Oxbryta May Be SCD Blood Transfusions Option in Pandemic, Case Report Finds
Treatment with Oxbryta (voxelotor) may be a feasible alternative to blood transfusions for sickle cell disease (SCD) patients who are experiencing respiratory distress and pneumonia related to COVID-19, a case report suggests.
These findings are particularly important during the ongoing pandemic in the U.S., in which rising blood shortages are limiting the availability of blood transfusions.
The researchers also noted that using Oxbryta instead of transfusions in COVID-positive patients would help reduce the exposure of health care providers to the virus, eliminating some risk.
The report, “Sickle Cell Anemia and COVID-19: Use of Voxelotor to Avoid Transfusion,” was published in the journal Transfusion.
Since the beginning of the pandemic, blood donations have significantly dropped in certain areas of the United States, and blood inventories are expected to continue to decrease.
The American Society of Hematology (ASH) has provided guidelines recommending different thresholds for blood transfusions when addressing common SCD symptoms, like anemia and vaso-occlusive crisis (VOC) — episodes of acute pain caused by small blood vessel blockage. For acute symptoms, including stroke or acute chest syndrome, blood transfusions are still recommended.
Now, researchers at the Inova Schar Cancer Institute, in Virginia, have successfully used Oxbryta as an alternative to a blood transfusion in a 39-year-old woman with SCD whose hemoglobin levels dropped after infection with the new SARS-CoV-2 virus, known as COVID-19.
The woman had the most severe form of SCD — HbSS, in which a mutation is found in both copies of the HBB gene — and was admitted to the hospital with skeletal pain that did not respond to the painkillers ibuprofen or oxycodone.
Both the patient and close family had been following the social distancing restrictions and had no recent contact with COVID-19-positive cases.
The woman had no fever, her vital signs were stable, and her oxygen saturation levels were normal (97%). Blood analysis, however, revealed signs of red blood cell damage, low blood cell counts, and low hemoglobin levels (7.9 grams per decilitre, g/dL). Hemoglobin is a protein in red blood cells that carries oxygen throughout the body. For comparison, hemoglobin levels in women normally range from 12.0 to 15.5 g/dL.
An X-ray of the chest revealed the woman had an enlarged heart and pulmonary problems. She was diagnosed with an acute sickle crisis and was treated with morphine and a saline intravenous (into the blood) solution.
Soon after, the patient developed a fever and became hypotensive, meaning she had very low blood pressure. A nasopharyngeal swab came back positive for SARS-CoV-2. Experiencing shortness of breath, the patient was treated with oxygen to keep saturation levels above 90%.
At this point, her hemoglobin levels had dropped to 6.7 g/dL and she received two red blood cell transfusions. However, this failed to increased her hemoglobin levels.
Severe anemia — a serious complication of red blood cell transfusion, called hyperhemolysis — and another complication known as volume redistribution after hydration were identified as potential causes for her lack of response.
To avoid additional blood transfusions, and the risk of exposing health care providers to COVID-19, clinicians decided to administer a daily, oral dose of 1,500 milligrams of Oxbryta.
This therapy, developed by Global Blood Therapeutics, increases the affinity of hemoglobin to oxygen and prevents sickle hemoglobin from forming polymers, very large molecules that make up many of the materials in living organisms. The goal was to help restore red blood cell function and oxygen delivery. Oxbryta was conditionally approved last year by the U.S. Food and Drug Administration for SCD patients ages 12 and older.
Two days after treatment, the patient’s hemoglobin levels had risen to 8.0 g/dL. She was clinically stable and was discharged without the need for supplemental oxygen at home. Ten days after being admitted to the hospital, her hemoglobin levels (10.3 g/dL) were closer to the normal range.
“To our knowledge, this is the first report of [Oxbryta] being used acutely in the setting of COVID-19 pneumonia in an individual with SCD and respiratory distress in lieu of transfusion,” the researchers wrote.
“In this case, the patient’s Hb [hemoglobin] and overall status improved quickly upon treatment, thereby avoiding exchange transfusion, decreasing hospital staff exposure to coronavirus and sparing RBC [red blood cells] units; important during this pandemic era of limited blood supply,” they concluded.