Rusfertide: Dosing Protocols

Investigational Status#

Rusfertide (PTG-300) is an investigational medication that has not yet received regulatory approval. All dosing information is derived from clinical trial protocols and published study results. Dosing should only occur within the context of clinical trials or, once approved, under the guidance of a qualified hematologist.

Clinical Trial Dosing#

REVIVE Trial (Phase 2)#

In the phase 2 REVIVE trial, rusfertide dosing followed a titration approach:

Dose-Finding (Part 1, 28 weeks):

• Starting dose: 20 mg subcutaneously once weekly
• Dose titration: Adjusted to achieve and maintain hematocrit <45%
• Dose range: 10-120 mg per week
• Mean final weekly dose: 41.3 mg

Randomized Withdrawal (Part 2, 12 weeks):

• Patients who achieved hematocrit control were randomized to continue rusfertide or switch to placebo

VERIFY Trial (Phase 3)#

The phase 3 VERIFY trial used a similar dosing approach:

• Starting dose: 20 mg subcutaneously once weekly
• Dose titration guided by hematocrit monitoring
• Goal: Maintain hematocrit <45% without phlebotomy

Induction Protocol (Alternative)#

An alternative induction approach has been studied:

• Initial dose: 40 mg subcutaneously twice weekly
• Once hematocrit drops below 45%, transition to once-weekly dosing
• Weekly dose then adjusted to maintain hematocrit control

Dose Titration#

Factors Affecting Dose Requirements#

• Sex: Female patients required lower average weekly doses than males
• Body weight: Patients weighing 85 kg or less required lower doses than heavier patients
• Concomitant therapy: Similar dose requirements whether used with phlebotomy alone or with cytoreductive therapy

Administration#

Injection Technique#

1. Administer subcutaneously in the abdomen or thigh
2. Rotate injection sites to minimize injection site reactions
3. Inject on the same day each week for consistency
4. Monitor for injection site reactions (common, usually grade 1-2)

Monitoring Requirements#

• Hematocrit: Regular monitoring is essential for dose titration
• Serum iron and transferrin saturation: To assess degree of iron restriction
• Complete blood count: Monitor at baseline and periodically
• Ferritin: Monitor iron stores to avoid excessive iron depletion

Treatment Interruption#

Clinical data has shown that interrupting rusfertide treatment leads to:

• Loss of hematocrit control within weeks
• Return of phlebotomy requirements
• Upon reinitiation, therapeutic benefit is restored

This reversibility underscores the need for ongoing treatment to maintain disease control.

Dosing Context#

Rusfertide belongs to the Immune category of research peptides. Dosing protocols for Rusfertide 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 Rusfertide:

Polycythemia Vera (Erythrocytosis Control)#

Dose: 20 mg subcutaneously once weekly as starting dose. Titrate in the range of 10-120 mg weekly to maintain hematocrit <45%.

Frequency: Once weekly subcutaneous injection

Duration: Ongoing (treatment interruption leads to loss of hematocrit control)

Mean final weekly dose in REVIVE was 41.3 mg. Female patients and those with lower body weight may require lower doses. Dose adjustments guided by hematocrit monitoring.

Protocol Quick Reference#

Primary Use: Polycythemia vera erythrocytosis control

Dosing Summary: 20 mg starting, titrate 10-120 mg administered Once weekly for Ongoing.

Route of Administration: subcutaneous (Once weekly).

Timing Notes: Consistent day of week; dose titrated to maintain hematocrit <45%

Cycle Duration: Ongoing.

Storage: Refrigerate at 2-8 degrees C. Protect from light.

Recommended Bloodwork#

Additional Considerations#

• Investigational drug - not yet approved by any regulatory authority
• Dose titration required based on hematocrit response
• Treatment interruption leads to loss of therapeutic benefit
• Can be used with or without concomitant cytoreductive therapy

Reconstitution and Preparation#

Rusfertide has been studied in both lyophilized powder (requiring reconstitution) and aqueous formulations for subcutaneous injection. The specific formulation depends on the clinical trial or eventual commercial product.

Injection Sites#

Recommended injection sites for Rusfertide include:

• Abdomen
• Thigh

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

Storage Requirements#

Storage conditions depend on formulation. Lyophilized powder: store at 2-8 degrees C. Aqueous formulation: store refrigerated. Consult specific product labeling.

Related Reading#

• Rusfertide overview and research guide
• Rusfertide side effects profile
• Rusfertide research evidence