BioPharma

Sangamo Therapeutics shares up on hemophilia A gene therapy update

An analyst wrote that while the data are encouraging, a longer follow-up is needed, and prior experience with gene therapy in the hemophilia A space means some roll-off of effect is likely.

dna, genomics

The race to develop a gene therapy to treat hemophilia A is getting tighter as another player has presented updated data.

Richmond, California-based Sangamo Therapeutics and its partner, New York-based Pfizer, announced Friday the presentation of updated data from the Phase I/II Alta study of SB-525. The data were presented at the International Society on Thrombosis and Haemostasis congress in Melbourne, Australia.

The companies highlighted data showing that of the four patients who received the highest dose, 30 trillion vectors per kilogram, two rapidly achieved normal, sustained levels of Factor VIII with no reported bleeding events or need to receive treatment with the factor for as long as 24 weeks. The other two demonstrated Factor VIII activity kinetics consistent with the first two patients.

Shares of Sangamo were up 14 percent Monday morning on the Nasdaq following the news. Pfizer shares were down 1.7 percent.

In a note to investors Monday, Cowen analyst Ritu Baral wrote that while the data are encouraging, investors anticipate that the effect of treatment could roll off over time, based on the experience with a competing product candidate, BioMarin’s BMN 270 (valoctocogene roxaparvovec), which is in Phase III development. In the case of BioMarin’s product, also known as valrox, there was significant roll-off of effect two to three years after treatment, but significant differences between valrox and SB-525 – in terms of viral vectors being used and so forth – make the relative rate of decline unknowable. Baral added that a much longer follow-up – likely two years or more – will be needed to gauge SB-525’s true potential.

Sangamo had presented interim data on eight patients treated with SB-525 in April, indicating that the therapy was well-tolerated and showing a dose-dependent increase in Factor VIII levels across the dosage cohorts.

Two other companies are developing gene therapies in hemophilia A, both well ahead of Sangamo in terms of advancement in the clinic. Philadelphia-based Spark Therapeutics, whose $4.8 billion acquisition by Swiss drugmaker Roche is pending, has a gene therapy in Phase III development for hemophilia A, SPK-8011. Meanwhile, BioMarin said Monday it plans to file for Food and Drug Administration and European Medicines Agency approval for valrox in the fourth quarter of this year.

Photo: iLexx, Getty Images

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