A first-in-human single and multiple ascending dose study of AX-202

INTERVENTION: Part A (Single‐ascending‐dose): A single dose of the monoclonal antibody AX‐202 or a matching placebo (Sodium Chloride; 0.9% NaCl) will be administered by intravenous infusion on Day 1. The starting dose in Cohort 1 is 0.5 mg/kg. Subsequent doses will be determined from the review of safety and Pharmacokinetic (PK) data from the preceding cohorts. The maximum dose will not be higher than 20 mg/kg and each dose escalation will not exceed a 3.3 dose increment. Part B (Multiple‐ascending‐dose): Doses of the monoclonal antibody AX‐202 or matching placebo (Sodium Chloride; 0.9% NaCl) will be administered by intravenous infusion on Days 1 and 22. The planned starting dose of AX‐202 to be administered in Part B Cohort 1 will be confirmed during the interim review of safety and PK data from Part A cohorts. The doses administered in Part B will not exceed the maximum dose administered safely in Part A. Subsequent doses in Part B will be determined from the review of safety and PK data from the preceding cohorts. All doses will be given as an infusion over approximately 30‐60 minutes. The participants will be randomised manually to AX‐202 or placebo at a single centre using a paper randomisation schedule for each dosing cohort and study part. All participants that are randomised and receive Investigational Medicinal Product (IMP) will be followed up until 99 days after their last dose of IMP. CONDITION: Healthy volunteers and patients with mild to moderate chronic plaque psoriasis ; Skin and Connective Tissue Diseases PRIMARY OUTCOME: ; Safety and tolerability in Part A/B of the study measured by monitoring AE’s, physical examinations, infusion site assessments, changes in vital signs, clinical laboratory parameters and ECG throughout the study to the time points defined below:; ; Physical Exams:; Part A Screen, Days ‐1, 4, 100; Part B Screen, Days ‐1, 4, 22, 25, 121; ; Vital signs:; Part A Screen, Days ‐1‐4 (pre, 0, 1, 2, 4, 8, 24, 48, 72 hours), 8, 15, 22, 57, 100; Part B Screen, Days ‐1‐4 (pre, 0, 1, 2, 4, 8, 24, 48, 72 hours), 8, 15, 22‐25(pre, 0, 1, 2, 4, 8, 24, 48, 72 hours), 29, 36, 57, 85, 121; ; Clinical labs; Part A Screen, Days 1‐4, 8, 15, 22, 57, 100; Part B Screen, Days 1‐4, 8, 15, 22, 23, 25, 29, 36, 57, 85, 121; ; ECG; Part A Screen, Days ‐1‐2 (pre, 0, 1, 24 hours), 15, 22, 57, 100; Part B Screen, Days ‐1‐2 (pre, 0, 1, 24 hours), 15, 22‐23 (pre, 0, 1, 24 hours), 36, 57, 85, 121; SECONDARY OUTCOME: ; 1. Quantification of AX‐202 in plasma will be performed followed by calculation of pharmacokinetic parameters, including but not limited to; Cmax, tmax, AUC (AUC [0‐8], AUC [0‐t]), and t1/2, CL, Vss. Dose and time dependency will be assessed for the pharmacokinetic parameters. In Part A, outcomes assessed on Days 1‐4 (pre, 0, 1, 2, 4, 8, 24, 48, 72 hours), 8, 15, 22, 57, 100 and in Part B on Days 1‐4 (pre, 0, 1, 2, 4, 8, 24, 48, 72 hours), 8, 15, 22‐25 (pre, 0, 1, 2, 4, 8, 24, 48, 72 hours), 29, 36, 57, 85, 121; 2. Antibodies to AX‐202 in serum will be measured to evaluate immunogenicity in Part A on Days 1 (pre‐dose), 22, 57, 100 and in Part B on Days 1 (pre‐dose), 22 (pre‐dose), 36, 85, 121; INCLUSION CRITERIA: Part A 1. Subjects must have written informed consent obtained prior to any study‐related procedures. 2. Subjects must be able to understand and comply with the requirements of the study, as judged by the Investigator. 3. Male and female subjects must be between 18‐55 years inclusive, at the time of informed consent. 4. Female subjects must either be of non‐childbearing potential or if of childbearing potential, must not be pregnant, breastfeeding or lactating and must use, with their partner, a condom with or without spermicide plus a highly effective birth control method from the time of informed consent and for 120 days following last administered dose. 5. Male subjects who are sexually active with a partner of childbearing potential must use, with their partner, a condom with or without spermicide plus an approved method of highly effective contraception from the time of informed consent and for 120 days following their