"Genentech has had a relationship with Array since 2004 on anumber of programs so we have a good sense of their scientific prowess," Dr.James Sabry, vice president of Genentech Partnering, tells
ddn. "Afundamental respect for science has been a deep and abiding part of Genentech'sculture—an outlook that's been maintained after our acquisition by
Roche. Wealready had that positive relationship with and respect for Array, and when werealized they had a program much like ours in ChK-1, it made sense to do a dealstructure like this."
Combining the two programs has great appeal in part becausedrug attrition is such a huge financial drain on pharma and biotech companies.With two compounds to pursue, Sabry notes, the overall costs will be higherthan going it alone, but the chances of success are so much better than itmakes it worth the somewhat elevated cost.
Only one of the two compounds is likely to move forward,though, so increased costs of R&D won't be a long-term issue, he adds.
"There's no particular reason we couldn't theoretically goforward with both," Sabry notes, "but it's not likely. Both compounds have verysimilar mechanisms of action, so there probably wouldn't be much benefit to usor patients to move both forward. The trial results will help us to determinewhich of the two seems most promising."
ChK-1 is a protein kinase that regulates tumor cells'response to DNA damage that is often caused by treatment with chemotherapy. Inresponse to DNA damage, ChK-1 blocks cell cycle progression in order to allowfor repair of damaged DNA, thereby limiting the efficacy of chemotherapeuticagents.
The companies believe that by inhibiting ChK-1 in combinationwith chemotherapy, they can enhance tumor cell death, and they say that bothGDC-0425 and ARRY-575 are highly selective, oral ChK-1 inhibitors designed toenhance the efficacy of some chemotherapeutic agents.