Why gene therapy for sickle cell is slow to catch on with patients

By Deena Beasley (Reuters)

 

LOS ANGELES,  (Reuters) - Student Zoe Davis, 20, was just weeks into her junior year when she landed back in the hospital with severe sickle cell pain earlier this month. She is doing what she can to prevent the crippling attacks in her arms, legs and abdomen that are becoming more frequent.

She knows new gene therapies may provide long-term relief to some of the 100,000 Americans like her who suffer from sickle cell disease. But she's holding off trying one.

"It is so new ... I wanted to see more success stories before I get committed to it," said Davis, who is studying veterinary science at North Carolina Agricultural and Technical State University in Greensboro.

Her hesitation illustrates a common reason why take-up for the potentially life-changing treatments, which cost $2 million to $3 million in the U.S., is proving even slower than expected,l as interviews with half a dozen U.S. specialists and six sickle cell patients show.

Younger patients – weighing school schedules and reluctant to add more medical burden to their lives – have been less enthusiastic than predicted, said Dr. Leo Wang, hematologist-oncologist at City of Hope Children's Cancer Center near Los Angeles.

"Some kids are just not interested," he said, adding that patients between ages 20 and 40 are, but some have such severe disease that they are not good candidates.

The new one-time treatments, approved in the U.S. last December, have so far been used on around 100 people globally, including in clinical trials. They require chemotherapy, which raises the risk of cancer and can cause infertility.

Some patients say the time involved – up to a year – is a daunting prospect for anyone whose condition is not critical.

Worldwide, 8 million people are estimated to have sickle cell disease, an inherited disorder, according to the National Institutes of Health. Most of those in the U.S. are Black.

Sufferers' red blood cells have an abnormal "sickle" shape that can block their flow through blood vessels, causing excruciating pain and sometimes leading to strokes, organ damage and premature death. The mutation that causes sickle cell is most prevalent in places where malaria is endemic: A single copy of the gene has been shown to protect against malaria infection.

By September, at least 30 people worldwide had begun a one-time gene therapy outside trials, according to the two drugmakers whose therapies were approved in America.

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