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Latinos Less Responsive to Hepatitis C Therapy

January 19, 2009

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Once again, ethnicity appears to be a factor in the effectiveness of Hepatitis C treatment. Sponsored by Roche, a recent study shows that Latinos have a lower response rate to standard treatment with peginterferon alfa-2a and ribavirin than non-Latinos.

HCV Therapy Less Effective in Latinos

By Michael Smith, North American Correspondent, MedPage Today

Reviewed by Zalman S. Agus, MD; Emeritus Professor
University of Pennsylvania School of Medicine.

SAN JUAN, Puerto Rico, Jan. 14 -- Latino whites with chronic hepatitis C virus infection respond poorly to therapy, compared with non-Latino Caucasians, researchers here said.

The finding, from a prospective but non-randomized study, adds ethnicity to the factors that predict outcomes to standard therapy for chronic HCV, according to Maribel Rodriguez-Torres, M.D., of the Fundacion de Investigacion de Diego, and colleagues.

And because the U.S. Latino population is growing, it may also highlight an important public health issue, Dr. Rodriguez-Torres and colleagues said in the Jan. 15 issue of the New England Journal of Medicine.

Previous studies have shown that blacks have a reduced response to standard treatment with peginterferon alfa-2a (Pegasys) and ribavirin (Copegus), the researchers noted, possibly because of a reduced sensitivity to interferon or diminished HCV-specific immunity.

At the same time, more limited data have hinted that a similar effect is present among Latinos, but because Latinos are often under-represented in clinical trials, the findings were not considered conclusive evidence that ethnicity plays a role in response, the researchers said.

To fill the gap, they enrolled 269 Latino and 300 non-Latino whites with chronic HCV genotype 1 infection, who had not previously been treated, for an open-label, non-randomized study.

They were given peginterferon alfa-2a at 180 mcg a week and ribavirin at 1,000 or 1,200 mg daily (depending on body weight) for 48 weeks and followed for another 24 weeks.

The primary endpoint of the study was sustained virologic response -- defined as undetectable HCV RNA level -- less than 28 IU/mL -- 24 weeks after the end of treatment.

The researchers also looked at secondary endpoints such as responses during treatment, rapid responses, and relapses.

Analysis showed:

* Baseline characteristics were similar, although more Latino patients were 40 or younger, had a body mass index of more than 27 or more than 30, and had cirrhosis.
* The rate of sustained virologic response was 49% among non-Latino whites compared with 34% among Latinos, a difference that was significant at P<0.001).
* Non-Latinos were significantly more likely (at P=0.045) to have undetectable HCV RNA in serum at week four and the advantage continued at all subsequent time points (P<0.001 for other comparisons.
* In an analysis adjusted for baseline differences in body mass index, cirrhosis, and other characteristics, non-Latinos were almost seven times more likely to have a sustained virologic response. The odds ratio was 6.93, significant at P<0.001.
* In both groups, a lower baseline HCV RNA level predicted a sustained virologic response.
* Adherence did not differ significantly between the two groups.
* And the number of patients with adverse events and dose modifications was similar, but fewer Latino patients stopped treatment owing to adverse events.

The findings "add to a growing body of evidence of differences in treatment responses among ethnic groups," Dr. Rodriguez-Torres and colleagues concluded.

They added that better treatment strategies are needed to improve the rate of sustained virologic response among Latinos with chronic HCV genotype 1.

They suggested that "Latinos should be considered for clinical trials involving specifically targeted antiviral therapies for hepatitis C to determine whether the addition of investigational agents to standard therapy improves the rate of response in this difficult-to-treat population."

The study was supported by Roche. Dr. Rodriguez-Torres reported financial links with Roche, Abbott Laboratories, Anadys, Pharmasset, Vertex, Glaxo-SmithKline, Bristol-Myers Squibb, Valeant, Novartis, Wyeth, Virochem Pharma, Idera, Intarcia, sanofi-aventis, Human Genome Sciences, Idenix, Pfizer, Gilead, Tibotec, and Merck.

Primary source: New England Journal of Medicine
Source reference:
Rodriguez-Torres M, et al "Peginterferon alfa-2a and ribavirin in Latino and non-Latino whites with hepatitis C" N Engl J Med 2009; 360: 257-67.

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URL for Article Source: http://www.medpagetoday.com/Gastroenterology/Hepatitis/12451

Posted by Editors at January 19, 2009 9:59 AM