Two years ago, the antibody-drug-conjugate story was "does the modality work?" That question is settled. At ASCO 2026 the ADC field has resolved into something more strategically interesting: a war for target antigens. Whoever owns the antigen owns the addressable market — and the radar makes the battle lines explicit. (For the broader pan-tumor view, see our companion ADC overview.)
The battle lines, by antigen
Group every ADC study by the antigen its conjugate targets, and a clear hierarchy emerges — with very different competitive dynamics at each target.
HER2 is the mature, dominant battleground (79 → 104 studies) and, remarkably, still growing — because HER2 itself keeps being redefined (positive, low, ultralow) and because multiple conjugates now compete on it. TROP2 (56 studies) is the crowded contest, with three ADCs fighting for the same antigen. Nectin-4 (enfortumab vedotin, 48) owns urothelial cancer outright. And the most important relative moves are at the edges: folate-receptor-α quadrupled (4 → 16) into a real ovarian franchise, and c-MET (2 → 9) is the emerging frontier.
| Target antigen | Lead ADCs | 2026 studies | Competitive read |
|---|---|---|---|
| HER2 | trastuzumab deruxtecan, T-DM1, disitamab vedotin | 104 | Most mature; still #1 and growing |
| TROP2 | sacituzumab govitecan, datopotamab deruxtecan, sac-TMT | 56 | Three-way contest, crowded |
| Nectin-4 | enfortumab vedotin | 48 | Owns 1L urothelial (EV-302) |
| Folate receptor α | mirvetuximab soravtansine | 16 | New ovarian franchise (×4 in 2 yrs) |
| c-MET | telisotuzumab vedotin / adizutecan | 9 | Emerging frontier (lung) |
| Tissue factor | tisotumab vedotin | 4 | Cervical niche |
When the antigen is settled, the payload decides
Here is the strategic consequence of antigen crowding: at validated targets like HER2 and TROP2, differentiation no longer comes from the antibody — it comes from everything attached to it. The competitive variables that matter now are:
- Payload class — topoisomerase-I-inhibitor warheads (the deruxtecan conjugates) versus microtubule inhibitors (the vedotins) versus maytansinoids — each with different potency and resistance profiles;
- Linker stability and bystander effect — whether the payload can kill neighboring antigen-low cells, which is what makes "HER2-low" and "HER2-ultralow" treatable in the first place;
- Tolerability — the class-defining toxicities now shape positioning: interstitial lung disease for the deruxtecan ADCs (the subject of a dedicated ASCO 2026 safety thread), ocular events for folate-receptor conjugates, and peripheral neuropathy for the vedotins.
The sequencing question nobody had two years ago
With several ADCs now approved in the same tumor, the field faces a genuinely new clinical problem: can you use a second ADC after the first? Real-world ASCO 2026 studies on ADC-after-ADC sequencing — for example, datopotamab deruxtecan after trastuzumab deruxtecan in breast cancer — mark a modality that has graduated from "does it work" to "how do we build a multi-ADC treatment journey." The answer hinges on whether the two conjugates share a payload class, because cross-resistance appears to track the warhead, not the antigen. This is the next competitive battleground.
The commercialization read
For BD teams: the validated antigens (HER2, TROP2, Nectin-4) are won or crowded — entering them now means competing on payload and tolerability, which is expensive. The live white space is in novel antigens (c-MET, the next wave of solid-tumor targets) and next-generation payloads (dual-payload, immune-stimulating, and non-cytotoxic warheads), several of which appear in early-phase ASCO 2026 studies. For investors: folate-receptor-α going from 4 to 16 studies is the template for how a non-obvious antigen becomes a franchise — watch c-MET for the next one.
Explore the underlying data
Every number above is live and pivotable on the Knitify ASCO Radar — analyze the 7,222 studies in the ASCO 2026 program by drug, indication, sponsor, or trial-in-progress status, and compare year over year against 2025 and 2024. Filter the board to an ADC target such as HER2 or TROP2 to reproduce every count in this article. The radar links to each study on the official ASCO program; it does not reproduce copyrighted text.
Methodology & scope: figures in this article are structured signals the Knitify ASCO Radar derives from the publicly released ASCO 2026 scientific program (7,222 studies presented; 6,511 in 2025; 5,885 in 2024) — counting how many studies reference a given drug, indication, or modality class. They quantify research attention and momentum, not clinical efficacy or market share. Named trial results are quoted from public company press releases, the ASCO press program, and peer-reviewed journals (cited below). The radar does not reproduce any copyrighted text — it links to each study on the official ASCO program. This is editorial commentary on public data — not investment, legal, regulatory, or medical advice.