TNBC roadmap: from 'nothing to target' to ADC + immunotherapy first line
How triple-negative breast cancer went from the subtype with no targeted therapy to one with immunotherapy, PARP inhibitors, three ADCs, and a positive bispecific ADC in six years.
The turning point was recognising that TNBC did not need an oncogenic driver to be targeted: immune infiltration, DNA repair deficiency, and surface antigen abundance are all exploitable. The next phase moves these gains into the curative setting and attacks residual disease.
- 2000-2015historic
Chemotherapy only
Basal-like subtype defined (2000); TNBC named by exclusion (2007). Anthracycline-taxane chemotherapy; carboplatin added (2014). Median metastatic OS was about 13-18 months, and EGFR, VEGF, and PARP inhibitor (iniparib) trials failed repeatedly.
- 2018-2020historic
Immunotherapy and PARP arrive
The pivotal trials are IMpassion130 (atezolizumab, later withdrawn), OlympiAD/EMBRACA (PARP inhibitors in gBRCA), KEYNOTE-355 (pembrolizumab CPS ≥10 first line), ASCENT (sacituzumab govitecan).
- 2021-2022historic
Curative setting transformed
KEYNOTE-522 makes chemo-immunotherapy the standard for stage II-III; OlympiA adds adjuvant olaparib for gBRCA. DESTINY-Breast04 makes HER2-low TNBC eligible for T-DXd.
- 2024-2026current
ADCs move to first line; bispecific ADC succeeds
KEYNOTE-522 OS benefit confirmed. ASCENT-03/04 and TROPION-Breast02 read out positive, bringing first-line approvals for sacituzumab govitecan and Dato-DXd (2026). Iza-bren posts a positive phase 3 (2026). TIL-based de-escalation in stage I gains evidence.
- 2026-2029emerging
Next: residual disease, de-escalation, selection
OptimICE-pCR (omit adjuvant pembrolizumab after pCR), SCARLET (drop anthracycline), ctDNA-guided escalation for RCB II-III, ADCs in the post-neoadjuvant setting, sac-TMT and TROPION-Breast05 first-line readouts, IZABRIGHT-Breast01, TROP2 PET.
- 2029+speculative25%–50%likely
Speculative: cure for most, control for the rest
Neoadjuvant ADC + IO replacing anthracyclines; personalised vaccines in the adjuvant setting for high-risk residual disease; payload-switching ADC algorithms guided by PET and ctDNA; mesenchymal-subtype-specific therapy; brain-penetrant ADCs.
Probability ranges are named estimates that the claim is borne out on roughly a five-year horizon. They are meant to be argued with: propose a revision with your name and reasoning via a pull request to src/data/confidence.ts.
Story
topChemotherapy only
Basal-like subtype defined (2000); TNBC named by exclusion (2007). Anthracycline-taxane chemotherapy; carboplatin added (2014). Median metastatic OS was about 13-18 months, and EGFR, VEGF, and PARP inhibitor (iniparib) trials failed repeatedly.
Carboplatin is a platinum chemotherapy that crosslinks DNA; it is part of the standard pre-surgery regimen for triple-negative breast cancer.
Platinum agents such as cisplatin and carboplatin work by crosslinking DNA. They are curative in testicular cancer and central to lung, ovarian, bladder, head and neck, and TNBC treatment.
Immunotherapy and PARP arrive
The pivotal trials are IMpassion130 (atezolizumab, later withdrawn), OlympiAD/EMBRACA (PARP inhibitors in gBRCA), KEYNOTE-355 (pembrolizumab CPS ≥10 first line), ASCENT (sacituzumab govitecan).
IMpassion130 was the first immunotherapy success in breast cancer, later undermined when a sister trial failed and the approval was withdrawn.
Olaparib was the first PARP inhibitor, and turned an inherited BRCA mutation from a risk factor into a drug target, including after surgery in breast cancer.
Talazoparib is the most potent PARP trapper, approved in BRCA breast cancer and with enzalutamide in prostate cancer.
Established immunotherapy plus chemotherapy as first-line treatment for metastatic triple-negative breast cancer with PD-L1 expression.
The trial that proved a TROP2 ADC could nearly double survival in heavily pretreated triple-negative breast cancer.
Curative setting transformed
KEYNOTE-522 makes chemo-immunotherapy the standard for stage II-III; OlympiA adds adjuvant olaparib for gBRCA. DESTINY-Breast04 makes HER2-low TNBC eligible for T-DXd.
The trial that added immunotherapy to pre-surgery chemotherapy for triple-negative breast cancer and, uniquely, improved survival.
Showed that a year of a PARP inhibitor after standard treatment improves survival in women with inherited BRCA mutations.
Created a new category of breast cancer, HER2-low, by showing Enhertu works in tumours previously called HER2-negative.
ADCs move to first line; bispecific ADC succeeds
KEYNOTE-522 OS benefit confirmed. ASCENT-03/04 and TROPION-Breast02 read out positive, bringing first-line approvals for sacituzumab govitecan and Dato-DXd (2026). Iza-bren posts a positive phase 3 (2026). TIL-based de-escalation in stage I gains evidence.
Moved Trodelvy into first-line use for triple-negative patients who cannot receive immunotherapy.
Showed that pairing an ADC with immunotherapy beats chemotherapy plus immunotherapy in first-line PD-L1-positive TNBC.
The first trial to show an overall survival benefit for a first-line ADC in triple-negative breast cancer.
The first phase 3 win for a bispecific ADC, in triple-negative breast cancer, announced February 2026.
Immune cells that have got inside the tumour. More of them means better outcomes in triple-negative breast cancer.
Next: residual disease, de-escalation, selection
OptimICE-pCR (omit adjuvant pembrolizumab after pCR), SCARLET (drop anthracycline), ctDNA-guided escalation for RCB II-III, ADCs in the post-neoadjuvant setting, sac-TMT and TROPION-Breast05 first-line readouts, IZABRIGHT-Breast01, TROP2 PET.
Asks whether patients whose cancer completely disappeared before surgery still need a year of immunotherapy afterwards.
Tests whether the anthracycline can be dropped from TNBC pre-surgery treatment without losing effect.
Tests whether Dato-DXd plus a PD-L1 blocker beats today's immunotherapy-chemotherapy standard.
IZABRIGHT-Breast01 is the global first-line trial of the EGFR×HER3 bispecific ADC in triple-negative breast cancer.
Sacituzumab tirumotecan is a third TROP2 ADC from China, licensed to Merck for a very large global programme. It is approved in China; in the US it has a priority voucher but not yet approval.
An experimental PET scan that shows whether a tumour carries the TROP2 protein, so doctors could pick the right ADC before giving it.
An ultra-sensitive blood test after surgery that detects leftover cancer months before a scan would.
Speculative: cure for most, control for the rest
Neoadjuvant ADC + IO replacing anthracyclines; personalised vaccines in the adjuvant setting for high-risk residual disease; payload-switching ADC algorithms guided by PET and ctDNA; mesenchymal-subtype-specific therapy; brain-penetrant ADCs.
A vaccine made for one patient, encoding the unique mutations in their own tumour, to train the immune system to hunt it.
A dual-payload ADC is an ADC carrying two different poisons at once, so the tumour cannot escape by becoming resistant to one.
How a cancer cell changes shape to migrate and to shrug off drugs. Transcription factors like ZEB1 and SNAIL loosen the cell, switch on pumps that eject chemotherapy, and hide it from the immune system.
Patients whose TNBC survives chemo-immunotherapy before surgery have a high relapse risk. Give them an ADC after surgery.