Before any study-specific procedures begin, the study staff will review the Informed Consent Form which provides a detailed explanation of this clinical research study and its potential risks and benefits. The doctor and study center staff will answer any questions. If you agree to participate in this study, you will sign the Informed Consent Form.

In total, this study will involve 7 visits to the study center over a period of about 6 to 10 weeks. After the Informed Consent Form is signed, the screening period of the study begins. During the screening visit, the study doctor and staff will review medical history and conduct a series of study-related examinations and assessments to see if the requirements to proceed are satisfied. The screening visit can occur from 7 to 35 days before the 2nd study visit.

Those participants who are determined to satisfy all screening requirements will enter the treatment period of the research study. Participants in the treatment period will receive either PH94B or placebo to be taken 4 times per day. The chance of receiving either PH94B or placebo is 50%, like flipping a coin. The placebo has no medicine and looks like PH94B. The treatment period will last 28 days and involves 5 visits to the study center. After these visits there will be 1 follow-up visit for assessments and a safety check.