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12 treatment settings, 11 with more than one named option. Each section lays out the options the standard of care names, what each is for, the trials behind them with their recorded results, the side effects and cautions on record, and questions to ask. Built from the cancer page's standard-of-care rows; nothing here is advice for your case.
Neoadjuvant THP or T-DXd → surgery → trastuzumab/pertuzumab (pCR) or T-DXd/T-DM1 (residual).
The first targeted antibody for a solid tumour (1998), which turned HER2-positive breast cancer from the worst subtype into one of the most treatable.
Trastuzumab deruxtecan (Enhertu) is the most successful ADC ever. It redefined HER2 by working in tumours with only tiny amounts of the protein, and in 2026 moved into early-stage breast cancer.
Trastuzumab emtansine (Kadcyla, T-DM1) was the first ADC for a solid tumour (2013). It is still standard after surgery for HER2+ breast cancer patients whose tumour did not fully respond to pre-surgery treatment.
pCR 67.3% vs 56.3%.
| Side effect | Any grade | Grade 3+ |
|---|---|---|
| Neutropenia · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 18% |
| Nausea · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 7% |
| Anaemia · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 7% |
| Fatigue · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 6% |
Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.
| Side effect | Any grade | Grade 3+ |
|---|---|---|
| Thrombocytopenia · KATHERINE (adjuvant) | 29% | 6% |
| Fatigue · KATHERINE (adjuvant) | 50% | - |
| Nausea · KATHERINE (adjuvant) | 42% | - |
| Transaminases increased · KATHERINE (adjuvant) | 32% | - |
Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.
Add these to your appointment list, or take the full question set for this cancer.
T-DXd + pertuzumab first line (DESTINY-Breast09); tucatinib + trastuzumab + capecitabine for brain metastases; palbociclib maintenance if HR+.
A HER2-selective pill that works in the brain, for HER2-positive breast cancer with brain metastases.
Palbociclib was the first CDK4/6 inhibitor (2015), and in 2026 became the first approved as maintenance in HER2-positive, hormone-positive breast cancer.
PFS HR 0.56.
| Side effect | Any grade | Grade 3+ |
|---|---|---|
| Neutropenia · PALOMA-2 with letrozole | 80% | 66% |
| Leukopenia · PALOMA-2 with letrozole | 39% | 25% |
| Infections · PALOMA-2 with letrozole | 60% | 7% |
| Anaemia · PALOMA-2 with letrozole | 24% | 6% |
Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.
Add these to your appointment list, or take the full question set for this cancer.
Surgery then weekly paclitaxel × 12 + trastuzumab × 1 year (APT); T-DM1 × 17 cycles is an alternative (ATEMPT). Endocrine therapy if HR+.
A microtubule poison discovered in the Pacific yew tree, among the most used chemotherapies in breast, lung, and ovarian cancer.
The first targeted antibody for a solid tumour (1998), which turned HER2-positive breast cancer from the worst subtype into one of the most treatable.
Trastuzumab emtansine (Kadcyla, T-DM1) was the first ADC for a solid tumour (2013). It is still standard after surgery for HER2+ breast cancer patients whose tumour did not fully respond to pre-surgery treatment.
Averages across everyone diagnosed, often years ago. Your stage, subtype, age, fitness and the treatment you receive matter more than the average, and the numbers are improving quickly.
| Side effect | Any grade | Grade 3+ |
|---|---|---|
| Thrombocytopenia · KATHERINE (adjuvant) | 29% | 6% |
| Fatigue · KATHERINE (adjuvant) | 50% | - |
| Nausea · KATHERINE (adjuvant) | 42% | - |
| Transaminases increased · KATHERINE (adjuvant) | 32% | - |
Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.
Add these to your appointment list, or take the full question set for this cancer.
TCHP (docetaxel, carboplatin, trastuzumab, pertuzumab) or anthracycline-taxane + HP; from 2026, T-DXd × 4 → THP (DESTINY-Breast11, pCR 67%). PET-adapted chemotherapy omission (PHERGain) in trials.
Trastuzumab deruxtecan (Enhertu) is the most successful ADC ever. It redefined HER2 by working in tumours with only tiny amounts of the protein, and in 2026 moved into early-stage breast cancer.
A second HER2 antibody that binds a different spot from trastuzumab, blocking HER2 from pairing with HER3; together they extended survival by 16 months in CLEOPATRA.
pCR 67.3% vs 56.3%.
Averages across everyone diagnosed, often years ago. Your stage, subtype, age, fitness and the treatment you receive matter more than the average, and the numbers are improving quickly.
| Side effect | Any grade | Grade 3+ |
|---|---|---|
| Neutropenia · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 18% |
| Nausea · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 7% |
| Anaemia · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 7% |
| Fatigue · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 6% |
Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.
Add these to your appointment list, or take the full question set for this cancer.
Complete 1 year of trastuzumab (± pertuzumab if node-positive at diagnosis); endocrine therapy if HR+; radiation per stage.
The first targeted antibody for a solid tumour (1998), which turned HER2-positive breast cancer from the worst subtype into one of the most treatable.
A second HER2 antibody that binds a different spot from trastuzumab, blocking HER2 from pairing with HER3; together they extended survival by 16 months in CLEOPATRA.
Averages across everyone diagnosed, often years ago. Your stage, subtype, age, fitness and the treatment you receive matter more than the average, and the numbers are improving quickly.
Averages across everyone diagnosed, often years ago. Your stage, subtype, age, fitness and the treatment you receive matter more than the average, and the numbers are improving quickly.
No side-effect rates or interaction flags are recorded for these options yet. The side-effect lookup and interaction checker cover the products that have them.
Add these to your appointment list, or take the full question set for this cancer.
T-DXd (DESTINY-Breast05, iDFS HR 0.47 vs T-DM1; approved 2026) replacing T-DM1 (KATHERINE); consider extended adjuvant neratinib for HR+ high-risk.
Trastuzumab deruxtecan (Enhertu) is the most successful ADC ever. It redefined HER2 by working in tumours with only tiny amounts of the protein, and in 2026 moved into early-stage breast cancer.
Trastuzumab emtansine (Kadcyla, T-DM1) was the first ADC for a solid tumour (2013). It is still standard after surgery for HER2+ breast cancer patients whose tumour did not fully respond to pre-surgery treatment.
A pill taken for a year after trastuzumab to further reduce recurrence in HER2-positive, hormone-positive breast cancer, limited by severe diarrhoea.
Averages across everyone diagnosed, often years ago. Your stage, subtype, age, fitness and the treatment you receive matter more than the average, and the numbers are improving quickly.
iDFS HR 0.50; OS HR 0.66.
| Side effect | Any grade | Grade 3+ |
|---|---|---|
| Neutropenia · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 18% |
| Nausea · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 7% |
| Anaemia · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 7% |
| Fatigue · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 6% |
Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.
| Side effect | Any grade | Grade 3+ |
|---|---|---|
| Thrombocytopenia · KATHERINE (adjuvant) | 29% | 6% |
| Fatigue · KATHERINE (adjuvant) | 50% | - |
| Nausea · KATHERINE (adjuvant) | 42% | - |
| Transaminases increased · KATHERINE (adjuvant) | 32% | - |
Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.
Add these to your appointment list, or take the full question set for this cancer.
Chemotherapy + trastuzumab + pertuzumab for 1 year (APHINITY); trastuzumab alone for lower risk; 6 months acceptable where resources are limited (PERSEPHONE).
A second HER2 antibody that binds a different spot from trastuzumab, blocking HER2 from pairing with HER3; together they extended survival by 16 months in CLEOPATRA.
The first targeted antibody for a solid tumour (1998), which turned HER2-positive breast cancer from the worst subtype into one of the most treatable.
Averages across everyone diagnosed, often years ago. Your stage, subtype, age, fitness and the treatment you receive matter more than the average, and the numbers are improving quickly.
Averages across everyone diagnosed, often years ago. Your stage, subtype, age, fitness and the treatment you receive matter more than the average, and the numbers are improving quickly.
No side-effect rates or interaction flags are recorded for these options yet. The side-effect lookup and interaction checker cover the products that have them.
Add these to your appointment list, or take the full question set for this cancer.
T-DXd + pertuzumab (DESTINY-Breast09, PFS 40.7 months; approved 2025) or taxane + trastuzumab + pertuzumab (CLEOPATRA) followed by maintenance: HP ± tucatinib (HER2CLIMB-05) and, if HR+, endocrine therapy + palbociclib (PATINA, approved 2026).
Trastuzumab deruxtecan (Enhertu) is the most successful ADC ever. It redefined HER2 by working in tumours with only tiny amounts of the protein, and in 2026 moved into early-stage breast cancer.
A second HER2 antibody that binds a different spot from trastuzumab, blocking HER2 from pairing with HER3; together they extended survival by 16 months in CLEOPATRA.
A HER2-selective pill that works in the brain, for HER2-positive breast cancer with brain metastases.
Palbociclib was the first CDK4/6 inhibitor (2015), and in 2026 became the first approved as maintenance in HER2-positive, hormone-positive breast cancer.
PFS HR 0.56.
OS 57.1 vs 40.8 months, HR 0.69.
PFS 24.9 vs 16.3 months, HR 0.64.
| Side effect | Any grade | Grade 3+ |
|---|---|---|
| Neutropenia · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 18% |
| Nausea · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 7% |
| Anaemia · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 7% |
| Fatigue · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 6% |
Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.
| Side effect | Any grade | Grade 3+ |
|---|---|---|
| Neutropenia · PALOMA-2 with letrozole | 80% | 66% |
| Leukopenia · PALOMA-2 with letrozole | 39% | 25% |
| Infections · PALOMA-2 with letrozole | 60% | 7% |
| Anaemia · PALOMA-2 with letrozole | 24% | 6% |
Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.
Add these to your appointment list, or take the full question set for this cancer.
T-DXd if not used first line (DESTINY-Breast03, PFS HR 0.33 vs T-DM1); tucatinib + trastuzumab + capecitabine, especially with brain metastases (HER2CLIMB).
Trastuzumab deruxtecan (Enhertu) is the most successful ADC ever. It redefined HER2 by working in tumours with only tiny amounts of the protein, and in 2026 moved into early-stage breast cancer.
A HER2-selective pill that works in the brain, for HER2-positive breast cancer with brain metastases.
PFS HR 0.33; OS HR 0.64.
OS 21.9 vs 17.4 months, HR 0.66; CNS-PFS HR 0.32.
| Side effect | Any grade | Grade 3+ |
|---|---|---|
| Neutropenia · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 18% |
| Nausea · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 7% |
| Anaemia · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 7% |
| Fatigue · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 6% |
Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.
Add these to your appointment list, or take the full question set for this cancer.
T-DM1; neratinib or lapatinib + capecitabine; margetuximab + chemotherapy; trastuzumab + chemotherapy (continued HER2 blockade); zanidatamab and Chinese ADCs (trastuzumab rezetecan, disitamab vedotin) where available; trials.
Trastuzumab emtansine (Kadcyla, T-DM1) was the first ADC for a solid tumour (2013). It is still standard after surgery for HER2+ breast cancer patients whose tumour did not fully respond to pre-surgery treatment.
A pill taken for a year after trastuzumab to further reduce recurrence in HER2-positive, hormone-positive breast cancer, limited by severe diarrhoea.
Lapatinib was the first HER2-blocking pill (2007) and is now mostly a comparator arm and a late-line option, displaced by tucatinib and ADCs.
A trastuzumab look-alike with an engineered tail that binds immune cells more tightly; approved in 2020 but rarely used after ADCs arrived.
Zanidatamab (Ziihera) is an antibody that grabs HER2 at two different spots, approved for HER2+ bile duct cancer.
Hengrui's HER2 ADC, approved in China for lung cancer and showing Enhertu-scale results in breast cancer, part of a wave of Chinese ADCs heading for global trials.
Disitamab vedotin is a Chinese HER2 ADC approved for gastric and bladder cancer, now in global trials with Pfizer.
No trial record is attached to this row yet. The trials tab lists what is recruiting and the landmark trials for this cancer.
| Side effect | Any grade | Grade 3+ |
|---|---|---|
| Thrombocytopenia · KATHERINE (adjuvant) | 29% | 6% |
| Fatigue · KATHERINE (adjuvant) | 50% | - |
| Nausea · KATHERINE (adjuvant) | 42% | - |
| Transaminases increased · KATHERINE (adjuvant) | 32% | - |
Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.
Add these to your appointment list, or take the full question set for this cancer.
Systemic: tucatinib triplet or T-DXd (DESTINY-Breast12, intracranial ORR 72%); local: stereotactic radiosurgery or surgery for symptomatic or large lesions; whole-brain RT reserved.
A HER2-selective pill that works in the brain, for HER2-positive breast cancer with brain metastases.
Trastuzumab deruxtecan (Enhertu) is the most successful ADC ever. It redefined HER2 by working in tumours with only tiny amounts of the protein, and in 2026 moved into early-stage breast cancer.
Stereotactic body radiotherapy converges multiple beams with sub-millimetre accuracy to deliver tumour-destroying doses in one to five outpatient sessions, doing the job of surgery for inoperable early lung cancer and for metastases in liver, spine and brain. Tumour size and location limit its use, and late toxicity is a concern near the central airways.
OS 21.9 vs 17.4 months, HR 0.66; CNS-PFS HR 0.32.
CNS ORR 71.7%; 12-month PFS 61.6% in brain-metastasis cohort.
| Side effect | Any grade | Grade 3+ |
|---|---|---|
| Neutropenia · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 18% |
| Nausea · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 7% |
| Anaemia · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 7% |
| Fatigue · DESTINY-Breast03/04; all-grade rates ≥20% per label | - | 6% |
Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.
Add these to your appointment list, or take the full question set for this cancer.
LVEF every 3 months during anti-HER2 therapy; hold and cardioprotect for declines; anthracycline-free regimens preferred; long-term surveillance for late recurrence in HR+/HER2+.
Cardio-oncology builds heart risk assessment, monitoring and prevention into cancer care so patients can finish curative treatment without trading cancer for heart failure. It targets anthracycline and trastuzumab damage, checkpoint-inhibitor myocarditis and radiation heart disease using echocardiography, troponin tests and protective drugs; specialist clinics are concentrated in large centres.
Averages across everyone diagnosed, often years ago. Your stage, subtype, age, fitness and the treatment you receive matter more than the average, and the numbers are improving quickly.
Add these to your appointment list, or take the full question set for this cancer.