Dimitry Nuyten
Analyst · Goldman Sachs. Your line is open
Thank you, Howard. I will provide a quick update on the BEMPEG program and the timing for registrational studies, which are tracking in line with our prior guidance. First, for the 760 patient Phase III first-line metastatic melanoma study which is being run by our partner, BMS. We and BMS are very much looking forward to completion of the study and future data. As Howard stated, BMS informed us in October that the study was fully enrolled. BMS has an excellent track record in melanoma, with multiple successful registrational trials for IO agents under their belt. Melanoma has proven to be a very immune-sensitive tumor setting and the promise of BEMPEG, an agent that can deepen responses and extend responses for these patients is very exciting. The BEMPEG plus nivolumab combination received a breakthrough therapy designation from the FDA in August 2019 based upon this panel in melanoma patients. If the Phase III study results are similar, we envision a unique opportunity for the BEMPEG nivolumab doublet to emerge as new standard of care in this setting. As we noted last quarter, BMS has told us they intend to conduct their first analysis of data for both ORR and PFS endpoints and a number of defense, as outlined in the statistical analysis plan for PFS endpoint are reached. Current projections from BMS indicates that this data analysis could occur in the early part of 2022. Given the breakthrough therapy designation I mentioned earlier for this indication, we believe that we would be able to move rapidly toward a regulatory filing, if warranted by the data. Of course, since PFS analysis is an event-driven analysis, a number of factors, including the actual rate of PFS defense might impact the timing of the analysis. The next study, which Nectar is running, is a 620 patient Phase III first-line renal cell carcinoma study comparing BEMPEG plus nivolumab versus a TKI agent of physician's choice, which can be either sunitinib or cabozantinib. We expect that we could reach our first interim analysis for the primary endpoint of overall survival sometime in the second quarter of 2022. BMS and Nektar are taking a comprehensive approach to the development of BEMPEG plus nivolumab in this particular tumor type. Additionally, BMS is conducting a 250-patient randomized Phase II study in RCC that combines BEMPEG plus nivolumab with Exelixis cabozantinib, which allows us to compare it to the treatment of nivolumab cabozantinib to pave the way for a TKI inclusive regimen in RCC with BEMPEG and nivolumab. Earlier this year, BMS and Nektar expanded the strategy in RCC to include a new collaboration with Exelixis, who will be conducting a study evaluating BEMPEG plus nivolumab with their novel next-generation TKI-XL92. The study will also include other geo cancers, including urothelial cancer. With respect to the Phase II study in first line eligible urothelial carcinoma, which Nektar is running, the study is designed to serve as basis for a potential filing for accelerated approval. The study includes about 110 cisplatinum ineligible urothelial carcinoma patients who have a baseline CPS score of 10 or lower as a measure of PD-L1 expression. The primary endpoint for this trial are overall survival -- sorry, overall response and duration of response as determined by central radiology review. For this study, we are looking to achieve a median follow-up of 18 months for measuring the duration of response, and we expect our first data from this study to come in the first half of 2022 as well. As Howard noted earlier, the BEMPEG nivolumab program has also large Phase III studies in muscle invasive bladder cancer and adjuvant melanoma. The Phase III periadjuvant muscle invasive bladder cancer, which is being run by BMS, is enrolling approximately 540 patients who will receive BEMPEG plus nivolumab or nivolumab monotherapy, first in a neoadjuvant setting prior to radical cystectomy and then in the adjuvant setting for a 12-month treatment period following their surgery. As this study treatment is a longer period, we expect the first data readout to be in 2024 or 2025. This study is also designed to serve as a confirmatory study for our planned potential accelerated approval in metastatic cis-ineligible urothelial carcinoma setting. Second, the Phase III adjuvant melanoma trial, which Nektar is running. This study is enrolling a total of approximately 950 patients with a 12 month treatment period post-surgery and an endpoint of recurrence-free survival by blinded independent central refuel. This study continues to rapidly enroll and as Howard stated earlier, enrollment is now ahead of schedule. As of November 1, we have enrolled 450 patients, which we believe reflects physicians' and patients' enthusiasm for the potential of BEMPEG plus nivolumab in melanoma. The adjuvant study is designed to position BEMPEG as standard of care for the treatment of melanoma, building upon the recent approval of nivolumab in this setting. Initial data from the study are expected in 2024. I will now turn to the PROPEL study evaluating BEMPEG plus pembrolizumab in non-small cell lung cancer. As Howard stated, we plan to present the initial data from PROPEL multiple cell lung cancer for patients who received the BEMPEG plus pembrolizumab doublet at ESMO-IO in December. The abstract submitted and accepted at ESMO-IO was a placeholder only and did not include any data beyond the initial evaluation. This is because at the time of the abstract submission to date, the blind independent review of the data set from PROPEL have not been completed yet. As Howard stated, we will host an analyst event around ESMO-IO, which will include the invited investigator, Dr. Daniel Johnson from the Arsenic Cancer Center, who enrolled a number of patients both in the dose escalation portion of the trial and also in the non-small cell lung cancer expansion portion of the study, and he has observed a positive experience with the doublet. As a reminder, this presentation will include data of approximately 60 to 70 patients with squamous or nonsquamous non-small cell lung cancer. The patients are spread across 3 separate PD-L1 expression subgroups. The study was designed as a single-arm study to evaluate the benefit of the doublet compared to historical overall response rates achieved with single-agent pembrolizumab, which are well documented across 2 registrational trials. In non-small cell lung cancer, which is not typically recognized as an immune-sensitive cancer, we know that baseline tumor PD-L1 expression status dictates the expected clinical benefit of pembrolizumab. As a benchmark, we call the pembrolizumab monotherapy results in an overall response rate of approximately 8% in patients with PD-L1 tumor expression of less than 1, about 15% in patients at PD-L1 tumor expression of 1 to 49 and for patients with a PD-L1 tumor expression greater or equal to 50% single agent pembrolizumab delivers approximately an overall response rate of 40% to 45%. Although, this was an open-label study, as we have stated in the past, we determined that we should be blinded to the efficacy data until the time of completion of the blinded independent review. We recently completed database lock for the initial analysis of the study and received the aggregate efficacy data with detailed efficacy evaluation for patients in the study from the blinded independent review for the doublet in non-small cell lung cancer arms of the PROPEL study. I'd like to share some initial observations from this report ahead of the ESMO-IO Congress. First, we are pleased with a number of takeaways that reinforce for us that the additive benefit that BEMPEG provides to single-agent pembrolizumab. We observed a notable depth and duration of responses in various cohorts, including the number of patients that achieved complete responses and also patients who achieved 100% tumor volume reduction, which is not common with single agent pembrolizumab and even with the combination of chemotherapy and pembrolizumab. Because we enrolled patients prior to the completion of an independent baseline PD-L1 assessment, we overenrolled the under 1% and the 1% to 49% cohorts with approximately 28 efficacy evaluable patients for cohort versus our original targets of 20 and 18 patients, respectively. In the greater than 50% population, we had a total of 15 efficacy evaluable patients. In the under 1% or negative population for PD-L1 status, we doubled the single agent response rate for pembrolizumab. Notably, 2 of the patients in this cohort achieved 100% reduction in their resi target lesions. One patient experienced this at the first on-treatment scan. The second patient experienced this gradually over time. The median duration of response in this cohort has not been reached, and the current median depth of response is notable at 77% tumor volume reduction for the responders in this cohort. We are very pleased that we saw both the doubling and a depth of response for patients with PD-L1 negative tumors, which historically have seen limited treatment effect from a single agent checkpoint therapy. In the 1% to 49% cohort, although we had over half of the patients in this cohort achieve extended stable disease, the overall response rate was in the low single digits, which we were surprised by that result. Although we were surprised by the results, it is important to note that we did observe 3 key differences in the patient population enrolled into the 1 to 49 cohort versus the single agent pembrolizumab studies. First and most notably, we discovered that in this cohort of 1% to 49%, 25% of patients had had prior chemotherapy for either Stage 3 disease or as adjuvant treatment for stage 1 or 2 disease before coming on to the study. This was allowed per protocol with a minimum interval of 6 months. In the KEYNOTE studies, this percentage of patients, however, was much lower at 4% to 6%. Furthermore, this cohort also enrolled patients with the highest baseline median and mean tumor burden in our study, and we had a higher proportion of patients with squamous histology in this cohort as compared to the single agent pembrolizumab studies. We believe the combination of these factors might have impacted the surprising overall response rates we saw in this cohort. For the over 50% population cohort with 15 efficacy alliable patients, we are pleased to see 13% of patients experiencing a complete response with the doublet treatment. As we previously said, we did not expect to see any notable increase in overall response rate in this cohort as pembrolizumab single agent overall response rate is already pretty high and in such a small patient population. In this case, in 15 patients, the overall response rate was 40%, which we knew it could be challenging to show the difference. So our demonstrated ORR was consistent with what we expected from the trial. However, we were hopeful going into the study that we could see even in a small patient set a higher quality of responses than we typically see with single agent pembrolizumab. With several complete responses, we achieved this and the patients with complete responses continue to be responders and stay on treatment for over 1 and over 2 years, respectively. Overall, across the non-small cell lung cancer cohort, we had a median depth of response for all responders of 72%, as mentioned by blind independent review, and this too was something we had hoped to see in the study. Overall, we are pleased with the key number of observations from PROPEL. First, the overall response rate and the depth of response in the under 1% was notable. We saw a doubling of ORR in patients that respond to experience a notable depth of response. Second, across cohorts, the depth and duration of response was notable here with an overall median depth of response of 72% and a median response not yet reached. In the 50% cohort, we observed a 13% complete response rate, and this speaks to the phenomenon we have observed with BEMPEG. In other tumor types, complete responses with either chemotherapy IO or IO alone in lung cancer are not common. Notably, there were some factors that made the patients in the study overall more challenging population for treatment and the keynote studies, such as high tumor burden and prior chemotherapy for metastatic disease, most notably in the 1 to 49 cohorts. For PROPEL, we are also treating patients with a higher dose of 0.01 milligrams per kilogram of BEMPEG in combination with pembrolizumab. While the cohort is still early and ongoing, we have observed AE increases with the dose, but most patients are too early in their scan cycles to assess efficacy. We are continuing to monitor this cohort, but due to the standard of care in first-line non-small cell lung cancer, mostly being a chemotherapy inclusive backbone and the history of successful treatment of non-small cell lung cancer with chemotherapy, our development focus will be on chemotherapy combination arms in the PROPEL study to guide future development in this setting. Hence, given how well tolerated BEMPEG is at the 0.006 milligram per kilogram dose and the signal we have seen in the doublet BEMPEG is being combined with pembrolizumab and chemotherapy at the 0.006 milligram per kilogram dose. To that end, as Howard stated earlier, we also recently added a chemotherapy combination arm to the PROPEL study. We did this in order to allow us to potentially develop a registrational path that captures the appropriate standard of care for patients in the under 50% PD-L1 category. Over 70% of patients have tumors with an expression level of less than 50% and these patients mostly receive a chemotherapy inclusive regimen. IO monotherapy is uncommonly used in this setting. As we know only that also in the over 50% group only about half of the patients are receiving pembrolizumab monotherapy. The chemo combo part of the study can provide us with initial data sometime in the middle of 2022. And we will use the totality of the data from PROPEL to determine a comprehensive registrational of path for BEMPEG in non-small cell lung cancer. For our new registrational Phase II/III trial in head and neck cancer, we recently opened enrollment, and we expect to randomize our first patient before the end of the year. We have collaborations in place with both Merck and SFJ Pharmaceuticals for this study, and we are very excited about this opportunity to address a large patient population in the frontline setting. The 500-plus patient trial is designed to support the potential global registration of BEMPEG plus pembrolizumab in head and neck cancer. It includes an interim analysis of overall response rate after 200 patients are enrolled. If the overall response rate bases a prespecified futile boundary, the study will continue and the remaining 300 patients will be enrolled to the Phase 3 portion of the study. For the Phase 3 portion of -- a total of 500 patients will be evaluated for the primary endpoint of overall response rate and overall survival. Given the favorable competitive landscape, we see this as a unique opportunity for us to establish BEMPEG as first IL-2-based mechanism for the treatment of head and neck cancer. So, let me now turn over the call to JZ, who will review the NKTR-255 program and our NKTR-358 program. JZ?