Safety, Tolerability, Pharmacokinetics and Pharmacodynamics Study of RLYB116 in Healthy Participants

Multiple Dose Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of RLYB116 in Healthy Participants

This study will investigate the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of RLYB116 (with an improved impurity profile) following repeated administration of RLYB116 in healthy participants.

Study Overview

• Status: Completed
• Conditions: Autoimmune Diseases; Hematologic Diseases
• Intervention / Treatment: Drug: RLYB116 for Injection

• Study Type: Interventional
• Enrollment (Actual): 16
• Phase: Phase 1

Contacts and Locations

Study Locations

• Australia
  • Queensland
    • Brisbane, Queensland, Australia, 4006
      • Nucleus Network Brisbane

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. Male and female participants, 18 to 55 years of age.
2. Able to provide written informed consent.
3. Body mass index (BMI) of 18.0 to 32.0 kg/m2.

4. Must have been vaccinated against N. meningitidis and S. pneumoniae with approved vaccine according to product label. All participants considered eligible for enrollment will be vaccinated or willing to receive vaccination according to the following:

   1. Vaccination with Meningococcal Group A, C, W135, and Y conjugate vaccine (Menveo® or an acceptable alternative) + Pneumococcal Polysaccharide Vaccine (Pneumovax® 23 or an acceptable alternative) at least 28 days prior to receiving the first dose of RLYB116.
   2. Vaccination with Meningococcal Group B (Bexsero®) at least 14 days prior to receiving the first dose of RLYB116.

Exclusion Criteria:

1. Participants that smoke more than 10 cigarettes per week
2. Positive serology for HIV or active infection with hepatitis B virus or hepatitis C virus.
3. Pregnant or nursing
4. Donation or loss of greater than 400 mL of blood within 56 days of study enrollment
5. History of severe hypersensitivity to any drug, including penicillin or ciprofloxacin, or to N. meningitidis or S. pneumoniae vaccines.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: RLYB116 Dose 1; RLYB116 for Injection Dose 1, weekly for 5 weeks	Drug: RLYB116 for Injection; RLYB116 is a small protein composed of an Affibody® Z-domain that binds with high affinity to C5, inhibiting terminal complement activation, and an albumin binding domain (ABD) that extends the effective plasma half-life of the protein by targeting serum albumin.
Experimental: RLYB116 Dose 2; RLYB116 for Injection Dose 2, weekly for 5 weeks	Drug: RLYB116 for Injection; RLYB116 is a small protein composed of an Affibody® Z-domain that binds with high affinity to C5, inhibiting terminal complement activation, and an albumin binding domain (ABD) that extends the effective plasma half-life of the protein by targeting serum albumin.
Placebo Comparator: Placebo for Injection; Sodium chloride injection, 0.9% saline (for both RLYB116 doses), weekly for 5 weeks	Drug: RLYB116 for Injection; RLYB116 is a small protein composed of an Affibody® Z-domain that binds with high affinity to C5, inhibiting terminal complement activation, and an albumin binding domain (ABD) that extends the effective plasma half-life of the protein by targeting serum albumin.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Number of participants with treatment related adverse events as defined by CTCAE 5.0.	From baseline to Day 1, 2, 3, 4, 5, 8, 9, 15, 16, 22, 23, 29, 30, 32, 33, 36, 43, 57, 71, 99

Secondary Outcome Measures

Outcome Measure	Time Frame
Inhibition of complement activation measured by free/total C5 concentrations and hemolytic activity	Day 1, 2, 8, 15, 29, 20, 32, 33, 43, 57, 71, 99
Anti-RLYB116 antibodies measured in serum	Day 1, 29, 99
Exposure to RLYB116 as measured in serum	Day 1, 2, 3, 4, 5, 8, 15, 29, 53, 57, 71, 99

Collaborators and Investigators

• Sponsor: Rallybio

Study record dates

Study Major Dates

• Study Start (Actual): April 14, 2025
• Primary Completion (Actual): February 9, 2026
• Study Completion (Actual): February 23, 2026

Study Registration Dates

• First Submitted: January 22, 2025
• First Submitted That Met QC Criteria: January 22, 2025
• First Posted (Actual): January 28, 2025

Study Record Updates

• Last Update Posted (Actual): February 27, 2026
• Last Update Submitted That Met QC Criteria: February 24, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: complement-mediated diseases
• Additional Relevant MeSH Terms: Immune System Diseases; Hemic and Lymphatic Diseases; Autoimmune Diseases; Hematologic Diseases; Therapeutics; Drug Administration Routes; Drug Therapy; Injections
• Other Study ID Numbers: IPC2401

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
• product manufactured in and exported from the U.S.: Yes