A hyaluronic acid-based drug delivery system being developedby Hyal Pharmaceutical Corp. is able to enhance the delivery ofa chemotherapeutic drug to tumors in animal models, accordingto results presented Monday at the Sixth InternationalConference on Regional Cancer Treatment being held inWeisbaden, Germany.

Ehud Klein of Israel's Sheba Medical Center reported that instudies on mice with either mammary or bladder cancers, theuptake of the anti-cancer drug 5-fluorouracil (5-FU) into thecancer was significantly higher when formulated withhyaluronic acid (HA) than when administered alone. Also, theHA-formulated drug was retained by the cancer forsignificantly longer periods of time than when given alone.

The site-specific targeting of HA is apparently a response tolocal tissue trauma. "We've seen that when there is damagedtissue -- physical or physiological -- there is local depletion ofHA (which is an integral part of the extracellular matrix foundin most tissues and organs) at the site of injury," explainedSamuel Asculai, president and chief executive officer of Hyal ofMississauga, Ontario. "When we add HA back (via topicalapplication or injection) it seems to target that area ofdepletion."

And then, Asculai told BioWorld, it appears that the presence ofHA at this site up-regulates additional receptors for HA. Thismeans that the HA "will be bound more intimately, and thedrug (it carries) will remain there for a while," he added.

Hyal (NASDAQ:HYALF) is currently conducting advanced clinicaltrials of three of its HA-formulated pharmaceuticals. Allcontain the non-steroidal anti-inflammatory drug diclofenac(which is off patent) in three different formulations that mayrepresent distinct mechanisms of action, explained Asculai.

Phase III trials are being conducted at 14 independent centersin Canada, the U.S., Australia and a number of Europeancountries on Hyal-CT1101 (for basal cell carcinoma), Hyal-AT2101 (for the topical treatment of pain) and Hyal-AV2201(for the intravenous treatment of moderate to severe pain).

-- Jennifer Van Brunt Senior Editor

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