OnCo
drugsProductApproved2020🇪🇺🇬🇧🇨🇳🇦🇺

Tucatinib

A HER2-selective pill that works in the brain, for HER2-positive breast cancer with brain metastases.

HER2CLIMB (with trastuzumab and capecitabine; OS benefit including active brain metastases). Also in HER2+ colorectal cancer with trastuzumab (MOUNTAINEER, 2023). Pfizer (Seagen).

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Tucatinib
PubChem
Mechanism, step by step
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1.Oral drug is absorbed and reaches the tumour

Modality
Small-molecule kinase inhibitor (HER2)
Mechanism
Highly HER2-selective reversible TKI sparing EGFR.
Brand / code
Tukysa
Dosing & schedule
Route
Oral
Schedule
300 mg twice daily with trastuzumab and capecitabine (breast) or trastuzumab (colorectal)
Dose modifications
Reduce to 250 then 200 mg for hepatotoxicity or diarrhoea
Monitoring
LFTs every 3 weeks; diarrhoea management

Source: www.fda.gov/drugs/resources-information-approved-drugs/oncology-cancer-hematologic-malignancies-approval-notifications. Doses are for orientation; the current label governs.

Medicare
Part D (self-administered)

Oral, self-administered, so it is a Part D drug: covered through a stand-alone Part D plan or Medicare Advantage drug benefit, usually on the specialty tier with 25 to 33% coinsurance until the annual cap ($2,000 in 2025, $2,100 in 2026).

Commercial insurance
covered with prior authorisation

Covered for FDA-labelled and NCCN-listed uses, but almost always behind prior authorisation confirming diagnosis, biomarker and line of therapy; dispensed through a specialty pharmacy.

Assistance programmes

Part D out-of-pocket capped at $2,000 (2025) / $2,100 (2026). Medicare patients cannot use manufacturer co-pay cards; charity funds (PAN, HealthWell, CancerCare) and the Extra Help subsidy are the routes.

Sources: Medicare.gov: Drug coverage (Part D) · Medicare.gov: Costs for Medicare drug coverage (annual out-of-pocket cap). Not medical or financial advice; verify with your plan.

NICE recommendedNICE TA786 · 2022SMC: accepted
Appraised for
With trastuzumab and capecitabine for HER2-positive breast cancer after 2 or more anti-HER2 treatments
NHS England
Routinely funded for the appraised indication (or via managed access)

Sources: NICE TA786 · SMC advice: tucatinib. Funding decisions are indication-specific and change monthly; verify with NICE and your treating team.

Regulatory

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  1. 17 Apr 2020ApprovalUS

    HER2+ metastatic breast cancer including brain metastases, with trastuzumab and capecitabine (HER2CLIMB) source

  2. 19 Jan 2023ApprovalUS

    HER2+ RAS wild-type metastatic colorectal cancer with trastuzumab (MOUNTAINEER, accelerated) source

Approvals

RegionYearIndication
US2020HER2+ metastatic breast cancer including brain metastases, with trastuzumab and capecitabine
US2023HER2+ RAS-wild-type mCRC with trastuzumab

Safety

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Toxicity profile
Adverse event
Diarrhoea
Palmar-plantar erythrodysaesthesia
Nausea
Fatigue
Hepatotoxicity
Stomatitis

HER2CLIMB: 81% any grade, 13% grade 3. Events listed without rates were not read from a primary source; see the label. Blank cells mean the figure was not sourced, not that it is zero.

Cost & access

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Cost & access
CountryReimbursement
United StatesMedicare Part D (oral); commercial plans per formulary, often with prior authorisation
United KingdomNICE: recommended with trastuzumab and capecitabine for HER2+ breast cancer after ≥2 anti-HER2 regimens (TA786)

List prices are manufacturer or Medicare figures where publicly disclosed; net prices after rebates are usually lower. Reimbursement changes; check the payer.

Trials

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ClinicalTrials.gov · phase 2/3
refreshed 2026-09-09
47 studies15 recruiting43 Phase 26 Phase 3
Search “Tucatinib” on ClinicalTrials.gov →
Counts are from a name search and may include unrelated studies; up to 100 studies are summarised.

Recruiting now (live from ClinicalTrials.gov)

Recruiting trials near you · live from ClinicalTrials.gov
Tucatinib
intervention: Tucatinib
Open on ClinicalTrials.gov →

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Latest papers

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Literature trend69 papers in the last 12 months+44% vs prior 12How this is computed
Latest papers · live from Europe PMC
Open in Europe PMC

Query for this drug: (TITLE:"Tucatinib" OR ABSTRACT:"Tucatinib" OR TITLE:"Tukysa" OR ABSTRACT:"Tukysa") AND (cancer OR tumor OR tumour OR oncology OR carcinoma OR lymphoma OR leukemia OR leukaemia OR myeloma OR sarcoma OR melanoma OR glioma). Results are unfiltered search hits about Tucatinib, not a curated reading list.

Connected

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