Study of PDR001 and/or MBG453 in Combination With Decitabine in Patients With AML or High Risk MDS

1. Written informed consent must be obtained prior to any screening procedures

2. Male or female patients ≥ 18 years of age who present with one of the following:

Arms 1-3:

- Refractory/relapsed AML following ≥1 prior therapies and are deemed by the
investigator not to be candidates for standard therapy, including re-induction
with cytarabine or other established chemotherapy regimens for patients with AML
(patients who are suitable for standard re-induction chemotherapy or
hematopoietic stem cell transplantation and willing to receive it are excluded)

- De novo AML patients who are suitable for treatment with decitabine (patients who
are suitable for standard induction chemotherapy or hematopoietic stem cell
transplantation and willing to receive it are excluded)

- High risk MDS (patients who are suitable for standard re-induction chemotherapy
or hematopoietic stem cell transplantation and willing to receive it are
excluded)

Arms 4-5:

- Refractory / relapsed AML following ≥1 prior therapies (Arms 4a & 5a)

- High risk MDS who have failed hypomethylating agent therapy (Arms 4b & 5b) (Note:
hypomethylating agent failure is defined as progressive disease on
hypomethylating agent therapy or lack of clinically meaningful response as deemed
by investigator after at least 4 cycles of hypomethylating agent therapy.)

3. Patient has an Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2

4. Patient must be a candidate for serial bone marrow aspirate and/or biopsy according to
the institutions guidelines and be willing to undergo a bone marrow aspirate
and/biopsy at screening, during and at the end of therapy on this study. Exceptions
may be considered after documented discussion with Novartis.

5. Arms 1-3: Patients must be fit for standard treatment with decitabine as determined by
the investigator and as per local decitabine package insert.