Cadisegliatin as Adjunctive Therapy to Insulin in Participants With Type 1 Diabetes Who Are Using Hybrid Closed Loop (HCL) Systems (Hybrid CATT1)

Hybrid CATT1: Hybrid Closed Loop Insulin Pumps With Cadisegliatin as Adjunctive Treatment in Patients With Type 1 Diabetes A Phase 2a Double Blind Randomized Cross-Over Study

TTP399-206 is a Phase 2a multicenter double blind cross over randomized study of cadisegliatin in participants with T1D using hybrid closed loop systems to manager their diabetes. Patients using a hybrid closed loop insulin pump to manage their diabetes will be randomized to either receive blinded cadisegliatin 800 mg QD as an adjunctive therapy to their insulin treatment or placebo QD along with their insulin treatment. The trial begins with a screening period of up to 2 weeks, followed by a device training and insulin adjustment period of 1-2 weeks leading into the first double-blind treatment period of 6 weeks. There will then be a washout period of 1-2 weeks followed by the second double-blind treatment period of 6 weeks where the patient will cross-over to the treatment arm that they did not receive in the first treatment period.

Study Overview

• Status: Not yet recruiting
• Conditions: Type 1 Diabetes (T1D)
• Intervention / Treatment: Drug: Placebo; Drug: Cadisegliatin 800 mg QD

Detailed Description

TTP399-206 is a 20 week, Phase 2a trial designed to evaluate efficacy and safety of cadisegliatin in participants with T1D who are using hybrid closed loop (HCL) systems to manage their condition to gather preliminary data to understand how cadisegliatin performs in an HCL setting.

• Study Type: Interventional
• Enrollment (Estimated): 40
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: Meaghan Marnell; Phone Number: (336) 888-0435; Email: clinicaltrials@vtvtherapeutics.com

Study Locations

• United States
  • Georgia
    • Atlanta, Georgia, United States, 30318
      • Atlanta Diabetes Associates
      • Principal Investigator: Bruce W Bode, MD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Key Inclusion Criteria:

• Participants >= 18 years of age
• Fasting plasma C-peptide levels <0.6 ng/ml
• Average TIR < 70% at the end of the screening period
• Currently on a hybrid closed loop device for at least 3 months and willing to stay on the same model of pump device for study duration
• Willing to wear a study provided CGM for study duration
• Capable of participating in a 30-minute lasting exercise test

Key Exclusion Criteria:

• Have Type 2 Diabetes Mellitus (DM), monogenic diabetes, maturity-onset diabetes, other unusual or rare forms of DM, or diabetes resulting from a secondary disease.
• Have been hospitalized for DKA within 3 months
• Have uncontrolled hypothyroidism or hyperthyroidism
• Have QTcF interval > 450 msec for males or > 470 msec for females
• Have a personal or family history of long QT syndrome, Torsades de pointes, or other complex ventricular arrhythmias
• Have persistent, uncontrolled hypertension
• Have clinically significant cardiovascular or cerebrovascular disease
• Have proliferative retinopathy or maculopathy requiring acute treatment
• Have a serious concomitant systemic disorder incliuding but not limited to HIV or active Hep B or Hep C
• Diagnosed and/or treated for malignancy within 3 years
• Have used any of the following medications within the specified time periods: any non-insulin anti-diabetic therapies (e.g.SGLT-2 inhibitors, GLP-1 receptor agonists, metformin, sulfonylureas, DPP-4 inhibitors, pramlintide, a-glucosidase inhibitors, or glucose dependent insulinotropic polypeptide agonists) within 30 days, antipsychotic medications (e.g. olanzapine, risperidone, clozapine, quetiapine, and haloperidol) within 30 days, systemic corticosteroids for ≥7 days for a temporary medical condition within 30 days,

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Cadisegliatin 800 mg QD: Double Blind, Randomized Crossover Trial Design; If a patient is randomized to receive cadisegliatin 800 mg QD as an adjunctive therapy to their insulin treatment in the first double-blind treatment period of 6 weeks, there will then be a washout period of 1-2 weeks followed by the second double-blind treatment period of 6 weeks where the patient will cross-over to the placebo QD along with their insulin treatment arm	Drug: Cadisegliatin 800 mg QD; Cadisegliatin is an orally bioavailable small-molecule glucokinase activator, adjunctive therapy to insulin; Other Names: TTP399
Placebo Comparator: Placebo: Double Blind, Randomized Crossover Trial Design; If a patient is randomized to receive placebo QD along with their insulin treatment in the first double-blind treatment period of 6 weeks, there will then be a washout period of 1-2 weeks followed by the second double-blind treatment period of 6 weeks where the patient will cross-over to the cadisegliatin 800 mg QD as an adjunctive therapy to their insulin treatment arm	Drug: Placebo; Placebo (insulin alone)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
To assess the change in Time in Range (TIR)	Time in Range (TIR) based on study CGM in participants with T1D who are using hybrid closed loop systems on cadisegliatin vs placebo	last 2 weeks of the two 6-week treatment periods

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
CGM-based metric for glycemic control	Time In Tight Range (TITR)	last 2 weeks of the two 6-week treatment periods
CGM-based metric for glycemic control	Time Above Range (TAR)	last 2 weeks of the two 6-week treatment periods
CGM-based metric for glycemic control	Time Below Range (TBR)	last 2 weeks of the two 6-week treatment periods
CGM-based metric for glycemic control	Glucose Management Indicator (GMI)	last 2 weeks of the two 6-week treatment periods
CGM-based metric for glycemic control	Glucose variability (GV)	last 2 weeks of the two 6-week treatment periods
CGM-based metric for glycemic control	Time in Range (TIR) > 70%	last 2 weeks of the two 6-week treatment periods
Change in glucose control after standardized mixed meal tolerance test (MMTT)	Glucose Peak Plasma Concentration (Cmax) based on study CGM after standardized mixed meal tolerance test (MMTT)	12 weeks
Change in glucose control after standardized mixed meal tolerance test (MMTT)	Glucose Area under the plasma concentration versus time curve (AUC) based on study CGM after standardized mixed meal tolerance test (MMTT)	12 weeks
Change in glucose control after a standardized exercise test	Glucose Peak Plasma Concentration (Cmax) based on study CGM after a standardized exercise test	12 weeks
Change in glucose control after a standardized exercise test	Glucose Minimum Plasma Concentration (Cmin) based on study CGM after a standardized exercise test	12 weeks
Change in glucose control after a standardized exercise test	Glucose Area under the plasma concentration versus time curve (AUC) based on study CGM after a standardized exercise test	12 weeks
To assess the change in Level 1, Level 2 , and Level 3 hypoglycemic incidence	Number of events of Level 1, Level 2, and Level 3 hypoglycemia as determined by CGM and adjudicated level 3 hypoglycemic events per patient year in participants with T1D who are using hybrid closed loop systems on cadisegliatin vs placebo	12 weeks
Assess incidence of Serious Adverse Events (SAEs)	Number of Serious Adverse Events (SAEs)	14 weeks
Assess incidence of Treatment Emergent Adverse Events (TEAEs)	Number of treatment emergent adverse events (TEAEs)	14 weeks
Assess incidence of Treatment Emergent Adverse Events (TEAEs) leading to discontinuation	Number of treatment emergent adverse events (TEAEs) leading to discontinuation of study drug	14 weeks
Assess incidence of Adverse Events of Special Interest (AESIs)	Number of adverse events of special interest (AESIs)	14 weeks
Change from baseline in average daily total insulin dose	Change from baseline in average daily total insulin dose in units (IU) based on manual entry in eDiary records from participants with T1D who are using hybrid closed loop systems on cadisegliatin vs placebo	last week of the two 6-week treatment periods

Collaborators and Investigators

• Sponsor: vTv Therapeutics
• Investigators: Study Director: Thomas Strack, MD, vTv Therapeutics LLC

Study record dates

Study Major Dates

• Study Start (Estimated): July 1, 2026
• Primary Completion (Estimated): April 1, 2027
• Study Completion (Estimated): May 1, 2027

Study Registration Dates

• First Submitted: May 15, 2026
• First Submitted That Met QC Criteria: May 22, 2026
• First Posted (Actual): June 1, 2026

Study Record Updates

• Last Update Posted (Actual): June 1, 2026
• Last Update Submitted That Met QC Criteria: May 22, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Hybrid Closed Loop
• Additional Relevant MeSH Terms: Endocrine System Diseases; Metabolic Diseases; Autoimmune Diseases; Immune System Diseases; Glucose Metabolism Disorders; Diabetes Mellitus; Nutritional and Metabolic Diseases; Diabetes Mellitus, Type 1; TTP399
• Other Study ID Numbers: TTP399-206

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No