A Phase II Study Evaluating the Efficacy and Safety of AbGn-168H in Patients With Active Psoriatic Arthritis

This is an open-label, multi-center, multi-dose phase II proof of principle trial to study
the efficacy and safety of AbGn-168H in patients with moderate to severe active psoriatic
arthritis. A minimum of 15 patients and a maximum of 20 will be recruited in 1 dosing group.
For safety evaluation, the parameters to be assessed include physical examination, vital
signs (blood pressure, heart rate, respiratory rate and body temperature), 12-lead ECG,
safety laboratory tests, adverse events and tolerability. For efficacy evaluation, patients
will be evaluated for proportion of subject reaching American College of Rheumatology 20
(ACR 20) in week 12 and proportion of subjects reaching ACR 20, ACR 50 and ACR 70 at
different time points; Disease Activity Score 28 (DAS28) at different time points, as well
as Target Lesion Psoriasis Severity Score (TLPSS) and static Physician Global Assessment
(sPGA) for subjects with active skin lesions at different time point.

Inclusion criteria

1. Patient must give informed consent and sign an approved consent form prior to any
study procedures

2. Age 18 to 75 (inclusive), males or females

3. Body weight < 140 kg

4. Subject has had a diagnosis of psoriatic arthritis for at least 6 months and
currently meets the CASPAR criteria.

5. Patients must have moderate to severe active PsA at screening and baseline, defined
as having greater than or equal to 3 tender (out of 68) and 3 swollen (out of 66)
joints.

6. Patients must have at least one evaluable skin plaque, 2 cm in diameter, that can be
followed with a target lesions score (scalp and groin lesions cannot be used), or
documented psoriasis history.

7. Patients must have history of inadequate response or intolerance to NSAID or DMARD
defined by the investigator.

8. If the patient is taking background corticosteroids, dose must be ≤ 10 mg/day
prednisone (or equivalent) and must have been at a stable dose for at least 4 weeks
prior to screening.

9. Use of nonsteroidal anti-inflammatory drugs (NSAIDs) for the treatment of psoriasis
arthritis is permitted if the dose has been stable for at least 2 weeks prior to
screening.

10. If the patient is taking methotrexate (MTX), the patient must have received
methotrexate 7.5-25 mg/wk (p.o. or parenteral) for at least 12 weeks and at a stable
dose for 4 weeks prior to screening. If the patient is not taking MTX, they must have
been off the drug for at least 8 weeks prior to receiving the first dose (baseline).

11. Folic acid or folinic acid is required at least 1 mg per day or 5 mg per week for all
patients taking MTX.

12. Whether or not the patient is taking methotrexate, all DMARDs (other than MTX) should
be withdrawn at least 4 weeks prior to baseline (Visit 2) of first drug
administration (4 weeks for etanercept, 8 weeks for infliximab, adalimumab,
golimumab, certolizumab pegol and leflunomide, and 12 weeks for ustekinumab, c.f.
Section 4.2.2). Subjects taking appremilast should discontinue the medication 2 weeks
prior to receiving the first dose (baseline).

13. Females of childbearing potential must have a negative pregnancy test result prior to
enrolment. Male and female of childbearing potential must agree to use a highly
effective method of birth control during the study.

A female is considered of childbearing potential following menarche and until becoming
post-menopausal unless permanently sterile. Permanent sterilization methods include
hysterectomy, bilateral salpingectomy, bilateral tubal ligation and bilateral
oophorectomy. A postmenopausal state is defined as no menses for 12 months without an
alternative medical cause. A high follicle stimulating hormone (FSH) level in the
postmenopausal range may be used to confirm a post-menopausal state in women not using
hormonal contraception or hormonal replacement therapy. However in the absence of 12
months of amenorrhea, a single FSH measurement is insufficient.

A man is considered fertile after puberty unless permanently sterile by bilateral
orchidectomy.

A highly effective method of birth control is defined as one which results in a low
failure rate (less than 1% per year).

Exclusion criteria

1. History of malignancy in the past 5 years or suspicion of active malignant disease.

2. Evidence of current or previous clinically significant disease, medical condition
other than psoriatic arthritis, or finding of the medical examination (including
vital signs and ECG), that in the opinion of the Investigator, would compromise the
safety of the patient or the quality of the data. This criterion provides an
opportunity for the investigator to exclude patients based on clinical judgment, even
if other eligibility criteria are satisfied.

3. Presence of another rheumatic or skin disease that, in the opinion of the
investigator, could confound the ability to discern response.

4. HIV infection or a known HIV-related Malignancy.

5. Chronic or acute hepatitis B and C, or carrier status.

6. History of recurrent significant infection; known active bacterial, viral, fungal,
mycobacterial infection, or any major episode of infection requiring hospitalization
or treatment with iv antibiotics within 4 weeks of screening or oral antibiotics
within 2 weeks prior to screening.

7. Tuberculosis or a positive Quantiferon test for tuberculosis.

8. History of allergy/hypersensitivity to a systemically administered biologic agent or
its excipients.

9. Intake of restricted medications (c.f. Section 4.2.2) or other drugs considered
likely to interfere with the safe conduct of the study.

10. Previous treatment with any cell-depleting therapies, including investigational
agents (e.g., CAMPATH, anti-CD4, anti-CD5, anti-CD3). Patients with Orencia or
Toclizumab treatment within 8 weeks, IVIG, Natalizumab or Prosorba Column treatment
within 6 months, and anti-CD19 or anti-CD20 treatment within 1 year should be
excluded.

11. Immunization with a vaccine within 4 weeks prior to baseline (Visit 2) of the first
drug administration (e.g.; MMR, Varivax).

12. Current alcohol abuse.

13. Current drug abuse or positive drug screen at screening visit. Subjects with
legitimate medically supervised uses of the drugs which are not excluded for other
reasons (Section 4.2.2 of the protocol) can be enrolled.

14. Patients with any of the following laboratory values at screening and are considered
clinically significant by the investigators:

- Haemoglobin < 9 g/dL, hematocrit, white blood cell count, absolute lymphocyte or
platelet count < LLN (below the lower limit of the reference normal range), or
absolute neutrophil < 1500/µL

- ALT, AST and/or total bilirubin > 2 x ULN

- Serum creatinine > 1.5 x ULN

15. Any clinically significant laboratory abnormalities other than those listed on
Exclusion Criteria 14, based on the investigator's medical assessment at screening