Avrobio has shared data on the first Gaucher disease patient to receive its gene therapy AVR-RD-02. The patient, who was stable on enzyme replacement therapy at baseline, experienced a 22% drop in a toxic metabolite after receiving AVR-RD-02 and stopping taking the standard of care.
Gaucher, like the Fabry disease targeted by Avrobio’s lead prospect, is currently treated using enzyme replacement therapies sold by Sanofi and Takeda, which entered the market through its takeover of Shire. However, a significant minority of patients experience physical limitations despite treatment. Negative outcomes include bone pain and spleen enlargement. Johnson & Johnson’s Zavesca offers an oral alternative, but there remain unmet medical needs.
Avrobio is developing AVR-RD-02 to address those needs. The data shared as part of Avrobio’s R&D day mark the start of the effort to show AVR-RD-02 performs as hoped in the clinic.
The first patient to receive AVR-RD-02 discontinued enzyme replacement therapy one month before taking the gene therapy. Three months after receiving the gene therapy, levels of Gaucher biomarker lyso-Gb1 had fallen 22%. The patient’s level of plasma chitotriosidase, a biomarker of cells associated with severe organ damage, was down 17%. Hemoglobin and platelets were in the normal range.
AVR-RD-02 triggered those changes without causing serious adverse events. The data drop offers an early indication that Avrobio may be able to improve outcomes by harvesting hematopoietic stem cells, adding a gene that encodes for glucocerebrosidase and reinfusing the cells back into the same patient. With enzyme replacement therapies costing healthcare systems up to $400,000 a year per patient, there is scope for AVR-RD-02 to cut the cost of treating Gaucher disease.
Avrobio shared the early look at clinical data on AVR-RD-02 alongside updates about other assets. There is now more than three years of data on some Fabry patients treated with Avrobio’s lead asset, putting the company in a position to plot a path to accelerated approval. Avrobio plans to submit its briefing book to the FDA by the end of the year to align on an accelerated approval strategy.
The update also covered cystinosis candidate AVR-RD-04. The first patient to receive the candidate is off oral and eye drop cysteamine 12 months after receiving the gene therapy. The number of crystals in the patient’s skin are down 56%, leading Avrobio to posit they may have gained the ability to make their own functional cystinosin protein.