Deshawn “DJ” Chow waited a year to receive treatment that would change his life. The 19-year-old was born with sickle cell disease, which makes his red blood cells crescent-shaped and sticky. Misplaced cells build up and block blood vessels, cutting off oxygen to parts of the body and causing episodes of severe pain. The condition affects about 100,000 people in the United States, most of whom are Black.

The pain became more and more frequent for Chow in high school, and he was often hospitalized. He misses school, birthday parties, and sleepovers with friends. Sometimes, the pain lasts for several days. “It felt like my body was on fire,” he said.

A year later, he learned about a new treatment called Casgevy that could end his long battle with pain. This is first approved drug to use the Nobel Prize-winning technology known as Crispr, a type of gene editing. Chow received Casgevy on December 5 at the City of Hope Cancer Center in Los Angeles. He was one of the first patients in the US to undergo the treatment since it was approved in December 2023. It was also approved for beta thalassemia, a related blood disorder, this January.

Due to manufacturing complexities, insurance delays, and the extensive preparation involved for patients, few individuals in the US have been dosed with Casgevy since it became commercially available. The slow launch highlights the complex nature of commercializing cutting-edge medical treatments and bringing them to patients. Another genetic treatment for sickle cell, Lyfgenia, won approval last December, and the first patient was treated in September. Made by Bluebird Bio, it uses an old technology that introduces a new gene to treat the disease.

Vertex Pharmaceuticals and Crispr Therapeutics, which developed Casgevy, have not said publicly how many patients have received the therapy so far. WIRED reaches everyone 34 US hospitals are approved to administer it in December. Of the 26 that provided responses, only City of Hope and Children’s National Hospital in Washington, DC, said they administered Casgevy. (Three hospitals declined to comment, and five others did not respond to multiple inquiries.) Chow was City of Hope’s first sickle cell patient, while a beta thalassemia patient was treated at Children’s National. Several authorized centers told WIRED that they will begin infusing Casgevy in early 2025.

“The process of taking this medicine is very different from just taking a pill,” said Leo Wang, Chow’s hematologist-oncologist at City of Hope. This is a one-time therapy that involves collecting and editing a person’s stem cells. For the patient, this means a harsh round of chemotherapy before the cells are removed, and a month in the hospital afterwards.