Quantum-Si laid off about 20% of its workforce as it pushed the Proteus protein sequencing system launch to Q2 2027. The proteomics company said the timing shift supports an additional integrated instrument design cycle, after internal builds revealed variable performance, repeatability concerns, and execution risk for moving the design directly into production. The company expects cost-reduction actions to generate roughly $12 million in annualized operating expenses once fully implemented and extend cash runway from Q2 2028 to Q4 2028. Quantum-Si previously targeted early-access Proteus availability this summer and a full commercial launch by end of the year. At the same time, Quantum-Si said reagent development remains on track, with launch detection expected for 19 or 20 amino acids versus an earlier plan for 18. The Proteus program also represents a shift from Quantum-Si’s initial semiconductor-based detection approach to a more traditional optical detection approach designed to scale to proteome-scale workloads. For protein sequencing suppliers, delays like this are often a test of internal manufacturing readiness; the key near-term signals will be improved consistency metrics across integrated instruments and continued reagent performance.