John A. Scarlett
Analyst · Stiefel
Thank you, Olivia, and good afternoon, everyone, and thank you for dialing in to our call. As you all know, our IND for imetelstat is presently on full clinical hold, which affected the ongoing company-sponsored studies and has resulted in the remaining patients in the ET and myeloma trials discontinuing treatment. Another consequence of the full clinical hold in our IND is our development plans for imetelstat have been delayed. We announced in March 2013 that we did not intend to develop imetelstat for ET, but instead planned to focus our development plans on imetelstat in hematologic myeloid malignancies with a higher unmet need, such as MF. However, until the every FDA permits us to study such patients, we're unable to submit any new clinical trial protocols to the FDA under our existing IND for imetelstat and are unable to initiate any new clinical trials for imetelstat in the United States. As the basis for this hold, the FDA cited the lack of evidence of reversibility of hepatotoxicity, a risk for chronic liver injury and a lack of adequate follow-up in patients who experience hepatotoxicity. I'll discuss what we need to do to address the full clinical hold on our IND after I discuss the status of Dr. Ayalew Tefferi's investigative-sponsored trial in myelofibrosis. Dr. Tefferi's trial in myelofibrosis, which we call the Myelofibrosis IST, is being conducted at Mayo Clinic under an investigator-sponsored IND, which is separate from Geron's IND. This trial was placed on a partial clinical hold by the FDA shortly after our IND was placed on full clinical hold. The partial clinical hold means that no new patients may be enrolled into the Myelofibrosis IST. The patients who are currently enrolled and were deriving clinical benefit may continue to receive treatment with imetelstat. Dr. Tefferi had already ceased enrolling new patients in Myelofibrosis IST in January 2014, having enrolled approximately 79 patients. This number included 9 patients with blast-phase MF and 9 patients with a subtype of myelodysplastic syndrome or MDS, known as refractory anemia with ringed sideroblasts or RARS. In their notice to us, Mayo Clinic did not indicate that its decision to cease enrollment in the Myelofibrosis IST was due to any concerns regarding efficacy or safety. According to Dr. Tefferi, just prior to the partial clinical hold, 45 patients remained in the study. The reason cited by the FDA for the partial clinical hold on the Myelofibrosis IST was that a safety signal of hepatotoxicity has been identified in clinical trials of imetelstat and that it was not known if this hepatotoxicity is reversible. In order to resolve the partial clinical hold on the Myelofibrosis IST, Dr. Tefferi is required to provide the FDA with follow-up liver function test, or LFT, information for all patients who received imetelstat in the Myelofibrosis IST. For patients who did not experience any LFT abnormality, LFT follow-up data needs to be obtained until 30 days after the last imetelstat dose. For patients who experienced any LFT abnormalities, follow-up LFT data must be obtained until resolution to baseline or to within the normal range for at least 2 consecutive determinations. Dr. Tefferi has informed us that he and the team at Mayo Clinic are working to compile and analyze this LFT data and that they intend to submit the LFT data and their analysis of those data to the FDA to address the partial clinical hold. At some point after Mayo submit their data package to the FDA, we expect to have access to the contents of that submission. But investors should not expect an update as these are Mayo's, and not Geron's data. We would expect to inform investors if and when the FDA takes action on Dr. Tefferi's IND. Dr. Tefferi has also informed us that he intends to submit several abstracts for presentation at the 2014 annual meeting of the American Society of Hematology scheduled for December of this year. The first is expected to include updated follow-up efficacy and safety data from the imetelstat-treated patients with myelofibrosis that he reported at last year's ASH meeting, as well as data from additional myelofibrosis patients who had been subsequently treated with imetelstat in his IST. An abstract with data from the MDF's RARS patients treated with imetelstat in his IST and an abstract with data from patients from blast-phase MF treated in his IST are also planned. I'd like to switch back to our IND and our plans for further development of imetelstat. To address the full clinical hold on our IND, we are required to provide the FDA information regarding a reversibility of liver toxicity after chronic administration in animals, and to provide clinical follow-up information in patients who experienced LFT abnormalities until these have resolved to normal or baseline. To address the non-clinical information, we have reviewed data from our non-clinical toxicology studies of long-term administration of imetelstat in animals that were conducted previously. These studies included a 6-month study in mice and a 9-month study in cynomolgus monkeys. In these studies, no consistent biochemical LFT abnormalities were identified as being associated with imetelstat treatment. In light of the clinical hold, we have had the results of these studies reexamined by 2 external, non-clinical toxicology experts, one of whom has specific expertise in all nucleotides and oncology products. This review has confirmed that there were no clinical or pathologic changes that would indicate having cellular injuries in the imetelstat-treated animals. We are currently assessing whether we can identify any subtle changes in the LFTs that may be helpful in assessing reversibility of the imetelstat treatment effects in the animals after the drug was discontinued. To address the required clinical information regarding the reversibility of LFT abnormalities observed in patients treated in our ET and myeloma studies, we are currently pursuing the necessary activities to enable us to collect and analyze LFT and other information from patients who recently discontinued imetelstat due to the clinical hold, as well as the patients who had previously discontinued from these trials for other reasons. Where possible, we are committed to collecting and analyzing long-term follow-up information on LFT reversibility. However, this process is time-intensive, with some aspects that are not within our control. For example, we have amended our clinical trial protocols to allow for a longer follow-up of patients after discontinuing imetelstat. And these must be approved by the IRB of each site. In addition, an appropriate informed consent must be obtained from each of the relevant patients to permit us to collect LFT information, as well as other relevant information, such as subsequent therapies. Also, following up on all the patients is challenging because many patients have already left our clinical trials and may have returned to the care of their primary treating physicians or may be lost to follow-up for other reasons. Both the timing for submitting the requisite data and information and resolving the clinical hold on our IND are uncertain and are dependent on several factors, including the timing of obtaining clinical information and data being collected from our studies and Dr. Tefferi's Myelofibrosis IST, the results of that information and data, and possibly, on the assessment of the benefit risk profile when imetelstat is used to treat diseases, such as MF, which have a high unmet medical need. We believe there maybe multiple scenarios regarding timing. For example, if data from a subset of imetelstat-treated patients with hematologic malignancies, such as patients in Dr. Tefferi's Myelofibrosis IST, are obtained and submitted in a timely manner and adequately address reversibility of LFT abnormalities or suggest an acceptable benefit risk profile in high, unmet medical need indications, we might possibly be able to initiate a Geron-sponsored Phase 2 clinical trial of imetelstat in MF, as early as the first quarter of 2015. On the other hand, if such data are not obtained in a timely manner or are inadequate to address reversibility of LFT abnormalities or the risk of chronic liver injuries, then initiation of Geron-sponsored clinical trial with imetelstat in MF in the United States would be further delayed. At this time, it is difficult to project the possible extent of such a delay in the absence of the clinical information and data being collected from our studies and from Dr. Tefferi's Myelofibrosis IST. For that reason, we are exploring on a parallel track our options for pursuing development of imetelstat outside of the United States, starting in Europe. So with that, operator, let's open the call to questions.