MEK and MET Inhibition in Colorectal Cancer

This is a two stage study. Firstly a dose escalation step is used to define the best dose for the drug combination, using the rolling 6 design where up to 6 patients are recruited at each dose level, and increasing the dose of one or other agent according to the side effects of treatment. An initial dose escalation phase was completed where 25 patients were enrolled, using the study treatment combination of PD-0325901 with PF-02341066. Following discontinuation of the MEKi (inihibitor), PD-0325901, the study was updated to include a further dose escalation phase using the new combination study treatment, MEKi, Binimetinib with METi, PF-02341066. The effects of this drug combination will be assessed to define the recommended dose level for the dose expansion phase of the study. Second the new drug combination is observed in 42-98 patients with bowel cancer for its efficacy and tolerability. Patients who give consent will have their archival tumour samples tested for RAS and c-MET status. Potential participants will, after giving consent, undergo screening tests to ensure that it is safe for them to take part. These involve a detailed medical history, physical exam, blood tests, ophthalmology exam, ECG and ultrasound and skin biopsies. The size and extent of tumours is also assessed by CT and/or MRI scan. For the initial dose escalation phase, on assurance that the test results are satisfactory, patients start on PD-0325901 first for one week. On Day -7 a physical exam, ECG and blood test is performed, with a repeat blood test on Day -6. End of first week PD samples of blood are taken to observe the level of PD-0325901. Day 1 PF-02341066 is introduced after further clinical safety assessments. There are further blood samples taken over 24 hours to measure levels of PD-0325901 and PF-02341066 on days 21 and 28 of the first cycle. For the further dose escalation phase, again assuming that the screening test results are satisfactory, patients start on Day 1 with the combined treatment of PF-02341066 with Binimetinib. A physical exam, ECG and blood test is performed, with a repeat blood test on Day 2. There are further blood samples taken over 24 hours to measure levels of Binimetinib and PF-02341066 on day 21of the first cycle. Patients have weekly visits when side effects are reviewed and a physical examination is performed. On Day 15 a second skin biopsy is taken along with blood tests to assess liver and renal function. At the end of the first 4 weeks cycle, for the initial dose escalation phase, and at end of 8 weeks for the new combination therapy dose escalation phase, an ophthalmology exam is compared with the baseline assessment. For subsequent cycles in both the initial dose escalation and further dose escalation phases, visits remain weekly and include safety assessments as per Day 1. Blood levels of PD-0325901 or Binimetinib and PF-02341066 are measured on day 21 of even numbered cycles. In addition the tumour size is checked every second cycle, and the study treatment stopped if the tumour continues to grow. When patients stop taking the study treatment they will be reviewed after 4 weeks for any side effects and have a physical examination and other safety tests performed. For patients entering the expansion phase of the trial the procedures are similar, except that there is a pre-screening stage where tumour biopsies are required. Patients will have a sample of their tumour assessed, following consent, to determine their RAS and cMET status. This may involve a fresh biopsy. If suitable, the patient will be entered into the screening for the dose expansion phase and a fresh tumour biopsy may be taken if not already done so. The study schedule is the same as for the escalation phase using Binimetinib with PF-02341066. At the end of treatment a further, optional, tumour biopsy may be taken. After trial participation patients will be offered further care with the trial team or their referring oncology team as appropriate.