Study of ME-401 in Subjects With Follicular Lymphoma After Failure of Two or More Prior Systemic Therapies

This is a global, multicenter, randomized, double-blind, placebo-controlled, 2 arm, Phase 2
study of the PI3Kδ inhibitor ME-401 in subjects with relapsed/refractory follicular lymphoma
after failure of at least 2 prior lines of systemic therapy which must have included an
anti-CD20 antibody and chemotherapy with an alkylating agent or a purine analogue. The study
will evaluate the efficacy and safety of ME-401 administered using two different schedules:
daily continuously or daily continuously for 2 cycles then daily for the first 7 days of each
subsequent cycle. Approximately 165 subjects will be randomized into the study.

Inclusion Criteria:

1. Histologically confirmed diagnosis of follicular lymphoma (FL) as defined in the World
Health Organization (WHO) classification scheme, limited to Grade 1, 2, or 3a

2. Progression of disease after at least 2 prior systemic therapies for FL

3. No prior therapy with PI3Kδ inhibitors

4. No disease progression on prior therapy with Bruton tyrosine kinase (BTK) inhibitors

5. At least one bi-dimensionally measurable nodal lesion > 1.5 cm in its longest diameter
by computed tomography (CT) scan as defined by the Lugano Classification

6. Adequate hematologic, renal and hepatic parameters at screening unless abnormal values
are due to FL per Investigator assessment

7. QT-interval corrected according to Fridericia's formula (QTcF) ≤ 450 milliseconds
(msec);

8. Left ventricular ejection fraction (LVEF) ≥ than institutional lower limit of normal
as measured by echocardiogram

Exclusion Criteria:

1. Known active histological transformation from FL to an aggressive lymphoma

2. Any uncontrolled clinically significant illness

3. Subjects who have tested positive for hepatitis B surface antigen and/or hepatitis B
core antibody plus have a positive hepatitis B

4. Ongoing or history of drug-induced pneumonitis

5. History of clinically significant cardiovascular abnormalities

6. History of clinically significant GI conditions