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Black patients (& new HCV therapy) fare well on Vertex hepatitis C drug
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from Jules: this nice response rate (SVR) by black patients to the regimen of a HCV protease inhibitor telaprevir + peginterferon/ribavirin is what can be expected from the new oral HCV therapies in development. The data reported below (62% cure rates for blacks) shows that blacks respond equally well as whites to the new oral regimens. In fact, Vertex reported for blacks with a good response by week 4 of therapy 88% achieved a cure after 24 or 48 weeks of triple drug therapy. The difference in response rates 75% vs 62% is due to the differential response rates between whites & blacks to peginterferon/ribavirin, where we know blacks don't respond as well to peg/rbv as whites. Other HCV protease inhibitors in development like those by BMS, Roche, BI, Gilead, Merck are likely to provide similar SVR rates. Moreso, when you combine 2 HCV oral drugs with peg/rbv the SVR rates will increase much more for blacks, perhaps to 75-80%, and when we have a regimen that includes 3 oral HCV drugs SVR rates for blacks and whites will truely soar. The idea of getting rid of peg/rbv from therapy and having a regimen of only oral HCV drugs is being studied but we don't know yet if an all oral regimen can sustain the SVR, the cure as we can see with peg/rbv. Either way the future of HCV therapy holds the promise of cure rates of 90%+ for most patients. In development are numerous classes of HCV drugs including HCV protease inhibitors, nucleosides (R7128), potent nucleotides (PSI-938, PSI-7977), NNRTIs (non-nucleoside reverse transcriptase inhibitors), potent NS5A inhibitors, so there will be lots of opportunities for putting together 3 drug regimens, with or without peg/rbv. The nucleoside (R7128) and the nucleotides (7977, 938) appear to be very friendly to developing drug resistance, it appears more difficult to develop resistance to these drugs than to the other classes of drugs, which make them very appealing. It will take a few more years for all these other drugs to be in the pharmacy, I would say 2-3 years for these other drugs to start flowing into the clinic & pharmacy. for the interim, next year the 1st 2 HCV protease inhibitors are expected to be FDA approved & in the pharmacy after or during the summer of 2011.
By Bill Berkrot
NEW YORK | Sat Oct 30, 2010 2:12pm BST
NEW YORK (Reuters) - A closer look at data from a late stage trial of Vertex Pharmaceuticals Inc's eagerly anticipated hepatitis C drug telaprevir showed impressive cure rates for black patients and for patients with advanced liver disease.
In the Phase III study known as Advance, 62 percent of black patients who received telaprevir achieved sustained viral response (SVR), which is considered tantamount to a cure. That compared with just a 25 percent cure rate from the current standard drugs of pegylated interferon and ribavirin.
"If you look at that treatment difference and then you look at the difference in the overall population, in fact the benefit relatively speaking is even greater," Robert Kauffman, Vertex's chief medical officer, said in a telephone interview.
"Obviously, from an absolute point of view it's still a little bit lesser response," he said.
The study's overall cure rates -- 75 percent for telaprevir in combination with the current standard drugs versus 44 percent for the standard drugs alone -- was previously released. But full details of the trial were being presented for the first time at the American Association for the Study of Liver Diseases meeting in Boston.
Breaking out an analysis of black patients in the trial was significant because of the greater prevalence of hepatitis C and historically lower cure rates for that population.
"African Americans bare a large proportion of the burden of hepatitis C in the United States" compared with Caucasians and the overall general population, Kauffman said.
According to data compiled from 1999 to 2002, one in seven African American men between the ages of 50 and 59 in the United States is living with hepatitis C.
Telaprevir, from a new class of antiviral drugs, is widely expected to be approved by U.S. regulators next year. Vertex plans to complete its application seeking approval this year.
Excitement has been high over the drug, and a similar experimental medicine being developed by Merck & Co, because they have demonstrated significantly higher cure rates than current drugs and the potential to cut treatment duration in half for many patients.
Cutting treatment duration from the current 48 weeks is a huge advantage as the current drugs, which must still be taken with the new medicines, can cause debilitating flu-like symptoms that cause many patients to discontinue treatment or avoid it altogether. It is believed that thousands of patients with hepatitis C have been putting off treatment to await the new, more effective medicines.
In the Advance study, 58 percent of patients who received telaprevir met the criteria for a 24-week treatment duration. That criteria called for levels of the virus in the blood to fall to undetectable levels after four and 12 weeks of treatment.
A separate study demonstrated no additional benefit from extending telaprevir treatment to the full 48 weeks in patients who met the criteria for shorter duration treatment.
A further sub-group analysis of the Advance data showed that telaprevir led to a 62 percent cure rate in hepatitis C patients with advanced liver fibrosis or cirrhosis compared with a 33 percent SVR rate on standard drugs. Patients with those conditions, which can lead to liver cancer or need for a transplant, are also traditionally more difficult to treat than the overall hepatitis C population.
"In our Phase III program, starting people with 12 weeks of telaprevir-based combination therapy resulted in significant improvements in viral cure rates, regardless of race, extent of liver damage or experience with prior treatment," Kauffman said.
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