The aim of PERKA-812-003 study is to investigate the safety, pharmacokinetics and preliminary anti-tumor activity of treatment with NMS-03597812 as single agent in Relapsed/Refractory Acute Myeloid Leukemia (R/R AML) patients who have exhausted standard treatment, including a subset of patients with TP53 mutations. It is anticipated that combination with venetoclax will be further evaluated following a future protocol amendment, once the Recommended Range Dose (RDR) as single agent has been defined.

Inclusion Criteria:

• Confirmed diagnosis of refractory/relapsed (R/R) AML according to 2022 ELN recommendation:

Phase Ia

• single agent dose escalation of NMS-03597812: R/R AML patients who have exhausted standard therapy: a) prior fit patients to intensive chemotherapy (IC): failed at least one cycle of IC in front-line therapy or b) prior unfit to IC: failed at least 2 cycles of hypomethylating agents (HMA)/venetoclax combination therapy, or at least 4 cycles of HMA monotherapy; c) patients must have failed all other approved therapies for which they are eligible, including FLT3 inhibitors, IDH1/2 inhibitors, and CD33 directed therapy

Phase Ib

• Cohort A: single agent in R/R AML TP53mt patients who have exhausted standard therapy: a) prior unfit to intensive chemotherapy (IC): failed at least 2 cycles of HMA/venetoclax combination therapy, or at least 4 cycles of HMA monotherapy; b) patients must have failed all other approved therapies for which they are eligible, including FLT3 inhibitors, IDH1/2 inhibitors, and CD33 directed therapy
• Cohort B: single agent in R/R AML TP53wt patients who have exhausted standard therapy: a) prior fit patients to intensive chemotherapy (IC): failed at least one cycle of IC in front-line therapy or b) prior unfit to IC: failed at least 2 cycles of HMA/venetoclax combination therapy, or at least 4 cycles of HMA monotherapy; c) patients must have failed all other approved therapies for which they are eligible, including FLT3 inhibitors, IDH1/2 inhibitors, and CD33 directed therapy
• Adult (age ≥ 18 years) patients
• Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2
• Unless agreed with sponsor, the interval from prior antitumor treatment should be at least 2 weeks or 5 half-lives, whichever is longer, other than hydroxyurea
• All acute toxic effects (excluding alopecia) of any prior therapy must have resolved to NCI CTCAE version 5.0 Grade≤ 1
• Adequate organ function
• Must use highly effective contraception or true abstinence. Female patients must be surgically sterile or, if patient is of childbearing potential, must agree to use effective contraception of therapy and in the following 210 days after discontinuation of study treatment. Since NMS-03597812 has potential induction of CYP3A4, women of childbearing potential must be advised that hormonal contraceptives might lose efficacy and must use alternate form of highly effective contraception. Male patients must be surgically sterile or must agree to use highly effective contraception or true abstinence during the period of therapy and in the following 120 days for male patients who must refrain from donating sperm during this period after discontinuation of study treatment.
• Capability to swallow capsules intact (without chewing, crushing, or opening)
• Willingness and ability to comply with scheduled visits, treatment plan, laboratory tests and other study indications or procedures
• Signed and dated Independent Ethics Committee (IEC) or Institutional Review Board (IRB)-approved informed consent form indicating that the patient is aware of the neoplastic nature of his/her disease and has been informed of the procedures to be followed, the investigational nature of the therapy, potential benefits, side effects, discomforts, risks, and alternative treatments.

Exclusion Criteria:

• Current enrollment in another interventional clinical study unless only participating in survival follow up
• White blood cells (WBC) count >20×10^3/microliter (μL). However, patients can be treated with hydroxyurea and/or leukapheresis prior to study treatment start to reduce the WBC to ≤ 20×10^3/μL to enable eligibility for study drug dosing.
• Diagnosis of acute promyelocytic leukemia or BCR-ABL-positive leukemia
• Currently active second malignancy, except for adequately treated basal or squamous cell skin cancer and/or cone biopsied in situ carcinoma of the cervix uteri and/or superficial bladder cancer.
• Patients with known leukemia involvement of central nervous system (CNS).
• Hematopoietic stem cell transplantation (HSCT) within 3 months of treatment start and/or persistent non- hematologic toxicities of Grade ≥2 related to the transplant
• Active acute or chronic graft versus host disease (GVHD) requiring immunosuppressive treatment
• Patients with QTcF interval ≥ 470 milliseconds or with risk factors for torsade de pointes (e.g., uncontrolled heart failure, uncontrolled hypokalemia, history of prolonged QTc interval or family history of long QT syndrome). For patients receiving treatment with concomitant medications known to prolong the QTc interval, replacement with another treatment needs to be considered. If replacement or discontinuation is not clinically feasible, a careful risk/benefit evaluation should be performed prior to enrollment.
• Pregnancy. All female patients with reproductive potential must have a negative pregnancy test (serum or urine) within the screening period prior to start of study drug.
• Breast-feeding or planning to breast feed during the study or within 90 days after study treatment.
• Known active gastrointestinal disease (eg, gastro-duodenal ulcer, gastrectomy, Crohn's disease, ulcerative colitis, or short gut syndrome) or other malabsorption syndromes that would impact on drug absorption.
• Patient who are receiving concomitant medications with antacids (proton pump inhibitors are strictly prohibited; calcium carbonate antacids are only allowed 6 hours prior to a dose or 1 hour after). Note: exclusion criterion not applicable to optional backfill cohort for investigation of drug-drug interaction with antiacids.
• Patient who are receiving concomitant medications that are strong inducers or inhibitors of CYP3A4 (with the exception of azole antifungals) and CYP2C9 that cannot be replaced with alternative therapy.
• Patients who are receiving concomitant medications that are sensitive substrates of CYP3A4,CYP2D6, CYP1A2 and CYP2B6 with narrow therapeutic window that cannot be replaced with alternative therapy. Drugs with broad therapeutic indices may still be acceptable.
• Patients who are receiving concomitant medications that are strong or moderate P-gp inhibitors that cannot be replaced with alternative therapy.
• Major surgery within 4 weeks before study treatment start.
• Radiotherapy within 4 weeks before study treatment start. However, if the radiation portal covered ≤5 % of the bone marrow reserve, the patient may be enrolled irrespective of the end date of radiotherapy.
• History of necrotic pancreatitis or acute severe pancreatitis, requiring medical intervention and/or hospitalization, in the previous 6 months before study treatment start.

NOTE: Other protocol defined inclusion/exclusion criteria may apply.