How it is administered

Imetelstat is given as an intravenous (IV) infusion. It comes as a sterile, preservative-free, white to off-white or slightly yellow powder that is reconstituted and diluted before use. The recommended dose is 7.1 mg/kg, administered over 2 hours every 4 weeks. Your healthcare team will prepare and give this medication through a vein in your arm at a medical facility. Premedications such as diphenhydramine and hydrocortisone are usually given before each infusion to help prevent infusion-related reactions.

How it works

Imetelstat is a telomerase inhibitor. Telomerase is an enzyme that helps cancer cells keep their telomeres (protective caps on the ends of chromosomes) long, which allows these cells to keep dividing and growing. By blocking telomerase, imetelstat causes the telomeres in cancer cells to shorten, which can slow down or stop the growth of these cells and may lead to their death.

In blood cancers like myelodysplastic syndromes (MDS), and potentially myelofibrosis, increased telomerase activity is often seen in malignant stem and progenitor cells. Imetelstat binds to the RNA component of telomerase, inhibiting its activity, reducing the proliferation of these abnormal cells, and promoting their death. This can help reduce the need for blood transfusions and improve blood counts in some patients.

Who Should take it

Imetelstat is indicated for adults with low- to intermediate-1 risk myelodysplastic syndromes (MDS) who have transfusion-dependent anemia (requiring 4 or more units of red blood cells over 8 weeks) and who have not responded to, have lost response to, or are ineligible for erythropoiesis-stimulating agents (ESAs).

If you have been diagnosed with MDS and are needing frequent blood transfusions, and other standard treatments have not worked or are not suitable for you, your doctor may consider imetelstat as a treatment option. While the main approval is for MDS, research is ongoing for its use in other blood cancers, including myelofibrosis.

Who should not take it

There are no absolute contraindications listed for imetelstat. However, it should be used with caution in certain populations:

• Pregnant women should not take imetelstat, as it can cause harm to an unborn baby. Effective contraception is recommended during treatment and for one week after the last dose.
• The safety and effectiveness of imetelstat in children have not been established.
• The effects of severe renal or hepatic impairment on imetelstat use have not been established, so caution is advised in these patients.

Always discuss your full medical history with your healthcare provider before starting imetelstat.

Commonly used with

Imetelstat is often used as a single agent in the treatment of MDS, especially in patients who have not responded to or are ineligible for ESAs. Supportive care such as blood transfusions and medications to prevent or treat infections may be given alongside imetelstat.

Premedications like diphenhydramine (an antihistamine) and hydrocortisone (a steroid) are routinely used before each infusion to reduce the risk of infusion-related reactions.

Commonly tested with

Imetelstat has been tested in clinical trials as a single agent for MDS. In these studies, all patients received supportive care, which included red blood cell transfusions as needed. It is also being studied in combination with other supportive treatments in blood cancers, but for MDS, its main use is as a single agent after other therapies have failed or are not suitable.