By 1995, BW conducted Phase 1 clinical trials of maribavir that proved the drug was nontoxic in humans, with the worst side effect reported being an unpleasant aftertaste.
Drach estimated maribavir could have been approved by the FDA before 2000, but progress was halted when BW merged with the Glaxo Corp. to become Glaxo Wellcome. As the new company decided which drugs to prioritize, maribavir was “put on a shelf,” and stayed there when the company was again bought out to become GlaxoSmithKline (GSK).
While the merging pharmaceutical companies put development on hold, Townsend’s group continued to make new drugs while Drach, Biron and their groups continued to research how maribavir and related compounds worked. Remarkably, although chemically similar to another compound, maribavir was found to inhibit CMV by a totally different mechanism.
“We discovered that maribavir had a very unique mechanism of action, one never before seen in an antiviral drug,” Drach said. The group also made interesting discoveries about how certain viral genes act to reproduce the virus.
Eventually, a company called ViroPharma was interested in licensing maribavir from GSK around the year 2000. While ensuring that the patents were in good order, it was found that Drach and Townsend were not listed as co-inventors, even though their ideas and efforts directly led to the drug’s discovery.
The issue of ownership of the patents went through an arbitration process, agreed to by GSK and the University of Michigan. Drach credited “divine guidance or pure dumb luck” in assisting being recognized for their contributions.
“One Saturday afternoon, [Townsend] was straightening out things in his office and found certain presentation materials that absolutely established that he and I had discussed compounds like maribavir before we ever met people at the pharmaceutical companies,” he said.
The arbitrator said Townsend was a co-inventor on four relevant patents, with Drach credited as co-inventor on three patents.
“So that’s why I can claim myself as a co-inventor on maribavir,” Drach said. “So essentially, two Davids took on Goliath and we won. It’s pretty remarkable.”