By Liz Highleyman

Research has consistently shown that people of African descent do not respond as well as Caucasians to interferon-based therapy for chronic hepatitis C virus (HCV) infection, but treatment response in people of Asian descent has not been as extensively studied.

As reported at the Digestive Disease Week (DDW 2009) annual meeting last week in Chicago, Philip Vutien of the Pacific Health Foundation and colleagues compared treatment responses in a large cohort of Asian-American and non-Asian patients in a real-life community setting.

The study included 307 consecutive treatment-naive chronic hepatitis C patients (162 Asian-American, 124 non-Asian) with HCV genotypes 1, 2, or 3. Between January 2002 and November 2007, participants were treated with pegylated interferon plus ribavirin at 3 community-based gastrointestinal clinics in Northern California. Treatment adherence was defined as receiving at least 80% of prescribed doses of both drugs for at least 80% of intended duration.

Results

	There were no statistically significant differences between Asian-American and non-Asian patients with regard to sex, age, baseline ALT level, or baseline HCV RNA level, but the non-Asians had a higher average body weight.
	There were no significant differences in overall treatment adherence between Asian-American and non-Asian participants.
	In an intention-to-treat analysis, there were no significant differences in sustained virological response (SVR) rates between the 2 groups:
	Genotype 1: 58% for Asian-Americans vs 49% for non-Asians (P = 0.20); Genotypes 2 or 3: 83% vs 77%, respectively (P = 0.52).
	SVR rates were also statistically similar in a sub-analysis of patients with adequate treatment adherence:
	Genotype 1: 74% for Asian-Americans vs 68% for non-Asians (P = 0.49); Genotypes 2 or 3: 96% vs 83%, respectively (P = 0.13).
	While sustained response rates were consistently slightly higher for the Asian-American patients, this did not reach statistical significance.
	In a multivariate analysis, treatment adherence, HCV genotype, and age were independent predictors of SVR, but baseline cirrhosis, baseline HCV RNA, and race/ethnicity were not:
	Good treatment adherence: OR 5.2 (P < 0.0001); Genotype 2 or 3 vs 1: OR 3.2 (P = 0.001); Older age (year year): odds ratio (OR) 0.97 (P = 0.04); Cirrhosis vs non-cirrhosis: OR 0.41 (P = 0.066). Asian-American vs non-Asian: OR 1.5 (P = 0.18). Baseline HCV viral load (per 1 log increase): OR 0.81 (P = 0.26);

"In a real-life community setting, we found SVR rates in Asian-Americans and non-Asians are comparable to results shown in registration trials for both genotypes 1 and 2/3," the investigators concluded. "Our results suggested an association between Asian ethnicity and SVR, but this did not reach statistical significance."

Pacific Health Foundation, San Jose, CA; San Jose Gastroenterology, San Jose, CA; GI and Hepatology, Stanford University Medical Center, Palo Alto, CA; Stanford Humboldt-Del Norte Clinic, Eureka, CA; Gastroenterology, Palo Alto Medical Foundation, Camino Medical Group, Mountain View, CA.

6/12/09

Reference
P Vutien, NH Nguyen, HN Trinh, and others. Response to Peginterferon (PEG IFN) and Ribavirin (RBV) in Asian Americans and Non-Asian Americans with Chronic Hepatitis C (CHC) in a Real-Life Community Setting: a Multi-Center Study. Digestive Disease Week (DDW 2009). Chicago. May 30-June 4, 2009. Abstract M1786.