inhale would receive milestones and royalties.

Harkonen characterized the agreement as a "straightforward licensing deal."

He said InterMune relaunched Infergen in January, just months after licensing the North American rights from Thousand Oaks, Calif.-based Amgen Inc. That deal was valued at about $29 million in up-front and milestone fees, plus future royalties. (See BioWorld Today, June 18, 2001.)

Sales figures for Infergen over the last six months were not available, however, but Harkonen did mention that there's been a strong growth in prescription trends since the relaunch. The company believes peak sales of the non-PEGylated version could reach $100 million a year.

Overall, Harkonen said the hepatitis C market could be worth $3 billion to $4 billion in five years, and Infergen is expected to compete well with existing products because of promising clinical data.

In non-PEGylated versions, Harkonen said when Infergen is matched against Intron A, it appears to produce better efficacy results.

"Infergen was engineered by Amgen to have five to 10 times the antiviral activity as a regular alfa interferon like Intron A," he said.

Last year InterMune released positive interim data from a Phase IV clinical trial showing that patients treated with Infergen in combination with ribavirin achieved a sustained virology response (SVR) of 56 percent compared with an SVR of 31 percent in patients treated with Interferon alfa-2b ribavirin (Rebetron, of Schering-Plough Corp.).

F. Hoffmann-La Roche Ltd. also sells a PEG-interferon called Pegasys and a non-PEG version called Roferon.

Harkonen said the company views the Infergen products as its third potential blockbuster in development.

"We think Actimmune for treating patients with idiopathic pulmonary fibrosis is a $400 million to $500 million market opportunity, and we'll be filing an NDA [new drug application] next year for oritavancin [a semisynthetic glycopeptide], which is an antibiotic for serious infections, and then right behind that is PEG-Infergen, which we believe will generate $750 million dollars for InterMune and that will help us reach our goal of $1 billion in revenues by 2008," he said.

In late August, InterMune's stock shot up 25.9 percent to close at $22.66 on news that Actimmune showed survival benefit in a Phase III trial involving 330 patients. The trial did not achieve statistical significance in reduction of disease progression. (See BioWorld Today, Aug. 29, 2002.)

Actimmune is on the market in the U.S. for chronic granulomatous disease and severe, malignant osteoporosis.

InterMune's stock (NASDAQ:ITMN) closed Monday at $31.49, up $1.21, while Inhale's stock (NASDAQ:INHL) closed at $5.38, up 42 cents.