Genes may predict response to diabetes drug

How well a person with type 2 diabetes responds to the anti-diabetes drug rosiglitazone (Avandia) may depend upon his or her genetic make-up.

Korean researchers have observed that type 2 diabetic patients with certain genetic variations in the adiponectin gene respond less favorably to Avandia treatment than do those who carry other genotypes. Adiponectin is a protein that is secreted by fat cells and is involved in regulating food intake and body weight.

The study, reported in the May issue of the journal Diabetes Care, joins a growing body of research focused on pharmacogenetics, that is how genetic factors influence a person's reaction to a specific drug.

In the study, Dr. Eun Seok Kang of Yonsei University School of Medicine in Seoul and colleagues studied 166 patients with type 2 diabetes who were treated with (Avandia) for 12 weeks.

"We found that variations in the adiponectin gene could affect the (Avandia) treatment response to the serum adiponectin level and blood glucose control," Kang told Reuters Health.

Compared with patients with other genotypes, carriers of the so-called GG genotype of the single nucleotide polymorphism (SNP) 45 of the adiponectin gene had a smaller reduction in fasting plasma glucose levels and HbA1c values, a measure of excess blood sugar. They also had a significantly smaller increase in blood adiponectin concentration.

Likewise, carriers of the GG genotype of SNP276 also showed less reduction in fasting glucose levels than did other patients.

These findings, the researchers say, might help doctors predict which patients will respond best to Avandia treatment. "Obviously knowing ahead of time which drugs will work best means we can eliminate the entire trial-and-error process of drugs that don't work or work poorly for some people," Kang said.

"Clearly we have a lot more to learn before we get to that stage, but this is an important first step."

SOURCE: Diabetes Care May 2005.