One hundred percent overall survival in just seven patients has provided the jet fuel needed by Rocket Pharmaceuticals to head to regulators for a rare childhood immunodeficiency disorder gene therapy.
The company unveiled the phase 2 pivotal results from patients with severe leukocyte adhesion deficiency-I (LAD-I) at the 25th Annual Meeting of the American Society of Gene and Cell Therapy Thursday.
The patients were assessed as of the data cutoff of March 9 at three to 24 months of follow-up, meaning seven patients were eligible for the 12-month overall survival assessment. Rocket reported that these seven patients achieved 100% overall survival.
With data from all nine patients, the company said the trial also showed a statistically significant reduction in hospitalizations, infection- and inflammatory-related hospitalizations and prolonged hospitalizations at three to 24 months of follow-up. Finally, data also suggested a reduction in skin rash and restoration of wound repair capabilities.
The company will now engage with regulators to discuss filing RP-L201 for approval in the first half of 2023.
LAD-I is a rare disease that causes the immune system to malfunction, leading to immunodeficiency that can prevent the body from fighting back against viruses, bacteria and fungi. Children with the disorder have a significantly shortened life expectancy.
Treatment typically involves addressing the symptoms and fighting the various infections through antibiotic therapy. The only curative therapy available is an allogeneic bone marrow transplant, which delivers donated stem cells to the patient. But this procedure can cause severe, life-threatening complications, so is typically reserved for the most severe form of LAD-I.
Rocket, therefore, believes it has a solution with RP-L201, a gene therapy that delivers hematopoietic stem cells from the patient that have been genetically modified to deliver a copy of the ITGB2 gene, which is mutated in patients with LAD-I. The ITGB2 gene contains instructions for encoding a protein called CD18, which is normally found on white blood cells. Absent this protein, white blood cells cannot stick to the endothelium, a membrane in the blood vessels that is critical to immune function and blood clotting.
Patients in the trial were aged five months to nine years old. All showed sustained CD18 restoration and expression, Rocket said.
As for safety, Rocket reported no serious adverse events related to RP-L201.
Rocket’s shares boosted upward about 10% from a prior close of $9.99 to $11.01 as the markets opened Friday morning. The company’s shares have been on a steady decline over the past year. As of May 20, 2021, Rocket shares were trading for around $40 apiece.