The fresh FDA approval allows the use of the cell therapy in patients as young as two years old with sickle cell disease (SCD) who have recurrent vaso-occlusive crises or transfusion-dependent beta thalassemia (TDT).

  • The supplemental approval significantly broadens access beyond the previous indication for patients aged 12 and older.
  • Crispr benefits from a 40% share of net profits from Casgevy under its collaboration agreement with Vertex.
  • Vertex Pharmaceuticals said the expansion makes approximately 5,500 additional children in the U.S. newly eligible for the one-time therapy.


Shares of Crispr Therapeutics (CRSP) jumped 8% on Thursday after the U.S. Food and Drug Administration approved an expanded indication for Casgevy, a gene therapy co-developed by Crispr and Vertex Pharmaceuticals (VRTX).

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The fresh approval from Wednesday allows the use of the cell therapy in patients as young as two years old with sickle cell disease (SCD) who have recurrent vaso-occlusive crises or transfusion-dependent beta thalassemia (TDT).

VRTX shares closed up 6% on Thursday and clocked its best day since March.

What Does The New Approval Mean?

The supplemental approval significantly broadens access beyond the previous indication for patients aged 12 and older. It is now the first gene therapy approved in the U.S. for children in this age group. The decision was based on late-stage data in patients ages 5–11 showing consistent results, including no severe vaso-occlusive crises for at least 12 months in sickle cell patients and transfusion independence in most beta thalassemia patients. The FDA completed its review in 53 days under a priority voucher program.

Vertex Pharmaceuticals said the expansion makes approximately 5,500 additional children in the U.S. newly eligible for the one-time therapy.

How Does Crispr Benefit?

Casgevy is a one-time gene therapy made from a patient’s own blood stem cells using CRISPR technology. It works by increasing fetal hemoglobin levels to help treat sickle cell disease and beta thalassemia. Before receiving the therapy, patients undergo chemotherapy to clear their bone marrow. The treatment is given only at specialized authorized treatment centers.

Crispr benefits from a 40% share of net profits from Casgevy under its collaboration agreement with Vertex. The pediatric approval expands the commercial opportunity for the company’s only approved product and directly increases the potential revenue pool in which Crispr participates.

How Did CRSP Retail Traders React?

On Stocktwits, retail sentiment around CRSP stock jumped from ‘neutral’ to ‘bullish’ over the past 24 hours, while message volume increased from ‘normal’ to ‘high’ levels.

Sentiment on VRTX, meanwhile, stayed within the ‘extremely bullish’ territory, coupled with ‘high’ message volume.

A Stocktwits user opined that Vertex will eventually acquire Crispr.

CRSP stock has gained 15% year-to-date, while VRTX gained 16%. 

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