Staff Writer

About seven months after closing its Phase III study with apricitabine (ATC) for HIV ahead of schedule, Avexa Ltd., quit development of the nucleoside reverse transcriptase inhibitor entirely, saying the final would-be partner has declined to submit a term sheet and staff is being reduced as the company considers options.

CEO Julian Chick has resigned, too.

Melbourne, Australia-based Avexa's stock (ASX:AVX) plunged A9 cents (US8 cents) on the news to close at A3 cents, which leaves the firm to consider a merger, acquisition, in-licensing opportunities and anything else that might help shareholders recoup. Partnering talks have gone on for about two years.

In October, Avexa said it was halting early the Phase III trial, and would evaluate 24-week data comparing the drug to Epivir (lamivudine, GlaxoSmithKline plc) while sorting would-be partners. The study had been intended to run through 2011.

Avexa's idea was to use ATC in patients who had developed resistance to other NRTIs, but high doses needed with the compound meant combinations were less feasible, even though the drug seemed to hit safety and efficacy goals. New NRTIs have faced an uphill climb for a while anyway, given the success of HIV therapies with differing targets in a crowded market, such as Whitehouse Station, N.J.-based Merck & Co.'s integrase inhibitor Isentress (raltegravir), cleared by the FDA in 2007. (See BioWorld Today, Oct. 28, 2008.)

The company's board believes all possibilities for a global licensing deal are off the table now, but discussions continue regarding a regional deal, though the firm cautioned that the prospects still are uncertain and "if completed, would be unlikely to generate a meaningful return" on money spent so far. As of March 31, Avexa had about A$26.6 million in cash, with nothing else to tout in the pipeline.

ATC, a cytidine analogue, was developed as BCH10618 by Laval, Quebec-based BioChem Pharma, which was acquired by UK-based Shire Pharmaceuticals plc in a deal disclosed in late 2000. Shire renamed the drug SPD754 before selling the rights to Avexa. (See BioWorld Today, Dec. 12, 2000.)

In vitro work suggested ATC might hit HIV strains resistant to the likes of Retrovir (zidovudine, GSK) and Epivir, and trial results affirmed efficacy against virus resistant to Epivir.

In 2009, Avexa shares took a 45 percent jump on word from a Phase IIb trial that ATC in 96-week data showed more than 85 percent of patients continuing with HIV loads below detectable levels and all patients staying on ATC treatment. CD4 cells kept rising over the period as well. Patients who entered the trial had already failed other HIV treatment, including Epivir, and some had failed multiple previous HIV treatments. (See BioWorld Today, March 17, 2009.)

Those results gave Avexa renewed hope after a foiled merger with Progen Pharmaceuticals Inc., of Brisbane, Calif., from which Avexa had hoped to gain funds to continue its work on ATC. Progen had just quit its Phase III bid with lead drug PI-88 in liver cancer since - like Avexa now - it couldn't find a global partner, partly due to the rise of Nexavar (sorafenib, Onyx Pharmaceuticals Inc. and Bayer Healthcare), which had just started Phase III trials. But Progen shareholders voted against the merger. (See BioWorld Today, March 11, 2009.)

Published  May 11, 2010