Safety and Efficacy of CTAP101 Capsules to Treat Secondary Hyperparathyroidism in Stage 3 or 4 CKD and Vitamin D Insufficiency

This is a phase 3, multi-center, randomized, double-blind, placebo-controlled study to
evaluate the efficacy and safety of CTAP101 Capsules administered for 26 weeks to treat SHPT
in subjects ≥18 years of age with stage 3 or 4 CKD and vitamin D insufficiency. The study
will be conducted at approximately 40 sites within the United States (US). Approximately 550
subjects will be screened to randomize approximately 210 eligible subjects, stratified by
CKD stage (approximately 105 subjects in each stage) in a 2:1 ratio to receive either
CTAP101 Capsules or matching placebo. An Interactive Voice Response System (IVRS) will
provide study treatment group assignments using the computer-generated randomization code
provided by the IVRS vendor. Subjects will receive an initial daily dose of 1 capsule
(CTAP101 Capsules, 30 µg, or matching placebo) for the first 12 weeks. After l2 weeks (visit
8) and per pre-defined criteria, the dose may be increased in a blinded fashion by the IVRS
with oversight by an independent medical monitor.

Inclusion Criteria:

1. Urinary albumin excretion ≤ 3000 mcg/mg of creatinine

2. Stage 3 or 4 CKD

3. Plasma iPTH: ≥ 85 pg/mL and < 500 pg/mL

4. Serum Ca: ≥ 8.4 mg/dL and < 9.8 mg/dL

5. Serum P: ≥ 2.0 mg/dL and < 5.0 mg/dL

6. Serum 25-hydroxyvitamin D: ≥ 10 ng/mL and < 30 ng/mL.

7. Stable dose of Vitamin D therapy ≤ 1600 IU/day and receiving same dose for at least 2
months

Exclusion Criteria:

1. History of kidney transplant or parathyroidectomy

2. Spot urine calcium:creatinine ratio > 0.2 (>200 mg/g Cr)

3. Current serious illness, such as malignancy, HIV, liver disease, cardiovascular event
or hepatitis

4. Currently on dialysis

5. Use of pharmacological dose of ergocalciferol or cholecalciferol (≥ 50,000 IU mcg per
month) during the study