Twice daily oral atovaquone will be added to standard concurrent chemoradiotherapy (CRT): 66 Gy in 33 fractions, once daily, 5 days a week (Monday-Friday), with cisplatin (80 mg/m2 IV on days 1 and 22 of CRT) and vinorelbine (15 mg/m2 IV on days 1, 8, 22 and 29 of CRT). Whilst awaiting CRT to start, patients will receive two weeks (+/- 7 days) of oral atovaquone to ensure steady state is reached (after seven days). Patients will be allocated one of four dose levels: 450 mg, 600 mg, 675 mg or 750 mg (all doses PO BD). Atovaquone dose will be assigned as per the TiTE-CRM statistical model. The first two trial participants will receive 450 mg BD. In the absence of unacceptable toxicity, subsequent patients will be assigned doses up to and including 750 mg BD.~Hypoxia biomarker data will be collected at baseline (start of atovaquone run-in) and following two weeks (+/- 7 days) of atovaquone treatment. Atovaquone will then be continued without break for the duration of CRT, with the CRT schedule remaining constant for all patients at both centres. Assessment for Dose Limiting Toxicities (DLTs) will be from the first scheduled dose of atovaquone until three months after completion of CRT. The CT scan performed at the three-month follow up visit will be reviewed to collect tumour response data.
This is a phase I, single arm, open-label trial that will utilise a Time To Event Continual Reassessment Method (TiTE-CRM) to determine the maximum tolerated dose (MTD) of atovaquone in combination with concurrent CRT in NSCLC. Twenty evaluable participants will be recruited at three centres.