Sickle Cell Disease

At Black Maple Magazine, we’re always on the lookout for important new developments in health and nutrition that impact black individuals and communities. We’re also on alert for innovative new treatments for illnesses and disorders that afflict black folks. Sickle Cell is one such illness. What is Sickle Cell Disease (SCD)?

According to the National Heart, Lung, and Blood Institute, Sickle Cell Disease (SCD), also known as Sickle Cell Anemia, is a group of inherited disorders that affects hemoglobin, the major protein that carries oxygen in red blood cells. This means that children who inherit SCD have two parents who are carriers. While normal blood cells are disc-shaped and flexible to move easily through blood vessels, a gene mutation which causes misshaped (sickle-shaped) cells results in SCD. The mutation of the hemoglobin also causes the red blood cells to become hard and sticky, affecting their ability to carry oxygen to the body’s tissues effectively.

If you’ve heard of SCD, you may also be familiar with Thalassemia, another inherited or genetic blood disorder that affects people from Africa, the Mediterranean, and Asia. But while SCD is often diagnosed in childhood, people with Thalassemia often remain in the dark until adulthood. Both blood disorders are characterized by problems with the hemoglobin. People with Thalassemia are incapable of making enough normal hemoglobin and therefore have fewer red blood cells and lower blood oxygen than normal (hypoxemia). Alarmingly, disorders like SCD and Thalassemia result in other disorders with a host of side effects. For instance, according to the Cleveland Clinic, hypoxemia can result in headache, difficulty breathing, rapid heart rate, coughing, wheezing, confusion, and discoloured skin.

Sickle Cell patients often suffer from “sickle cell crises,” severe pain caused by the blockages of blood flow. But other equally alarming side effects include organ damage, eye and lung problems, stroke, infections, and kidney disease. The recurrence of crises can lead to chronic fatigue, stunted growth, swollen hands and feet, jaundice, infections, detached retinas, life-threatening disabilities, and for men, painful erections known as priapism (due to blockages of blood vessels in the penis). Ouch! If that isn’t bad enough, SCD can also lead to premature death. Anemia (the lack of healthy red blood cells or hemoglobin) is another dangerous condition which is of course only acerbated when a female patient has other conditions like fibroids. All of this means that having Sickle Cell Disease does not just necessitate medical treatments, but sometimes, hospitalization.

So how prevalent is it? According to the American Society of Hematology, Sickle Cell Disease affects approximately 70,000 to 100,000 people in the U.S, mainly African American and secondarily, some Hispanics with ancestry from Central and South America. While people with SCD have two genes which cause this genetic abnormality, people with Sickle Cell Trait (SCT) carry only one defective gene and usually live normal lives. But since an estimated 8% of African Americans have SCT, knowing if you are a carrier becomes an urgent matter for black people who are contemplating having children. According to the Canadian Blood Services, SCD affects about 6,000 people in Canada, of which 3,500 live in the province of Ontario. But in case you are thinking that you need not concern yourself with this illness, the Sickle Cell Anemia Association of Quebec estimates that 1 in 400 children are affected by SCD and 1 in 10 people in the black population have the sickle cell trait.

According to the Cleveland Clinic, traditionally, SCD has been treated with transfusions, antibiotics to fight infections, and other medications to reduce symptoms. But recent developments have brought dramatic and promising new treatments. On December 08, 2023, the U.S. Food and Drug Administration (FDA) approved two cell-based gene therapies Casgevy (exagamglogene autotemcel) and Lyfgenia to treat SCD in patients 12 years and older with recurrent vaso-occlusive crises (VOC). Casgevy uses gene-editing technology (CRISPR/Cas9) to remove, add, and replace DNA which is then attached and multiplied in the patient’s bone marrow to increase the flow of fetal hemoglobin which facilitates oxygen delivery. Lyfgenia is a cell-based gene therapy used to modify a patient’s blood cells to produce a type of hemoglobin that mimics that produced in a normal adult.

Importantly, since both products are manufactured from the patient’s own blood stem cells, modified and administered as a one-time, single-dose infusion, patients must undergo a procedure known as myeloablative conditioning (high-dose chemotherapy), to remove cells from the bone marrow so they can be replaced with the newly treated, modified cells.

Currently, these two innovative cures for Sickle Cell Disease are available in the following countries – Casgevy in the UK, USA, Saudi Arabia, and Bahrain; and Lyfgenia in the USA only. These life-changing cures for SCD will forever change the face of the disease and its impact on the lives of those affected.

So, where does Canada stand on these innovative new protocols?  Due to our stricter standards on gene therapy, Canada has moved more slowly to approve these treatments. However, as of spring 2024, Health Canada granted priority review to the application of the gene-editing therapy examgamglogene autotemcel (exa-cel) for patients ages 12 and older with Sickle Cell Disease. The agency is expected to complete its review of Vertex Pharmaceutical’s application in 180 days as opposed to the typical 300.

As new technologies are developed and approved, it looks promising that the days of Sickle Cell as an incurable and debilitating disease are numbered.