SGMO and its partner Pfizer PFE announced encouraging interim data from the phase I/II Alta study evaluating their gene therapy candidate, SB-525, in patients with severe hemophilia A. Data showed that the gene therapy candidate holds potential.
Shares of Sangamo rallied almost 28% on Apr 2 following the data readout. However, shares of the company have increased 7% so far this year compared with the industry ‘s rise of 11.7%.
The phase I/II study evaluated four doses of SB-525 – 9e11 vg/kg, 2e12 vg/kg, 1e13 vg/kg and 3e13 vg/kg – with two patients per cohort. Data from the study showed that patients treated with the highest dosage (3e13 vg/kg) achieved normal factor VIII levels. Dose dependent increase in factor VIII levels were observed in the eight patients treated with SB-525 gene therapy across the four dosage cohorts. Factor VIII boosts blood clotting, which is a major symptom of haemophilia. Moreover, the candidate was well tolerated in every dosage cohort.
The company believes that SB-525 may achieve predictability and sustained treatment effect, which can lead to clinical benefit in haemophilia A patients.
Based on the data from the study, the Safety Monitoring Committee (“SMC”) recommended expansion of the 3e13 vg/kg cohort. Total patients in the cohort will increase to five. Longer-term follow up data will be presented at a future scientific meeting.
Although interim data from the study seems promising, the clinical development of SB-525 is in early stage with commercialization prospects years away.
We note that there are other treatments available for treating hemophilia A and several others are in development including gene therapies. In February 2019, Novo Nordisk’s NVO Esperoct was approved for the indication. Companies developing gene therapy candidates for treating hemophilia A include Spark Therapeutics ONCE and uniQure. The most advanced gene therapy for hemophilia A treatment in clinical studies is BioMarin’s valoctocogene roxaparvovec (BMN-270). Late-stage studies are evaluating 6e13 vg/kg and 4e13 vg/kg doses of the candidate.