In phase 1B part, patients will receive Varlitinib plus Gemcitabine and Cisplatin, and follow a modified 3+3+3 study dose escalation scheme starting from Varlitinib 200 mg BID. The primary objective of the phase 1B part is to determine the MTD of Varlitinib when given in combination with Gemcitabine and Cisplatin, and to characterise the safety profile of the study treatment regimen.~Based on the determined MTD and clinical information obtained from phase 1B part of the study, the DSMB will review the safety data and other clinical data, together with the sponsor, determine the MTD as well as the recommended phase 2 dose (RP2D). The sponsor will make a decision when to proceed with the phase 2A part of the study.~The phase 2A part of the study is designed as a single arm expansion, enrolling a further 20 patients at the RP2D. The purpose of the phase 2A expansion study is to confirm the safety and tolerability of the RP2D in a larger number of patients, and to provide preliminary estimates of the clinical activity of Varlitinib in combination with Gemcitabine and Cisplatin, prior to embarking on the larger, randomised phase 2B part of the trial.~The phase 2B part will be a two-arm, double-blinded, placebo controlled study. Patients will be randomised into 2 arms to receive Varlitinib plus Gemcitabine and Cisplatin, or placebo plus Gemcitabine and Cisplatin. The primary endpoint of the phase 2B part is progression-free survival (PFS). The randomisation will be stratified by primary tumour location (gall bladder or non-gall bladder).~Patient screening activities including informed consent and study eligibility verification will be performed within 21 days prior to first dose of the study medication. Radiological imaging to assess the disease status will be performed at baseline and every 6 weeks from Cycle 1 Day 1. Blood samples will be taken during the screening phase, treatment period until end of treatment. Patients will be required to complete safety follow-up within 28 days after the last administration of study medication.
The study intends to evaluate the following objectives in patients with advanced or metastatic biliary tract cancer who have not received systemic therapy for advanced/metastatic disease.~Primary Objectives:~Phase 1B~To determine the maximum tolerated dose (MTD), as determined by dose-limiting toxicities (DLTs), and to characterise the safety profile of Varlitinib in combination with Gemcitabine and Cisplatin.~Phase 2A~To further evaluate the safety and tolerability of Varlitinib in combination with Gemcitabine and Cisplatin at the recommended phase 2 dose (RP2D).~To provide a preliminary assessment of the clinical activity of Varlitinib in combination with Gemcitabine and Cisplatin at the RP2D as measured by Objective Response Rate (ORR) and progression-free survival (PFS) (based on RECIST v1.1)~Phase 2B~To compare the efficacy of Varlitinib in combination with Gemcitabine and Cisplatin to placebo in combination with Gemcitabine and Cisplatin as measured by progression-free survival (based on RECIST v1.1).