Xaira Therapeutics Launches X-Cell: First AI Virtual Cell Model Testing Scaling Laws on Massive Perturbation Data

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Xaira Therapeutics announced X-Cell on March 17, 2026, a 4.9-billion-parameter diffusion language model, the largest virtual cell model to date, trained on X-Atlas/Pisces, the largest genome-wide CRISPRi Perturb-seq dataset with 25.6 million perturbed single-cell transcriptomes across seven diverse contexts.12

X-Cell predicts cell responses to genetic perturbations, outperforming existing models by up to five-fold on metrics like Pearson delta, and generalizes zero-shot to unseen biological contexts such as iPSC-derived melanocyte progenitors and primary human CD4+ T cells.12

The model follows power-law scaling dynamics similar to large language models, using a novel diffusion architecture that iteratively refines predictions.2

Xaira, founded in 2024 with over $1 billion funding, plans to expand X-Atlas to primary cells, organoids, and in vivo perturbations, focusing on inflammatory/immunological diseases and antibody therapeutics.13

A subset of the Pisces dataset and X-Cell model is being made available to the scientific community.23

Sources:

1. https://www.biopharmatrend.com/news/xaira-therapeutics-launches-x-cell-its-first-virtual-cell-model-1532/

2. https://www.biospace.com/press-releases/xaira-therapeutics-launches-x-cell-its-first-virtual-cell-model-trained-on-the-largest-ever-genome-wide-perturbation-dataset-x-atlas-pisces

3. https://www.fiercebiotech.com/biotech/xaira-exec-divulges-rd-focus-how-ai-company-chasing-what-industry-hungriest