West Coast Editor

Sunesis Pharmaceuticals Inc. in-licensed the Phase I cyclin-dependent kinase inhibitor BMS-38702 from Bristol-Myers Squibb Co. - the second time in a week that a biotechnology firm has tapped the pharmaceutical giant for a drug candidate.

"They were running an auction and we heard about it," said Eric Bjerkholt, chief financial officer for South San Francisco-based Sunesis. "We're building an expertise in cell-cycle inhibitors and kinases, and the CDKs are both, so it fit very well with what we're doing strategically."

Also, the company's head of biology "has a lot of experience with CDKs," he added.

Privately held Sunesis gets an exclusive worldwide license to the compound (renamed SNS-032) and any future CDK inhibitors derived from the related intellectual property, providing in return an equity stake of $8 million and milestone payments of as much as $29 million in cash and equity, based on development and approval of the cancer drug.

Added milestones could total up to $49 million in cash and equity, and Sunesis would make royalty payments on net sales.

Specifically, SNS-032 is a novel aminothiazole small-molecule cell-cycle modulator that targets CDK2, CDK7 and CDK9, designed to halt uncontrolled cell division. Preclinical studies showed the drug brings about cell-cycle arrest and apoptosis across multiple cell lines, the company said.

Though currently being tested in an intravenous formulation, the drug has potential as an oral therapy. Sunesis plans to get SNS-032 into a Phase I trial this year in patients with advanced solid tumors and relapsed lymphoid malignancies.

Others are busy in CDK research. Just this month, New York-based Innovate Oncology Inc. signed a deal with Prostagenics LLC, of East Rutherford, N.J., for the rights to Capridine-Beta, a nitroacridine derivative for prostate cancer that works by stimulating expression of p16, the tumor-suppressor gene that inhibits CDK2, CDK4 and CDK6. An investigational new drug submission is under way for a Phase I dosing trial for advanced solid tumors.

CDK2 seems of particular interest, and UK-based Cyclacel Group plc has advanced its CDK inhibitor seliciclib (CYC202, or R-roscovitine) to Phase II trials for multiple myeloma, B-cell chronic lymphocytic leukemia and mantle-cell lymphoma. Cyclacel reported positive data from the myeloma trial late last year at the American Society of Hematology meeting in San Diego.

"Different people are interested in different members [of the class]," Bjerkholt said. "The ones you hear about the most are CDK2, CDK4 and CDK6. I won't claim that I'm the expert on that, but as part of our strategy we keep track of what the competition is doing."

He noted Sunesis is in registration for its initial public offering and thus could not comment at length.

The company filed for its IPO late last year, estimating proceeds at $86.25 million, with about $17 million earmarked for development of its cytotoxic agent SNS-595, currently in Phase I trials. (See BioWorld Today, Dec. 28, 2004.)

Phase II studies in multiple tumor types are set to begin in the second half of the year, along with a Phase Ib study in leukemia, Bjerkholt said. Work so far has shown the drug is able to selectively target cells undergoing DNA synthesis to induce apoptosis and G2 cell-cycle arrest, and is not affected by the loss of the p53 tumor-suppressor gene - signaling instead through p73.

On Wednesday, Cambridge, Mass.-based Elixir Pharmaceuticals Inc. entered a licensing deal with BMS to develop and sell the latter's preclinical growth hormone secretagogue, BMS-604992, and five related compounds. Squeezed by generic competition, BMS might be looking to out-license more and sharpen its focus. Overall sales by the pharmaceutical giant dipped in the first quarter, despite a strong showing by the colorectal cancer drug Erbitux (cetuximab), partnered with New York-based ImClone Systems Inc., which sold $87 million.