This is a Phase I dose escalation study to assess the safety, tolerability and activity of three different strengths of topical KX01 in the treatment of patients with plaque-type psoriasis.

This is a Phase I dose escalation study to assess the safety, tolerability and activity of three different strengths of topical KX01 (Tirbanibulin Ointment) in the treatment of patients with plaque-type psoriasis. The study will be performed in four stages as below.

Stage I: 6 patients (KX01 0.01% [0.1 mg/g]) + 2 patients (placebo); Stage II: 6 patients (KX01 0.1% [1.0 mg/g] + 2 patients (placebo); Stage III: 6 patients (KX01 1% [10 mg/g]) for 5 days; Stage IV: 6 patients (KX01 1% [10 mg/g]), duration escalation for up to 4 cycles.

If there's no major safety concern in the previous stage with an unanimous consent by the sponsor and the principle investigator, the study proceeded to the next stage.

The primary objective is to evaluate the safety and tolerability of three different strengths of KX01 ointment in patients with plaque-type psoriasis. The secondary objective is to gain evidence regarding the activity of three different strengths of KX01 ointment in patients with plaque-type psoriasis.

Inclusion Criteria:

• Male and female patients with plaque-type psoriasis, 20 years and older.
• Patient has a confirmed diagnosis of chronic plaque-type psoriasis for at least six months. For stage 4, PGA should be ≧3 &≦5 at baseline.
• A single lesion of ≥ 16 square centimetre and ≤ 625 square centimetre in size for Stage 1 and 2, and ≥ 16 square centimetre and ≤ 100 square centimetre in size for Stage 3 and 4 are selected as the target lesion (assessed at screening and Day 1).
• Medical history, vital signs, physical examination, standard 12-lead ECG and laboratory investigations have to be clinically insignificant or within laboratory reference ranges for the relevant laboratory tests, unless the investigator consider the deviation for out of range values to be irrelevant for the purpose of the study.
• No other disorders that, in the investigator's opinion, will prevent the patient from safely participating in this study or interfere with the evaluation of the patient's psoriasis.
• Patient is able to discontinue the use of any systemic medication or therapy for psoriasis.
• For females, either of the following conditions will be met: 1. Not of childbearing potential: Surgically sterilized, undergone a hysterectomy, amenorrhea for ≥ 12 months and considered post-menopausal; 2. Of childbearing potential: Negative serum pregnancy test at screening and not lactating, Either abstaining from sexual activity, or have to agree to use an accepted method of contraception, and agree to continue with the same method throughout the study.
• Male patients with partners of childbearing potential have to be willing to use contraception during the study and three months after end of treatment and is not to donate sperm for the duration of the study and for 3 months thereafter.
• Patient have to be able to provide written informed consent prior to the initiation of any study related procedures and able to comply with all the requirements of the study.

Exclusion Criteria:

• History of hypersensitivity to the investigational medicinal product (IMP) or to medicinal products with similar chemical structures.
• Presence of a skin disorder other than psoriasis in the target areas to be evaluated, including forms of inflammatory or non-inflammatory skin disorders that might interfere with determining efficacy or tolerability of the IMP.
• Severe forms of psoriasis or forms of psoriasis other than plaque psoriasis.
• All systemic psoriasis medications, including psoralens and ultraviolet A radiation treatments or other systemic immunosuppressive medication, are not allowed within five half-lives or 4 weeks (whichever is longer) prior to the first administration of the IMP.
• The use of topical therapies for psoriasis, including ultraviolet light B, on the target lesion to be studied within two weeks prior to the first administration of the IMP.
• Previous treatment with anti-tumor necrosis factor/interleukin (IL)-12/IL-23 or any other monoclonal antibodies within three months prior to the first administration of the IMP.
• Presence or history of any clinically significant acute or chronic disease which could interfere with the patient's participation or study outcome and at discretion of the clinical investigator.
• Patient with drug-induced psoriasis and is unable to discontinue the causal agent(s).
• Patient using prescription or non-prescription systemic drugs (e.g. vitamins and dietary, herbal supplements, paracetamol, aspirin or non-steroidal anti-inflammatory drugs [NSAIDs]) that might have an effect on psoriasis and is unable to maintain the stable dose or discontinue the dose during the study period.
• Participation in another study with an experimental drug, where the last administration of the previous IMP is within 4 weeks (or within five elimination half-lives for chemical entities or two elimination half-lives for antibodies or insulin, whichever is longer) before administration of IMP in this study, at the discretion of the investigator.
• A positive serum pregnancy test (beta human chorionic gonadotropin) or lactation.
• Vulnerable patients, e.g. persons in detention.

Randomization and masking will be conducted in stage 1 and stage 2. Eight patients are randomized to received KX01 or placebo control in a ratio of 3:1 (KX01 versus placebo) in these 2 stages. Double blind are applied to the assignment of KX01 and placebo.