Phase 1 Single Ascending Dose Study With ATX101

This is a single-center, double-blinded, placebo-controlled, phase I, single ascending dose study in healthy participants. A maximum of three ATX101 dose levels are pre-planned to be investigated in three separate sequential cohorts. Each of these cohorts will consist of 8 healthy participants (6 participants randomized to ATX101 and 2 to placebo). The study will consist of:

• a screening period, within 7 to 21 days before investigational product administration (Day -21 to Day -7),
• a treatment period, including admission to confinement, 3-night confinement, and discharge from confinement.
• a follow-up period, which includes two ambulatory follow-up visits (Day 4 and Day 7).

Total duration of study participation for each participant will be approximately 4 weeks.

Inclusion criteria

• Free written informed consent prior to any procedure required by the study.
• Male or female participant ≥18 and ≤50 years-old, at the time of signing the informed consent.
• Body mass index (BMI) between 18.5 and 29.9 kg/m2 and a minimum weight of 48 kg for women and 50 kg for men and maximum weight of 100 kg (inclusive).
• No clinically relevant diseases captured in medical history.
• No clinically relevant abnormalities at screening and admission.
• Negative test results for anti-Human Immunodeficiency virus 1 and 2 antibodies (anti-HIV-1Ab and anti-HIV-2Ab), Hepatitis B surface antigen (HBsAg), and anti-Hepatitis C virus antibodies (anti-HCVAb).
• A female participant is either be of non-childbearing potential; or using an accepted contraceptive method.

Exclusion criteria

• Previous exposure to ATX101 or to ATX101 drug substance.
• Known hypersensitivity/allergic reaction to the study drug substance or any of the excipients.
• Known severe hypersensitivity reaction to any other drug.
• If woman, she is breast-feeding.
• Rest systolic blood pressure (SBP) <90 mmHg or >140 mmHg.
• Rest diastolic blood pressure (DBP) <50 mmHg/or >95 mmHg.
• Resting heart rate outside the range of 50 to 90 bpm, in the ECG.
• Hematological and biochemistry parameters outside the normal range.
• Renal function outside normal range.
• Positive result in drugs-of-abuse or ethanol tests.
• If woman of childbearing potential (WOCBP), positive pregnancy test.
• Use of a depot injection or an implant of any drug within the previous 6 months.
• Average weekly alcohol consumption of >14 units for males and >7 units for females, within the previous 6 months.
• Average daily consumption of methylxanthines-containing beverages or food (e.g., coffee, tea, cola, sodas, chocolate) equivalent to >500 mg of methylxanthines, within the previous 6 months.
• Participation in any interventional clinical trial within the previous 2 months.
• Participation in more than 2 clinical trials within the previous 12 months.
• Blood donation or significant blood loss (≥450 mL) due to any reason or had plasmapheresis within the previous 2 months.
• Any other condition that the Investigator considers to render the participant unsuitable for the study.
• Any recent disease or condition or treatment that, according to the Investigator, would put the participant at undue risk due to study participation or occurred at a timeframe in which may interfere with the pharmacokinetics of study drug.
• Fever (≥38 ºC) in the previous week.
• Use of prescription or nonprescription medicinal products, vitamins, food supplements or herbal supplements (including St John's Wort) within 2 weeks prior to admission to the study, unless in the Investigator's opinion the medication does not interfere with the pharmacokinetics of study drug or compromise participant safety.