United States-based Pfizer and Sangamo Therapeutics have revealed that an investigational SB-525 haemophilia A gene therapy has indicated a sustained increased factor VIII (FVIII) levels in the phase 1/2 Alta study, it was reported yesterday.

The product has already received orphan drug, fast track, and regenerative medicine advanced therapy designations from the US Food and Drug Administration (FDA), and orphan medicinal product designation from the European Medicines Agency (EMA).

The SB-525 covers a recombinant adeno-associated virus serotype six vector, which encodes the complementary deoxyribonucleic acid for B domain deleted human FVIII. Its transcriptional cassette merges multi-factorial modifications to the liver-specific promoter module, FVIII transgene, synthetic polyadenylation signal and vector backbone sequence. The patients indicated a dose-dependent increase in FVIII levels and a dose-dependent reduction in the use of FVIII replacement therapy across the dose cohorts. The phase 1/2 Alta trial is an open-label and dose-ranging clinical study, aimed at assessing the safety and tolerability of SB-525 in patients with severe haemophilia A.