Inclusion Criteria:

          1. Provision of signed and dated, written informed consent prior to any study specific
             procedures.

          2. Documented diagnosis of TP53-mutant MDS, according to WHO criteria that is
             relapsed/refractory or previously untreated MDS.

          3. Adequate organ function as defined by the following laboratory values:

               1. Creatinine clearance ≥60 mL/min (by Cockcroft-Gault method, Appendix I),

               2. Total serum bilirubin ≤1.5 × upper limit of normal (ULN) unless due to Gilbert's
                  syndrome or MDS organ involvement,

               3. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤2.5 × ULN,
                  unless due to MDS organ involvement.

          4. Age ≥18 years at the time of signing the informed consent form.

          5. Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1 or 2 (Appendix
             II).

          6. Projected life expectancy of ≥12 weeks.

          7. Clear ocular media and adequate pupil dilation to permit fundus examination and
             retinal imaging.

        Exclusion Criteria:

          1. Cardiac abnormalities, which includes, but not limited to:

               1. Myocardial infarction within six months prior to enrollment

               2. New York Heart Association Class III or IV heart failure or known LVEF <40%

          2. Concomitant malignancies or previous malignancies with less than a 1 year disease-free
             interval at the time of signing informed consent.

          3. Use of cytotoxic chemotherapeutic agents, or experimental agents for the treatment of
             MDS within 14 days or 5 half-lives of the product (whichever is shorter) of the first
             day of study drug treatment.

          4. Prior exposure to eprenetapopt (APR-246).

          5. A female subject who is pregnant or breast-feeding.

          6. Known history of human immunodeficiency virus (HIV), active hepatitis B or active
             hepatitis C infection.

          7. Malabsorption syndrome or other condition likely to affect gastrointestinal absorption
             of APR-548.

          8. Known history or current evidence of ocular disease in either eye