Nearly all of the hepatitis C patients taking a combination of three Abbott drugs -- ABT-450, ABT-267, and ABT-333 -- and a generic called ribavirin were free of virus 12 weeks after finishing the drug regimen, which itself lasted 12 weeks. Just one of the 77 patients who have gotten that far in the trial had a relapse. There were also two patients with missing data, so those patients could bring down the 99% cure rate a little.
What's truly amazing is that 93% of patients who failed to respond to previous treatments were free of virus 12 weeks after treatment ended. That number might come down a little when we get data for longer sustained virological response, but it still towers over the current treatments. Vertex Pharmaceuticals' (NASDAQ:VRTX) Incivek cured 32 % of null responders. Patients who had a partial response to previous treatment, which tend to have better response the next time, achieved only a 52 % cure rate for Merck's (NYSE:MRK) Victrelis.
Abbott's four-drug regimen isn't exactly simple, especially compared with Gilead's combination of GS-7977 and GS-5885. Gilead might also include ribavirin in the combination, but three drugs are still less than four.
Abbott might be able to combine the drugs to reduce the number of pills taken, but under the current treatment regimen, there won't be a single pill because two of the drugs are taken once daily while another has to be taken twice daily.
Pill burden is a big issue for HIV patients and has helped Gilead make a lot of money with its combination pills, but I'm not sure it'll be as big of an issue for hepatitis C patients. HIV patients have to take the drugs for the rest of their lives; hepatitis C drugs will be taken for only a few months.
This is only phase 2 data; we need to wait for the phase 3 data to declare a winner. I think doctors will prescribe the drug with the best efficacy assuming it has a tolerable safety profile. If the two drug combinations are fairly equal on both those fronts, then the one with the best convenience will certainly win.
Of course, cure rates can't get higher than 100%, so safety and convenience will become an increasingly important aspect of hepatitis C drug characteristics. Investors in hepatitis C drugmakers, such as Achillion Pharmaceuticals (NASDAQ:ACHN) and Idenix Pharmaceuticals (NASDAQ: IDIX), with drugs further back in the clinic had better take notice if they don't want to get stomped on.