University of Michigan researchers have successfully usedmuscle cells to ferry a human gene that would correct a type ofhemophilia.

Mice given the gene by this route made "a high level ofrecombinant Factor IX," the scientists reported in the currentProceedings of the National Academy of Sciences.

Factor IX deficiency, or hemophilia B, can be treated usingprotein derived from donor plasma. But the risk of blood-bornepathogens has focused efforts on correcting the inheriteddisease by gene therapy.

So far, attempts using skin cells as the carrier have notachieved the degree of success now reported with the musclecells, an approach called myoblast gene therapy.

Levels of human Factor IX peaked in the mice at day 12, thendeclined due to the immune attack mounted by the miceagainst the foreign, human protein. Peak levels attained wereat least five to 10 times those seen when skin cells were thevehicle for the therapy, the researchers said.

Direct injection of the gene construct into muscle, a strategyused by Vical Inc., did not work for these researchers.

Myoblast injection is in clinical trials for Duchenne musculardystrophy, with normal relatives as donors of the normal gene.Immune suppression is required for this Stanford Universitystrategy, but fixing the damaged gene in patients' myoblastsamples would be a better approach, the Michigan scientistssuggested.

The Michigan group concluded that the next step should be totest their approach in dogs who have hemophilia B. -- RobertaFriedman, Ph.D.

(c) 1997 American Health Consultants. All rights reserved.