HMPL-004 Maintenance Treatment in Subjects With Mild to Moderate Ulcerative Colitis

A two-phase multi-center study with an open label 8-week induction phase and a randomized,
double-blind, placebo controlled maintenance phase to evaluate the efficacy and safety of
HMPL-004 for a 52-week maintenance therapy in adults with mild to moderate UC and who have
demonstrated a sub-optimal response to mesalamine treatment. The study participants will
consist of subjects who have completed either the HMPL-004-03 or HMPL-004-05 induction study,
complemented by the enrollment of additional subjects in the open label induction phase who
meet the entry criteria of this study. . Subjects entering this maintenance study from one of
the HMPL-004 induction studies will have their modified Mayo baseline score from that study
as their baseline score for this study. All subjects enrolled in the open label induction
phase of the study will be re-evaluated for clinical response and remission after the 8-week
open label 2400 mg HMPL-004 treatment period. Clinical responders and remitters will be
randomized 2:1 (HMPL-004: placebo) to HMPL-004 1800 mg/day or placebo group for the 52-week
maintenance phase of the study.

Inclusion Criteria:

1. Completion of induction study HMPL-004-03 or HMPL-004-05 and achieving clinical
remission or response with no disruption of study treatment in the transition to
HMPL-004-04, or, for the open label induction phase of the study: have active mild to
moderate Ulcerative Colitis defined by a modified Mayo Score of 4 to 10 and with
endoscopy score activity of 2-3 points confirmed by a full colonoscopy within 2 weeks
prior to study.

2. Subjects must be currently receiving mesalamine ≥ 2.4 g/day (or the equivalent) for at
least 6 weeks prior to randomization and on a stable dosage for at least 2 weeks prior
to entering the screening phase of the study to ensure a stable dose is established at
least 2 weeks prior to the endoscopic procedures.

3. Have adequate renal, hepatic and bone marrow function (see exclusion criteria).

4. Age ≥ 18 years

5. All fertile male and female subjects must agree to use one of the following types of
contraception: intrauterine device, implantable progesterone device, progesterone
intramuscular injection, oral contraceptive which has been started at least one month
prior to visit one and continues for the duration of the trial, contraceptive patch,
or condom with spermicide.

6. Show evidence of a personally signed and dated informed consent document indicating
that the subject (or legally acceptable representative) has been informed of all
pertinent aspects of the trial.

Exclusion Criteria:

1. Subjects with intolerance to mesalamine (or equivalent medications).

2. Diagnosed with Crohn's disease or with lesions such as fistulas or granulomas on
biopsy noted either in history or at baseline endoscope, which would be suspicious for
Crohn's disease, or with a diagnosis of indeterminate colitis.

3. Severe disease with a Ulcerative Colitis modified Mayo Clinic score above 10 points at
baseline.

4. Positive stool test for pathogens on sample taken within the 2 weeks prior to study
entry.

5. Active clostridium difficile (C. diff) infection.

6. Use of Inflammatory Bowel Disease related herbal supplements including supplements
containing andrographis or the use of probiotics two weeks prior to study entry or
during the study.

7. Toxic megacolon or toxic colitis.

8. Probable requirement for intestinal surgery within 12 weeks after the start of
investigational product.

9. Receiving oral or rectal steroids within 1 month prior to study entry.

10. Receiving rectal mesalamine within 1 week prior to study entry.

11. Receiving azathioprine, 6-mercaptopurine, methotrexate, tacrolimus, cyclosporine, or
other immunosuppressive therapy at the time of screening or within the preceding 6
weeks.

12. Receiving anti-TNF-α agents such as infliximab, adalimumab, golimumab, or certolizumab
pegol at the time of screening or within the preceding 8 weeks.

13. Receiving other investigational drugs or biologics within 1 month or five half-lives,
whichever is longer.

14. Receiving antibiotics within 2 weeks of study entry.

15. Hemoglobin concentration <9 g/dl.

16. WBC below 3,000/cm3, or platelets below 100,000/cm3.

17. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), and/or alkaline
phosphatase >2.5 upper limit of normal.

18. Serum creatinine >1.5 times upper limit of normal.

19. Significant concurrent medical diseases including: active peptic ulcer disease;
uncompensated congestive heart disease; myocardial infarction within the last 12
months; unstable angina pectoris; uncontrolled hypertension; and pulmonary disease
requiring oxygen therapy.

20. Chronic Hepatitis B or any history of Hepatitis C.

21. Previous colonic surgery except for simple polypectomy.

22. History of cancer within the last 5 years other than resected cutaneous basal and
squamous cell carcinomas, and/or in situ cervical cancer.

23. Subjects with a history of or concurrent colonic dysplasia associated with UC, except
those with completely excised sporadic colorectal polyps.

24. Women who are pregnant or breast feeding.

25. Subjects known to be seropositive for HIV, or who have had an AIDS defining illness,
or a known immunodeficiency disorder.

26. History of alcohol or drug abuse that would interfere with the ability to be compliant
with the study procedure.

27. Known allergy to plants of the Acanthaceae family.

28. Unwillingness to participate in the study.

29. Any underlying medical condition that in the Investigator's opinion will make the
administration of study drug hazardous to the subject or would obscure the
interpretation of Adverse Events.