CT-388: Dosing Protocols

Important Disclaimer#

CT-388 is an investigational drug not yet approved by any regulatory authority. All dosing information is derived from clinical trial protocols and published results. CT-388 should only be used within approved clinical trials. The information below is for educational purposes only.

Clinical Trial Dosing#

Phase 2 Trial (48 Weeks)#

The Phase 2 trial evaluated three subcutaneous dose levels of CT-388 versus placebo in 469 adults with obesity or overweight over 48 weeks:

• Three dose cohorts were evaluated with dose escalation
• Highest dose: 24 mg once weekly
• 22.5% placebo-adjusted weight loss at the 24 mg dose
• Dose-dependent weight loss across cohorts
• No weight loss plateau at 48 weeks

Phase 1b Trial (24 Weeks)#

The Phase 1b multiple ascending dose study evaluated CT-388 over 24 weeks:

• 18.8% placebo-adjusted weight loss
• 100% of treated participants achieved at least 5% weight loss
• 85% achieved at least 10% weight loss
• 70% achieved at least 15% weight loss
• 45% achieved at least 20% weight loss

Dose Escalation#

CT-388 uses a dose escalation approach consistent with other GLP-1/GIP class therapies. Patients start at a lower dose and gradually titrate up to the target maintenance dose over several weeks. This approach minimizes the incidence and severity of GI adverse events during initiation.

Administration#

Subcutaneous Injection#

• Once-weekly injection
• Standard subcutaneous injection sites (abdomen, thigh, upper arm)
• Rotate injection sites between doses
• No oral formulation is currently in development (unlike VK2735)

Dose-Response Relationship#

Phase 2 demonstrated a clear dose-response across the three dose levels:

The absence of a weight loss plateau at 48 weeks suggests that longer treatment or higher doses could potentially produce even greater weight loss.

Phase 3 Dosing Plans#

Roche plans to initiate two Phase 3 trials in Q1 2026. The Phase 3 dosing regimen has not been publicly disclosed but will be informed by the Phase 2 dose-response data.

Dosing Context#

CT-388 belongs to the Metabolic category of research peptides. Dosing protocols for CT-388 are derived from available clinical trial data. These protocols are provided for research reference only and do not constitute medical advice. Actual dosing decisions should be made by qualified healthcare providers based on individual patient factors.

Research Protocols#

The following dosing protocols have been documented in clinical research for CT-388:

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Dose: undefined

Frequency: Once weekly (subcutaneous)

Duration: 48 weeks in Phase 2

Dose escalation was used to mitigate GI adverse events. The 24 mg dose showed the greatest weight loss with no plateau at 48 weeks.

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Dose: undefined

Frequency: Once weekly (subcutaneous)

Duration: 24 weeks

Phase 1b results informed dose selection for Phase 2. All TEAEs were mild to moderate with no serious adverse events.

Reconstitution and Preparation#

Not applicable - CT-388 is provided as a ready-to-use subcutaneous injection

Injection Sites#

Recommended injection sites for CT-388 include:

• Abdomen
• Thigh
• Upper arm

Site rotation is recommended to minimize local tissue reactions and ensure consistent absorption.

Storage Requirements#

Storage conditions have not been publicly disclosed. Clinical trial formulations are managed per protocol requirements.

Related Reading#

• CT-388 overview and research guide
• CT-388 side effects profile
• CT-388 research evidence