The European Commission has granted marketing authorization to Rytelo (imetelstat) monotherapy for the treatment of adult patients with transfusion-dependent anemia due to very low–, low– or intermediate-risk myelodysplastic syndromes (MDS), according to a press release from Geron Corporation. Moreover, this regulatory decision has approved the agent for patients without an isolated deletion 5q cytogenetic abnormality, as well as those who are ineligible for or did not respond to erythropoietin-based therapy.
This marketing authorization supports the use of Rytelo in the European Union and is backed by data from the phase 3 IMerge clinical trial, which had significant clinical benefit in this patient population, reducing their need for red blood cell transfusions in the first 24 weeks of treatment versus placebo.
Regarding safety, the agent was described to have had manageable and short-lived side effects, including thrombocytopenia and neutropenia. These side effects occurred at grade 3 (severe) or higher in 69% and 63% of patients, respectively, and at a median duration of less than two weeks. In more than 80% of patients, the side effects were resolved to a grade less than 2 (moderate) in under four weeks.
Glossary
Anemia: when there is a lower-than-normal number of red blood cells or hemoglobin in the blood.
Erythropoietin-based therapy: using synthetic versions of the hormone erythropoietin to stimulate the bone marrow to produce more red blood cells.
Red blood cell transfusions: giving a person donated red blood cells to increase their oxygen-carrying capacity.
Thrombocytopenia: also known as low platelet count; a condition where the blood has fewer platelets than normal.
Neutropenia: a condition in which the body has a low level of neutrophils.
Telomerase inhibitor: substance or compound that specifically blocks or reduces the activity of the telomerase enzyme.
“As the first and only treatment of its kind, Rytelo represents an important new option — significantly reducing the need for red blood cell transfusions for people living with lower-risk MDS who are battling debilitating symptoms like anemia and fatigue,” said Dr. Joseph Eid, Geron’s executive vice president of Research and Development. “This approval from the European Commission, just nine months following approval in the U.S., underscores the positive benefit for these patients demonstrated in our clinical trials and we look forward to making this innovative therapy accessible to eligible patients in Europe.”
Rytelo represents the first and only telomerase inhibitor — a compound that blocks or slows down the enzyme which cancer cells often use to keep growing — that is approved by the European Commission.
The regulatory approval applies to all 27 European Union member states, as well as Iceland, Norway and Liechtenstein, according to the press release. Moreover, Geron plans to make Rytelo available in other European countries starting in 2026, pending approval for coverage in each country. The company is also looking into special programs that could help eligible patients access Rytelo on a case-by-case basis.
More Information on Rytelo
Lower-risk MDS is a type of blood cancer that often will progress (worsen) over time, leading to symptoms like anemia and fatigue. Many patients eventually require frequent red blood cell transfusions, which can impact quality of life and shorten survival. Because of these outcomes in patients, there is a need for better treatment options, especially for patients with a poor prognosis, as current therapies are limited.
Investigators aimed to address this unmet medical need with Rytelo in the phase 3 trial. The investigative agent is a targeted therapy — which is already approved in the U.S. — for adults with lower-risk myelodysplastic syndromes who have anemia requiring frequent red blood cell transfusions and have not responded to or cannot receive standard treatments. It is given as an intravenous infusion over two hours every four weeks.
The agent works by blocking telomerase, an enzyme that helps abnormal bone marrow cells keep dividing. By inhibiting this process, Rytelo may slow disease progression. Notably, it is also the first and only telomerase inhibitor approved by the U.S. Food and Drug Administration (FDA).
“I am thrilled that the European Commission has approved Rytelo in lower-risk MDS. The long-term and durable responses observed in the phase 3 IMerge study reinforce the practice-changing potential of telomerase inhibition as a clinically meaningful and differentiated option for the treatment of lower-risk MDS,” said Dr. Uwe Platzbecker, IMerge investigator and a co-lead author of the phase 3 results published in The Lancet. “Physicians and patients in Europe are now one step closer to accessing a novel treatment that, in addition to having a generally manageable safety profile, has the potential to provide extended and continuous red blood cell transfusion independence.”
Platzbecker is also the chief medical officer at the University Hospital Carl Gustav Carus Dresden in Germany.
More on the Safety of Rytelo
According to the press release, Rytelo can lower platelet levels, which may increase the risk of bleeding. A patient’s doctor is expected to monitor their blood counts regularly and may delay or adjust treatment if needed, though platelet transfusions may be given if necessary. Additionally, Rytelo may also lower neutrophil levels, which help fight infections. A doctor should your check a patient’s blood counts often and monitor for infections, including sepsis. If needed, medications to boost white blood cells or prevent infections may be given.
Some patients may also experience reactions during or after Rytelo treatment, such as headache or, in rare cases, high blood pressure. To help prevent this, patients can receive medications like diphenhydramine and hydrocortisone before treatment.
Serious side effects occurred in 32% of patients receiving Rytelo. These included infections like sepsis (4.2%), fractures (3.4%), heart failure (2.5%) and bleeding (2.5%). Fatal reactions were reported in 0.8% of patients, primarily due to sepsis. The most common side effects (reported in at least 10% of patients and more frequently than with placebo) included low platelets, low white blood cells, increased liver enzymes, fatigue, muscle or joint pain, prolonged blood clotting times, COVID-19 infections and headache.
For more news on cancer updates, research and education, don’t forget to subscribe to CURE®’s newsletters here.
