John A. Scarlett
Analyst · Charles Duncan, Piper Jaffray
Thanks, Olivia. Good afternoon, everybody. I'll begin with the updated clinical results from the Phase II trial of imetelstat in patients with essential thrombocythemia, or ET, that was presented at the European Hematology Association conference in June, and then I'll provide a brief update on the recent progress that has been reported to us by Dr. Tefferi on his investigator-sponsored trial in myelofibrosis ongoing at the Mayo Clinic. Our rationale for studying imetelstat and ET was to provide a proof of concept for further development of imetelstat in a broader range of hematologic myeloid malignancies including myelofibrosis, where there's a clear unmet medical need for a product that could be disease modifying. The updated results from the ET trial presented at EHA included data for an additional 6 months of treatment and follow-up for the 14 patients presented at the original American Society of Hematology, or ASH, annual meeting in December of last year and also included data from 4 additional patients enrolled in the trial after the data cutoff for the ASH presentation. As of the May 2013 data cutoff for EHA, the medium time on imetelstat treatment was 14 months, ranging from 3 months to 2.5 years. The updated data were consistent with the high hematologic and molecular response rates reported at ASH. In addition, since the hematologic and molecular responses were maintained in patients on treatment, imetelstat appears to have good durability of its effects on the disease. The ET trial has been closed to further patient enrollment, but we continue to treat and follow the patients previously enrolled in the trial. Long-term administration of imetelstat was generally well tolerated in this trial. There were no new safety signals observed in the 6-month update and no patients discontinued from the trial due to drug-related adverse events. On our last quarterly call, we discussed our internal investigation in the liver function test observations in the ET trial. The investigation was conducted in collaboration with external liver experts that we engaged as consultants. We have now completed the current investigation process. Based on the data from the investigation, the liver function test abnormalities do not appear to progressively worsen over time and have not resulted in any clinical sequelae. No patients discontinued to study treatment due to the liver biochemistry abnormalities. Based on the conclusions from the investigation, the external liver experts recommended no changes to the use or administration of imetelstat. I'd like to comment now on Dr. Tefferi's investigator-sponsored trial in myelofibrosis at Mayo Clinic. Because MF is also like ET, a myeloproliferative neoplasm, driven by malignant myeloid progenitor cells, we and Dr. Tefferi reasoned that imetelstat might have a similar disease modifying effect in patients with MF, and therefore, he initiated a study at Mayo Clinic late last year. His study is an open label trial in patients with intermediate or high-risk primary myelofibrosis, post-essential thrombocythemia MF or post-polycythemia vera MF. The study is designed to validate the safety and efficacy of imetelstat, as well as determine an appropriate dose and schedule for further evaluation. The primary end point is overall response rate, which is defined by the proportion of patients who are classified as responders according to the International Working Group for Myelofibrosis Research and Treatment, or IWG, criteria. This means that they have achieved either clinical improvement, a CI, partial remission, a PR, or complete remission, a CR. Secondary endpoints for this study include reduction of spleen size, transfusion independence, safety and tolerability. Dr. Tefferi has provided the following communications to us regarding the enrollment status of this MF trial. First, enrollment of the first 11 patients in which the dose of imetelstat was given once every 3 weeks was completed at the end of March 2013. Second, enrollment of the second cohort of 11 patients in which Dr. Tefferi increased the dose intensity of imetelstat to levels similar to those used in ET trial was completed at the end of May of this year. Third, in both cohorts, the prespecified criteria in the clinical protocol of at least 2 responders according to IWG criteria were met and enabled expanded enrollment into those cohorts. In addition, Dr. Tefferi has communicated to us that the Mayo Clinic Institutional Review Board has recently approved a protocol amendment to add a new cohort of 11 patients with MF that has transformed into acute leukemia known as blast-phase MF. Blast-phase MF is largely refractory to the conventional induction chemotherapy that is used for acute myelogenous leukemia. As a consequence, these patients have a dire prognosis with a median survival of less than 6 months and are in great need of novel and effective therapies. We continue to be pleased of the progress that Dr. Tefferi has made and expect that data from the study will positively enable us to design and initiate a Geron-sponsored multi-center study in MF. We believe that the diseases such as MF and possibly acute myelogenous leukemia, or AML, and myelodysplastic syndrome, or MDS, represent the greatest value-creating opportunity for Geron because many patients have significant unmet medical needs and unlike existing therapies, we believe imetelstat has the potential to be a disease-modifying treatment. Before we move on to questions, I would like to comment that because the MF study is ongoing and because the intention is for a mature data set to be presented at an appropriate peer-reviewed medical conferences in the future, we're not going to comment further today on any safety or efficacy observations from Dr. Tefferi's ongoing IST. So with that, operator, let's open the call to questions.