First-in-class telomerase inhibitor approved for blood cancer

The first telomerase inhibitor has been approved by the US Food and Drug Administration (FDA). RYTELO ™ (imetelstat) is authorised for adults with low- to intermediate-1 risk myelodysplastic syndromes (MDS) with transfusion-dependent (TD) anaemia.

The first-in-class oligonucleotide telomerase inhibitor is indicated for these patients who need four or more red blood cell units over eight weeks, who are unresponsive to or ineligible for erythropoiesis-stimulating agents (ESA).

“With the approval and availability of RYTELO, we believe eligible patients with lower-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 anaemia,” stated Dr John Scarlett, Chairman and Chief Executive Officer of Geron Corporation.

“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 haemoglobin levels, all within a well-characterised safety profile of generally manageable cytopenias,” commented Dr Rami Komrokji, Vice Chair, Malignant Hematology Department, Moffitt Cancer Center, and an investigator of the pivotal IMerge clinical trial.

Dr Komrokji remarked that the FDA’s approval of RYTELO (imetelstat) is important because normally, these patients who are transfusion dependent “have very few options” meaning that they “often cycle through available therapies”. Therefore, authorisation of the therapy provides an innovative new option for patients.

IMerge Phase III trial results

FDA based its decision on findings from the IMerge Phase III clinical trial for the telomerase inhibitor imetelstat, published in The Lancet.

Geron shared that the rate of red blood cell transfusion independence (RBC-TI) for at least eight consecutive weeks in patients given RYTELO was 39.8 percent. The rate in patients given placebo treatment was 15.0 percent. The statistic for these patients given RYTELO or placebo for at least 24 weeks was 28.0 percent and 3.3 percent, respectively.

The median RBC-TI duration for 8-week responders and 24-week responders treated with RYTELO was approximately one year and 1.5 years, respectively, Geron confirmed.

The company also highlighted that exploratory analysis showed RYTELO-treated patients achieved median increases in haemoglobin of 3.6 g/dL and 0.8 g/dL in individuals given placebo treatment.