Pfizer has voluntarily withdrawn Oxbryta (voxelotor), a treatment for sickle-cell anemia, from all markets globally. This decision coincides with an ongoing review by the European Medicines Agency (EMA) and stems from safety concerns identified in clinical studies. The withdrawal reflects an imbalance observed between vaso-occlusive crises (VOCs) and fatal events among patients treated with the drug.
The pharmaceutical giant's action has prompted Jefferies to lower its price target for Pfizer from $35 to $33, while reiterating a 'buy' recommendation. The adjustment reflects the removal of both Oxbryta and GBT601 from Jefferies' financial model, pending further clarification on the underlying issues.
Safety Data and Mechanism of Action
The specific data leading to the withdrawal indicated a potential safety signal that warranted immediate action. While the precise mechanism contributing to the observed imbalance remains unclear, the company has taken a cautious approach by removing the drug from the market. Jefferies analysts noted in their report that the mechanism of action (MOA) of Oxbryta is under scrutiny, contributing to their decision to remove related assets from their financial models.
Impact on Pfizer's Portfolio
The withdrawal of Oxbryta represents a setback for Pfizer's hematology portfolio. Oxbryta, which was initially developed by Global Blood Therapeutics (GBT) and later acquired by Pfizer, is an important treatment option for patients with sickle-cell disease. The drug functions by increasing hemoglobin's affinity for oxygen, reducing the polymerization of hemoglobin S and subsequent sickling of red blood cells.
Analyst Perspective
Jefferies' decision to lower the price target reflects the uncertainty surrounding the future of Oxbryta and related compounds. The analyst's note emphasized the need for further information to assess the potential impact on Pfizer's long-term prospects. The situation underscores the inherent risks in pharmaceutical development and the importance of continuous monitoring of drug safety profiles.
