Merck (MRK) stock closed at $97.44 on Wednesday, which is close to its 52-week low of $94.48.The company is facing several headwinds like declining sales of the second-largest product, the human papillomavirus (HPV) vaccine, Gardasil in China, weakness in the diabetes franchise and generic erosion of some drugs. There are concerns about the firm’s ability to grow its non-oncology business ahead of the loss of exclusivity of its largest drug, Keytruda, later in the decade.To top that, the drug and biotech se ...