8-K: Sangamo Therapeutics Announces Positive Preliminary Data for Fabry Disease Gene Therapy

Sangamo Therapeutics reported updated positive preliminary clinical data from its Phase 1/2 STAAR study of isaralgagene civaparvovec for Fabry disease, showing sustained enzyme activity and clinical improvements.

Summary

• Sangamo Therapeutics announced updated preliminary clinical data from its Phase 1/2 STAAR study for isaralgagene civaparvovec, a gene therapy for Fabry disease.
• The data, as of a September 19, 2023 cutoff, includes 24 patients, with an additional four patients dosed since then, bringing the total to 28.
• The study is a multicenter, open-label, dose-ranging study assessing the safety and tolerability of a single infusion of the therapy.
• Patients are followed for 52 weeks, with a separate long-term follow-up study for up to five years.
• The primary endpoint is the incidence of treatment-emergent adverse events, with secondary endpoints including changes in enzyme activity and disease markers.
• The dose escalation phase included males with classic Fabry disease, while the expansion phase included females and patients with more severe disease.
• The therapy was generally well-tolerated, with most adverse events being mild or moderate.
• Sustained, elevated expression of alpha-galactosidase A (Gal A) activity was observed in all patients in the dose escalation phase for nearly three years for the longest treated patient.
• Patients who were on enzyme replacement therapy (ERT) were able to withdraw from ERT, with continued elevated levels of Gal A activity.
• Patients receiving the highest dose showed significantly higher levels of Gal A activity.
• Lyso-Gb3 levels were reduced or stabilized, with the largest reductions in patients with the highest baseline levels.
• Renal function was maintained in patients with 12 months of follow-up.
• Improvements were seen in disease severity, quality of life, and gastrointestinal symptoms.
• Antibodies against Gal A associated with ERT decreased or became undetectable in most patients.
• The company is deferring additional investments in planning for a potential registrational trial until a collaboration partnership or trial financing is secured.

Sentiment

Score: 7

Explanation: The document presents positive clinical data with some risks related to funding and future trials. The overall sentiment is positive but tempered by the need for additional financing.

Positives

• The gene therapy demonstrated sustained, elevated expression of the deficient enzyme, alpha-galactosidase A (Gal A).
• Patients were able to withdraw from enzyme replacement therapy (ERT) without needing to resume it.
• The therapy showed a dose-dependent effect, with higher doses leading to higher enzyme activity.
• There was a reduction or stabilization of lyso-Gb3 levels, a key marker of Fabry disease.
• Renal function was maintained in patients over 12 months.
• Patients experienced improvements in disease severity, quality of life, and gastrointestinal symptoms.
• The therapy reduced or eliminated antibodies against Gal A associated with ERT.
• The study has completed screening and enrollment.

Negatives

• Four patients experienced treatment-related serious adverse events (SAEs), including left arm pain, sepsis, enthesopathy, and stroke/ischemic stroke.
• One patient experienced a Grade 3 pyrexia adverse event.
• Three patients experienced post-infusion hypertension.
• The company is deferring additional investments in planning for a potential registrational trial until a collaboration partnership or trial financing is secured.

Risks

• The company needs to secure a collaboration partnership or trial financing to proceed with a potential registrational trial.
• The therapeutic effects observed in the preliminary data may not be durable in patients.
• Final clinical trial data may not validate the safety and efficacy of the therapy.
• Patients withdrawn from ERT may need to resume it.
• The regulatory approval process for the therapy is unpredictable.
• The company relies on results of early clinical trials, which are not necessarily predictive of future results.
• There is a risk of technological developments that could obviate the technologies used by Sangamo.
• The company relies on collaborators and may be unable to secure additional collaborations.
• The company needs substantial additional funding to execute its operating plan and continue as a going concern.

Future Outlook

The company plans to seek a collaboration partner or additional financing to proceed with potential Phase 3 trials of isaralgagene civaparvovec. Dosing of the remaining enrolled patients is expected in the first half of 2024.

Management Comments

• Productive discussions continue with the U.S. FDA and other health authorities on pathways to registration.
• The Company is deferring additional investments in planning for a potential registrational trial until a collaboration partnership or trial financing is secured.

Industry Context

This announcement is significant in the context of gene therapy development for rare diseases, particularly Fabry disease, where current treatments like enzyme replacement therapy have limitations. The positive data suggests a potential alternative treatment option with long-term benefits.

Comparison to Industry Standards

• The results of the STAAR study are promising when compared to the current standard of care for Fabry disease, which primarily involves enzyme replacement therapy (ERT).
• ERT requires frequent infusions and does not always prevent disease progression, whereas the gene therapy aims for a one-time treatment.
• The sustained enzyme activity and reduction in disease markers observed in the study are notable improvements over ERT.
• Other companies developing gene therapies for Fabry disease include Avrobio and Freeline Therapeutics, and the results from Sangamo appear competitive.
• The ability to withdraw patients from ERT and maintain enzyme activity is a key differentiator for Sangamo's therapy.

Stakeholder Impact

• Shareholders may view the positive clinical data favorably, but the need for additional financing could be a concern.
• Patients with Fabry disease may see this as a promising potential treatment option.
• Employees may be impacted by the company's financial situation and the need for a collaboration partner.
• The company's financial situation may impact suppliers and creditors.

Next Steps

• Dosing of the remaining enrolled patients in the Phase 1/2 STAAR study is expected in the first half of 2024.
• The company will seek a collaboration partner or additional financing to proceed with potential Phase 3 trials of isaralgagene civaparvovec.

Key Dates

Keywords

Fabry disease, gene therapy, isaralgagene civaparvovec, ST-920, clinical trial, enzyme replacement therapy, alpha-galactosidase A, lyso-Gb3, renal function, adverse events