Selinexor in Advanced Liposarcoma

In the Phase 2 portion of the study, 57 patients were randomized to selinexor (60 mg) or
placebo at a 1:1 allocation ratio.

In the Phase 3 portion of the study, approximately 222 patients will be randomized to
selinexor (60 mg) or placebo with a 2:1 allocation ratio.

Patients who progress during the blinded portion of the study will be unblinded and if
receiving:

- placebo, may cross over to open-label selinexor (60mg twice weekly)

- selinexor, will be withdrawn from further treatment and followed for survival

Study treatment will be given twice weekly on Day 1 and Day 3 during Weeks 1-6 of each
six-week (42 day) cycle until disease progression or intolerability.

Treatment will continue until one or more of the following occurs:

- Disease progression, as defined by RECIST v1.1 Response Criteria

- Clinical progression, as determined by the treating physician

- Unacceptable AEs or failure to tolerate study treatment

- Patient withdrawal

- Patient discontinuation due to non-compliance

Inclusion Criteria:

1. Patients ≥12 years of age

2. Body surface area (BSA) ≥ 1.2 m2

3. Histologic evidence of DDLS at any time prior to randomization AND current evidence of
DDLS requiring treatment

4. Must have measurable disease per RECIST v1.1 Response Criteria

5. Radiologic evidence of disease progression within 6 months prior to randomization. If
the patient received other intervening therapy after documented disease progression,
further disease progression must be documented after the completion of the intervening
therapy

6. Must have had at least two (2) prior lines of systemic therapy for liposarcoma (not to
exceed 5 prior lines)

7. If patient received any previous systemic therapy, the last dose must have been ≥ 21
days prior to randomization (or ≥ 5 half-lives of that drug - whichever is shorter)
with all clinically significant therapy- related toxicities having resolved to less
than or equal to Grade 1

Exclusion Criteria:

1. Patients with pure WDLS, myxoid/round cell or pleomorphic tumor histologic subtypes.

2. Known active Hepatitis B (HepB), Hepatitis C (HepC) or human immunodeficiency virus
(HIV) infection.

3. Known central nervous system metastases