Michael Kauffman
Analyst · Jefferies
Thank you, John. A critical milestone for us in the second quarter included the formal presentation of the positive BOSTON study results. As a reminder, this was the first large Phase III study in previously treated myeloma to directly compare a once-weekly triplet regimen with standard, but twice-weekly Velcade. We were thrilled that the study met its primary endpoint of a statistically and clinically significant improvement in PFS with a 47% increase in the median progression-free survival on the SVd arm as compared to the Vd arm, representing a 4.47 month improvement. The median progression-free survival in the SVd arm was 13.93 months compared to 9.46 months in the Vd arm with a hazard ratio of 0.70. SVd was superior to Vd across other key efficacy endpoints such as overall response rate, the rate of very good partial response or better and the duration of responses. The results were consistent across most of the subpopulations, including patients over the age of 65, patients who are frail, those with prior lenalidomide treatment and those with high-risk cytogenetics. Median overall survival on the SVd arm has not yet been reached, but it was 25 months on the Vd arm. Moreover, there were numerically fewer deaths on the SVd arm than on the Vd arm. We were also pleased to report the rate of peripheral neuropathy on the SVd arm was significantly lower than the rate in the Vd control arm. Remember, the peripheral neuropathy is among the most common causes of treatment limitation and discontinuation of Vd and combination Vd regimens, and a significant differentiator for the Boston regimen, pending future regulatory approval. The data also showed no new safety signals in the SVd arm relative to previously reported adverse events from other selinexor myeloma trials. In summary, we are able to conclude from the BOSTON study that in patients with multiple myeloma who have received 1 to 3 prior therapies, including prior lenalidomide or a proteasome inhibitor, once-weekly SVd offers patients an effective, convenient triplet regimen, requiring approximately 40% fewer clinic visits and a reduced rate of peripheral neuropathy, pending future regulatory approval, of course. On Slide 9, I'll provide a brief update on our key upcoming regulatory activities. Our BOSTON sNDA was accepted for filing in July with a decision expected by March 19, 2021. In Europe, we plan to submit the final additional monitoring data requested by EMA from the STORM study in patients with advanced refractory myeloma in September. We then expect to submit the BOSTON data to the EMA in the fourth quarter of this year. The exact timing of potential regulatory decisions based on both the STORM and BOSTON data will be determined following feedback from EMA. As we turn to Slide 10, I will highlight our recent accelerated approval for XPOVIO for the treatment of adult patients with relapsed or refractory DLBCL. In the SADAL study, which served as a basis for approval, XPOVIO demonstrated an overall response rate of 29%, including a complete response rate of 13%. Responses were seen in all subgroups, regardless of age, gender, prior therapy, GCB or ABC subtype or prior stem cell transplant therapy. Importantly, responses were associated with longer survival, underscoring the potential of oral XPO1 inhibition as a simple nontherapeutic option for patients with recurrent DLBCL. While we have just kicked off our commercial launch in this indication, we believe XPOVIO's product profile addresses several key treatment considerations for this difficult-to-treat disease, as displayed on Slide 11. Physicians commonly examine patient history and disease subtype, previous therapies used and treatment efficacy and durability when deciding on an appropriate treatment pathway. The simple administration, single agent and novel mechanism of action of XPOVIO provides additional advantages for use with a manageable safety profile. Next, please turn to Slide 12, where I review the updates from our COVID-19 study. Based on anti-SARS corona viral activity in vitro and anti-inflammatory activity in vitro and in vivo, Karyopharm began enrollment in a placebo-controlled randomized Phase II study to evaluate low-dose oral selinexor in hospitalized patients with severe COVID-19 in April of this year. These patients require supplemental oxygen and are at high-risk for clinical worsening. Many of them had already received remdesivir, steroids, combos and plasma and other agents used to treat COVID-19. As mentioned previously, the Data Safety Monitoring Board for the study concluded that the trial is unlikely to demonstrate a statistically significant efficacy benefit across the entire population of severe patients who were enrolled. However, they also concluded that the trial was likely to show a benefit in the subpopulation of patients who are less than 75 years old and have a COVID-GRAM non-high score which represented approximately 75% of the entire population enrolled in the study. Preliminary results from the unaudited site data indicate that in this specific sub population, on the primary endpoint for the entire study, which was a 2-point improvement in ordinal score at day 14, statistically significant results were obtained. In addition, on day 28, improvement in ordinal score by 2 points also reached statistical significance with P is less than or equal to 0.05. And very importantly, the rate of hospital discharge by day 14 was significantly higher with selinexor as compared with placebo. In other words, patients treated with selinexor stopped requiring supplemental oxygen more rapidly than those on placebo and could leave the hospital sooner. Finally, while all patients entering the study were required to have positive SARS-CoV-2 PCR results, conversion to SARS-CoV-2 PCR negative status was significantly higher on the selinexor arm as compared with the placebo arm across the entire population. Fatalities were similar in the subpopulation mentioned above. While the rate of fatalities in the study were imbalanced in the patients 75 years or older or with the COVID-GRAM high-risk score, the DSMB considered that all deaths on the study were due to severe COVID-19 disease and/or underlying comorbidities without a clear contribution of selinexor. Moving forward, and based on these data, we are following the DSMB recommendation to discontinue the current trial and plan to analyze the data to further characterize the specific subpopulation that will likely benefit from selinexor. We plan to work with the FDA and other regulatory bodies to identify a path forward for future clinical development, given these initial positive findings. Furthermore, we plan to engage with potential partners to seek external funding to advance future clinical development in COVID-19. Before turning the call over to Mike Mason, I do want to take a moment to sincerely thank all of the patients and investigators who participated in this study in support of our collective efforts to make a positive difference in the ongoing pandemic. With that, I'll now turn the call over to Mike for a review of the financials. Mike?