Clinical Pearls for Imetelstat (Rytelo)

Indication and Usage

• Indication: Rytelo (imetelstat) is approved for the treatment of adult patients with low- to intermediate-1 risk myelodysplastic syndromes (LR-MDS) with transfusion-dependent anemia. These patients require four or more red blood cell (RBC) units over eight weeks and have not responded to, lost response to, or are ineligible for erythropoiesis-stimulating agents (ESAs)[1][2][3][4][5].

Mechanism of Action

• Mechanism: Rytelo is an oligonucleotide telomerase inhibitor. It works by inhibiting telomerase enzymatic activity, which prevents the rebuilding of telomeres in abnormal bone marrow cells, thereby limiting uncontrolled cell division[1][2][3].

Administration

• Dosage: The recommended dosage is 7.1 mg/kg administered as an intravenous infusion over two hours every four weeks[1][2][3][4].

• Administration: It is crucial to administer Rytelo as an intravenous infusion over two hours. Ensure proper monitoring during the infusion to manage any potential adverse reactions[1][2][3].

Efficacy

• Clinical Trials: The efficacy of Rytelo was demonstrated in the phase 3 IMerge trial. Key findings include:
• 8-week RBC Transfusion Independence (RBC-TI): 39.8% in the Rytelo group vs. 15% in the placebo group.
• 24-week RBC-TI: 28% in the Rytelo group vs. 3.3% in the placebo group[3][4][5].

• Hemoglobin Increase: Median increases in hemoglobin were 3.6 g/dL for Rytelo-treated patients[1][2].

Safety and Adverse Reactions

• Common Adverse Reactions: The most common adverse reactions (≥10% incidence with a difference >5% compared to placebo) include:
• Thrombocytopenia (decreased platelets)
• Neutropenia (decreased neutrophils)
• Fatigue
• Increased liver enzymes (AST, ALT, ALP)
• Prolonged partial thromboplastin time
• Arthralgia/myalgia
• COVID-19 infections
• Headache[1][2][3][4][5].

• Serious Adverse Reactions: Serious adverse reactions occurred in 32% of patients, with sepsis being the most common (4.2%)[2][3].

Monitoring and Management

• Monitoring: Regular monitoring of blood counts is essential due to the risk of cytopenias. This includes:
• Platelet counts
• White blood cell counts
• Liver function tests (AST, ALT, ALP)[1][2][3].

• Management of Cytopenias: Cytopenias are generally manageable with dose modifications. Thrombocytopenia and neutropenia are common but typically short-lived and resolve to Grade <2 in under four weeks in most patients[2][3].

Patient Education

• Support Programs: Geron’s REACH4Rytelo™ Patient Support Program provides resources to support access and affordability for eligible patients[1][2].

• Patient Counseling: Educate patients on the importance of regular blood tests and monitoring for side effects. Inform them about the potential for serious infections and the need to report any signs of infection immediately[1][2][3].

Conclusion