• progression free survival [ Time Frame: every 8 weeks (first year of treatment) and every 12 weeks (second year of treatment) a CT/MRI scan will be made to asses PFS until progressive disease ]
  progression free survival is defined as time from study enrollment until disease progression or death. Outcome will be scored as 'progressed' or 'censored' according to the FDA guidance for industry of clinical trial endpoints.
• overall survival [ Time Frame: Every OPD visit (starting with every 2 weeks, increasing to every 12 weeks after 1 year) ]
  overall survival is defined as time from study enrollment until date of death of any cause. Analysis of OS will be done at the end of the study (study related follow-up will be until 3 years after start of treatment)
• duration of response [ Time Frame: every 8 weeks (first year of treatment) and every 12 weeks (second year of treatment) a CT/MRI scan will be made to asses duration of response until progressive disease ]
  duration of response is defined as time from study enrollment until date of documented tumor progression or death. Only patients with a CR or PR will be included in the assessment of duration of response.
• clinical benefit rate [ Time Frame: every 8 weeks (first year of treatment) and every 12 weeks (second year of treatment) a CT/MRI scan will be made to asses the clinical benefit rate until progressive disease ]
  defined as the sum of complete remissions, partial responses, and patients with stable disease for >6 months.
• Number of participants with treatment-related adverse events as assessed by CTCAE v5.0 [ Time Frame: through study completion. At every visit AE's will be recorded. Scheduled visits will be planned 2, 4, 6, 8, 12, 16, 20, 24, 32, 40, 48, 56, 68, 80, 92 and 104 weeks after start of treatment ]
  adverse events will be reported as descriptive statistics in a table
• quality of life based on the EORTC QLQ-C30 questionnaire [ Time Frame: patients are asked to fill in the questionnaires in week 0 (before start of treatment), week 8, 16, 24, 40, 56, and at progressive disease (up to 104 weeks after start of study medication). ]
• quality of life based on the EORTC QLQ-H&N35 questionnaire [ Time Frame: patients are asked to fill in the questionnaires in week 0 (before start of treatment), week 8, 16, 24, 40, 56, and at progressive disease (up to 104 weeks after start of study medication). ]
• quality of life based on the PSSHN questionnaire [ Time Frame: patients are asked to fill in the questionnaire in week 0 (before start of treatment), week 8, 16, 24, 40, 56, and at progressive disease (up to 104 weeks after start of study medication).. ]
• pain level assessed by the VAS(visual analog scale) questionnaire [ Time Frame: patients are asked to fill in the questionnaire in week 0 (before start of treatment), week 8, 16, 24, 40, 56, and at progressive disease (up to 104 weeks after start of study medication). ]
  scale range 0-10, in which a higher score represents more pain
• response rate with continues tumor shrinkage end-points [ Time Frame: every 8 weeks (first year of treatment) and every 12 weeks (second year of treatment) a CT/MRI scan will be made to asses the response rate until progressive disease ]
  response rate depicted in a waterfall plot
• circulating tumor DNA levels [ Time Frame: circulating tumor DNA levels will be measured at baseline, at week 2, week 4 and before every evaluation CT/MRI scan. ]
  circulating tumor DNA levels will be assessed to evaluate whether treatment response and disease progression can be predicted.
• correlation of c-MET immunohistochemical score with treatment response [ Time Frame: c-MET will be measured once (before treatment). Response will be measured every 8 weeks (first year) and every 12 weeks (second year of treatment) ]
  c-MET immunohistochemical score ranges from 0 to 300.

• progression free survival [ Time Frame: every 8 weeks (first year of treatment) and every 12 weeks (second year of treatment) a CT/MRI scan will be made to asses PFS until progressive disease ]
  progression free survival is defined as time from study enrollment until disease progression or death. Outcome will be scored as 'progressed' or 'censored' according to the FDA guidance for industry of clinical trial endpoints.
• overall survival [ Time Frame: Every OPD visit (starting with every 2 weeks, increasing to every 12 weeks after 1 year) ]
  overall survival is defined as time from study enrollment until date of death of any cause. Analysis of OS will be done at the end of the study (study related follow-up will be until 3 years after start of treatment)
• duration of response [ Time Frame: every 8 weeks (first year of treatment) and every 12 weeks (second year of treatment) a CT/MRI scan will be made to asses duration of response until progressive disease ]
  duration of response is defined as time from study enrollment until date of documented tumor progression or death. Only patients with a CR or PR will be included in the assessment of duration of response.
• clinical benefit rate [ Time Frame: every 8 weeks (first year of treatment) and every 12 weeks (second year of treatment) a CT/MRI scan will be made to asses the clinical benefit rate until progressive disease ]
  defined as the sum of complete remissions, partial responses, and patients with stable disease for >6 months.
• Number of participants with treatment-related adverse events as assessed by CTCAE v5.0 [ Time Frame: throug study completion. At every visit AE's will be recorded. Scheduled visits will be planned 2, 4, 6, 8, 12, 16, 20, 24, 32, 40, 48, 56, 68, 80, 92 and 104 weeks after start of treatment ]
  adverse events will be reported as descriptive statistics in a table
• quality of life based on the EORTC QLQ-C30 questionnaire [ Time Frame: patients are asked to fill in the questionnaires in week 0 (before start of treatment), week 8, 16, 24, 40, 56, and at progressive disease (up to 104 weeks after start of study medication). ]
• quality of life based on the EORTC QLQ-H&N35 questionnaire [ Time Frame: patients are asked to fill in the questionnaires in week 0 (before start of treatment), week 8, 16, 24, 40, 56, and at progressive disease (up to 104 weeks after start of study medication). ]
• quality of life based on the PSSHN questionnaire [ Time Frame: patients are asked to fill in the questionnaire in week 0 (before start of treatment), week 8, 16, 24, 40, 56, and at progressive disease (up to 104 weeks after start of study medication).. ]
• pain level assessed by the VAS(visual analog scale) questionairre [ Time Frame: patients are asked to fill in the questionnaire in week 0 (before start of treatment), week 8, 16, 24, 40, 56, and at progressive disease (up to 104 weeks after start of study medication). ]
  scale range 0-10, in which a higher score represents more pain
• response rate with continues tumor shrinkage end-points [ Time Frame: every 8 weeks (first year of treatment) and every 12 weeks (second year of treatment) a CT/MRI scan will be made to asses the response rate until progressive disease ]
  response rate depicted in a waterfall plot
• circulating tumor DNA levels [ Time Frame: circulating tumor DNA levels will be measured at baseline, at week 2, week 4 and before every evaluation CT/MRI scan. ]
  circulating tumor DNA levels will be assessed to evaluate whether treatment response and disease progression can be predicted.
• correlation of c-MET immunohistochemical score with treatment response [ Time Frame: c-MET will be measured once (before treatment). Response will be measured every 8 weeks (first year) and every 12 weeks (second year of treatment) ]
  c-MET immunohistochemical score ranges from 0 to 300.

Rationale: Salivary gland cancer (SGC) is a rare cancer with 24 histological subtypes. Treatment options for locally advanced and/or metastatic SGC are limited. The tyrosine kinase inhibitor cabozantinib suppresses tumor growth, angiogenesis, and metastasis, and has been approved for renal cell carcinoma and thyroid cancer. Cabozantinib may also be of value in advanced SGC because c-MET, one of the targets of cabozantinib, is frequently overexpressed in SGC.

Objectives: To assess the objective response rate (ORR), progression free survival (PFS), overall survival (OS), duration of response (DoR), toxicity, and quality of life (QoL) of patients with advanced SGC treated with cabozantinib in 3 cohorts: salivary duct carcinoma (SDC), adenoid cystic carcinoma (ACC), other SGC's.

Study design: Single arm, single center, phase II clinical trial in 3 cohorts: ACC, SDC and other SGC's.

Study population: Patient with c-MET positive, locally advanced, recurrent, and/or metastatic SGC.

Intervention: Cabozantinib tablets 60 mg once daily until progressive disease, intolerable toxicity, or investigator and/or patient decision to withdraw for a maximum duration of 2 years.

Inclusion Criteria:

Disease specific

• locally advanced, recurrent, and/or metastatic SGC (excluding sarcomas and mesenchymal tumors)
• c-MET positive disease
• Measurable disease per RECIST version 1.1 Cohort-specific criteria
• SDC cohort: direct inclusion (no objective tumor growth prior to inclusion needed)
• ACC cohort: inclusion after objective growth in the last three months or complaints due to the disease
• Other SGC's: inclusion after objective growth in the last three months or complaints due to the disease General conditions
• Age ≥18 years
• Eastern Cooperative Oncology Group performance status of 0 or 1.
• Normal number of neutrophils and thrombocytes
• Liver function: ALT and AST < 2.5 x upper limit of normal (ULN), total bilirubin ≤ 1.5 x ULN (except for Gilbert's syndrome), serum albumin ≥28 g/L
• Renal function: creatinine < 1.5 x ULN or calculated creatinine clearance ≥ 40 ml/min, Urine protein/creatinine ratio ≤113.1 mg/mmol (≤1 mg/mg) or 24-hour urine protein <1 g
• Hemoglobin A1c (HbA1c) ≤ 8% or a fasting serum glucose ≤ 9 mmol/l

Exclusion Criteria:

General conditions

• A known allergy for cabozantinib or its components
• Long QT-syndrome
• Pregnancy or lactation
• Patients (M/F) with reproductive potential not implementing adequate contraceptives measures
• Known brain metastases or cranial epidural disease unless adequately treated with radiotherapy and/or surgery and stable for at least 3 months before inclusion
• Major surgery within 3 months before randomization. Complete wound healing from major surgery must have occurred 1 month before inclusion and from minor surgery at least 10 days before inclusion
• Uncontrolled illness including, but not limited to cardiovascular disorders including symptomatic congestive heart failure, unstable angina pectoris, or serious cardiac arrhythmias, uncontrolled hypertension defined as sustained systolic BP > 150 mm Hg, or diastolic BP > 100 mm Hg, stroke (including TIA), myocardial infarction, or other ischemic event within 6 months before inclusion, serious active infections Concomitant treatments
• Concomitant (or within 4 weeks before inclusion) administration of any other experimental drug under investigation.
• Concurrent treatment with any other anti-cancer therapy.
• Concomitant anticoagulation. Low dose aspirin for cardioprotection and low dose LMWH are permitted.
• Radiation therapy within the last 4 weeks before inclusion