Inclusion Criteria:

- Histologically confirmed mycosis fungoides or Sezary Syndrome

- Stage IB to IVB disease at screening

- Recurrent or refractory disease after at least 1 prior systemic therapy

- Have adequate organ function defined as:

- At least 30 days must have passed since other treatment for CTCL.

Exclusion Criteria:

- Receiving concurrent treatment for CTCL

- Unable to swallow tablets

- Receiving high potency oral or topical steroids. Low potency oral steroid may be
permitted in patients who have been on a stable dose for at least 4 weeks prior to
screening. Oral or topical antihistamine is allowed.

- Unable to discontinue use of carbamazepine, phenobarbital, or phenytoin

- Have a serious concomitant systemic disorder or HIV

- Have a serious cardiac condition such as myocardial infarction within past 6 months,
angina, or heart disease as defined by the New York Heart Association (NYHA) Class
III or IV

- Have ECG abnormalities,

- Are pregnant or breastfeeding