OPTI - DOSE: Optimal Dosing of Oral Anticancer Drugs in Older Adults (OPTI-DOSE)

The study hypothesis is that a lower starting dose of anticancer tablet treatments can lead to better treatment tolerability in older patients, while the benefits of treatment can be the same. The trial population consists of 30 patients aged 65 years or older, who are starting treatment with one of these anti cancer tablet treatments: pazopanib, olaparib, lenvatinib, sunitinib or palbociclib. The control group (half of the participants) will be treated with the standard-of-care, the interventional group will start with the lowest dose of the anti cancer tablets as described in the drug label. The dose will be increased every two weeks in case of good tolerability. Results of this pilot study will be used to inform the design of the larger randomised phase 2 trial.

Information about the benefits and side effects of treatments for cancer is mainly derived from studies with younger patients. It is known that elderly patients experience more side effects from treatments, which can lead to a worse quality of life. The study hypothesis is that a lower starting dose of anticancer tablet treatments can lead to better treatment tolerability in older patients, while the benefits of treatment can be the same. The trial population consists of 30 patients aged 65 years or older, who are starting treatment with one of these anti cancer tablet treatments: pazopanib, olaparib, lenvatinib, sunitinib or palbociclib. This is a randomized study with 1:1 randomisation, stratified by type of anti-cancer treatment. The control group (half of the participants) will be treated with the standard-of-care, that means with the recommended starting dose of the anti cancer tablets as described in the drug label. The dose can be adjusted (lowered) if this is necessary, for example because of side effects, based on the judgment of the treating physician. The interventional group (half of the participants) will start with the lowest dose of the anti cancer tablets as described in the drug label. The dose will be increased every two weeks in case of good tolerability. Results of this pilot study will be used to inform the design of the larger randomised phase 2 trial, for example the primary endpoint, the amount of investigations and the size of the study population. Study visits are planned every 2 weeks for a total study duration of 12 weeks, the time point for analysis of the primary endpoint. Blood samples for PK analysis are collected every 2 weeks. A baseline blood sample will be collected for pharmacogenomic analysis.

Control group: standard SmPC dosing. Intervention group: lower starting dose with dose-escalation inversely following the dosing steps from the SmPC every 2 weeks in case of good tolerability.

Lower starting dose with dose-escalation inversely following the dosing steps from the SmPC every 2 weeks in case of good tolerability

Starting dose of 20mg 1dd for RCC or endometrial carcinoma, starting dose of 24mg 1dd for thyroid carcinoma.

Feasibility of investigating whether a lower starting dose with step-up approach leads to a better overall treatment utility compared to standard dosing

The percentage of patients that are willing to participate, from all eligible patients The percentage of patients that successfully complete the first 12 weeks of the trial The percentage of data points that are successfully collected during the first 12 weeks of the trial

measured by the investigator. See: https://blogs.ed.ac.uk/canceroutcomes/overall-treatment-utility/#:~:text=In%20Oncology%20clinical%20research%2C%20Overall%20Treatment%20Utility%20%28OTU%29,balance%20of%20benefits%20and%20harms%20from%20cancer%20treatments

From date of randomization until the date of first documented progression or date of death from any cause, whichever came first, assessed up to 60 months

Inclusion Criteria: Adult patients ≥ 65 years of age. Indication for starting treatment with pazopanib (for renal cell carcinoma), olaparib (for ovarian carcinoma), lenvatinib (as monotherapy for thyroid carcinoma, or in combination with pembrolizumab for renal cell carcinoma or endometrium carcinoma), sunitinib (for renal cell carcinoma) or palbociclib (for breast carcinoma). No contra-indications for starting treatment at the recommended starting dose as per SmPC. All patients must provide written informed consent prior to enrolment. Exclusion Criteria: • Planned starting dose lower than the recommended starting dose as per SmPC For Pazopanib: Use of a strong CYP3A4-inhibitor or PgP-inhibitor Creatinine clearance <30ml/min Moderate or severe hepatic impairment (bilirubin >1.5x ULN) For Olaparib: Use of a moderate or strong CYP3A4-inhibitor Creatinine clearance <50 ml/min Severe hepatic impairment (Child-Pugh 10-15) For Lenvatinib: Creatinine clearance <30ml/min Severe hepatic impairment (Child-Pugh score 10-15) For Sunitinib: Use of a strong CYP3A4-inhibitor Use of a strong CYP3A4-inducer For Palbociclib: Use of a strong CYP3A4-inhibitor Severe hepatic impairment (Child-Pugh score 10-15) Other findings at interview or physical examination that hamper compliance to the study protocol