Please select the eligibility criteria that correspond to the clinical trial below.
Title: A Multi-Center, Open Label Study to Evaluate Chitosan Chewing Gum in Patients With Chronic Kidney Disease
Brief Summary: The purpose of this study is to determine the efficacy of chitosan chewing gum (K2CG) in reducing serum phosphorus in subjects with chronic kidney disease.


Options:
A: Inclusion Criteria:

* Renal failure stage 3B
* 25(OH)vitamin D level above 50 nmol/l
* Age over 18 years
* Written consent

Exclusion Criteria:

* Major surgery during the previous 6 months
* Myocardial infarct during the previous 6 months
* Unstable heart failure
* Ongoing treatment for any malignancy
* History of frequent infections
* Pregnancy
* Ongoing treatment with steroids, lithium or biphosphonates
B: Inclusion Criteria:

1. Men or women \> 18 years of age;
2. The subject has voluntarily signed and dated the most recent informed consent form approved by an Institutional Review Board (IRB);
3. The subject will, in the opinion of the investigator, be compliant with prescribed therapy and all study visits;
4. Subject must be able to communicate and be able to understand and comply with the requirements of the study;
5. For subjects not on dialysis estimated GFR at screening \< or equal to 60 ml/min + 10 % that in the opinion of the investigator is stable and not expected to initiate dialysis within 3 months;
6. Subject must have serum phosphorus at screening of greater than or equal to 3.5 mg/dL;
7. Subjects must have a screening salivary flow rate by Saxon test ≥ 1 g/2 min;
8. All subjects must have NO change in prescribed dose or frequency of any of the following medications ≥ 14 days prior to Run-In Visit 2 (Day -15):

a. Phosphate binding products including prescribed and over-the counter b. Oral or injectable active vitamin D c. Oral nutritional vitamin D d. Calcium supplements e. Anti-osteoporotic medication (e.g. bisphosphonates) f. Cinacalcet i. Subject must be prescribed a diet appropriate for patients with their stage of CKD, must be willing to avoid intentional changes in diet and must have stable nutritional status in the opinion of the investigator.

j. Subjects on dialysis must, in the opinion of the investigator, have a stable dialysis prescription, stable dialysis access and a URR \>/= 65% for at least 4 weeks prior to Day -15.

Exclusion Criteria:

1. Subject is receiving or has received an investigational product (or is currently using an investigational device) within 14 days prior to Visit 2 (Day -15);
2. Subject has a known sensitivity to chitin or allergy to shellfish;
3. Subject has had dental work other than cleaning, cavity filling or crown placement within 48 hours prior to Visit 4 (Day 1) or at any time during the course of the trial;
4. Subject has a clinically significant infection requiring treatment with antibiotics (within 7 days prior to Visit 2 (Day -15));
5. Subject has had an inpatient hospitalization within 14 days prior to Visit 2 (Day -15) with the exception of hospitalizations related to vascular access procedures;
6. Subject has a known history of immunodeficiency diseases, including a positive HIV (ELISA and Western blot) test result;
7. Active drug or alcohol dependence or abuse (excluding tobacco use) in the opinion of the principal investigator;
8. In the opinion of the investigator, subject is unable to chew gum for 30 minutes;
9. Subject has an unstable medical condition which in the opinion of the investigator would compromise successful completion of the study;
10. Subject is receiving calcimimetic therapy (acceptable if subject is on dialysis);
11. Subject has known salivary gland dysfunction or Sjogren's syndrome;
12. Subjects is receiving niacin therapy within 7 days prior to Run- In Visit 2(Day -15) (use as part of standard multivitamin is acceptable);
13. Subject has had a major cardiovascular event within 90 days of screening. The investigator should be guided by evidence of any of the following;

a. Acute myocardial infarction b. Acute cerebral vascular event c. Vascular surgical intervention d. Coronary Revascularization e. Decompensated congestive heart failure

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C: Inclusion Criteria:

* Stable CKD patients who are currently on hemodialysis three times a week for at least 12 weeks prior to the acquisition of informed consent
* Patients on stable dose(s) of phosphate binder(s) for at least 28 days prior to the acquisition of informed consent.
* Patients on stable dose(s) of Vitamin D or calcitonin agent for at least 28 days prior to the acquisition of informed consent, in case patients are treated by those agents

Exclusion Criteria:

* History of major gastrointestinal surgery, or swallowing disorders, bowel obstruction, hemorrhagic gastrointestinal lesion
* Continuous severe constipation/diarrhea.
* History of parathyroid intervention \[parathyroidectomy（PTx），percutaneous ethanol injection therapy（PEIT）etc.\] within 1 year of the acquisition of informed consent
* Diet restriction such as fasting and/or excessive dieting
* Uncontrolled hypertension
D: Inclusion Criteria:

* Age \> 18 years
* Evidence of CKD Stages II, III or IV
* Stage II CKD; eGFR 60-89 ml/min
* Stage III CKD: eGFR 30-59 ml/min
* Stage IV CKD: eGFR 15-29 ml/min
* Proteinuria (\>200 mg/day or 300 mg/gm creatinine on a spot urine) on urinalysis on two occasions within 18 months of recruitment
* Diagnosis of diabetes and receiving at least one medication for diabetes mellitus
* HbA1c\>6.5%

Exclusion criteria:

* Age \<18
* Patients receiving active treatment for hyperphosphatemia
* Biopsy proven renal disease other than diabetic nephropathy
* Hypophosphatemia
* Hypercalcemia
* Any history of significant gastrointestinal disorders
* Any history of significant gastrointestinal surgery such as ileostomy, colostomy and colectomy.

Answer: B