Jonathan Zalevsky
Analyst · Barclays. Your line is open
Thank you Howard. Let me begin with a quick review the bempeg data from the PIVOT-02 melanoma cohort presented at SITC. As Howard noted, we reached the median PFS of 30.9 months. Overall response rate was 53%, with 34% of patients achieving a complete response. Importantly, we have also observed a median depth of response at 78.5%. Our results are notable when you look at historical data from published literature for depth of response for single-agent nivo and ipi/nivo, which were 35% and 52%, respectively. As we have discussed before, an FDA meta-analysis of melanoma trial has shown the depth of response in target lesions highly correlates with improved PFS and OS. And indeed with our median PFS of 30.9 months, we have observed a correlation very consistent with the FDA meta-analysis. We have not yet reached a median overall survival for this cohort. But as Howard stated earlier, our landmark OS at two years was substantially better than historical rates recorded for the current standards of care in this setting, nivo as well as ipi/nivo. The data reinforces our confidence as we advance our ongoing trials for bempeg, including our five ongoing registrational trials and with the coming study in head and neck cancer will soon be a total of six registrational studies. Now let me start with an update on the first-line metastatic melanoma study, which is being run by our partner, BMS. As a reminder, in 2019 we received a breakthrough therapy designation for bempeg plus nivo based on the high complete response rate we observed in this setting. In the second Phase 3 study, which compares the doublet to single-agent nivo, we have three primary endpoints, overall response rate or ORR, progression free survival or PFS and overall survival or OS. The ORR endpoint was designed as a potential early submission opportunity for the bempeg plus nivo combination and the PFS endpoint was designed to support a potential full approval. As you know, BMS is running this study and we currently expect that they could have initial data from this trial available some time in the time frame of late this year or the first part of 2022. PFS is an event-driven analysis and a number of other factors, including the rate of PFS event accumulation might impact this timing. The original design of the study assumes a median PFS for the nivolumab arm to be comparable to the 6.7 months observed in the Checkmate 067 study. The next study where we expect Phase 3 data is our first-line renal cell carcinoma study. We has completed enrollment in this study and based upon our original projections for the study design and modeling of the TKI comparator arm, we project that we could reach our first interim analysis on the primary endpoint of overall survival sometime in the first half of 2022, consistent with our prior guidance. Based upon the early data generated for bempeg plus nivo in renal cell carcinoma, BMS and Nektar are taking a comprehensive approach to the development of bempeg in this indication. And as Howard stated earlier, BMS also recently initiated a Phase 1/2 study in RCC, which combines bempeg plus nivo with a TKI allows us to compare this treatment to a nivo/TKI regimen to pave the pathway for a TKI inclusive regimen in RCC for the doublet as well. With respect to the registrational study in first-line cisplatin-ineligible urothelial carcinoma, last summer we also reached our enrollment goal for this study. The study is designed to serve as a basis for a potential accelerated approval filing. As a reminder, the primary endpoints in this study are ORR and duration of response and determined by central radiology review for about 100 cisplatin-ineligible urothelial carcinoma patients who have a combined PD-L1 positive baseline score or a CPS score of 10 of lower. The duration of response is a critically important endpoint in this patient population because this endpoint was the differentiating factor that led to accelerated approvals for single-agent checkpoint inhibitors in this setting, as compared to gemcitabine/carboplatin standard of care regimen. And for this study, we are looking to achieve a median follow-up of 18 months to measure duration of response. This brings the time line for our first data from this study to the middle of 2022. We have two large Phase 3 studies that builds on our other work in urothelial carcinoma and melanoma. First, the muscle-invasive bladder cancer study, which is being run by BMS is enrolling approximately 540 patients who will receive bempeg plus nivo or nivo monotherapy for a 12-month treatment period following surgery. As this study is large, we expect the first data readouts to be in 2024. This study is also designed to serve as a confirmatory study for a potential accelerated approval in the cis-ineligible urothelial carcinoma study. Second, for the adjuvant melanoma trial, we initiated this important additional Phase 3 registrational trial in the third quarter of 2020 and the study is now actively enrolling. The trial will enroll 950 patients with a 12-month treatment period postsurgery and an endpoint of event-free survival. This study is designed to position bempeg as a standard of care for the treatment of melanoma building on the recent nivo approval in this setting. In melanoma, this study increases significantly the number of patients than can benefit from our agent. Initial data from this study is expected in 2024 as well. As Howard stated earlier, for PROPEL, our study in non-small cell lung cancer in combination with pembro, we have had great interest in the study from leading thoracic cancer treatment sites. And as we said at JPMorgan, this allowed us higher than expected enrollment in the last two months of 2020, despite COVID site challenges being faced by many companies running very early stage studies. We expect to report on the three PD-L1 expressers subgroups from the study, less than 1%, 1 to 49% and greater than or equal to 50% in the second half of this year. We anticipate having approximately 60 patients who have had two or more scans spread across these subgroups. This study is designed to show the benefit of the bempeg plus pembro doublet compared to historical response rates achieved with single-agent pembro. In non-small cell lung cancer, we know that the quantity of underlying inflammation in the tumor microenvironment has a big impact on the efficacy of single-agent checkpoint inhibitors such a pembro. And indeed, the clever scientists at Merck knew this very well and created the now commonplace diagnostic paradigm for defining non-small cell lung cancer based on PD-L1 expression status. The basic stratification of less than 1%, 1 to 49% and greater than or equal to 50% PD-L1 expression in the tumor biopsy essentially defined the scale of inflammation of a tumor microenvironment with patients in the greater than or equal to 50% having the greatest amount. And consequently, we see the greatest benefit of single-agent pembro in treating this patient subgroup. The mechanism of bempeg is very powerful because it targets and increases the inflammatory state of the tumor microenvironment. Bempeg achieves this by promoting T-cell infiltration, increased expression of effector cytokines, including interferon gamma and its downstream genes as well as increasing expression of PD-1 on lymphocytes and PD-L1 on tumor tissue. We are very excited to add bempeg MOA with pembro in non-small cell lung cancer and believe that the synergy of the combined mechanisms could improve the efficacy of the doublet in multiple PD-L1 expression subgroups. We also recently added a chemotherapy combo on to the PROPEL study in order to allow us to potentially include in our Phase 2 strategy the doublet with chemo option. The data from PROPEL will allow us to design a Phase 2 strategy for bempeg in non-small cell lung cancer and we are looking forward to presenting this data in the second half of 2021. For our new registrational Phase 2/3 trial in head and neck cancer, we are sponsoring this study in collaboration with Merck on the protocol. This will be a 500-patient study with overall survival as the primary endpoint. We plan to start the trial in the second half of this year. As Howard stated earlier, SFJ will fund the study and they will also help Nektar operationalize it. The trial is designed to support a potential global registration for the bempeg plus pembro doublet. It includes an interim analysis of ORR after the first 200 patients are enrolled. If the ORR passes a prespecified futility boundary, the study will continue and the remaining 300 patients will be enrolled to the Phase 3 portion of the study and all 500 patients evaluated for the primary endpoint of OS. We are very excited about the potential of this doublet to increase and deepen the response versus pembro alone in this immune-sensitive cancer, specially given the data we have seen combining bempeg plus nivo in melanoma and other immune-sensitive cancer. Historically, IL-2 has shown activity in head and neck cancer with several published studies in both the metastatic and adjuvant setting and we are very excited to develop bempeg plus pembro here. Additionally, there are limited late stage studies going on in this front line indication. And so we see this as a unique opening for us to establish the bempeg backbone as a first-line IL-2 mechanism in the head an neck cancer. And lastly before I turn to NKTR-255 and NKTR-262, I want to briefly touch on our study of bempeg in adult patients with mild COVID-19 infection. We remain on track to report data from this study by the middle of this year. As a reminder, last November, we started this Phase 1b study, which is a randomized double-blind placebo-controlled trial to evaluate safety, tolerability and PK/PD profile of single dose of bempeg given to adult patients with mild COVID-19. In this initial trial, we are enrolling up to 30 adult patients with a confirmed COVID-19 infection who have mild symptomology. And we are defining this as oxygen saturation above 93% without supplemental oxygen, a respiratory rate below 20 breaths per minute permitted the heart rate below 90 beats per minute. The trial will have three cohorts of patients with a maximum of 10 patients in each cohort. Patients are being randomized one-to-one to receive a single dose of bempeg or placebo. The primary objective of this trial are to establish the tolerability of bempeg in patients with mild COVID, evaluate the changes in immune activation over time and identify a recommended dose for the next study. As secondary endpoints, we are also tracking the need for supplemental oxygen and monitoring clinical status on 10-point ordinal scale for 30 days after bempeg administration with additional inclusion of SARS-CoV-2 serology and immune cell profiling over that time interval as well. Following the successful completion of this initial Phase 1b study, our plan is to advance development of bempeg into moderate COVID-19 patients combined with standard of care. We are considering an approach combining bempeg with a single standard of care, such as remdesivir in comparison to standard of care alone. We are hopeful that this unique approach could ultimately lead to a reduction in the severity in disease and increase recovery time as well as reduced hospitalization time for patients with moderate COVID-19 who require hospitalization and have low lymphocyte count. This would combine antiviral mechanism with the mechanism that promotes T-cell responses which we believe could helped those patients in particular who have an inability to develop proper T-cell response to the virus on their own. Moving on NKTR-262, our TLR agonist. The study is ongoing with patients being treated at the recommended Phase 2 dose in combination with bempeg or bempeg plus nivo. The population here is relapsed refractory melanoma, post checkpoint inhibitor therapy with about 20 patients per arm. This study has completed enrollment of these two cohorts and we look forward to presenting data from this study later this year. Now turning NKTR-255, our IL-15 agonist program and our next cytokine therapy in clinical development. As Howard stated earlier, the IL-15 mechanism is well recognized by the scientific community as being a robust means for engaging natural killer cell biology in the treatment of cancer. And we believe there is a potential for an agent like NKTR-255 that engages the full biology of the IL-15 pathway to be combined with a range of mechanisms in different settings. Our first clinical work focuses on ADCC combination and we have developed a clinical strategy to combine with leading ADCC in both liquid and solid tumor settings. The first with our Phase 1/2 study in patients with relapsed refractory hematologic malignancy, we reported data from the first set of patients treated with NKTR-255 at SITC 2020. NKTR-255 was shown to be biologically active and demonstrated consistent expansion of lymphocytes with durable and sustained increases in NK and CD8 T cells in this population of highly refractory patients of myeloma or Non-Hodgkin's lymphoma. We found that NKTR-255 expanded NK cells by fivefold and CD8 T cells at threefold. Moreover proliferative capacity was maintained across multiple cycles of NKTR-255 and peaked in around eight to 10 days on each cycle. We also shared case studies of two very heavily pretreated patients where disease progression was held at bay over multiple cycles of treatment with NKTR-255. Of the two patients, one had a metabolic response. In addition, we observed evidence of CD19 CAR T cell increases in one patient who was treated with NKTR-255 many weeks after CAR T therapy. We were pleased to see that NKTR-255 was well tolerated with low-grade cytokine -related AEs that were transient and easily managed and NKTR-255 exhibited a half-life of approximately 30 hours and there was no evidence of drug accumulation on this every three weeks dose administration regimen. We expect to complete the dose escalation monotherapy portion of the study in the first part of 2021 with data to be presented later this year. Once the dose escalation is complete, we will expand into several arms with approximately 20 patients per arm. The first arm will evaluate NKTR-255 as a monotherapy at the recommended Phase 2 dose for NHL patients that have previously progressed following CD19 CAR T. The second arm will evaluate NKTR-255 in combination with cetuximab in third-line or greater follicular lymphoma or low grade NHL. In the third arm, we will evaluate NKTR-255 with Darzalex Faspro in third-line or greater multiple myeloma. We entered into a drug supply collaboration with Janssen late last year for the Darzalex Faspro supply for this study. The subcutaneous form of Darzalex continues to take more share of the franchise since its approval in May of last year and we are very pleased to be working with Janssen to include Darzalex Faspro in our NKTR-255 study. Our second Phase 1/2 study is evaluating NKTR-255 in combination with cetuximab in two distinct groups of highly refractory late-line patients with metastatic colorectal cancer or head and neck cancer. We have already dosed patients in this study and we plan to enroll 80 patients in the U.S. and Europe. As you know, cetuximab has a very low response rate, about 10% or 15% in these settings. And so our goal is to improve upon that with the addition of NKTR-255. There is a high unmet of this later line setting and if we are able to demonstrate a higher response rate, we will have several potential paths forward with NKTR-255. The trial is beginning with a dose finding portion for the combination which will then be expanded into dedicated cohorts for colorectal cancer and head and neck cancer patients. We expect to have some initial data from the dose finding portion of this study later this year. I will now turn the call over to Brian to review the NKTR-358 program in more detail.