Study of Abexinostat in Patients With Relapsed or Refractory Follicular Lymphoma

Inclusion Criteria: * Is able to understand and voluntarily sign an informed consent document before any study related assessments/procedures are conducted. * Has histologically confirmed Grade 1, 2, or 3a follicular lymphoma. * Has follicular lymphoma that has relapsed after (progressed after 6 months from the start of therapy) or is refractory to the last line of therapy (no response or progression within 6 months from the start of therapy) and needs treatment (must have at least 1 lymph node or extranodal lymphoid malignancy radiologically measuring ≥ 3 cm in its longest diameter). * Female patients must fulfil the following criteria: a. Be of non-childbearing potential, defined as follows: i. Postmenopausal (ie, ≥ 1 year without any menses) prior to Screening, or ii. Documented surgically sterile (≥ 1 month prior to Screening) * Male patients must agree not to donate sperm starting from the time of Screening, throughout the study, and until after 90 days following the last dose. * Use highly effective forms of birth control (women of childbearing potential only), which include the following: i. Consistent and correct use of established oral contraception ii. Established intrauterine device or intrauterine system iii. Barrier methods of contraception: condom or occlusive cap (diaphragm or cervical/vault caps) with spermicidal foam/gel/film/cream/suppository. * Female patients must agree not to breastfeed starting from the time of Screening, throughout the study, and until after 90 days following the last dose. * Male patients and their female spouse/partners who are of childbearing potential must use highly effective contraception methods consisting of 2 forms of birth control (at least 1 of which must be a barrier method) from the time of Screening, throughout the study, and until after 90 days following the last dose. * Male patients must agree not to donate sperm starting from the time of Screening, throughout the study, and until after 90 days following the last dose. Exclusion Criteria: * Has diagnosis of Grade 3b follicular lymphoma, or transformation to diffuse large B-cell lymphoma * Has a history of central nervous system lymphoma (either primary or secondary). * Has had prior treatment with abexinostat. * Has had allogeneic stem cell transplant within the last 6 months, or autologous stem cell transplant within the last 3 months before enrollment * Has any types of cardiac impairment at the time of enrollment * Has received any investigational medication within 30 days or 5 half-lives prior to Day 1, whichever is longer * Has prior history of malignancies, other than follicular lymphoma, unless the patient has been free of the disease for ≥ 3 years