As previously reported, BofA/Merrill downgraded Spero Therapeutics to Underperform from Neutral and cut its price target to $9 from $19. Analyst Jason Gerberry reviewed Spero's pipeline and has a more conservative view for lead asset, SPR994 for the treatment of complicated urinary tract infections. Gerberry views SPR994 as more of a niche drug than the previous analyst team and expects it to be used in a small subset of patients who are resistant to multiple antibiotics and are candidates for early hospital discharge. Further, the analyst sees a 55% probability of success given prior Ph2 had a limited read-through to'994's registration study given protocol differences, and said the early-stage antibiotic potentlator program is unlikely to unlock meaningful value until validated in larger studies.