Clonidine HCl MBT vs. Placebo to Prevent Chemoradiotherapy-Induced Severe Oral Mucositis in Oropharyngeal Cancer.

This is a sequential design Phase 2b/3 multicenter, randomized (1:1), double-blind, placebo-controlled, parallel group study to compare the efficacy and safety of clonidine HCl MBT to placebo MBT in the prevention of severe oral mucositis (SOM) in patients with oropharyngeal cancer (OPC) undergoing chemoradiotherapy (CRT). Best supportive care (BSC) will be allowed as per individual institutional practice with some exceptions as described in the inclusion and exclusion criteria. Eligible patients will be randomized to receive either clonidine MBT or placebo. Patients will be centrally randomized in a 1:1 ratio. The randomization will be stratified by p16 status (positive or negative). Randomized patients will be required to self-apply the study drug to the gum once a day in addition to BSC. The first application of MBT study drug will be performed on Day 1 of the CRT regimen. Each site will require the patient to follow the same local practice for BSC per Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology (MASCC/ISOO) guidelines with some exceptions as described in the inclusion and exclusion criteria. Daily, self-administered MBT study drug will be continued once daily for the entire duration of CRT treatment; defined as from Day 1 of CRT until the last day of CRT (anticipated to be approximately 4-8 weeks depending on the patient's prescribed CRT plan). Patients will be recruited sequentially into either the Phase 2b or the Phase 3 part of the study. An interim analysis will be conducted when Phase 2b patients have either completed their CRT or discontinued from the study. The Data Monitoring Committee (DMC) will review the Phase 2b efficacy and safety data at the interim analysis and will make a recommendation on proceeding with the Phase 3 part of the study.