Washington Editor

GlaxoSmithKline plc terminated a licensing deal with Inex Pharmaceuticals Corp. to develop the cancer drug topotecan hydrochloride, using Inex's proprietary liposomal drug delivery technology.

Inex's stock (TSE:IEX) Wednesday fell C51 cents, or 10.1 percent, to close at C$4.55 (US$3.46).

Signed in November 2001, the agreement was valued at $36 million for Inex, a Vancouver, British Columbia-based company that uses its drug delivery technology to improve on generic drugs. (See BioWorld Today, Nov. 21, 2001.)

While GSK officials in Philadelphia could not immediately be reached for comment, Ian Mortimer, Inex's senior director of investor relations, referred BioWorld Today to a press statement that said GSK had experienced a number of technical problems in manufacturing the necessary supply of materials needed for clinical trials, and the problems delayed the commencement of clinical development.

To date, GSK has paid Inex $5.25 million in up-front and milestone payments.

GSK had planned to apply the liposomal technology to its camptothecin compound, topotecan hydrochloride, currently marketed by GSK as Hycamtin, a treatment for recurrent ovarian cancer and recurrent small-cell lung cancer.

GSK completely stopped development of the candidate, INX-0076, leaving Inex wondering whether it should pick up the drug and take it forward on its own.

"We are evaluating options on whether we have the opportunity to develop it ourselves, or whether we should develop a similar drug in the same class," Mortimer said.

When applied to chemotherapy drugs, the liposomal drug delivery technology offers prolonged blood circulation, tumor accumulation and extended drug release at the cancer site.

The GSK licensing agreement was a little unusual for Inex, a firm that prefers to control and own 100 percent of its products until it seeks marketing and commercialization partners.

For example, the firm's lead candidate, Onco TCS, comprised of the off-patent cancer drug vincristine encapsulated in the liposomal delivery technology, currently is under FDA review. Inex's Prescription Drug User Fee Act (PDUFA) date is Jan. 15. The company is requesting approval for Onco TCS as a single-agent treatment for patients with relapsed aggressive non-Hodgkin's lymphoma previously treated with at least two combination chemotherapy regimens.

In early 2004, Inex partnered Onco TCS with Bridgewater, N.J.-based Enzon Pharmaceuticals Inc. in a deal valued at $75.75 million for Inex, counting an up-front payment and development and sales-based milestone payments. There also is a royalty agreement. (See BioWorld Today, Jan. 21, 2004.)

Onco TCS initially was partnered with Elan Corp. plc, of Dublin, Ireland. Elan terminated the deal when it decided to focus its operations outside oncology. (See BioWorld Today, April 4, 2003.)

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