Case studies on RetroMAD1™, an orally administered recombinant chimeric protein to treat naturally infected Feline Leukemia Virus (FeLV) cats

Abstract

Treatment options for Feline leukimia are presently very limited due to lack of efficacy and drug toxicity. A recombinant chimeric protein RetroMAD1 is described for the first time in the treatment of FeLV. The chimera has an A-B-C configuration comprising of multiple documented antiviral domains that can potentially overcome single point mutation driven resistance by multidomain action. Oral administration of RetroMAD1 was given daily at 0.4mg/kg/day divided equally into two feeds roughly 12 hours apart for one month to highly symptomatic FeLV cats in Brazil. RetroMAD1 treated cats were monitored for survival until day 433 and untreated cats were monitored until day 173. A significant different in survival rate of 73% (treated N=55) versus 33% (untreated N=21) existed. Gingivitis, F.U.R.D. and anaemia were shown to improve significantly as signs indicating improvement in quality of life. Some of the RetroMAD1 treated cats were given interferon treatment by their respective vets as supportive treatment (N=14) that gave a slightly improved survival outcome compared to those given only RetroMAD1 and other supportive medication. Being orally administered, this protein may be easily administered by cat owners. In addition, biochemistry and CBC data also indicated that RetroMAD1 is safe and well tolerated. A safe, efficacious oral delivery antiviral chimera will be very useful for veterinary treatment especially if it is also broad-spectrum in nature.