A Phase 1 Study of EXT608 in Healthy Adults

EXT608 in Human Healthy Adults; A First-in-Human, Randomized, Double-Blind, Placebo-controlled, Single Dose Escalation Study

This is a Phase 1, randomized, double-blind, placebo-controlled, single ascending dose safety and tolerability study of EXT608 in healthy subjects. There will be up to 6 sequential dose escalation cohorts of 4 participants. In each cohort 3 participants will receive EXT608 and 1 participant will receive placebo.

Study Overview

• Status: Completed
• Conditions: Safety Issues
• Intervention / Treatment: Drug: EXT608; Other: Placebo

Detailed Description

This is a randomized, double-blind, first-in-human, placebo-controlled single ascending dose study to study the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of EXT608 in healthy adult participants.

Participants will be enrolled into 1 of up to 6 planned single dose cohorts in ascending fashion.

Each cohort will consist of 4 participants randomized to receive either EXT608 or placebo, whereby 3 will receive a single injection of EXT608 and 1 will receive matching placebo.

Up to 6 dosing cohorts are planned with no single dose escalation to exceed a 3-fold dose increment. A Data Monitoring Board will review the seven-day safety data in each cohort before authorizing the initiation of the next cohort.

A screening visit will take place within 28 days of dosing. Eligible participants for each cohort will be admitted to the Clinical Research Unit (CRU) 1 day prior to dosing and remain in the CRU through at least 72 hours after dosing for safety and PK assessments before discharge. The total confinement period will be 4 nights, unless extended for management of Adverse Events (AEs) at the discretion of the Investigator

• Study Type: Interventional
• Enrollment (Actual): 24
• Phase: Phase 1

Contacts and Locations

Study Locations

• United States
  • Kansas
    • Lenexa, Kansas, United States, 66219
      • PRA

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 55 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. Male or female between 18 and 55 years of age.
2. Body mass index between 18.5 and 32 kilogram per square meter (kg/m2), inclusive, with a body weight greater than or equal to (>=) 45 kg.
3. In general good medical health with no clinically significant or relevant abnormalities,
4. A clinical safety laboratory parameter of hemoglobin greater than (>) 11.7 gram per deciliter (g/dl) (females) or 13.1 g/dl (males) and less than (<) 16 g/dl (females) or 17.4 g/dl (males) or, if out of this range, deemed not clinically significant by the Investigator.
5. Total serum calcium (Se-Ca) within laboratory normal limits.
6. Serum parathyroid hormone (PTH) concentration within normal laboratory limits.

Exclusion Criteria:

1. Evidence of clinically significant (CS) neurologic, cardiovascular, pulmonary, hepatic, hematopoietic disease, renal, metabolic, gastrointestinal, urologic, immunologic, endocrine disease, serious allergy, allergic skin rash, or psychiatric disorder
2. History of drug abuse
3. Currently using any medication including over-the-counter (OTC), herbal or homeopathic preparations
4. Pregnant, nursing, or planning a pregnancy during the course of or within 3 months of completing this study
5. History of cancer or other malignancy, with the exception of basal cell carcinoma that has been in remission for at least 5 years
6. Positive test result for hepatitis B surface antigen (HBsAg), hepatitis C virus (HCV) antibody or a human immunodeficiency virus (HIV)
7. Alanine transaminase (ALT) and/or aspartate transaminase (AST) >1.5 the upper limit of normal (ULN)
8. Increased baseline risk for osteosarcoma

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Sequential Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Experimental- EXT608; Up to 6 sequential dose escalation cohorts will receive a single dose of EXT608 administered as a subcutaneous injection	Drug: EXT608; EXT608 is an investigational drug administered via subcutaneous injection; Other Names: test drug
Placebo Comparator: Placebo comparator; Up to 6 participants will receive matching placebo administered as a subcutaneous injection	Other: Placebo; matching placebo administered via subcutaneous injection

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Characterize the Safety and Tolerability of EXT608	Incidence, nature and severity of adverse events (AEs) and withdrawals due to Treatment-Emergent Adverse Events (TEAEs)	Day 0 to Day 28
Characterize the Safety and Tolerability of EXT608	Frequency and severity of post-dose change from baseline of hematology, serum chemistry, urinalysis, electrocardiogram (ECG), vital signs and physical examination findings	Day 0 - Day 28
Characterize the Safety and Tolerability of EXT608	Percentage of participants with injection or infusion site reactions - edema	Day 0 - Day 28

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Single Dose Pharmacokinetics (PK) - Area Under the Curve (AUC)	Area under the curve	Day 0 to Day 7
Single Dose PK - Cmax	Maximum observed concentration	0-24 hr
Single Dose PK - Tmax	Time to reach maximum observed plasma concentration	Day 0 to Day 7

Collaborators and Investigators

• Sponsor: Extend Biosciences Inc.
• Collaborators: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK); Pharmaceutical Research Associates; Integrated Medical Development
• Investigators: Study Director: Laura Hales, PhD, Extend Biosciences

Study record dates

Study Major Dates

• Study Start (Actual): July 21, 2022
• Primary Completion (Actual): June 13, 2023
• Study Completion (Actual): June 13, 2023

Study Registration Dates

• First Submitted: May 31, 2022
• First Submitted That Met QC Criteria: June 3, 2022
• First Posted (Actual): June 7, 2022

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: January 11, 2025
• Last Verified: January 1, 2025

More Information

Terms related to this study

• Other Study ID Numbers: EXT608-101; R44DK107231 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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