Vertex Pharmaceuticals Touts Potential of CRISPR Gene Editing Therapy

Vertex Pharmaceuticals is touting the potential of the first CRISPR-based gene editing therapy after the treatment recently gained praise from the FDA’s Cellular, Tissue, and Gene Therapies Advisory Committee.¹

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Exagamglogene autotemcel (Exa-Cel) emerged from a strategic partnership between CRISPR Therapeutics and Vertex for the treatment of sickle cell disease (SCD) in patients aged 12 years and older with recurrent vaso-occlusive crises.²

The FDA granted priority review to Exa-Cel in the treatment of patients with SCD and assigned a Prescription Drug User Fee Act action date of December 8, 2023. Exa-Cel’s Biologics License Application for transfusion-dependent beta-thalassemia was assigned a PDUFA date of March 30, 2024.¹

During Vertex’s third quarter earnings call, the company said the therapy represented a multibillion-dollar opportunity.

“Vertex has delivered another strong quarter across the business. We remain relentless in our commitment to reach more patients with our cystic fibrosis medicines, while preparing for the potential launch of Exa-Cel in multiple geographies,” said Reshma Kewalramani, MD, chief executive officer and president of Vertex, in a press release. “Our R&D pipeline continues to make remarkable progress and we have a milestone-rich period coming up, with multiple major, near-term milestones, including completion of the Phase 3 pivotal trials for the vanzacaftor triple in cystic fibrosis and VX-548 in acute pain, as well as the Phase 2 VX-548 study data read-out in diabetic peripheral neuropathy.”

During the FDA committee meeting on October 31, 2023, independent advisers praised Exa-Cel. Vertex Pharmaceuticals noted that the treatment appears to be safe and highly effective at preventing episodes of excruciating pain that plague patients with SCD.² The treatment worked in 29 of 30 patients who were followed for at least 18 months and doesn't appear to cause any serious short-term safety concerns, the company reported.

"In totality, the data support the remarkable clinical benefit of Exa-Cel in patients with SCD," William Hobbs, MD, PhD, vice president, clinical development, Vertex told the committee.²

The FDA concurred with the potential benefits of Exa-Cel and did not ask advisers to take the usual step of assessing Exa-Cel's benefits or whether the agency should approve the therapy. Instead, because of the high stakes of approving an entirely new kind of technology to treat people for the first time, the FDA asked advisers to focus on whether sufficient research had been done to spot "off-target" effects of the treatment—unintended editing errors that missed their mark in the DNA and that could potentially cause long-term health problems.²

The advisers suggested that Vertex and CRISPR could assess the potential safety risks of their SCD gene therapy after approval. If the therapy is approved, Vertex has proposed a 15-year follow up of patients to evaluate the safety outcomes of exa-cel. This 15-year follow up will help generate data from real-time monitoring of the therapy, which uses the new gene editing CRISPR technology.²

During the earnings call, Vertex said its launch preparations are on schedule, with approximately 50 treatment centers located in the United States and 25 in Europe, which should be able to treat approximately 32,000 eligible patients, which includes 25,000 patients with SCD and 7,000 with beta thalassemia.

"It's really exciting to see how many patients have been treated and how positive the results have been," said Scot Wolfe of the UMass Chan Medical School. "We want to be careful to not let the perfect be the enemy of the good."²

References

1. Vertex Reports Third Quarter 2023 Financial Results. Business Wire. Published [Date Not Available]. Accessed November 7, 2023. Available at: https://www.businesswire.com/news/home/20231106937081/en/Vertex-Reports-Third-Quarter-2023-Financial-Results
2. Studna A. CRISPR Therapeutics Announces Completion of FDA Advisory Committee Meeting for Exagamglogene Autotemcel for Severe Sickle Cell Disease. Applied Clinical Trials Online. Published November 1, 2023. Accessed November 7, 2023. Available at: https://www.appliedclinicaltrialsonline.com/view/crispr-therapeutics-announces-completion-of-fda-advisory-committee-meeting-for-exagamglogene-autotemcel-for-severe-sickle-cell-disease