Pharmacokinetics, Tolerability and Safety of NEX-18a

Inclusion Criteria:

1. Provision of written informed consent prior to any study specific procedures.
2. Female and male patients ≥ 18 years of age.
3. Body Mass Index (BMI) \> 19 and \< 30 kg/m2 BSA at screening.
4. Treatment with azacitidine corresponding to 100 mg/m2 BSA x 5 per treatment cycle for at least six cycles for:

   1. intermediate-2 and high-risk myelodysplastic syndromes (MDS) according to the International Prognostic Scoring System (IPSS)
   2. chronic myelomonocytic leukemia (CMML) with 10-29 % marrow blasts
   3. acute myeloid leukemia (AML) according to World Health Organization (WHO) classification
5. Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2.
6. Recovery of Hematology and Clin. Chemistry assessment according to clinical praxis at the start of the last azacitidine treatment cycle before the screening visit.
7. Female subject must be of non-childbearing potential (defined as pre-menopausal females with a documented tubal ligation or hysterectomy or bilateral oophorectomy; or as post-menopausal females defined as 12 months' amenorrhoea \[in questionable cases a blood sample with simultaneous follicle stimulation hormone 25-140 IE/L and estradiol \< 200 pmol/L is confirmatory\])
8. Male patients must agree to use an adequate method of contraception. Male patients who are sexually active must use, with their partner, a condom AND one of the following methods of highly effective contraception from the time of IMP administration until 90 days after the last dose of IMP.

   1. oral (except low-dose gestagen (lynestrenol and norestisteron)), injectable or implanted hormonal contraceptives
   2. intrauterine device
   3. intrauterine system (for example progestin-releasing coil)
   4. vasectomized male (with appropriate post vasectomy documentation of the absence of sperm in the ejaculate)
   5. bilateral tubal occlusion or hysterectomy
9. Willingness and ability to comply with study procedures, visit schedules, study restrictions, and requirements.

Exclusion Criteria:

1. The patient has participated in any other investigational/interventional trial including an investigational drug within 30 days (or five half-lives of the study drug prior to screening, whichever is longer) prior to screening.
2. Diagnosis of malignant disease within the previous 5 years (excluding basal cell carcinoma of the skin without complications, "in-situ" carcinoma of the cervix or breast, or other local malignancy excised or irradiated with a high probability of cure).
3. Any significant medical condition, laboratory abnormality, or psychiatric illness that would prevent the patient from participating in the study.
4. The patient has a history of alcohol abuse or drug abuse within the past 12 months.
5. Any condition including the presence of laboratory abnormalities, which places the patient at unacceptable risk if he/she were to participate in the study.
6. Lack of suitability for participation in the study, for any reason, judged by the Investigator.