Analysts Predict Slower Rollout but Ultimate Victory for Casgevy in Race with Lyfgenia

Casgevy and Lyfgenia delivery

Pictured: An illustration of a semi-truck hauling an IV bag/Nicole Bean for BioSpace

After winning FDA approvals to treat sickle cell disease and beta thalassemiaVertex Pharmaceuticals and partner CRISPR Therapeutics are working to expand the number of authorized treatment centers to administer Casgevy (exagamglogene autotemcel), with the world’s first CRISPR-based therapy. Four months post-approval, Vertex has expanded its network from 9 to 12 ATCs in the U.S., three in Europe, and one in Saudi Arabia, all ready to treat patients.

That’s a step behind bluebird’s Lyfgenia, a gene therapy for sickle cell disease that was approved the same day that Casgevy got the greenlight for that indication. Bluebird already has infrastructure used for its two other FDA-approved gene therapies, Zynteglo, a twin medicine to Lyfgenia approved in August 2022 to treat beta thalassemia, and Skysona, a gene therapy to treat boys with early, active cerebral adrenoleukodystrophy.

Nevertheless, analysts at William Blair say Casgevy is set to be a blockbuster. “We think it could be a billion-dollar product,” the firm’s Sami Corwin told BioSpace.

Casgevy’s rollout does face its fair share of challenges, Corwin said. In addition to needing to launch ATCs for Casgevy from scratch, Lyfgenia and Casgevy are the first gene therapies approved for sickle cell disease—a patient group that’s largely covered by Medicaid as opposed to private insurance groups, adding another layer of complexity for both medications.

But she and her colleagues still think Casgevy will outperform Lyfgenia in the long run, thanks to Vertex’s top-tier commercialization expertise in rare diseases and the fact that Casgevy is targeted at U.S. and international markets, whereas Lyfgenia is targeting only U.S. patients.

“Given Vertex’s multiple business development deals centered on gene editing, we view the commercial success of Casgevy as foundational to its long-term corporate development,” William Blair analysts wrote in a report, which rated both CRISPR and Vertex’s stocks to outperform.

“We continue to think that CRISPR and Vertex’s therapy is a best-in-class therapy,” Corwin said.

Racing to Meet Patient Demand

Casgevy has been approved for use in both sickle cell disease and beta thalassemia in the U.S., Great Britain, the European Union, the Kingdom of Saudi Arabia and Bahrain. Vertex COO Stuart Arbuckle noted in a Q4 earnings call that the company is also advancing their reimbursement discussions in other countries and seeing strong progress in the Middle East.

The company’s goal is to have 50 ATCs in the U.S. and 25 in Europe. Vertex works with each individual transplant center to complete qualification assessments, contractual agreements, IT setup and required training before ATCs can place orders for Casgevy, a Vertex spokesperson told BioSpace.

“We are in close dialogue with all our targeted ATCs and are working with local healthcare professionals to establish the required infrastructure to meet patient demand,” the Vertex spokesperson said. “The process is different for every ATC since each hospital has a different set-up, different ways of working and other nuances.”

An estimated 35,000 people live with severe sickle cell disease and transfusion-dependent beta thalassemia across the U.S. and Europe, Kewalramani said. The company estimates that 1,000 beta thalassemia patients in the U.S. alone are eligible for treatment with Casgevy, and another 16,000 with sickle cell disease based on eligibility criteria, the Vertex representative said. The company is also working to expand treatment to a younger age group, and recently completed enrollment in a Phase III study in patients 5 to 11 years of age. Neither Casgevy nor Lyfgenia is approved in young children currently.

Corwin added that according to Vertex’s marketing research, the company has seen a trend to physicians preferring a gene edited therapy as opposed to an insertional lentiviral-delivered therapy like Lyfgenia.

But Jess Rowlands, bluebird vice president of corporate communications, said the company is optimistic about the Lyfgenia rollout. “We have a validated commercial strategy informed by our real-world experience bringing gene therapies to patients and have significant momentum behind the Lyfgenia launch,” she said.

As of January 5, bluebird had 49 centers activated for Zynteglo, which are the same centers where Lyfgenia will be available, Rowlands said. She added that the company expects all 49 of these centers to be ready to administer Lyfgenia by the end of the first quarter this year.

With a second outcomes-based reimbursement agreement inked in December, up to 200 million people are covered with plans that pay for Lyfgenia treatment. Bluebird is in ongoing discussions with more than 15 Medicaid agencies representing 80 percent of Medicaid-insured individuals in the U.S., and recently inked its first Medicaid deal with the state of Michigan. The company anticipates 85 to 105 patient starts combined across all three of its FDA-approved therapies in 2024. In 2023, it had 20 new patients start Zynteglo and 6 start Skysona.

Other Factors in the Competition

Casgevy has a U.S. list price of $2.2 million per patient, and bluebird set the wholesale acquisition cost of Lyfgenia in the U.S. at $3.1 million.

“I don’t think that’s something that payers and patients are going to take lightly, and that can change how they negotiate prices in the long run,” Corwin said.

“Although [bluebird] has executed on its early launch goals for Zynteglo and Skysona, it remains unclear to us if bluebird will be able to successfully transition into a profitable, commercial-stage company,” according to the William Blair report. In addition to the cost, this is also because of Lyfgenia’s black box warning about the risk of developing a blood cancer.

“[Lyfgenia] also has a black box warning, whereas Casgevy does not, and although [bluebird] thinks that physicians understand the implications of the black box warning, I think that is something that could concern patients and lead to reduced uptake for bluebird’s therapy compared to CRISPR/Vertex’s,” Corwin said.

Mollie Barnes is a freelance science writer based in Los Angeles. Reach her at Follow her on Threads and Instagram @shejustlikedtogo and see more of her work at

Editor's note (March 27) This story has been updated to reflect that bluebird has 49 centers, and to remove the name of the Vertex spokesperson who commented for this story.

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