Waiv Foundation Models

Foundation models made for the clinic

Trained on hundreds of millions of H&E image tiles and fine-tuned to capture tissue biology rather than scanner or staining differences, our foundation models give consistent results from one laboratory to the next.

From compact 86-million-parameter models to billion-parameter ones, our foundation models form the basis of Waiv’s AI tests.

19M+
downloads of Phikon
+23%
average robustness gain across 10 foundation models
~10x
faster feature extraction with AquaViT
5
open models released since 2023
Why it matters

Our fine-tuning makes models care less about the scanner and more about the tissue.

Pathology foundation models have grown to billions of parameters. Yet they still encode where a slide was scanned and stained, not just what the tissue shows. So a model that tops a benchmark can give a different answer in a different lab. We build models that don’t.

Robust by design

Our fine-tuning teaches models to ignore scanner and stain, and focus on biology.

Efficient to deploy

We distil billion-parameter knowledge into models small enough to run anywhere.

Proven, openly

Every model is benchmarked publicly, released to the community, and used in our own validated tests.

Our models

Four years of foundation models, each one a step further

Five open models, each solving a real deployment problem: scale, open data, speed, then robustness.

 
2026
Robustness
 
AquaViT
Most robust ViT-B on PathoROB

Distilled from H-Optimus-0 without its projection heads, then fine-tuned, it beats its 13× larger teacher on robustness and slide-level performance.

86M parameters, better internal version of H0-mini
 
Phaet
+72% robustness

Our fine-tuning raised Phikon-v2’s robustness index from 0.47 to 0.81, with better scores on every downstream benchmark.

307M parameters, fine-tuned Phikon-v2
View on Hugging Face →
 
Mascaret
#1 on PathoROB among public models

Also the best average score across 63 slide-level tasks on Patho-Bench, from mutation prediction to survival.

1.1B parameters, fine-tuned Midnight-12k
View on Hugging Face →
2025
Efficiency
 
H0-mini
~10x faster than its teacher

The most robust model on the PLISM scanner and staining benchmark at publication (MICCAI 2025), at under 8% of its teacher’s size.

86M parameters, distilled from the 1.1B H-Optimus-0 with Bioptimus
View on Hugging Face →
2024
Scaling with open data
 
Phikon-v2
456M tiles from 58,000+ public slides

Trained only on publicly available data across 30+ cancer sites, it performs on par with models trained on proprietary data.

2023
Beginning
 
Phikon
19M+ downloads

First open pathology foundation model, trained on 43M tiles from 6,000 TCGA slides across 16 cancer types. It powered the winning solution of the UBC-OCEAN Kaggle challenge.

Evidence

Same tissue, same answer, any scanner

Robustness leaderboard

Mascaret is the most robust publicly available pathology foundation model on PathoROB, the benchmark that measures sensitivity to hospital, scanner and staining differences.

Publicly available models only, except AquaViT, which is an internal model similar to H0-mini but fully trained and owned by Waiv. It followed the distillation recipe of H0-mini, but without access to the projection heads typically needed for distillation. It was then fine-tuned like Mascaret and Phaet.

Average PathoROB robustness index
Mascaret (Waiv)
0.924
GenBio-PathFM
0.888
AquaViT (Waiv)
0.875
Virchow2
0.861
CONCH 1.5
0.852
H0-mini
0.815
H-Optimus-0
0.812
UNI2-h
0.757
Prov-GigaPath
0.630
Source: Robustifying pathology foundation models via fine-tuning (arXiv:2607.22861v1, 2026), Table 7.
Chart: fine-tuning improves robustness and performance jointly across ten foundation models
Robustness and performance together

Our fine-tuning made all ten foundation models we tested more robust (+23% on average) and better on downstream tasks (+43%), with no trade-off.

Biology, not the hospital

Same tissue, five hospitals, three scanners. Before fine-tuning, Phikon-v2 groups tiles by where they were scanned; after, Phaet groups them by tumour versus normal tissue, for hospitals it never saw in training.

Chart: fine-tuning reorganizes Phikon-v2’s feature space around biology
Relative time to extract features from 10,000 tiles
AquaViT (Waiv)
1x
UNI2-h
5.7x
Virchow2
6.1x
Prov-GigaPath
7.0x
H-Optimus-0
10.1x
Source: Distilling foundation models for robust and efficient models in digital pathology (MICCAI 2025).
Speed

AquaViT extracts features about 10x faster than its 1.1B-parameter teacher, while staying competitive on gene-expression prediction.

From model to test

Our foundation models are the starting point for Waiv’s AI tests. The published validations of RlapsRisk BC (Nature Communications, 2025) and MSIntuit CRC (Nature Communications, 2023) were built on Phikon and an earlier, colorectal-specific version of it, and the latest versions of our products use our fine-tuned models. Most recently, BRCAura, which predicts germline BRCA1/2 mutations from routine H&E slides, was built on AquaViT and validated on 1,025 patients across six centres, with consistent performance across staining protocols and scanners (npj Precision Oncology, 2026).

Build your next biomarker on models that hold up

From target discovery to companion diagnostics, we partner with pharma and biotech teams to find biomarkers in routine H&E slides, enrich and stratify trials, and turn those signals into tests that hold up in every lab.