A Study to Evaluate ALN-6222 in Participants With Obesity

A Phase 1, Randomized, Double-blind, Placebo-controlled Study of the Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Efficacy of ALN-6222 in Adult Participants With Obesity

This is a first in human, randomized, double-blind (DB), placebo-controlled, single ascending dose (SAD), Phase 1 study to evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and efficacy of ALN-6222 administered subcutaneously (SC) in adult participants with obesity.

Study Overview

• Status: Not yet recruiting
• Conditions: Obesity
• Intervention / Treatment: Drug: Placebo; Drug: ALN-6222

• Study Type: Interventional
• Enrollment (Estimated): 88
• Phase: Phase 1

Contacts and Locations

• Study Contact: Name: Alnylam Clinical Trial Information Line; Phone Number: 1-877-ALNYLAM; Email: clinicaltrials@alnylam.com
• Study Contact Backup: Name: Alnylam Clinical Trial Information Line; Phone Number: 1-877-256-9526; Email: clinicaltrials@alnylam.com

Study Locations

• Canada
  • Mount Royal, Canada, H3P 3P1
    • Clinical Trial Site

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria -

• Is an adult patient with a body mass index ≥30 kg/m^2 to <40 kg/m^2
• Has a hemoglobin A1c <6.5%

Exclusion Criteria -

• Has alanine aminotransferase (ALT) or aspartate aminotransferase (AST) >1.5 times the upper limit of normal (ULN)
• Has known human immunodeficiency virus (HIV) infection; or known current or chronic hepatitis C virus or hepatitis B virus infection
• Has an estimated glomerular filtration (eGFR) of <60 mL/min/1.73m^2 at screening

Note: other protocol defined inclusion / exclusion criteria apply

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo; Participants will be administered a single dose of placebo.	Drug: Placebo; Placebo will be administered SC.
Experimental: ALN-6222; Participants will be administered a single dose of ALN-6222.	Drug: ALN-6222; ALN-6222 will be administered subcutaneously (SC).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Frequency of Adverse Events	Up to 12 months

Secondary Outcome Measures

Outcome Measure	Time Frame
Concentrations of ALN-6222 in Plasma	Predose and up to 3 days postdose
Change from Baseline Protein Markers in Plasma	Predose and up to 12 months postdose

Collaborators and Investigators

• Sponsor: Alnylam Pharmaceuticals
• Investigators: Study Director: Medical Director, Alnylam Pharmaceuticals

Study record dates

Study Major Dates

• Study Start (Estimated): June 3, 2026
• Primary Completion (Estimated): December 14, 2027
• Study Completion (Estimated): December 14, 2027

Study Registration Dates

• First Submitted: May 29, 2026
• First Submitted That Met QC Criteria: May 29, 2026
• First Posted (Actual): June 3, 2026

Study Record Updates

• Last Update Posted (Actual): June 3, 2026
• Last Update Submitted That Met QC Criteria: May 29, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: siRNA, RNAi therapeutic
• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight; Overweight; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Obesity
• Other Study ID Numbers: ALN-6222-001

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: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes