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CTAP101

Phase 3

Chronic Kidney Disease | Small molecule | Endocrine |Opko Health Inc.|Last Updated: Aug 20, 2026

Success Probability

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Market & Valuation

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Trial Design

RandomizedCONTROLLED
Total Trials2
Total Enrollment326

FDA Designations

No designations recorded

Clinical trial landscape

CTAP101 · 5 trials · 14 indications

Phase 3 1Phase 2 1Phase 1 3
NCT02282813Extension Study of CTAP101-CL-3001 or CTAP101-CL-3002Chronic Kidney Disease
COMPLETED298 Analytics
PHASE3COMPLETED
Extension Study of CTAP101-CL-3001 or CTAP101-CL-3002
Chronic Kidney DiseaseUnlock trial analytics

Study Endpoints

Primary Endpoints

Number of Participants in the Intent to Treat Population With a Mean Reduction in Plasma Intact Parathyroid Hormone (iPTH) of >/= 30% From Baseline Values at End of Treatment (EOT)
up to 6 months

Number of subjects in the intent to treat population with a mean reduction in plasma intact parathyroid hormone (iPTH) of \>/= 30% from pretreatment baseline values at end of treatment (EOT), classified as responders

Apparent clearance (CL/F)
Up to 14 weeks

To determine the CL/F of CTAP101 Capsules during and after repeated dosing

Volume of distribution (Vd/F)
Up to 14 weeks

To determine the Vd/F of CTAP101 Capsules during and after repeated dosing

Terminal elimination half-life (t1/2)
Up to 14 weeks

To determine the t1/2 of CTAP101 Capsules during and after repeated dosing

Incidence of treatment emergent adverse events (TEAE)
Up to 14 weeks

TEAEs will be graded as mild, moderate, severe.

Number of participants with treatment-related AEs as assessed by industry standards
8 weeks

Incidence of AEs will be summarized by arm for all treatment-emergent AEs. Number and percent of participants with AEs will be summarized by system organ class and preferred term and presented overall and by arm.

Change in baseline of peak plasma concentration
8 weeks

Baseline finding will be measured against the different time points collected

Change in mean total of the different components of calcifediol
8 weeks

Descriptive statistics will be calculated for PD assessment in the per protocol population.

Effect of repeated, escalating doses of CTAP101 on serum calcium and plasma iPTH levels
up to 52 weeks
Effect of repeated, escalating daily doses of CTAP101 on serum calcifediol
up to 52 weeks
Safety and tolerability of CTAP101
up to 52 weeks

Measured by the number of participants with treatment related adverse events and abnormal physical examinations, vital signs, clinical laboratory tests (hematology, coagulation, and clinical chemistry, urine calcium, albumin and creatinine), and 12-lead ECG.

To assess the PK and bioavailability of CTAP101 in Stage 3 and 4 CKD subjects with vitamin D insufficiency and SHPT
from 3 to 0 hours prior to dosing until 42 days post dosing

Secondary Endpoints

Number of Participants in the Per Protocol Population With Mean Reduction in Plasma Intact Parathyroid Hormone (iPTH) of >/= 30% From Baseline Values at End of Treatment (EOT)
up to 6 months
Number of Participants in the Intent to Treat Population With Normal Serum 25-hydroxyvitamin D at End of Treatment (EOT)
up to 6 months
Number of Participants in the Per Protocol Population With NormalSerum 25-hydroxyvitamin D at End of Treatment (EOT)
up to 6 months
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Study Design & Arms

AllocationRANDOMIZED
MaskingNONE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
CTAP101 Capsules aloneEXPERIMENTALCTAP101 Capsules 30 or 60 mcg daily for up to 26 weeks
CTAP101 Capsules +calcitriolEXPERIMENTALCTAP101 Capsules 60 mcg +calcitriol daily for 14 weeks
CTAP101 Capsules +doxercalciferolEXPERIMENTALCTAP101 Capsules 60 mcg +doxercalciferol daily for 14 weeks
CTAP101 Capsules +paricalcitolEXPERIMENTALCTAP101 Capsules 60 mcg +paricalcitol daily for 14 weeks
Cohort 1 - Group AEXPERIMENTAL30 mcg CTAP101 Capsules
Cohort 1 - Group BEXPERIMENTAL30 mcg or 60 mcg CTAP101 Capsules
CTAP101 Capsules 450mcg/weekly fastedEXPERIMENTAL -
CTAP101 Capsules 900mcg/weekly fastedEXPERIMENTAL -
CTAP101 Capsules 1800mcg/weekly fastedEXPERIMENTAL -
CTAP101 Capsules 900mcg/weekly fedEXPERIMENTAL -
CTAP101 CapsulesEXPERIMENTALCTAP101 Capsules daily
Low Dose CTAP101 CapsulesEXPERIMENTALCTAP101 Capsules, 450 mcg dose
High Dose CTAP101 CapsulesEXPERIMENTALCTAP101 Capsules, 900 mcg dose
CTAP101 InjectionEXPERIMENTALIV injection, 448 mcg dose

Interventions

NameTypeDescription
CTAP101 CapsulesDRUGAt week 12, eligible subjects will continue to take 1-2 capsules (30 mcg each capsule) CTAP101 daily
CalcitriolDRUGAt week 12, eligible subjects will be randomized to also take calcitriol 0.25 mcg dose one capsule daily
DoxercalciferolDRUGAt week 12, eligible subjects will be randomized to also take doxercalciferol 0.5 mcg one capsule daily
ParicalcitolDRUGAt week 12, eligible subjects will be randomized to also take paricalcitol 1 mcg one capsule daily
CTAP101DRUGCapsules
CTAP101 InjectionDRUGsingle IV injection
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersNo

Inclusion Criteria: * Completed either of the phase 3 double-blind, placebo-controlled studies, CTAP101-CL-3001 or CTAP101-CL-3002 * Taking no more than 1000 mg/day of elemental Ca and willing/able to remain on this dose for the duration of the study * Taking no more than 1600 IU/dose vitamin D (er...

Countries:United States
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Recent Changes (Last 90 Days)

LOWAug 20, 2026NCT07494045Status: NOT_YET_RECRUITING → RECRUITING
LOWAug 20, 2026NCT07494045Status: NOT_YET_RECRUITING → RECRUITING

Frequently asked questions about CTAP101

What is CTAP101 used for?

CTAP101 is an investigational small molecule being studied for vitamin D insufficiency, chronic kidney disease (CKD) stage 3, and breast cancer. It is also being evaluated in conditions related to these, such as secondary hyperparathyroidism and hypocalcemia in cancer patients. The drug is in clinical development and is not approved.

Who is developing CTAP101?

CTAP101 is being developed by Opko Health Inc., a biopharmaceutical company listed on the NASDAQ under the ticker symbol OPK. The company is conducting clinical trials of CTAP101 in the United States across multiple patient populations.

What phase is CTAP101 in?

CTAP101 is in Phase 1 and Phase 2 clinical trials. Most completed studies are Phase 1, and an ongoing Phase 2 trial is recruiting pediatric participants. The drug is investigational and has not been approved by regulatory authorities.

What clinical trials is CTAP101 in?

CTAP101 has been studied in several clinical trials, including NCT00888069 in chronic kidney disease patients, NCT02274623 in advanced breast and prostate cancer patients, and NCT03660800 in healthy subjects. An active Phase 2 trial, NCT07494045, is recruiting pediatric participants with CKD.

How does CTAP101 work?

CTAP101 is a small molecule being evaluated for its effects on calcium and parathyroid hormone levels in conditions like secondary hyperparathyroidism. It is being studied as an extended-release capsule formulation in ongoing trials.