BioWorld International Correspondent
Shares in Medivir AB dropped by 21.25 percent Tuesday on news that partner Boehringer Ingelheim GmbH opted to discontinue development of the HIV drug MIV-310 (alovudine) following a Phase IIa trial in which the compound failed to attain a target efficacy level.
Boehringer Ingelheim had licensed the compound, a nucleoside analogue reverse transcriptase inhibitor, in 2003 in a deal potentially worth up to €122 million in milestone payments to Medivir, of Huddinge, Sweden. (See BioWorld International, July 16, 2003.)
But Medivir ultimately gained only an up-front payment of €1 million from the alliance, as Boehringer, of Ingelheim, Germany, failed to replicate at a lower dose efficacy data that Medivir had obtained in an earlier Phase IIa study. In the latter trial, a 7.5-mg dose of MIV-310 resulted in a reduction of viral load of almost 99 percent in an open-label proof-of-principle study in patients with multidrug-resistant HIV.
Boehringer tested a 2-mg dose and, said Medivir CEO Lars Adlersson, saw a reduction of viral load of 70 percent.
"There is a class effect of nucleoside analogues causing toxicity long term," he said. "That long-term effect might have impacted Boehringer Ingelheim's decision to go for a lower dose." The efficacy level is similar, he said, to that of tenofovir, marketed in the U.S. as Viread by Gilead Sciences Inc., of Foster City, Calif., and no serious adverse effects were reported in the study or in the earlier high-dose trial.
However, Medivir does not plan to pursue development of the compound itself, Adlersson said. It is advancing another HIV compound, MIV-210, which also was recently dropped by a big pharma licensee, London-based GlaxoSmithKline plc.
"That's in preparation for a Phase IIa study," he said. Investment of a further $1 million will take that program to a position where it might be picked up by another partner, he said, whereas MIV-310 would require more resources to take it to the same point. Nevertheless, it might still be of interest, he said, if the trend toward increasing HIV drug resistance continues.
"We will, of course, have to see how other companies will look at that opportunity," he said.
The reverse will have no impact on the company's other programs or on its budget plans, as Boehringer Ingelheim had assumed all development costs associated with the program. Medivir reported SEK440.6 million (US$64.6 million) in cash at Dec. 31.