Double-blinded, Placebo-controlled Plasmid GHRH Trial for Cancer-associated Anemia in Dogs

Abstract

The use of growth hormone releasing hormone (GHRH) plasmid-based therapy to treat companion dogs with spontaneous malignancies and anemia receiving a cancer-specific treatment was examined in a double-blinded, placebo-controlled trial. The dogs (age 10.5 +/- 2.5 years, weight 24.9 +/- 12.9 kg) received a single 0.35 mg dose of plasmid or placebo intramuscularly (i.m.), followed by electroporation (EP), and were analyzed for up to 120 days. The response rate was defined as > or = 5% increase above the nadir in the red blood cell (RBC), hemoglobin (Hb), and hematocrit (Ht) levels. Plasmid-treated dogs had at least a 7% increase in all three parameters. The initial response rates for the plasmid-treated dogs were 40.6 and 35.5%, respectively on days 40 and 60, which increased to 54.2% on day 90. Although the response rate reduced to 47.1% by day 120, it was still 22.1% higher than in the control dogs. Post-hoc analysis of the GHRH-treated group showed that responder dogs survived 84% longer, 178 +/- 26 days post-treatment, while nonresponders and controls survived for 95 +/- 16 and 97 +/- 31 days post-treatment, respectively. The quality of life, defined by 10 different parameters, dramatically improved with treatment. Overall, the possibility of a GHRH plasmid-based therapy for anemia in cancer-afflicted subjects is important enough to deserve further investigation.