Bain Capital Life Sciences Investors, LLC

Bain Capital Life Sciences' Q1 2026 filing shows a $1.11B life-sciences-dedicated fund in the middle of a sector rotation — trimming its top two cardiovascular/renal biotech names (Heartflow -$108.7M, Olema Pharmaceuticals -$101.3M) by roughly 12-35% while opening new weight-loss, metabolic, and rare-disease positions that represent a deliberate reallocation toward the next generation of clinical-stage therapeutics. The fund cut Heartflow from $362.9M (27.8% of AUM) to $254.2M (22.9%) — a 16.1% share reduction that is still the single largest absolute decline in the filing but signals a desk that is confident enough in the long thesis to take a partial profit and redeploy rather than exit. Olema Pharmaceuticals was reduced by $101.3M (-12.2% shares) and Upstream Bio by $28.3M (-34.8%), both cardiovascular names that had benefited from the 2023-2025 GLP-1-driven cardiovascular-outcomes narrative. The offset was four new opens: Centessa Pharmaceuticals ($25.2M, rare hematology), Alkermes ($21.6M, CNS-and-dermatology), Disc Medicine ($9.0M, hematology), and Xilio Therapeutics ($5.6M, immuno-oncology) — all early-stage biotech with 2026-2027 catalysts, none overlapping with the cardiovascular names being reduced. One existing name, Solid Biosciences ($70.6M, Duchenne muscular dystrophy gene therapy), was increased by $26.0M (+24.0% shares) — the single largest increase in the book. A $1.11B fund holding 20 positions with a 79.00 whaleScore is highly concentrated by design — the Q1 changes show the manager rotating within the biotech vertical, away from cardiovascular-and-renal plays that have had their run and into next-generation rare-disease, immuno-oncology, and metabolic names that are earlier in their clinical and commercial trajectories.