Lawsuit Alleges Oxbryta Side Effects Resulted in Higher Rate of Vaso-Occlusive Crisis, Other Debilitating Symptoms

According to allegations raised in a recently filed product liability lawsuit, side effects of Oxbryta caused an Illinois man to suffer a stroke and other debilitating injuries just before the drug makers recalled the sickle cell disease treatment from the market earlier this year.

The complaint (PDF) was brought by Tirrell Allen in the U.S. District Court for the Northern District of California on November 7, indicating that Global Blood Therapeutics Inc. and Pfizer Inc. knew or should have known for years that Oxbryta may cause or contribute to higher rates of vaso-occlusive crisis (VOC) and other side effects, but failed to warn consumers or the medical community.

Oxbryta (voxelotor) was introduced by Global Blood Therapeutics in 2019, after it was granted accelerated approval by the U.S. Food and Drug Administration (FDA). The expensive drug was promoted as the first medication to treat the root cause of sickle cell disease, by improving hemoglobin levels in the body and helping the blood cells retain more oxygen.

In 2022, Pfizer acquired Global Blood Therapeutics for $5.4 billion, continuing to sell Oxbryta at an estimated annual cost of more than $88,000 for each patient. However, following a large number of reports involving users experiencing painful sickle cell complications and deaths, Pfizer announced a global Oxbryta recall in September, after determining that risks associated with the treatment outweigh the potential benefits.

Since then, several Oxbryta side effects lawsuits have been filed, alleging that the drug makers placed a desire for profits before the health and safety of individuals with sickle cell disease.

Allen indicates in the lawsuit that he was diagnosed with sickle cell disease (SCD) as a child, and just recently began taking Oxbryta in August 2024. However, he immediately began to suffer significant Oxbryta side effects, including pain, swelling, and a higher rate of SCD-related incidents, known as vaso-occlusive crisis.

Vaso-occlusive crises (VOC) occur when the red blood cells block blood flow, and the tissues become deprived of oxygen. This can cause an inflammatory response, which can lead to symptoms like pain in the chest, back and limbs, as well as fever. Patients often have to be hospitalized and can suffer kidney failure and stroke. Additionally, many patients can suffer death following a vaso-occlusive event.

In September 2024, just before the Oxbryta recall was announced, Allen indicates that he suffered a stroke and was still hospitalized at the time the lawsuit was filed.

The complaint accuses Pfizer of failing to provide proper warning about the risk of increased VOC events to the medical community and patients before the drug was recalled.

“At the time of injury, Plaintiff Tirrell Allen was unaware that Oxbryta had a higher rate of vaso-occlusive crisis,” the lawsuit states. “He was also unaware that there were more deaths in the Oxbryta treatment group as compared to the placebo group in post-marketing studies or that there were higher rates of vaso-occlusive crises in patients with sickle cell disease receiving Oxbryta in two real-world registry studies.”

In July 2024, European drug regulators warned that out of a clinical trial involving only 236 subjects, there were at least eight deaths reported among Oxbryta users, compared to two among patients given a placebo, the lawsuit reports. The study subjects were children between the ages of 2 and 15 years old.

In his lawsuit, Allen presents claims of strict liability, design defect, failure to warn, negligence, breach of warranties, unjust enrichment, false and misleading advertising, and violations of California civil codes.