In its first phase 3 trial, 96% of patients taking AbbVie's five-drug combo -- ABT-333, ribavirin, ABT-450, ritonavir, and ABT-267 -- were virus-free 12 weeks after finishing the medication. Essentially, the drug combination cured almost all the patients.
The trial enrolled patients infected with genotype 1 hepatitis C virus, the most common in the U.S. Within that genotype, there are two subtypes, 1a and 1b, and the drug combo did quite well on the harder-to-treat genotype 1a, scoring a cure rate of 95%.
More to come
This is just the first in a six-trial phase 3 program. AbbVie is also testing patients that already failed a previous treatment containing Roche's Pegasys or Merck's (NYSE:MRK) Pegintron. Vertex Pharmaceuticals' (NASDAQ:VRTX) Incivek, the first-generation oral drug that has to be combined with Pegasys, grabbed some of those treatment-experienced patients -- that's part of the reason Vertex had such a successful launch -- but there are still an awfully large number of them considering that Roche's and Merck's drugs were the only thing available for a long time and they only cured about half of the patients that took the drugs.
AbbVie is also testing a five-drug combination that skips the ribavirin. The generic drug can cause birth defects, so leaving it out would be an advantage if it doesn't lower the cure rate substantially. The company expects the trials to read out in the coming months, putting it on target to file marketing applications in the second quarter of next year.
Picking a winner
We'll have to wait for Gilead's phase 3 trials for its all-oral combination in genotype 1 patients to know which drug cures patients the best. When you're comparing the two, make sure it's an apples-to-apples comparison. Genotype, including the subtype, and whether the patient has failed a previous treatment affect how easy it is to treat patients.
Ultimately, though, the competition between AbbVie and Gilead is likely to end up being less about the cure rate than the other factors. If one combination beats the other by a couple of percentage points, I doubt that's going to sway doctors much. The difference might not even be meaningful since the breakdown of the populations in trials might be different.
With comparable efficacy, doctors' and patients' preference is likely to come down to side effects, cost, and convenience, likely in that order. So far, AbbVie's safety profile looks good; if Gilead can match it, the battle might come down to price. Part of AbbVie's regimen has to be taken twice a day while other drugs have to be taken three times a day, so AbbVie may lose on the convenience factor if it comes down to that.
The biggest winner might be Enanta Pharmaceuticals (NASDAQ:ENTA), which helped develop ABT-450 and is due up to $195 million in regulatory milestones, as well as double-digit royalties on sales of ABT-450. If AbbVie can make ABT-450 a blockbuster, Enanta Pharmaceuticals will benefit substantially considering it doesn't have any costs associated with the developing or selling the drug.