There’s some wonderful news for people living with myelodysplastic syndrome (MDS), a rare type of blood cancer: the U.S. Food and Drug Administration (FDA) has recently approved a new treatment option that reduces the need for regular blood transfusions.
Over 70% of patients with MDS, are classified as having lower-risk disease, and the majority of these patients require blood transfusions as a component of their care to treat anemia.
This novel therapy known as imetelstat (brand name Rytelo) is indicated for the treatment of adult patients with low- to intermediate-risk MDS with transfusion-dependent anemia requiring four or more red blood cell units over eight weeks who have not responded to, have lost response to, or are ineligible for erythropoiesis-stimulating agents (ESAs).
“With the approval and availability of Rytelo, we believe eligible patients with LR [low risk] MDS can potentially experience meaningful clinical benefit, particularly the potential for greater than 24 weeks of freedom from the burden of red blood cell transfusions and symptomatic anemia,” said Dr. John A. Scarlett, chairman and chief executive officer of Geron, in a news release.
“The approval of Rytelo as the first telomerase inhibitor is a testament to the power of our science and the passion of our people to innovate in the field of blood cancer.”
What’s the Data?
The FDA approval is based on results from the IMerge phase III clinical trial, which were published in The Lancet Journal.
Study participants were randomly assigned 2:1 to receive either imetelstat 7.1mg/kg via IV infusion every 4 weeks (n=118) or placebo (n=60) in 28-day treatment cycles until disease progression, unacceptable toxicity, or withdrawal from the study.
The primary endpoint was the rate of RBC transfusion independence (RBC-TI) lasting at least 8 weeks, defined as the proportion of patients without any RBC transfusion for at least 8 consecutive weeks since entry to the trial.
The trial met its primary and key secondary end points, with the new drug demonstrating significantly higher rates of continuous red blood cell transfusion independence.
Results showed 39.8% of patients treated with imetelstat met the primary endpoint of 8-week transfusion independence vs 15% of those treated with placebo (treatment difference, 24.8% [95% CI, 9.9-36.9]; P <.001).
To summarize: more patients in the imetelstat group avoided blood transfusions compared to the placebo group. And the difference between the two groups is statistically significant.
“For patients with LR-MDS and anemia who are transfusion dependent, we have very few options today and often cycle through available therapies, making the approval of Rytelo potentially practice-changing for us,” said Dr. Rami Komrokji, vice chair of the Malignant Hematology Department at Moffitt Cancer Center and an investigator of the pivotal IMerge clinical trial, in the news release.
“What is exciting about Rytelo is the totality of the clinical benefit across LR-MDS patients irrespective of ring sideroblast status or high transfusion burden, including sustained and durable transfusion independence and increases in hemoglobin levels, all within a well-characterized safety profile of generally manageable cytopenias.”
Rytelo Safety and Side Effects
Although reducing how often patients with MDS need to undergo blood transfusions is a major advancement, like all cancer therapies, there is the potential for side effects.
This new study found that Rytelo has a manageable safety profile, with some side effects that can be controlled.
The most common adverse reactions (incidence ≥10% with a difference between arms of >5% compared to placebo), including laboratory abnormalities, were:
- Decreased platelets (thrombocytopenia)
- Decreased white blood cells
- Decreased neutrophils (neutropenia)
- Increased aspartate aminotransferase (AST)
- Increased alkaline phosphatase (ALP)
- Increased alanine aminotransferase (ALT)
- Fatigue
- Prolonged partial thromboplastin time
- Arthralgia/myalgia
- COVID-19 infections
- Headache
Clinically relevant adverse reactions in <5% of patients who received Rytelo included febrile neutropenia, sepsis, gastrointestinal hemorrhage, and hypertension.