Paige

Paige is a New York digital pathology company that builds AI to read digitized tissue slides for cancer. Founded in 2017 on a license from Memorial Sloan Kettering Cancer Center, it has been a wholly owned subsidiary of Tempus AI (NASDAQ: TEM) since August 2025. It is an AI vendor rather than an adopter: it sells diagnostic applications that help pathologists find and grade cancer on whole-slide images, and it licenses pathology foundation models to researchers and drug developers. None of it is self-serve; the clinical products are sold to laboratories and hospitals.

Its defining pattern is regulation-first. In September 2021 the FDA granted De Novo authorization to Paige Prostate, now marketed as Paige Prostate Detect, creating a new device category for software that assists pathologists. In the pivotal study, 16 pathologists read 610 prostate biopsy images with and without the software, and their sensitivity rose from 88.7 percent to 96.6 percent. In Europe, the prostate suite received certification under the In Vitro Diagnostic Regulation (IVDR) in 2025. The breast and gastrointestinal applications carry European marks or are for research use only, and Paige PanCancer Detect, which received Breakthrough Device designation in April 2025, is designated, not authorized.

The second pattern is foundation-model-first, built with Microsoft Research. Virchow, trained on about 1.5 million slides from Memorial Sloan Kettering, came first; Virchow2 expanded to about 3 million slides, and Virchow2G scaled to 1.8 billion parameters. PRISM2, announced in July 2025, pairs slide images with clinical reports so a language model can describe what it sees. The licenses differ by checkpoint: Virchow is Apache 2.0, while Virchow2 and the PRISM models carry non-commercial research licenses that bar clinical use, and Virchow2G is available only under a commercial license. A conversational co-pilot called Alba, unveiled in September 2024, remains in beta.

Tempus completed the acquisition on August 22, 2025, issuing about 1.26 million shares and paying 3 million dollars in cash, a combined fair value of 101.5 million dollars in its annual report, and it assumed 39.5 million dollars of Paige's Microsoft Azure commitments. Tempus said the deal grows its dataset; Paige's archive holds almost 7 million digitized slides. In January 2026 Tempus launched Paige Predict, which estimates the likelihood of 123 biomarkers and molecular pathways across 16 cancer types from a standard stained slide, for cases with too little tissue to sequence.

The honest framing: Paige's value rests on its slide archive and its regulatory record, and the FDA authorization covers one task, detecting cancer in prostate biopsies. Paige Predict's outputs are probabilities that point toward confirmatory testing, not a substitute for sequencing. PathAI, which Roche agreed to acquire in May 2026, is heading into a larger diagnostics company the same way; Bioptimus keeps an Apache-licensed H-optimus checkpoint open for commercial use; and Owkin sells an AI research agent built on its own oncology data. Paige's only commercially open weights belong to its oldest model.