Biotech stocks reversed course and closed the week ended Nov. 5 lower, squandering the gains notched early in the week. What was good news for Pfizer, Inc. turned out to be negative for several others engaged in COVID-19 vaccine and treatment research. Pfizer announced Friday its oral COVID-19 pill Paxlovid reduced the risk of COVID-19-related hospitalization or death by 89 percent. Merck & Co., Inc. (MRK: NYSE), which also has a competing medication in the pipeline, shed close to 10 percent on Friday. Stocks also reacted to the earnings, which came in thick and fast during the week. Five stocks belonging to the biotech and diagnostics spaces, debuted on Wall Street during the week. Here are the key upcoming catalysts that biotech investors are on in the unfolding week: Health Care Conferences: American College of Rheumatology, or ACR, Convergence 2021: Nov. 3–9 (virtual) BMO Biopharma Spotlight Series: Emerging Trends and …