Patent Expirations and Generic Competition: The loss of exclusivity for key pharmaceutical products exposes Pfizer to significant revenue declines as lower-cost generic and biosimilar alternatives enter the market.

Clinical Development and Regulatory Approval Challenges: The extensive and costly process of drug development is inherently risky, with potential for clinical trial failures, unexpected side effects, or a failure to obtain necessary regulatory approvals from health authorities like the FDA.

Product Liability and Litigation Risks: Pfizer faces potential legal challenges and substantial financial liabilities arising from product liability claims, including allegations of adverse drug reactions or insufficient warning labels for its products.