Metastatic triple-negative breast cancer: the decisions you may face

Cancer page →Second-opinion finder →

5 treatment settings, 4 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.

Advanced, first line

First line, combined positive score 10 or more

2 optionsCompare side by side →

Pembrolizumab with chemotherapy (KEYNOTE-355) or with sacituzumab govitecan (ASCENT-04).

The options, in plain words

PembrolizumabApprovedMonoclonal antibody (anti-PD-1)

Pembrolizumab is a PD-1 blocking antibody approved in more than 40 settings, from melanoma and lung cancer to the first tumour-agnostic approval for mismatch-repair-deficient tumours in 2017, and before and after surgery in triple-negative breast cancer. A subcutaneous form arrived in 2025, and it is the backbone partner for ADCs and personalised neoantigen vaccines.

Sacituzumab govitecanApprovedADC

The first TROP2-targeted ADC. It delivers a strong chemotherapy directly to breast and bladder cancer cells and is now a first-line option in triple-negative breast cancer.

Also referenced:Combined positive score (CPS)

The evidence behind it

KEYNOTE-355 Phase 3 NCT02819518 2020882 peopleevidence 95
Tests Pembrolizumab
First-line metastatic TNBC: pembrolizumab + chemotherapy vs chemotherapy
OS HR 0.73 in CPS ≥10.
Overall survival, PD-L1 CPS ≥10 (months): Pembrolizumab + chemotherapy 23 (n=220) vs Placebo + chemotherapy 16.1 (n=103) · HR 0.73 · source
ASCENT-04 / KEYNOTE-D19 Phase 3 NCT05382286 2025443 peopleevidence 87
Tests Pembrolizumab, Sacituzumab govitecan
First-line PD-L1+ (CPS ≥10) metastatic TNBC: sacituzumab govitecan + pembrolizumab vs chemotherapy + pembrolizumab
PFS HR 0.65; PFS2 improved.
Progression-free survival (BICR) (months): Sacituzumab govitecan + pembrolizumab 11.2 (n=221) vs Chemotherapy + pembrolizumab 7.8 (n=222) · HR 0.65 · source

The main trade-offs on record

Pembrolizumab all recorded rates →

Side effect	Any grade	Grade 3+
Hypothyroidism (immune-mediated) · Pooled monotherapy data, >2,800 patients	8%	-
Pneumonitis (immune-mediated) · Pooled monotherapy data, >2,800 patients	3.4%	-
Colitis (immune-mediated) · Pooled monotherapy data, >2,800 patients	1.7%	-
Hepatitis (immune-mediated) · Pooled monotherapy data, >2,800 patients	0.7%	-

No pharmacokinetic interactions expected (antibody). See the irAE guide for toxicity management.

Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.

Sacituzumab govitecan all recorded rates →

Side effect	Any grade	Grade 3+
Neutropenia · ASCENT, Trodelvy arm, n=258	78%	49%
Diarrhoea · ASCENT, Trodelvy arm, n=258	59%	11%
Anaemia · ASCENT, Trodelvy arm, n=258	94%	9%
Fatigue · ASCENT, Trodelvy arm, n=258	65%	6%

UGT1A1*28 homozygotes: higher neutropenia risk; G-CSF prophylaxis is often used.

Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.

Questions to ask about this decision

Between Pembrolizumab and Sacituzumab govitecan, which do you recommend for me, and what about my case would make you choose differently?
Why: Guidelines list several reasonable options; the choice turns on details of your tumour, your health and your priorities.
What is each option trying to achieve: cure, long control, or relief of symptoms, and over what time?
Why: The aim shapes how much side effect and disruption is worth accepting.
How closely do I match the people in KEYNOTE-355 and ASCENT-04 / KEYNOTE-D19, and does that change what the results mean for me?
Why: Trial populations are selected; age, fitness, prior treatment and biomarkers all affect how far results carry.
Which side effects of Pembrolizumab or Sacituzumab govitecan are most likely for me, which are reversible, and which would make us stop?
Why: The recorded rates below come from labels and trials; your own risk depends on dose, other medicines and your health.
What happens if I delay, or decline this step for now? Is the decision reversible?
Why: Some decisions can wait for a second opinion or a trial slot; others cannot. Knowing which is part of the choice.
For my situation (first line, combined positive score 10 or more), which of the standard options do you recommend and why?
Why: Guideline options include: Pembrolizumab with chemotherapy (KEYNOTE-355) or with sacituzumab govitecan (ASCENT-04).
Am I a candidate for Pembrolizumab, Sacituzumab govitecan, and what side effects should I expect?
Why: Knowing the expected toxicities helps you plan work, family, and supportive care.
How do the results of KEYNOTE-355 and ASCENT-04 / KEYNOTE-D19 apply to someone like me?
Why: Trial populations differ from individual patients; ask how closely you match.

Add these to your appointment list, or take the full question set for this cancer.

Advanced, first line

First line, PD-L1-negative or immunotherapy-ineligible

4 optionsCompare side by side →

Datopotamab deruxtecan (TROPION-Breast02) or sacituzumab govitecan (ASCENT-03); a taxane or platinum where antibody-drug conjugates are unavailable.

The options, in plain words

Datopotamab deruxtecanApprovedADC

Datopotamab deruxtecan (Datroway) is the second TROP2 ADC and shares Enhertu's payload. In 2026 it became a first-line option for triple-negative breast cancer patients who cannot receive immunotherapy.

Sacituzumab govitecanApprovedADC

The first TROP2-targeted ADC. It delivers a strong chemotherapy directly to breast and bladder cancer cells and is now a first-line option in triple-negative breast cancer.

Paclitaxel / nab-paclitaxelApprovedCytotoxic chemotherapy (taxane)

A microtubule poison discovered in the Pacific yew tree, among the most used chemotherapies in breast, lung, and ovarian cancer.

CarboplatinApprovedCytotoxic chemotherapy (platinum)

Carboplatin is a platinum chemotherapy that crosslinks DNA; it is part of the standard pre-surgery regimen for triple-negative breast cancer.

The evidence behind it

TROPION-Breast02 Phase 3 NCT05374512 2025644 peopleevidence 88
Tests Datopotamab deruxtecan
First-line metastatic TNBC, not candidates for PD-1/PD-L1: Dato-DXd vs chemotherapy
OS 23.7 vs 18.7 months; PFS also improved.
Progression-free survival (BICR) (months): Datopotamab deruxtecan 10.8 (n=323) vs Chemotherapy (ICC) 5.6 (n=321) · HR 0.57 · source
ASCENT-03 Phase 3 NCT05382299 2025558 peopleevidence 88
Tests Sacituzumab govitecan
First-line metastatic TNBC, not candidates for PD-1 inhibitors: sacituzumab govitecan vs chemotherapy
PFS HR 0.62.
Progression-free survival (BICR) (months): Sacituzumab govitecan 9.7 (n=279) vs Chemotherapy (TPC) 6.9 (n=279) · HR 0.62 · source

The main trade-offs on record

Datopotamab deruxtecan all recorded rates →

Side effect	Any grade	Grade 3+
Stomatitis · TROPION-Breast01, n=360	59%	7%
Fatigue · TROPION-Breast01, n=360	44%	4.2%
Nausea · TROPION-Breast01, n=360	56%	1.4%
Keratitis · TROPION-Breast01, n=360	24%	1.1%

Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.

Sacituzumab govitecan all recorded rates →

Side effect	Any grade	Grade 3+
Neutropenia · ASCENT, Trodelvy arm, n=258	78%	49%
Diarrhoea · ASCENT, Trodelvy arm, n=258	59%	11%
Anaemia · ASCENT, Trodelvy arm, n=258	94%	9%
Fatigue · ASCENT, Trodelvy arm, n=258	65%	6%

UGT1A1*28 homozygotes: higher neutropenia risk; G-CSF prophylaxis is often used.

Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.

Carboplatin all recorded rates →

Dose by Calvert formula using GFR (see the calculators).

Questions to ask about this decision

Between Datopotamab deruxtecan, Sacituzumab govitecan, Paclitaxel / nab-paclitaxel and the other options, which do you recommend for me, and what about my case would make you choose differently?
Why: Guidelines list several reasonable options; the choice turns on details of your tumour, your health and your priorities.
What is each option trying to achieve: cure, long control, or relief of symptoms, and over what time?
Why: The aim shapes how much side effect and disruption is worth accepting.
How closely do I match the people in TROPION-Breast02 and ASCENT-03, and does that change what the results mean for me?
Why: Trial populations are selected; age, fitness, prior treatment and biomarkers all affect how far results carry.
Which side effects of Datopotamab deruxtecan or Sacituzumab govitecan are most likely for me, which are reversible, and which would make us stop?
Why: The recorded rates below come from labels and trials; your own risk depends on dose, other medicines and your health.
What happens if I delay, or decline this step for now? Is the decision reversible?
Why: Some decisions can wait for a second opinion or a trial slot; others cannot. Knowing which is part of the choice.
For my situation (first line, pd-l1-negative or immunotherapy-ineligible), which of the standard options do you recommend and why?
Why: Guideline options include: Datopotamab deruxtecan (TROPION-Breast02) or sacituzumab govitecan (ASCENT-03); a taxane or platinum where antibody-drug conjugates are unavailable.
Am I a candidate for Datopotamab deruxtecan, Sacituzumab govitecan, Paclitaxel / nab-paclitaxel or related drugs, and what side effects should I expect?
Why: Knowing the expected toxicities helps you plan work, family, and supportive care.
How do the results of TROPION-Breast02 and ASCENT-03 apply to someone like me?
Why: Trial populations differ from individual patients; ask how closely you match.

Add these to your appointment list, or take the full question set for this cancer.

Other settings

Germline BRCA carriers

3 optionsCompare side by side →

Olaparib (OlympiAD) or talazoparib (EMBRACA) after or instead of first-line chemotherapy; platinum chemotherapy is also more active.

The options, in plain words

OlaparibApprovedSmall-molecule PARP inhibitor

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.

TalazoparibApprovedSmall-molecule PARP inhibitor

Talazoparib is a PARP inhibitor that traps PARP on DNA about 100 times more strongly than olaparib, which is why it works at a 1 mg daily dose. It is approved for germline BRCA-mutant HER2-negative breast cancer and, with enzalutamide, for HRR-mutant castration-resistant prostate cancer; anaemia is its dominant side effect.

CarboplatinApprovedCytotoxic chemotherapy (platinum)

Carboplatin is a platinum chemotherapy that crosslinks DNA; it is part of the standard pre-surgery regimen for triple-negative breast cancer.

Also referenced:Germline BRCA mutation (gBRCA)

The evidence behind it

OlympiAD Phase 3 NCT02000622 2017302 peopleevidence 86
Tests Olaparib
Germline BRCA-mutated, HER2-negative metastatic breast cancer after up to two chemotherapy lines: olaparib vs physician's choice chemotherapy
PFS 7.0 vs 4.2 months, HR 0.58; OS 19.3 vs 17.1 months, not significant.
Progression-free survival (months): Olaparib 7 (n=205) vs Chemotherapy 4.2 (n=97) · HR 0.58 · source
EMBRACA Phase 3 NCT01945775 2018431 peopleevidence 87
Tests Talazoparib
Germline BRCA-mutated, HER2-negative locally advanced or metastatic breast cancer: talazoparib vs physician's choice chemotherapy
PFS 8.6 vs 5.6 months, HR 0.54; OS HR 0.85, not significant.
Progression-free survival (months): Talazoparib 8.6 (n=287) vs Chemotherapy 5.6 (n=144) · HR 0.54 · source

The main trade-offs on record

Olaparib all recorded rates →

Side effect	Any grade	Grade 3+
Anaemia · OlympiA adjuvant, n=911	24%	9%
Neutropenia · OlympiA adjuvant, n=911	16%	5%
Leukopenia · OlympiA adjuvant, n=911	17%	3%
Fatigue · OlympiA adjuvant, n=911	42%	1.8%

Avoid grapefruit and Seville oranges.
200 mg twice daily for CrCl 31-50.

Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.

Talazoparib all recorded rates →

0.75 mg daily for CrCl 30-59; 0.5 mg for 15-29.

Carboplatin all recorded rates →

Dose by Calvert formula using GFR (see the calculators).

Questions to ask about this decision

Between Olaparib, Talazoparib and Carboplatin, which do you recommend for me, and what about my case would make you choose differently?
Why: Guidelines list several reasonable options; the choice turns on details of your tumour, your health and your priorities.
What is each option trying to achieve: cure, long control, or relief of symptoms, and over what time?
Why: The aim shapes how much side effect and disruption is worth accepting.
How closely do I match the people in OlympiAD and EMBRACA, and does that change what the results mean for me?
Why: Trial populations are selected; age, fitness, prior treatment and biomarkers all affect how far results carry.
Which side effects of Olaparib are most likely for me, which are reversible, and which would make us stop?
Why: The recorded rates below come from labels and trials; your own risk depends on dose, other medicines and your health.
What happens if I delay, or decline this step for now? Is the decision reversible?
Why: Some decisions can wait for a second opinion or a trial slot; others cannot. Knowing which is part of the choice.
For my situation (germline brca carriers), which of the standard options do you recommend and why?
Why: Guideline options include: Olaparib (OlympiAD) or talazoparib (EMBRACA) after or instead of first-line chemotherapy; platinum chemotherapy is also more active.
Am I a candidate for Olaparib, Talazoparib, Carboplatin, and what side effects should I expect?
Why: Knowing the expected toxicities helps you plan work, family, and supportive care.
How do the results of OlympiAD and EMBRACA apply to someone like me?
Why: Trial populations differ from individual patients; ask how closely you match.

Add these to your appointment list, or take the full question set for this cancer.

Third line and beyond

Second line and beyond

6 optionsCompare side by side →

Whichever TROP2 antibody-drug conjugate has not been used (ASCENT); trastuzumab deruxtecan for HER2-low tumours (DESTINY-Breast04); izalontamab brengitecan where available; eribulin, capecitabine or gemcitabine with carboplatin.

The options, in plain words

Sacituzumab govitecanApprovedADC

The first TROP2-targeted ADC. It delivers a strong chemotherapy directly to breast and bladder cancer cells and is now a first-line option in triple-negative breast cancer.

Trastuzumab deruxtecanApprovedADC

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.

Izalontamab brengitecanPhase 3Bispecific ADC

Izalontamab brengitecan is the first bispecific ADC to succeed in a phase 3 trial, hitting two growth receptors at once in triple-negative breast cancer.

EribulinApprovedSynthetic halichondrin B analogue (microtubule dynamics inhibitor)

A sea-sponge-derived chemotherapy that extended survival in heavily pretreated breast cancer and in liposarcoma, where almost nothing else had.

CapecitabineApprovedOral fluoropyrimidine prodrug (antimetabolite)

Capecitabine (Xeloda) is a tablet form of the chemotherapy fluorouracil. It is a backbone of treatment for bowel cancer and a standard option in advanced breast cancer.

GemcitabineApprovedNucleoside analogue (deoxycytidine)

A versatile chemotherapy used in pancreatic, bladder, lung, ovarian, breast and biliary cancers, in nasopharyngeal cancer, and as a bladder instillation.

The evidence behind it

ASCENT Phase 3 NCT02574455 2020529 peopleevidence 88
Tests Sacituzumab govitecan
Pretreated metastatic TNBC: sacituzumab govitecan vs chemotherapy
OS 12.1 vs 6.7 months, HR 0.48.
Progression-free survival (patients without brain metastases) (months): Sacituzumab govitecan 5.6 (n=235) vs Chemotherapy (TPC) 1.7 (n=233) · HR 0.41 · source
DESTINY-Breast04 Phase 3 NCT03734029 2022557 peopleevidence 88
Tests Trastuzumab deruxtecan
HER2-low metastatic breast cancer after chemotherapy: T-DXd vs chemotherapy
OS HR 0.64.
Progression-free survival, HR+ cohort (BICR) (months): Trastuzumab deruxtecan 10.1 (n=331) vs Chemotherapy (TPC) 5.4 (n=163) · HR 0.51 · source

The main trade-offs on record

Sacituzumab govitecan all recorded rates →

Side effect	Any grade	Grade 3+
Neutropenia · ASCENT, Trodelvy arm, n=258	78%	49%
Diarrhoea · ASCENT, Trodelvy arm, n=258	59%	11%
Anaemia · ASCENT, Trodelvy arm, n=258	94%	9%
Fatigue · ASCENT, Trodelvy arm, n=258	65%	6%

UGT1A1*28 homozygotes: higher neutropenia risk; G-CSF prophylaxis is often used.

Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.

Trastuzumab deruxtecan all recorded rates →

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%

Interstitial lung disease in 10-15%: hold for any respiratory symptom and image; permanently discontinue for grade 2 or above. Moderately emetogenic: three-drug prophylaxis.

Rates from the label or pivotal trial as recorded on the product page; each grade 3+ figure links to its source.

Eribulin all recorded rates →

Possible QT prolongation. QT prolongation observed on day 8; monitor ECG in patients with heart failure, bradyarrhythmia or QT-prolonging drugs.
1.1 mg/m² (mild) or 0.7 mg/m² (moderate).
1.1 mg/m² for CrCl 15-49.

Questions to ask about this decision

Between Sacituzumab govitecan, Trastuzumab deruxtecan, Izalontamab brengitecan and the other options, which do you recommend for me, and what about my case would make you choose differently?
Why: Guidelines list several reasonable options; the choice turns on details of your tumour, your health and your priorities.
What is each option trying to achieve: cure, long control, or relief of symptoms, and over what time?
Why: The aim shapes how much side effect and disruption is worth accepting.
How closely do I match the people in ASCENT and DESTINY-Breast04, and does that change what the results mean for me?
Why: Trial populations are selected; age, fitness, prior treatment and biomarkers all affect how far results carry.
Which side effects of Sacituzumab govitecan or Trastuzumab deruxtecan are most likely for me, which are reversible, and which would make us stop?
Why: The recorded rates below come from labels and trials; your own risk depends on dose, other medicines and your health.
What happens if I delay, or decline this step for now? Is the decision reversible?
Why: Some decisions can wait for a second opinion or a trial slot; others cannot. Knowing which is part of the choice.
For my situation (second line and beyond), which of the standard options do you recommend and why?
Why: Guideline options include: Whichever TROP2 antibody-drug conjugate has not been used (ASCENT); trastuzumab deruxtecan for HER2-low tumours (DESTINY-Breast04); izalontamab brengitecan where available; eribulin, capecitabine or gemcitabine with carboplatin.
Am I a candidate for Sacituzumab govitecan, Trastuzumab deruxtecan, Izalontamab brengitecan or related drugs, and what side effects should I expect?
Why: Knowing the expected toxicities helps you plan work, family, and supportive care.
How do the results of ASCENT and DESTINY-Breast04 apply to someone like me?
Why: Trial populations differ from individual patients; ask how closely you match.

Add these to your appointment list, or take the full question set for this cancer.

Special situations

Brain metastases

One path named

Stereotactic radiosurgery or whole-brain radiotherapy with continued systemic therapy; antibody-drug conjugates have early evidence of intracranial activity.

The path, in plain words

Stereotactic radiosurgery (Gamma Knife, CyberKnife, linac SRS)Established

A single very high dose, or a few doses, aimed at a small brain or spine target with millimetre precision, replacing whole-brain radiotherapy for most brain metastases.

One to five sessions
Spares healthy brain
Treats targets surgery cannot reach

Also referenced:Brain metastases (intracranial disease)

The evidence behind it

No trial record is attached to this row yet. The trials tab lists what is recruiting and the landmark trials for this cancer.

The main trade-offs on record

Stereotactic radiosurgery (Gamma Knife, CyberKnife, linac SRS)

Limited to small targets
Radiation necrosis in a minority
Needs precise imaging and immobilisation

Questions to ask about this decision

Is Stereotactic radiosurgery (Gamma Knife, CyberKnife, linac SRS) the only reasonable path for me, or is there a trial, a different sequence or a wait-and-see option?
Why: A single standard does not mean a single choice; timing and trials are decisions too.
What is each option trying to achieve: cure, long control, or relief of symptoms, and over what time?
Why: The aim shapes how much side effect and disruption is worth accepting.
What happens if I delay, or decline this step for now? Is the decision reversible?
Why: Some decisions can wait for a second opinion or a trial slot; others cannot. Knowing which is part of the choice.
For my situation (brain metastases), which of the standard options do you recommend and why?
Why: Guideline options include: Stereotactic radiosurgery or whole-brain radiotherapy with continued systemic therapy; antibody-drug conjugates have early evidence of intracranial activity.

Add these to your appointment list, or take the full question set for this cancer.

How to read this page. Options and results come from OnCo records with their sources; the settings are the standard-of-care rows on the cancer page, and the lines of therapy are on the sequencing grid. Where a setting names one path, the choice is usually about timing, trials and where to be treated: see expert centres. OnCo is orientation, not medical advice.