Tests a changed osimertinib dose plan in EGFR-mutated lung cancer
Tests a changed osimertinib dose plan in adults with lung cancer.
Plain-language title generated from the registry record
Registry title: OSIBOOST 2: Improving Osimertinib cost-effectiveness in Non-Small Cell Lung Cancer treatment using dose-modification and pharmacokinetic boosting with cobicistat or ritonavir
Key facts
- Where
- Amsterdam, Geleen, Groningen, Maastricht, and Rotterdam, NetherlandsSee the 5 sites
- Phase
- Phase 2
AI summary: who the study is looking for
From the trial's eligibility criteria. Machine-read from the registry text on this page, so it can be wrong. The registry text below and the trial team decide who can take part.
The trial is looking for adults with advanced EGFR-mutated non-small cell lung cancer who already take osimertinib 80 mg once daily as part of their regular care.
- Age
- 18 years or older
- Sex
- All sexes can join
- Disease stage
- Advanced non-squamous EGFR-mutated lung cancer. Part A: no signs of imminent progression on CT. Part B: symptom-free progression in the brain, not in a key brain area, with the disease outside the brain under control.
- Earlier treatment
- Must already receive osimertinib 80 mg once daily as standard treatment.
- Biomarker or test result
- EGFR mutation. The patient agrees to a blood test for CYP3A genotype.
Main reasons for not taking part
- Taking other drugs or herbal products that strongly affect CYP3A, P-gp or BCRP activity
- Gut problems that may change how osimertinib or cobicistat is absorbed
- Severe chronic liver disease (Child-Pugh class C)
- Pregnant or breastfeeding
Read by machine on 9 November 2026.
Where in Netherlands
- Het Nederlands Kanker Instituut-Antoni van Leeuwenhoek Ziekenhuis StichtingAmsterdam, NetherlandsTaking people
- Zuyderland Medisch Centrum StichtingGeleen, NetherlandsTaking people
- Universitair Medisch Centrum GroningenGroningen, NetherlandsTaking people
- University Hospital MaastrichtMaastricht, NetherlandsTaking people
- Erasmus Universitair Medisch Centrum Rotterdam (Erasmus MC)Rotterdam, NetherlandsTaking people
Questions to ask the study team
- How often do I need to come in, and for how long each time?
- Are travel costs paid?
- Can I keep my own doctor?
- What happens if I want to stop?
Trial details
- Who runs it
- University Hospital Maastricht
- Trial code
- NCT05748093EU 2023-505700-35-00
- Record updated
- 2 November 2026
- Original description
This study will consist of two sub-studies in patients with advanced EGFR mutated NSCLC. Depending on disease status, patients may be enrolled in sub-study A (stable disease or better) or B (CNS oligoprogression):Read full original descriptionShow less
Modified osimertinib dosing, with or without cobicistat (or ritonavir) as a pharmacokinetic booster, to improve cost-effectiveness of advanced Non-Small Cell Lung Cancer treatment - OSIBOOST 2
This study will consist of two sub-studies in patients with advanced EGFR mutated NSCLC. Depending on disease status, patients may be enrolled in sub-study A (stable disease or better) or B (CNS oligoprogression):
OSIBOOST 2-A: is a single-arm near-equivalence study, intended to assess the clinical feasibility of a modified osimertinib dosing strategy combining therapeutic drug monitoring, osimertinib dose-modification and pharmacokinetic (PK) boosting, in order to improve osimertinib cost-effectiveness and reduce toxicity while maintaining clinical efficacy. This study will include patients with advanced EGFR positive NSCLC who are treated with osimertinib as part of regular care. The primary objective is to evaluate the clinical feasibility of a modified osimertinib dosing strategy to allow for a personalized, more cost-effective osimertinib dosing schedule while maintaining osimertinib exposure within the provisional, clinically-proven, therapeutic window (125 – 259 ng/mL).
OSIBOOST 2-B: is an exploratory single-arm pharmacokinetic boosting study, designed to assess whether PK boosting provides a viable therapeutic option in patients with asymptomatic central nervous system (CNS) oligoprogression. The primary objective is to assess whether boosting standard (unaltered) osimertinib treatment can result in renewed CNS disease control, as a cost-effective alternative for off-label, non-reimbursable, dose-escalation to 160 mg osimertinib once daily (QD).
Inclusion: The patient receives osimertinib 80 mg once daily as part of their standard treatment plan; The patient has a World Health Organisation (WHO) Performance Status (PS) of 0-2; The patient is 18 years or older; The patient is able and willing to sign informed consent; The patient is able and willing to undergo additional blood sampling (e.g. for therapeutic drug monitoring); The patient consents to their blood being analysed for CYP3A-genotype; OSIBOOST 2-A: the patient has non-squamous advanced EGFR-mutated NSCLC with no signs of imminent progression (CT-confirmed). If the patient does have signs of progression, they are only eligible if their treating physician deems treatment beyond progression to be appropriate; OSIBOOST 2-B: the patient has non-squamous EGFR-mutated NSCLC with radiologically confirmed (RANO-progressive) asymptomatic intracranial progression, not in an eloquent area. Furthermore, extracranial disease should be controlled (no RECIST v1.1 progression).
Exclusion: The patient is taking any other drug or herbal substance which 1) is known to strongly inhibit CYP3A, P-gp or BCRP activity; 2) is primarily metabolized by CYP3A, P-gp or BCRP and has a small therapeutic range; or 3) may otherwise affect CYP3A, P-gp or BCRP metabolic activity; The patient has impaired gastrointestinal function that may alter the absorption of osimertinib or cobicistat (e.g. ulcerative disease, uncontrolled nausea or vomiting, malabsorption syndrome, small bowel resection); The patient has chronic liver disease (Child-Pugh score: class C); The patient is either pregnant or breastfeeding.