Reshma Rangwala
Analyst · Jefferies. Please go ahead
Thank you, Sohanya. Before I go into more detail on select programs, I would like to highlight how we have been working to optimize the dose of selinexor and how it relates to our ongoing clinical development programs on slide 10. As Sohanya mentioned due to the growing confidence among physicians in using the lower once-weekly dose of XPOVIO-based triplet regimens, both the patient and physician experience, as well as adherence is improving. Since XPOVIO is launched in 2019, we have utilized real-world experience coupled with observations from our clinical trials to demonstrate that lower doses of selinexor can optimize the patient benefit by improving its tolerability, which will ultimately allow patients to remain on therapy longer improving their overall benefit. As a result all of our ongoing clinical trials incorporate selinexor doses at 40 milligrams to 60 milligrams weekly, which is a quarter to less than half of the originally approved dose of 80 milligrams twice weekly. Such dose optimization will further enable our opportunity to accelerate new approvals in the next two to four years. On slide 11, I would like to highlight the advancements we have made in our development pipeline, which include initiation of the Phase 3 EC-042 trial in women with endometrial cancer and completion of enrollment in the Phase 1 portion of the MF-034 trial. In our eltanexor program, we have stopped enrollment on the Phase 1 combination trial in treatment-naive MDS, so that we can reevaluate the combination regimen. We have completed enrollment in the interim analysis in our relapsed refractory program and are awaiting for overall survival data to mature. Now as we turn to slide 12, I would like to discuss the unmet need in endometrial cancer and why we find this opportunity so exciting for women. Endometrial cancer is the most common form of gynecologic cancer in the US with approximately 50% of advanced and recurring tumors classified as TP53 wild-type. Second, the current treatment landscape for advanced or recurrent endometrial cancer consists of a first line chemotherapy. Upon completion of chemotherapy, the NCCN guidelines recommend a watch and wait approach until disease progression. This approach clearly needs improvement given that the five-year survival rate in this patient population is only 17%. The selinexor is administered orally and maintenance therapy is well-established in other cancer types, we believe selinexor has the potential to offer a maintenance option that could sustain the response from chemotherapy and improve the overall clinical benefit for these patients. Please turn to slide 13, presented at ASCO 2022 with the subgroup analysis and molecular classification data from the SIENDO study, evaluating selinexor in endometrial cancer as a maintenance therapy. As previously disclosed this analysis indicated that patients whose tumors were TP53 wild-type and treated with selinexor, demonstrated a median progression-free survival of 13.7 months compared to 3.7 months for patients treated with placebo. In contrast, patients whose tumors were either TP53 mutant or aberrant when treated with selinexor demonstrated a median PFS of 3.7 months compared to 5.6 months for patients treated with placebo. These data suggest that TP53 wild-type has the potential to be a robust biomarker and selinexor may provide a meaningful benefit to patients with TP53 wild-type endometrial cancer. We are very encouraged by the hypothesis generating data gained from our SIENDO study and are eager to study selinexor further in the TP53 wild-type population. As you can see on slide 14, we are excited to announce that we have initiated the Phase 3 maintenance study designed to evaluate the efficacy and safety of selinexor in TP53 wild-type patients with stage four or recurrent endometrial cancer and expect to dose the first patient in the fourth quarter. This study will utilize Foundation Medicine's tissue based next-generation sequence test to identify patients and enroll approximately 220 women whose tumors are TP53 wild-type. Patients will be randomized in a one-to-one manner to receive either once weekly selinexor at a dose of 60 milligrams or placebo. The study's primary endpoint is progression free survival with the key secondary endpoint of overall survival. The study is a collaboration between Karyopharm and ENGOT, the European Network for Gynecological, Oncological Trial Groups and GOG, the Gynecology Oncology Group. Data from this study are expected in 2024 and could represent a paradigm shift for women with endometrial cancer. If you would now turn to slide 15, I would like to highlight our rapidly advancing myelofibrosis program in the current treatment landscape. Ruxolitinib is the current standard of care for newly diagnosed myelofibrosis. However, only approximately 40% of patients respond to frontline treatment. Once patients stop responding the expected median survival is approximately 14 months and the five-year survival rate is only 18%. There is a clear unmet need for a novel new mechanism both in the front line and relapsed refractory setting as no other drug classes other than JAK inhibitors have been approved in the last 10 years. Selinexor has the potential to be a convenient safe and effective oral treatment for frontline and relapsed refractory patients. As seen on slide 16 as a novel agent targeting XPO1, selinexor has the potential to mediate relevant factors beyond the JAK-STAT pathway, which can enhance or complement the efficacy of JAK inhibitors and can also serve as a single agent in JAK resistant cells. On slide 17, the Phase 2 ESSENTIAL study evaluated single-agent selinexor in patients who received prior JAK one or two therapies. 40% of patients achieved a spleen volume reduction of 35% or greater following at least 24 weeks of treatment. The two-year probability of survival was 92%. To put these data into context, currently available therapies in a similar patient population lead to a spleen volume reduction of 35% or greater in only approximately 15% of patients. Furthermore in the ESSENTIAL trial, we observed positive impact from hemoglobin levels including 50% of patients achieving either stable or improved hemoglobin levels or transfusion independence, as well as hemoglobin increases by at least two grams per deciliter in 65% of patients, contrast this with other approved agents in which anemia often worsens on therapy. In this study, selinexor was generally well tolerated with a median treatment duration of 11 months. Although the ESSENTIAL study is small and the data are still preliminary, the results build on compelling non-clinical and pre-clinical data by demonstrating monotherapy activity and highlights the potential of this novel class of therapy to improve outcomes including durable spleen volume reduction and maintaining or even improving hemoglobin levels. Turning now to slide 18, we continue to enroll on our most advanced myelofibrosis study the ongoing Phase 2 MF-035 study and we look forward to reporting our top-line results in the second half of 2023. This study is a randomized open-label study evaluating single-agent selinexor versus physician's choice therapy in patients with myelofibrosis who have had at least six months of prior treatment with a JAK1/2 inhibitor. The primary objective of this study is to assess SVR35 and key secondary endpoints include TSS50, ORR, OS, anemia response and safety. Turning now to slide 19; here is our frontline myelofibrosis study a Phase 1 study evaluating the combination of selinexor and ruxolitinib in patients with treatment-naive myelofibrosis. In this study we completed enrollment of the Phase 1 portion in dose 24 patients. Our objectives for this study are to explore the combination of selinexor and ruxolitinib building on the single-agent activity of both of these compounds. Given the potential synergism between these two drugs we believe that the combination of selinexor plus ruxolitinib has the potential to improve upon key efficacy parameters including rapid spleen reduction, symptom improvement hemoglobin stabilization and overall survival. We are looking forward to advancing this combination into the registrational portion. Turning to slide 20; I am delighted to share updated results published in the ASH abstract earlier today. Based upon July data cut 79% of evaluable patients achieved a 35% or greater spleen volume reduction at week 12 and 86% of the valuable patients achieved a 35% or greater spleen volume reduction at week 24. In addition, 69% of evaluable patients achieved a 50% or greater reduction of their Total Symptom Score at week 12. And finally, 65% of transfusion independent patients for at least eight weeks of treatment maintained stable hemoglobin or improved hemoglobin levels at last follow-up. These results are notable given that the Grade 3/4 anemia rates observed with the combination were only 21% compared to the 45% observed with ruxolitinib alone. The combination of selinexor and ruxolitinib was generally well tolerated and had a manageable safety profile with the most common reported Grade 3/4 adverse events being thrombocytopenia, anemia and neutropenia. The hematologic adverse events were reversible with dose interruptions and reductions that occurred with both ruxolitinib and selinexor. Current observations suggest that the rates and grades of adverse events are dose-dependent. In light of the meaningful impact, we are seeing in patients across all relevant efficacy parameters combined with the manageable safety profile our investigators are very encouraged and enthusiastic about the potential of this novel combination for treatment-naive myelofibrosis patients. We look forward to presenting further updated results at ASH with a longer follow-up in additional patients in the 40 milligram dose arm. We will be hosting a webcast at ASH to discuss these data with investors. With that I'll now advance to slide 21 and turn the call over to Mike to review the third quarter financial highlights. Mike?