> ## Content Index > Fetch the complete content index at: https://www.theamericanquorum.com/llms.txt > Use this file to discover other available public pages before exploring further. # FDA Approves First U.S. CRISPR Therapy and a Second Gene Therapy for Sickle Cell Disease in Patients 12 and Older - URL: https://www.theamericanquorum.com/taq-historical-2023-12-09-healthcare/ - Published: 2023-12-10T04:59:00.000Z - Updated: 2023-12-10T04:59:00.000Z - Description: FDA approved Casgevy and Lyfgenia for sickle cell disease, including the first U.S. treatment using CRISPR/Cas9 gene editing, creating two new one-time options for patients 12 and older. - Author: Kenneth R. Deans Jr. - Tags: Healthcare, #Import 2026-09-01 08:58 The Food and Drug Administration has approved two cell-based gene therapies for sickle cell disease, including the first treatment in the United States to use CRISPR/Cas9 genome editing. The Dec. 8 approvals of Casgevy and Lyfgenia create new one-time treatment options for patients age 12 and older with severe forms of an inherited blood disorder that affects about 100,000 people in the United States. The [FDA announcement](https://www.fda.gov/news-events/press-announcements/la-fda-aprueba-las-primeras-terapias-genicas-para-tratar-pacientes-con-anemia-de-celulas-falciformes?ref=theamericanquorum.com) marks a milestone for both sickle cell care and gene editing. Casgevy, developed by Vertex Pharmaceuticals and CRISPR Therapeutics, modifies a patient’s own blood-forming stem cells using CRISPR/Cas9\. Lyfgenia, developed by bluebird bio, uses a lentiviral vector to add a modified form of the beta-globin gene. ## Casgevy uses CRISPR to reactivate fetal hemoglobin Sickle cell disease is caused by a mutation that produces abnormal hemoglobin, causing red blood cells to become rigid and sickle-shaped. Those cells can obstruct blood flow, producing severe vaso-occlusive pain crises, organ damage and other complications. Casgevy takes a patient’s hematopoietic stem cells, edits them outside the body and returns them after conditioning chemotherapy. The edit targets regulation of fetal hemoglobin, a form of hemoglobin normally produced before birth. By increasing fetal hemoglobin in red blood cells, the therapy is designed to reduce sickling and the resulting vascular obstruction. The FDA’s [Casgevy record](https://www.fda.gov/vaccines-blood-biologics/casgevy?ref=theamericanquorum.com) includes the Dec. 8 approval letter and regulatory review materials. In the principal efficacy analysis, 29 of 31 evaluable patients — 93.5% — remained free of severe vaso-occlusive crises for at least 12 consecutive months during the follow-up period. All treated patients achieved successful engraftment, according to FDA. Vertex and CRISPR Therapeutics said in their [approval announcement](https://investors.vrtx.com/news-releases/news-release-details/vertex-and-crispr-therapeutics-announce-us-fda-approval/?ref=theamericanquorum.com) that roughly 16,000 U.S. patients age 12 and older with severe disease may be eligible under the approved indication. ## Lyfgenia uses a different genetic strategy Lyfgenia is also made from a patient’s own stem cells, but it does not use CRISPR. Instead, a lentiviral vector delivers a modified beta-globin gene intended to produce an anti-sickling form of hemoglobin. The FDA’s [Lyfgenia approval materials](https://www.fda.gov/vaccines-blood-biologics/lyfgenia?ref=theamericanquorum.com) specify use for patients 12 and older with sickle cell disease and a history of vaso-occlusive events. Bluebird bio reported that 28 of 32 evaluable patients, or 88.2%, experienced complete resolution of vaso-occlusive events during the primary evaluation window and 30 of 32, or 94%, had resolution of severe events. The company’s [Dec. 8 statement](https://www.nasdaq.com/press-release/bluebird-bio-announces-fda-approval-of-lyfgeniatm-lovotibeglogene-autotemcel-for?ref=theamericanquorum.com) describes the treatment as a one-time therapy and says trial follow-up has shown durable production of anti-sickling hemoglobin. Lyfgenia also carries a boxed warning for hematologic malignancy. FDA requires lifelong monitoring for malignancies after treatment. Both products expose patients to risks associated with stem-cell collection, myeloablative conditioning chemotherapy and the period required for marrow recovery. ## Transformative efficacy comes with an intensive treatment process Neither therapy resembles a conventional outpatient prescription. Patients first undergo collection of their own hematopoietic stem cells. The cells are genetically modified at a specialized facility, while the patient later receives high-dose conditioning chemotherapy to clear marrow space. The engineered cells are then infused back into the patient, followed by close monitoring while blood-cell production recovers. The process can take months and requires centers with transplant and gene-therapy expertise. Common serious adverse effects reported in the programs include low blood-cell counts, febrile neutropenia, mouth inflammation and complications associated with conditioning. The [American Society of Gene & Cell Therapy](https://www.asgct.org/news-publications/asgct-news/u-s-first-gene-therapies-for-sickle-cell-disease-approved-by-fda?ref=theamericanquorum.com) called the dual approvals a major milestone while emphasizing that long-term follow-up remains central to assessing durability and late effects. The therapies’ costs will also shape access. [Reuters](https://kfgo.com/2023/12/08/vertex-crispr-price-sickle-cell-disease-gene-therapy-at-2-2-million/?ref=theamericanquorum.com) reported list prices of $2.2 million for Casgevy and $3.1 million for Lyfgenia. Those figures do not include the full cost of conditioning, hospitalization, cell collection and follow-up. Manufacturers argue that a successful one-time therapy can offset years of hospitalizations and chronic treatment, but insurers and public programs will need to develop coverage and payment approaches for multimillion-dollar products. ## A new therapeutic era with important unanswered questions The approvals are especially consequential because sickle cell disease has historically carried a severe burden with limited curative options. Allogeneic bone-marrow transplantation can cure the disease in some patients, but it depends on finding a suitable donor and carries risks including graft-versus-host disease. Autologous gene therapy eliminates the need for a donor and avoids graft rejection, although it introduces its own treatment and long-term safety considerations. The first U.S. approval of a CRISPR therapy also extends beyond sickle cell disease. Researchers have pursued CRISPR-based approaches for inherited blood disorders, cancers, eye diseases and other conditions since the genome-editing system was adapted for laboratory use. Regulatory approval of Casgevy demonstrates that edited human cells can move through large-scale clinical development and FDA review, but each future use will require separate evidence of safety and effectiveness. For patients, the immediate question is practical access. Only specialized centers can deliver the therapies, manufacturing slots will be limited at launch, and patients must be medically fit enough to undergo conditioning. Physicians will need to weigh disease severity, existing treatments, transplant options, fertility implications and the known and unknown risks of gene therapy. The FDA’s dual action does not end those debates. It does, however, change the therapeutic landscape. For the first time, U.S. patients with severe sickle cell disease have two approved autologous gene-therapy options, one using CRISPR and one using a viral vector, each designed to alter the biology driving recurrent vaso-occlusive disease rather than only manage its complications.