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RecruitingLast updated: 2 February 2024

MoST Addendum 9 (substudies 21-22): This phase II study is evaluating the effect of a combination of targeted therapies (tucatinib plus trastuzumab) in people with advanced or metastatic solid cancers with HER2 amplifications or mutationsSingle arm, open label, signal seeking, phase II trial of the activity of tucatinib plus trastuzumab in patients with tumours harbouring HER2 amplifications or mutations

Clinical summary


This is a substudy of the Cancer Molecular Screening and Therapeutics (MoST) Program (ACTRN12616000908437). Eligible participants will receive both trastuzumab and tucatinib. Trastuzumab will be given to participants via subcutaneous injections at a dose of 600mg every 3 weeks. Tucatinib will be given in the format of a tablet, to be taken orally by participants at a dose of 300mg twice daily.


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Trial Acronym

MoST Addendum 9 (substudies 21-22)

More information

Trial Identifiers

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Trial sponsor

University of Sydney,Australian Genomic Cancer Medicine Centre

Scientific Title

Single arm, open label, signal seeking, phase II trial of the activity of tucatinib plus trastuzumab in patients with tumours harbouring HER2 amplifications or mutations




1. Adults, aged 18 years and older, with pathologically confirmed advanced and/or metastatic solid cancer of any histologic type or an earlier diagnosis of a poor prognosis cancer.
2. Tumours harbouring somatic HER2 amplification (in the absence of a HER2 mutation) or mutations (with or without concomitant amplification)
3. At least one measurable site of disease according to RECIST Version 1.1 or by RANO criteria if primary brain tumours.
4. Left ventricular ejection fraction >/= 50%.
5. Confirmation of molecular eligibility by the molecular tumour board.
6. ECOG 0 - 2.
7. Received and failed all standard anticancer therapy or have documented unsuitability for any further standard therapy, if standard therapy exists.
8. Clinical or radiological progression on or following last anticancer therapy unless such anticancer therapy stopped due to toxicity / treatment intolerance
9. Adequate organ system function as assessed by the following minimal laboratory requirements (within 7 days prior to first administration of study drug):
a. bone marrow function; platelets >/= 100 x 109/L, ANC >/= 1.5 x 109/L, and haemoglobin >/= 9g/dL (5.6mmol/L);
b. liver function; ALT/AST < /= 3 x ULN (in the absence of liver metastases, < /= 5 x ULN for patients with liver involvement) and total bilirubin < /= 1.5xULN
c. renal function; serum creatinine < /= 1.5xULN
10. For non central nervous system (CNS) cancers if brain metastases are present, patients must have either:
a. untreated brain metastases < /= 2.0 cm in size not needing immediate local therapy (at the discretion of the treating physician and adjudicated by the Principal Investigator).
b. previously treated brain metastases not needing immediate local therapy (at the discretion of the treating physician).
c. newly diagnosed brain metastases which require treatment with whole brain radiotherapy given >/= 21 days, stereotactic radiosurgery given >/= 7 days or surgery performed >/= 28 days prior to the first dose of treatment.
11. Willing and able to comply with all study requirements, including treatment, timing and/or nature of required assessments.
12. Signed, written informed consent to participation in the specific treatment substudy.


1. Contraindications to investigational products.
2. Known history of hypersensitivity to active or inactive components of investigational products.
3. Previous treatment with the same agent or same class of agent e.g. other HER2-directed therapy.
4. Specific comorbidities or conditions (e.g. psychiatric) or concomitant medications which may interact with the investigational product(s)
5. Co-morbidities or conditions that may compromise assessment of key outcomes or in the opinion of the clinician, limit the ability of the patient to comply with the protocol.
6. Primary tumour histology is HER2 amplified breast adenocarcinoma or gastric adenocarcinoma.
7. Treatment with any of the following anti-cancer therapies prior to the first dose of study treatment:
a. Radiation therapy, surgery, or tumour embolisation within 14 days prior to the first dose of study treatment. Palliative radiotherapy (for analgesia) is acceptable only if the irradiated field does not include target lesions. Note additional requirements or exceptions in inclusion criteria 10c
b. Immunotherapy within 28 days prior to the first dose of study treatment.
c. Chemotherapy, biologic therapy, or hormonal therapy within 14 days or 5 half-lives of a drug prior to the first dose of study treatment or until recovery from previous therapy (whichever is longer).
8. Administration of any investigational treatment within 30 days or 5 half-lives (whichever is longer) prior to receiving the first dose of study treatment.
9. Use of a strong CYP2C8 inhibitor within 5 half-lives of the inhibitor or use of a strong CYP3A4 or CYP2C8 inducer within 5 days prior to the first dose of study treatment. Use of sensitive CYP3A substrates should be avoided two weeks before enrolment and during study treatment
10. Ongoing treatment with corticosteroids at a total daily dose of > 2mg dexamethasone daily (or equivalent). Exceptions include use of dexamethasone up to 4mg /day within 14 days of initial treatment for patients with primary brain tumours.
11. Clinically significant cardiopulmonary disease.
12. Any untreated brain lesions >/=2.0 cm in size or any brain lesions requiring immediate local therapy.
13. Known leptomeningeal disease.
14. Have poorly controlled (> 1/week) generalized or complex partial seizures, or manifest neurologic progression due to brain metastases notwithstanding CNS-directed therapy.
15. Any unresolved toxicity (>CTCAE grade 2) from previous anti-cancer therapy. Subjects with irreversible toxicity that is not reasonably expected to be exacerbated by the investigational product may be included (e.g., hearing loss, peripheral neuropathy).
16. For non central nervous system (CNS) cancers, patients with symptomatic CNS involvement of his/her cancer are excluded. Subjects with stable neurological function, on stable doses of steroids/anti-epileptics over 4 weeks, and with no evidence of CNS progression within 12 weeks prior to screening are eligible.
17. History of another malignancy within 2 years prior to molecular screening registration are excluded unless adequately treated and determined free of progressive and metastatic disease for at least 6 months. Patients with a past history of adequately treated carcinoma-in-situ, basal cell carcinoma of the skin, squamous cell carcinoma of the skin, or superficial transitional cell carcinoma of the bladder can be included.
18. Pregnancy, lactation, or inadequate contraception. Women must be post-menopausal, infertile, or use a reliable means of contraception. Women of childbearing potential must have a negative pregnancy test done within 7 days prior to registration. Men must have been surgically sterilised or use a (double if required) barrier method of contraception.


  • You are able to swallow medication by mouth.
  • You have had treatment but your cancer has gotten worse or has not responded to the treatment you have been given.
  • Your cancer has not spread to other parts of the body.
  • Your cancer has spread to other parts of the body.


  • You have been diagnosed with a prior or secondary type of cancer.
  • You have certain types of non-cancer medical conditions.
  • You have had certain treatments, surgical procedures or drugs.
  • You have previously been treated (or are currently being treated) on a clinical trial.

Clinical trials have complex eligibility criteria.

Ask your doctor if this trial could be right for you.

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