Arm A: Nelfinavir together with CRT Arm B: CRT (without nelfinavir) Arm C: Nelfinavir together with CRT (but using a higher than conventional dose of radiotherapy) Arm D: CRT without nelfinavir (but using a higher than conventional dose of radiotherapy) Arm E: Chemotherapy alone (without radiotherapy) Participants who are ineligible or refuse randomisation will be treated as per local standard but will remain in the study for follow up at 26, 39 and 52 weeks. Their data will contribute to an Overall Survival (OS) analysis.