Jonathan Zalevsky
Analyst · Oppenheimer
Thanks, Brian. Let me begin today with an update on our NKTR-255 program. Our therapeutic candidate NKTR-255 is an agent that engages the full biology of the IL-15 pathway to provide functional activation and homeostatic control of IL-15 responses of immune cells, namely natural killer cells, CD8 T cells and immune memory subsets.
Now as a full agonist of the IL-15 pathway, NKTR-255 can be combined with multiple mechanisms ranging from targeted agents to cell therapies, including CAR-Ts, and even immunological checkpoints to potentially improve the efficacy of these agents.
In our early dose escalation work with NKTR-255, we have observed a consistent increase of natural killer cells as well as CD8 T cells across multiple tumor types, including multiple myeloma, non-Hodgkin's lymphoma, colorectal cancer and head and neck cancer. We have seen up to a ninefold increase in NK cells and our pharmacokinetic profile is highly predictable, allowing us to dose NKTR-255 every 3 or 4 weeks. And importantly, we see increases in NK and CD8 T cells in even the most difficult-to-treat patients, including multiple myeloma patients with compromised bone marrow, and no increase of T regulatory cells in the peripheral blood, which is another very important attribute of NKTR-255.
In April, we unveiled that our new development plan for NKTR-255 is focused on key areas of differentiation and strength for the development of an IL-15 candidate. Additionally, our plan includes leveraging external collaborations with partners to generate proof-of-concept data. The first area of focus for our development work is being conducted by our collaborators, who are combining NKTR-255 with anti-PD-L1 agent.
This past quarter, Merck KGaA initiated the JAVELIN Bladder Medley Study. This Phase II randomized, open-label study will compare avelumab combinations with 3 antitumor agents, NKTR-255, Trodelvy, and one of Merck's own anti-TIGIT therapeutic candidates in the setting of maintenance treatment for bladder cancer in patients whose disease did not progress following a platinum regimen.
As Howard stated earlier, avelumab is annualizing at about a $500 million revenue run rate in this setting. We see significant potential for NKTR-255 in this setting.
In the JAVELIN study, the NKTR-255 arm will be compared against avelumab monotherapy. The study plans to recruit a total of 252 patients, 72 patients for each of the combination arms, including NKTR-255, and 36 patients for the avelumab bladder therapy arm.
The JAVELIN study has the primary end point of progression-free survival and should provide us with clear comparative proof-of-concept data in these patients.
In the registrational JAVELIN Bladder 100 trial in the same patient population, the PFS reported for avelumab plus best supportive care was 3.7 months. The study also gives NKTR-255 a possible path in the future registrational trial in this setting based upon the strength of the data generated in this Phase II study. We expect the first potential data from the Phase II study in late 2024.
So the reason we are very excited about this study is because unlike all other PD-1 checkpoint inhibitors, avelumab is an IgG1 monoclonal antibody directed to PD-L1. And as an IgG1, it contains an Fc region at combined HER receptors on immune effector cells and act as a bridge to induce ADCC mediated tumor cell license.
All other antibodies directed to PD-1 and PD-L1 lack the ability to trigger antibody-dependent cellular cytotoxicity because they harbor a mutated Fc region or belong to the IgG4 subclass.
The scientific hypothesis is that NKTR-255 will synergize with avelumab by both generating cytotoxic CD8 effector memory cells as well as by generating NK cells to enhance the unique ADCC effect of avelumab. With this dual mechanism of action augmenting the immune response and triggering ADCC, our unique combination has the capability to engage both the innate and adaptive immune response.
Our second study of NKTR-255 combined with an anti-PD-L1 agent is a single site collaboration trial being conducted at MD Anderson Cancer Center in the clinic of Dr. Steven Lin. The study, which plans to enroll 30 patients or combine NKTR-255 with durvalumab, also known as IMFINZI, in its approved indication of Stage II to Stage III non-small cell lung cancer following chemoradiation. And this is important because we know that many of these patients experience lymphopenia following chemoradiation. And this is associated with inferior progression-free survival. With the addition of an IL-15 stimulatory mechanism, we believe we have the opportunity to overcome this effect. The study will assess activity of the doublet and we expect the initial data in early 2024.
The second area of focus for our development work is to pursue NKTR-255 as a cell therapy potentiator in the broad and developing landscape of cell therapy. Now since their first approvals in 2017, a usage of chimeric antigen receptor T cells, or CD19 CAR-T therapy, has grown significantly in the B-cell lymphoma treatment landscape. Although these therapies offer great treatment benefit for those DLBCL patients who fail first- or second-line treatment, clinical responses to CAR-T tend to relapse over time for many patients. So there is both a high unmet need to provide an extended duration of response as well as to drive to a higher frequency of complete responses.
Preclinical data generated with the Fred Hutchinson Cancer Center has demonstrated the promise of combining NKTR-255 with CD19 targeted CAR T-cell therapies. At ASH 2019, the addition of NKTR-255 to a CD19 targeted CAR T-cell regimen in preclinical models of B-cell lymphoma was shown to increase survival of CAR-T cells and reduce tumor growth as compared to either treatment alone. And at EHA 2019, researchers showed that in vivo treatment with NKTR-255 and CAR-T cells resulted in rejection of a tumor reach out.
So based on these findings as well as data that we presented at ASH last year in relapsed patients, which showed an increase in baseline CAR-T cell levels after NKTR-255, and as Howard said earlier, we are highly focused on initiating a Nektar-sponsored study of NKTR-255 combined with approved CAR-T therapy.
The goal of this study is to generate comparative data with NKTR-255 or CAR-T versus placebo plus CAR-T in this setting, and our work here could enable future potential registrational trials. Since our announcement in April, we have held an advisory clinical board meeting to discuss the role of NKTR-255 or CAR-T therapy and to discuss the study design. We left that meeting with a lot of enthusiasm from the investigators, and we are on track to complete the study design and initiate the study by the first quarter of 2023. And based on this timing, we are expecting initial data for the third quarter of 2024.
We already have 2 studies underway with external collaborators to evaluate NKTR-255 in combination with CAR-T therapy. The first study is sponsored by Dr. Crystal Mackall, who is the founding Director of the Stanford Center for Cancer Cell Therapy. Stanford is combining their proprietary CD19/CD22 bispecific CAR T-cell therapy with NKTR-255 in patients with relapsed or refractory acute lymphoblastic leukemia. Although the CR rate is [ hopped ] with this therapy, there is a high rate of relapse and a short duration of response as well as a short median PFS. Our goal is to evaluate whether NKTR-255 can extend the duration of patient CRs with this regimen.
The study plans to enroll 24 patients. Recruitment for this IST is well underway, and we are looking forward to sharing results from the first several patients in the study around the end of this year or the early part of next year.
The second study is being conducted by Dr. Cameron Turtle's lab at the Fred Hutchinson Cancer Center. The Hutch is combining NKTR-255 with BREYANZI, or liso-cel, an approved CD19 CAR T-cell therapy in 24 relapsed or refractory large B-cell lymphoma patients. We expect to have results from the first several patients in the study in the first part of 2023.
The third and final areas of focus for NKTR-255 are our Nektar-sponsored ADCC combination studies underway with NKTR-255. We have 2 studies ongoing in liquid and solid tumors in combination with ADCC antibodies. We are planning to present data from the dose escalation portion of the liquid tumor study later this year at ASH.
Now turning to our preclinical research programs. We are cultivating our research pipeline with a near-term focus on biological programs that have applications in oncology and autoimmune disease. The first program we are working on, NKTR-288, is a PEG conjugate of the protein interferon gamma. This molecule is designed as a site-specific conjugated PEG to protein in order to modify binding of interferon gamma with one of its substrates, and overall, to greatly optimize the pharmacodynamic duration of interferon gamma signaling. This program has application in a number of potential indications, including oncology as well as infectious diseases and others. We are progressing this program and in addition to our internal work, will explore collaboration opportunities to bring this program into the clinic.
Our second preclinical program targets tumor necrosis factor receptor 2, or TNFR2, and is being developed in a collaboration with Biolojic design.
The antibody engineering capabilities of Biolojic are especially useful for the design of [ pepito ] specific antibody-based agonists. And so we are working together with them on a novel and unique bivalent agonistic antibody targeting TNFR2.
TNFR2 is highly expressed on T regulatory cells, neuronal cells and endothelial cells, and TNFR2 agonism has been shown to potentiate the suppressive effect and overall functional properties of Tregs, and if absent is associated with CNS autoimmunity and its presence has been associated with protective effects for neuronal cells as well as other cell populations and tissues in the body. We expect to choose a candidate for IND-enabling studies by year-end.
Our third program, which was invented in our research laboratories at Nektar, is also a novel biologic candidate that focuses on immune cell populations that participate in tissue repair and tissue protection. This program uses polymer engineering to modify a non-lymphocyte targeting cytokine. And we are excited about the applications for this candidate as well. And we are looking forward to keeping you updated on our progress as these programs mature.
And with that, I will turn the call over to Jill for a review of our financial guidance.