Liquid biopsy

Abbott + Exact Sciences ($21B, March 2026) consolidates the screening-and-Dx leader

Abbott completed its $21 billion acquisition of Exact Sciences on 23 March 2026 at $105 per share - the largest cancer-diagnostics M&A transaction in history. The deal brings Cologuard (stool-DNA CRC screen, the most-used non-invasive CRC test in the US with ~$3B annual revenue), Cancerguard (Exact Sciences' MCED blood test, launched September 2025 as a laboratory-developed test), Oncotype DX (breast cancer recurrence-risk assay), and Oncodetect (minimal residual disease and recurrence monitoring) under Abbott's broader diagnostics franchise. Abbott's total diagnostics annual sales now exceed $12 billion. The strategic consequence: the cancer-screening-and-diagnostics category is now anchored by Abbott at scale, with Guardant Health as the only remaining publicly-traded pure-play of size. Hologic, BD, Roche, and Illumina remain in the broader cancer-Dx ecosystem but at smaller scale relative to the new Abbott combined. The Miller-Meeks Bill Medicare MCED coverage from 2028-2029 (at ~$500/test for ages 50-65) creates the structural reimbursement framework Abbott will need to commercially scale Cancerguard behind Galleri.

State of the art (2026)

Liquid biopsy in mid-2026 splits into three commercial tiers moving at different speeds. Minimal residual disease (MRD) is the fastest-compounding layer: Natera Signatera processed roughly 249,000 clinical MRD units in Q1 2026 (+55% YoY) on its way to $2.74-2.82bn group revenue guidance, with Guardant Reveal and Personalis NeXT competing. Single-cancer screening is commercialising steadily behind Guardant Shield, the first FDA-approved blood-based colorectal screen. Multi-cancer early detection (MCED) is the stalled tier: GRAIL's 142,000-participant NHS-Galleri trial missed its primary late-stage-reduction endpoint on 19 February 2026, halving the shares. Abbott's $21bn Exact Sciences acquisition closed 23 March 2026, anchoring the screening-and-diagnostics category at scale.

Galleri MCED stumbled, the MCED commercialisation path is reset

Grail's Galleri multi-cancer early detection blood test was the highest-profile MCED product entering 2026 with $136.8M in 2025 revenue (+26% YoY) on 185,000+ tests sold. Grail submitted an FDA Premarket Approval Application for Galleri in 2025. In February 2026 a large pivotal screening study fell SHORT of efficacy targets - particularly on earlier-stage cancer detection where the MCED clinical-utility case is strongest - and Grail shares dropped approximately 50% on the readout. The PMA is still under FDA review but with a much less clear approval path than the company had projected through 2025. The structural consequence: MCED-as-routine-screening is on hold pending better efficacy data; commercial deployment will stay in concierge / cash-pay / direct-to-consumer mode rather than reimbursed primary care. Cancerguard (Exact / Abbott) launched as a laboratory-developed test in September 2025 rather than pursuing PMA - reflecting a different commercial strategy that may have been validated by Galleri's setback. The Medicare reimbursement framework (Miller-Meeks Bill, 2028-2029, ~$500/test) creates the future runway, but requires FDA-approved MCED tests to access it.

Minimal residual disease (MRD) testing is the highest-margin compounding tier

While MCED stumbles and single-indication screening commercialises slowly, minimal residual disease (MRD) testing is the highest-margin compounding tier within liquid biopsy. MRD detects ctDNA from cancer that remains after curative-intent surgery or chemo, allowing earlier intervention before clinical recurrence. Natera Signatera is the leader (Medicare coverage in CRC, breast cancer, bladder cancer, immunotherapy monitoring), Guardant Reveal competes, Personalis NeXT and ArcherDX cover the academic and pharma-trial segments. MRD test revenue compounds because oncologists order serial tests over a patient's post-treatment surveillance window (often 2-5 years), generating recurring revenue per patient compared to single-test screening. Natera's MRD revenue has been growing 40-60% YoY through 2024-2026 and is the structural growth tier of the broader liquid-biopsy category. The 2027-2028 question is whether MRD reimbursement extends across more indications (lung, hepatocellular, hematologic) and whether competitive pricing emerges as the assay technology commoditises.