All subjects will be started at 100 mg/day and the dose will be increased by 100 mg each month if the lower dose is tolerated without significant side effects. Adverse reactions will be scaled according to the CTCAE v.4. If the subject experiences severe adverse reactions at any dose, or if the subject requires dose reduction for toxicity from a dose of 100 mg/day, the subject will be removed from the study. If the subject experiences moderate adverse reactions at a dose >100 mg/day, the dose will be reduced by 100 mg and maintained at the lower dose for 1 month. If the subject experiences moderate or severe adverse reactions at this lower dose, the subject will be removed from the study. After 1 month, the dose will again be increased by 100 mg. If the subject does not experience any adverse reactions at this elevated dose, he/she will resume with the original up-titration schedule (i.e. increase by 100 mg every month up to 300 mg/day). If the subject experiences moderate symptoms at this elevated dose, the dose will again be reduced by 100 mg and will be maintained at this lower dose as the maximally tolerated dose.