Why Did Sangamo Stock Jump 20% Today?

Sangamo Therapeutics Inc SGMO announced preliminary results from the Phase 1/2 STAAR study evaluating isaralgagene civaparvovec, or ST-920, a gene therapy candidate for Fabry disease.
As of the September 17, 2021 cutoff date, results from the four patients treated in the first two dose cohorts (0.5e13 vg/kg and 1e13 vg/kg) showed that the gene therapy was generally well tolerated.
All four patients exhibited above normal alpha-galactosidase A (α-Gal A) activity, which was maintained for up to one year for the first patient treated and through 14 weeks for the most recently treated patient.
2-fold to 15-fold above mean normal was observed at the last measurement as of the cutoff date.
Withdrawal from enzyme replacement therapy (ERT) has taken place for one patient. It is planned for the other patient on ERT, based on the stability of their α-Gal A activity following treatment.
No treatment-related adverse events higher than mild and treatment-related serious adverse events were observed.
No patients experienced liver enzyme elevations requiring steroid treatment.
Price Action: SGMO shares gained 19.2% at $10.89 on Thursday.