BioMarin Pharmaceutical Inc. announced an update to its positive interim results of an open-label Phase 1/2 study of BMN 270, an investigational gene therapy treatment for severe hemophilia A, which will be presented as part of a company overview at the 35th Annual J.P. Morgan Healthcare Conference in San Francisco, Calif. These data are an update from previously reported results presented in July 2016. A total of nine patients with severe hemophilia A received a single dose of BMN 270, seven of whom have been treated at the high dose of 6 x 1013 vg/kg. As of the Dec. 9, 2016 data cutoff, post-treatment follow-up ranges from 34 to 50 weeks. Median Factor VIII levels for the high dose cohort have been consistently within the normal range from 20 weeks through 44 weeks of treatment. For those seven patients, as of each patient's most recent reading, six of seven patients continue to have Factor VIII levels above 50%, as a percentage calculated based on the numbers of International Units per deciliter (IU/dL) of plasma, and the seventh continues to be above 15%. For the six patients at the high dose and previously on a Factor VIII prophylactic regimen, the mean annualized bleeding rate dropped 91% from 16.3 before the BMN 270 infusion to 1.5 two weeks after being dosed (median annualized bleeding rate dropped from 16.5 to 0). For those same six patients, the mean annualized Factor VIII infusions fell 98% from 136.7 to 2.9 (median annualized Factor VIII infusions fell from 138.5 to 0). Since the last update, six of the seven patients at the high dose as of the most recent reading are within the normal alanine aminotransferase (ALT) range, and one patient is less than 5% above the upper limit of normal, which is 43 U/L for the central laboratory in this study. Patients successfully tapered off of steroids with no lasting significant impact on Factor VIII expression or ALT levels. The requirement for prophylactic corticosteroids has been removed for all newly enrolled patients in this study. Study medication was generally well tolerated. No serious adverse events were observed, and most common adverse events were mild in severity. The next steps for the program are to begin a potentially registration enabling phase 2b study in third quarter 2017. In addition, the company is expected to commission its commercial gene therapy manufacturing facility by mid-2017.