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Role of Cord Blood Transplants to Treat Sickle Cell Anemia & Thalassemia in the Age of Gene Therapy

A stem cell transplant is a one-time treatment that can cure Sickle Cell Anemia or Thalassemia. Cord blood transplants have an advantage over bone marrow transplants because they cause less GvHD. Pediatric patients that have experienced less organ damage from prolonged illness with hemoglobinopathies and less iron overload from repeated transfusions have better transplant outcomes. And pediatric patients are small enough to rely on cord blood as the graft source. Hence children with a “severe” hemoglobinopathy are considered good candidates for cord blood transplants.

For Sickle Cell this includes patients that have had a stroke, that have acute chest syndrome, that have recurrent pain crises despite medication, or other serious complications that make the benefits of the transplant outweigh the risks.

Similarly, a transplant is recommended for Thalassemia patients that are transfusion-dependent. In the United States, the first Sickle Cell patient to have a cord blood transplant was Keone Penn in 1998. Since then, several US-based Sickle Cell patients have become advocates for cord blood transplants. Marriam Carol Mulumba had a cord blood transplant at age 7 in 2008, and has been counseling other children going through transplant ever since. She published her life story at age 12 and again at age 17. In 2023, beauty pageant contestant Sosa Evbuomwan shared that she was the first child cured of Sickle Cell Anemia by a transplant of the expanded cord blood product from Gamida Cell. In India, about 12 to 14 thousand children are born each year with the severe form of Thalassemia.

Pediatric hematologists in India report that hemoglobinopathies are the most common indication (at 34%) for children receiving stem cell transplants. LifeCell, the largest cord blood bank in India, notes that the majority of cord blood units they have released were for sibling transplants to treat Thalassemia. Another study by hematologists reports that the typical cost for a sibling cord blood transplant in India is INR 20 lakhs, which is equivalent to U$D 25,00028. The costs of treatment in India are so much less than the United States that the entire cost of a cord blood transplant is less than the cost to acquire a cord blood unit from a public bank in the United States. In Iran, it was estimated in 2018 that 4% of the population were carriers of Beta Thalassemia and 18,783 patients suffering from Beta Thalassemia Major had been identified. A 2015 survey of the economic burden of the disease found that the average annual cost to support these patients with blood transfusions, iron chelation, etc. was U$D 8321.8031. This includes the indirect burden of lost wages, but the majority of the cost, U$D 7286.80, is direct medical expenses which under the Iranian public health system are an annual cost to society of over U$D 136 million for all the patients in the country. Royan Stem Cell Technology Company, the leading private and public cord blood bank in Iran, often provides sibling cord blood transplants for Thalassemia. The cost to privately store cord blood with Royan is about U$D 250 and the cost of the cord blood transplant is about U$D 2500.

This is another example of a country where a stem cell transplant is feasible and much more cost effective than lifelong supportive care of Thalassemia. In China, the public health burden of Thalassemia is compensated by the large inventory of donated cord blood in public banks, so that a matched donor can be found for transplant when a sibling is not available.

At the 2023 cord blood conference of the China Maternal and Child Health Association, it was said that one out of six people in the southern Chinese province of Guangdong is a carrier of Thalassemia. Professor Liu Sixi, chief physician of the Hematology and Oncology Department of Shenzhen Children’s Hospital, said, “In 11 years, we performed 909 cases of Thalassemia transplantation, and the overall survival rate was 99%. This data is ahead of countries and regions such as Europe and the United States.” In Thailand, close to the world’s epicenter for Thalassemia carriers, families are turning to assisted reproduction to help them conceive a savior sibling that can provide a cord blood transplant to an older child with Thalassemia. Relying on pure luck, the probability that the parents will conceive a child that is an exact HLA match to their sibling is 25%, while the probability that the new baby will also carry Thalassemia is 75%. Whereas, by relying on in-vitro fertilization (IVF) with preimplantation genetic diagnosis (PGD), the parents can guarantee conceiving a child that is both a perfect donor and not a carrier of Thalassemia.

The Superior A.R.T. and Jetanin fertility centers in Thailand, which have the largest case series in the Far East and Pacific, report a live birth rate of 44% with a total cost of U$D 10,000 to 30,000, including delivery of the baby. In Kenya, the Swiss cord blood bank CordSavings has entered a private-public partnership with local authorities for public health in geographic areas where HLA diversity appears to be particularly high. Their joint goal is to provide worldwide Sickle Cell patients with access to better matching cord blood units for transplants. During the first half of 2023, they succeeded in commencing collection, processing, and storage of cord blood units from a large public hospital. But, as of today this effort has been temporarily put on hold due to the current civil unrest in in Kenya.