Geron Receives Review Data For Two Imetelstat Trials

Geron Corporation (NASDAQ:GERN) announced the completion of second internal data reviews for the Imetelstat trials in lower risk myelodysplastic syndromes and relapsed or refractory myelofibrosis, conducted by Janssen Research and Development.
As quoted in the press release:

For IMerge, the benefit/risk profile of imetelstat in the treated patients supports continued development in lower risk myelodysplastic syndromes. A data package and proposed trial design refinements are planned to be provided to the FDA. For IMbark, the current results suggest clinical benefit and a potential overall survival benefit associated with imetelstat treatment in relapsed or refractory myelofibrosis; the trial will continue unchanged to evaluate maturing efficacy and safety data, including an assessment of overall survival.
IMerge
IMerge (NCT02598661) is a Phase 2/3 clinical trial evaluating imetelstat in transfusion dependent patients with Low or Intermediate-1 risk MDS who have relapsed after or are refractory to prior treatment with an erythropoiesis stimulating agent (ESA). The clinical trial is in two parts: Part 1 is a Phase 2, open-label, single-arm design in approximately 30 patients and Part 2 is designed to be a Phase 3, randomized, controlled trial in approximately 170 patients. The primary efficacy endpoint is the rate of red blood cell transfusion independence lasting at least 8 weeks. Key secondary endpoints include the rates of red blood cell transfusion independence lasting at least 24 weeks and hematologic improvement. Part 1 of the trial is fully enrolled.
The second internal review of IMerge included data from the approximately 30 patients enrolled in Part 1. Based on this second internal review, the Collaboration’s Joint Steering Committee has determined the following:

• The safety profile was consistent with prior clinical trials of imetelstat in hematologic malignancies, and no new safety signals were identified.
• The benefit/risk profile of imetelstat, including assessments of 8-week and 24-week transfusion independence and hematologic improvement by erythroid (HI-E) response, across multiple MDS sub-types, supports continued development in lower risk MDS.
• Part 1 of the trial will continue unmodified, and patients remaining in the treatment phase may continue to receive imetelstat.
• A data package, as well as proposed refinements to the trial design for Part 2 of IMerge, is planned to be provided to the FDA.
• Data from Part 1 are expected to be submitted for consideration for presentation at a medical conference in the future.

Geron expects that FDA feedback and the totality of imetelstat program information, including an assessment of the evolving treatment landscape in MDS and the potential application of imetelstat in multiple hematologic malignancies, will inform Janssen’s decision to initiate Part 2 of IMerge. If Part 2 of IMerge is initiated, Geron expects this Phase 3 stage of IMerge to be opened for patient enrollment in the fourth quarter of 2017.
IMbark
IMbark (NCT02426086) was originally designed as a Phase 2 clinical trial to evaluate two dose levels of imetelstat (either 4.7 mg/kg or 9.4 mg/kg administered every three weeks) in approximately 200 patients with Intermediate-2 or High risk MF who have relapsed after or are refractory to prior treatment with a JAK inhibitor. The co-primary efficacy endpoints for the trial are spleen response rate (≥35% reduction of spleen volume assessed by imaging) and symptom response rate (³50% reduction in Total Symptom Score) at 24 weeks.
The second internal review of IMbark included data from the approximately 100 patients who were enrolled in the trial, with each dosing arm analyzed separately. Based on this second internal review, the Collaboration’s Joint Steering Committee has determined the following:

• The safety profile was consistent with prior clinical trials of imetelstat in hematologic malignancies, and no new safety signals were identified.
• The data support 9.4 mg/kg as an appropriate starting dose for the relapsed or refractory MF patient population.
• In these relapsed or refractory MF patients treated in the 9.4 mg/kg dosing arm, the spleen volume response rate observed to date was less than that reported in front-line MF patients treated in trials with other drugs. However, activity within multiple outcome measures was observed with imetelstat treatment, which suggests clinical benefit in this relapsed or refractory MF patient population. These outcome measures included a range of spleen volume reductions, decreases in Total Symptoms Score, and improvements in hematologic parameters, such as anemia and peripheral blood counts. In addition, the data suggest a potential overall survival benefit associated with imetelstat treatment in these patients.
• The trial will continue without any modifications, including conduct of all safety and efficacy assessments as planned in the protocol, including overall survival. Patients remaining in the treatment phase may continue to receive imetelstat.
• Enrollment of new patients to the trial will remain suspended because the total number of patients enrolled to date is adequate to assess longer-term outcome measures when the data are fully matured.

During the next year, Geron expects Janssen to evaluate maturing efficacy and safety data from the trial, including an assessment of overall survival. Geron expects the longer-term data from the trial, potential health authority feedback, and the totality of imetelstat program information, including an assessment of the evolving treatment landscape in MF and the potential application of imetelstat in multiple hematologic malignancies, including MDS, will inform Janssen’s decision whether to continue development of imetelstat in relapsed or refractory MF.
About Imetelstat
Imetelstat (GRN163L; JNJ-63935937) is a potent and specific inhibitor of telomerase that is administered by intravenous infusion. This first-in-class compound, discovered by Geron, is a specially designed and modified short oligonucleotide, which targets and binds directly with high affinity to the active site of telomerase. Preliminary clinical data suggest imetelstat has disease-modifying activity by inhibiting the progenitor cells of the malignant clones associated with hematologic malignancies in a relatively select manner. Most commonly reported adverse events in imetelstat clinical studies include fatigue, gastrointestinal symptoms and cytopenias. Imetelstat has not been approved for marketing by any regulatory authority.
About the Collaboration with Janssen
On November 13, 2014, Geron entered into an exclusive worldwide license and collaboration agreement with Janssen Biotech, Inc., to develop and commercialize imetelstat for oncology, including hematologic myeloid malignancies, and all other human therapeutics uses. Under the terms of the agreement, Geron received an upfront payment of $35 million and is eligible to receive additional payments up to a potential total of $900 million for the achievement of development, regulatory and commercial milestones, as well as royalties on worldwide net sales. All regulatory, development, manufacturing and promotional activities related to imetelstat are being managed through a joint governance structure, with Janssen responsible for these activities. The joint governance structure includes a Joint Steering Committee with equal membership from both companies.
About Geron
Geron is a clinical stage biopharmaceutical company focused on the collaborative development of a first-in-class telomerase inhibitor, imetelstat, in hematologic myeloid malignancies. For more information about Geron, visit www.geron.com.

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