Evaluate the Safety, Tolerability, PK and PD of SAD of Intravenously Adminsterted ALTB-268 in Healthy Participants

A Phase 1, Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Safety Tolerability, Pharmacokinetics, and Pharmacosymics of Single Ascending Doses of Intravenously Administerted ALTB-268 in Healthy Participants

This study with ALTB-268 will determine the safety, tolerability, pharmacokinetics and pharmacodynamics of single ascending doses of intravenously administrated ALTB-268 in healthy participants.

Study Overview

• Status: Active, not recruiting
• Conditions: Ulcerative Colitis (UC)
• Intervention / Treatment: Other: Placebo; Biological: ALTB-268

Detailed Description

This is a Phase I, randomized, double-blind, single ascending dose (SAD) study to evaluate the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of intravenously administered ALTB-268 in healthy participants. Approximately 24 healthy participants will be recruited.

The primary objective is to evalute the safety and tolerability of intravenous infusion of SAD in healthy participants. The secondary objectives are (1) to characterize the PK profile of ALTB-268 in plasma following single IV doses in healthy participants, and (2) to assess the PD of ALTB-268 following single IV doses in healthy participants.

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

Contacts and Locations

Study Locations

• United States
  • Florida
    • Miami, Florida, United States, 33136
      • Syneos Health Clinical Research Services, LLC

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

1. Male or female, non-smoker (no use of tobacco or nicotine products within 3 months prior to screening), ≥18 and ≤55 years of age, with body mass index (BMI) >18.5 and <32.0 kg/m2 and body weight ≥50.0 kg for males and ≥45.0 kg for females.

2. Healthy as defined by:

   1. the absence of clinically significant illness and surgery within 4 weeks prior to dosing.
   2. the absence of clinically significant history of neurological, endocrine, cardiovascular, respiratory, hematological, immunological, psychiatric, gastrointestinal, renal, hepatic, and metabolic diseases.

3. Female participants of non-childbearing potential must be:

   1. post-menopausal (spontaneous amenorrhea for at least 12 consecutive months prior to dosing) with confirmation by documented follicle- stimulating hormone (FSH) levels ≥40 mIU/mL; or
   2. surgically sterile (bilateral oophorectomy, bilateral salpingectomy, hysterectomy, or bilateral tubal ligation) at least 3 months prior to dosing.
4. Able to understand the study procedures, agree to comply with all study visits, procedures, and restrictions, agree to comply with the prescribed dosage regimens and communicate to study personnel about AEs and concomitant medication use, and provide signed informed consent to participate in the study.

Exclusion Criteria:

1. Any clinically significant abnormal finding at physical examination at screening and/or Day -1.
2. Clinically significant abnormal laboratory test results at screening and/or Day -1; or positive serology test results for hepatitis B surface antigen (HBsAg), hepatitis C virus (HCV) antibody, or human immunodeficiency virus (HIV) antigen and antibody, or QuantiFERON®-TB test at screening.
3. Any history of suicidal ideation as evidenced by answering "yes" to questions 4 or 5 on the suicidal ideation portion of the C-SSRS completed at screening, or any history of suicide attempts.
4. Any history of clinical depression.
5. C-SSRS score at Day -1 (baseline) above Type 1 ideation.
6. PHQ-8 total score ≥5 at screening and/or Day -1 (baseline).

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: Biological: ALTB-268; Intravenously administered	Biological: ALTB-268; monoclonal antibody
Placebo Comparator: Placebo (Saline solution); Intravenously Administered	Other: Placebo; Saline solution

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
To evaluate the safety and tolerability of ALTB-268 following intravenous (IV) infusion in healthy participants - Adverse Events	- Numbers of participants with adverse events (AEs): seriousness, severity, relationship to the investigational products, outcome, duration, and management	Through study completion, up to day 71 of the study
To evaluate the safety and tolerability of ALTB-268 following intravenous (IV) infusion in healthy participants - Infusion Site Assessments	- Infusion site assessments, the extent of local reaction at the infusion site will be graded using the scores described below; a global severity rating for infusion site reactions will be included in the assessment of AEs. Infusion Site Reaction Score: None: No reaction; Mild: Tenderness with or without associated symptoms; Moderate: Pain; lipodystrophy; edema; phlebitis; Severe: Ulceration or necrosis; severe tissue damage; operative intervention indicated.	Through study completion, up to day 71 of the study
To evaluate the safety and tolerability of ALTB-268 following intravenous (IV) infusion in healthy participants - C-SSRS	- Columbia suicidality severity rating scale (C-SSRS) is a suicidal ideation and behavior rating scale to evaluate suicide risk.	Through study completion, up to day 71 of the study
To evaluate the safety and tolerability of ALTB-268 following intravenous (IV) infusion in healthy participants - PHQ-8	- Patient Health Questionnaire-8 (PHQ-8) depression scale is used for depression screening and severity.	Through study completion, up to day 71 of the study
To evaluate the safety and tolerability of ALTB-268 following intravenous (IV) infusion in healthy participants - Clinical Laboratory Test	- Clinical laboratory test results, including white blood cell, lymphocyte and neutrophail (cell counts/ul).	Through study completion, up to day 71 of the study

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pharmacokinetic (PK) of ALTB-268 AUC	AUC0-t, area under the concentration-time curve from time 0 to t hours; AUC0-inf, area under the concentration-time curve from time 0 to infinity	Through study completion, up to day 71 of the study
Pharmacokinetic (PK) of ALTB-268 Cmax	Mmaximum concentration (Cmax)	Through study completion, up to day 71 of the study
Pharmacokinetic (PK) of ALTB-268 Tmax	Time to reach Cmax (Tmax)	Through study completion, up to day 71 of the study
Pharmacokinetic (PK) of ALTB-268 T½	Terminal half-life (T½)	Through study completion, up to day 71 of the study
Pharmacokinetic (PK) of ALTB-268 CL	Total body clearance (CL)	Through study completion, up to day 71 of the study
Pharmacokinetic (PK) of ALTB-268 Vz	Volume of distribution (Vz)	Through study completion, up to day 71 of the study
Pharmacokinetic (PK) of ALTB-268 Vss	Steady-state volume of distribution (Vss)	Through study completion, up to day 71 of the study
Pharmacodynamics (PD) of ALTB-268 following single IV doses in healthy participants.	Levels of free soluble P-selectin glycoprotein ligand-1 (sPSGL-1) in plasma.	Through study completion, up to day 71 of the study
Immunogenicity of ALTB-268 in plasma following single IV doses in healthy participants	Incidence and level of anti-drug antibodies (ADAs).	Through study completion, up to day 71 of the study

Collaborators and Investigators

• Sponsor: AltruBio Inc.

Study record dates

Study Major Dates

• Study Start (Actual): November 17, 2025
• Primary Completion (Estimated): September 26, 2026
• Study Completion (Estimated): September 28, 2026

Study Registration Dates

• First Submitted: December 1, 2025
• First Submitted That Met QC Criteria: January 11, 2026
• First Posted (Actual): January 20, 2026

Study Record Updates

• Last Update Posted (Actual): May 1, 2026
• Last Update Submitted That Met QC Criteria: April 29, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Intestinal Diseases; Digestive System Diseases; Gastrointestinal Diseases; Colonic Diseases; Gastroenteritis; Inflammatory Bowel Diseases; Colitis; Colitis, Ulcerative
• Other Study ID Numbers: ALTB-268-102

Drug and device information, study documents

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