Jonathan Zalevsky
Analyst · Goldman Sachs. Your line is open
Thank you, Howard. Starting off with our lead immunology program, REZPEG. As Howard stated earlier, this program is uniquely positioned as the most advanced IL-2-based Treg mechanism in the clinic and has potential in multiple autoimmune diseases, including our current focus areas of atopic dermatitis and alopecia areata. Last month, Dr. Jonathan Silverberg presented compelling data for REZPEG from the Phase 1b trial in atopic dermatitis during a late-breaking abstract session at the 2023 EADV congress. This presentation of the final study results for that trial highlighted the potential of REZPEG for the treatment of atopic dermatitis. Through the 12-week induction period, REZPEG demonstrated dose-dependent efficacy across both physician-assessed and patient-reported efficacy measurements, reaching statistical significance across many of these measures. Importantly, we are encouraged by the extended durability seen for REZPEG, long after the completion of the 12-week induction period. Many patients maintain durable disease control for an additional 36 weeks after the end of dosing. And this type of extended disease control after the end of dosing is not observed for Dupilumab or for JAK inhibitors. Time to response was rapid with over 40% of atopic dermatitis patients, achieving EASI 75 by week three after only two doses of REZPEG at the highest dose level. REZPEG's rapid onset of action, rivals that of JAK inhibitors, which have outperformed Dupilumab in head-to-head studies to date in this regard. Durability of the EASI 75 response was also observed with approximately 70% of EASI 75 responders maintaining their response for 36 weeks after the end of the 12-week induction period. This is a very exciting result and suggests that REZPEG has the potential to be the first immunotherapy for atopic dermatitis. Additionally, REZPEG was well tolerated and treatment with REZPEG did not induce antidrug antibodies in patients, which has been reported with some examples in the IL-2 mutein class. Compared with placebo, there were sustained increases in absolute numbers of circulating total and CD25bright Tregs in the REZPEG treatment arms. The big increase in CD25bright Treg number was tenfold above baseline at the highest REZPEG dose group. Despite a shorter than typical induction period of 12 weeks, as compared with a 16- to 24-week induction period for most other biologics, there were clear improvements for all efficacy endpoints, including EASI scores, the vIGA, BSA, Itch-NRS, DLQI and POEM. These improvements begin as early as weeks two to four and continue through week 12 of treatment. To give you some perspective, with historical studies in atopic dermatitis at the lower dose level of REZPEG, the improvements we saw were similar to those observed for biologic therapy. And at the higher dose level, REZPEG demonstrated a comparable activity to those reported with JAK inhibitors. The 83% improvement in EASI score for baseline observed that only 12 weeks of induction with REZPEG was superior to what was seen in the Dupilumab studies after 16 weeks. These promising data have us and KOLs very enthusiastic about the potential for long-lasting responses and the frequent maintenance dosing with REZPEG in the setting of atopic dermatitis. The results we have obtained so far with REZPEG are significant for a number of reasons. Firstly, before this work was conducted, relatively little was known about the ability to restore Treg function to reverse immunological pathogenesis and improve the severity of dermal or cutaneous diseases. Now with REZPEG and its Treg mechanism, we have demonstrated clinical efficacy against the cutaneous manifestations of lupus, psoriasis and atopic dermatitis. These results begin to validate the Treg mechanism for the treatment of multiple pathologies of the skin. REZPEG's attractive mechanism employs the body's own immune system to restore tolerance by inducing the Treg pathway and presents a novel approach differing from the available broad or targeted strategies to block inflammatory pathways in dermal diseases such as atopic dermatitis. Secondly, our hypothesis is that administration of the agonist drug REZPEG, induces Treg expansion and engages multiple immunoregulatory mechanisms to facilitate immune tolerance and regulation by attenuating Th1, Th2 and Th17 effector T cells, suppressing antigen-presenting cell activity and fostering tolerogenic dendritic cells. We believe this science translate to the durability of response we observed in the atopic dermatitis trial and is the differentiating element that allows us to pursue in every three month dosing regimen in our ongoing Phase 2b atopic dermatitis study. Biologically speaking, REZPEG through its central pathway of Treg rescue is uniquely poised to address the diversity of immunopathology, giving a broad potential for targeting multiple dermal diseases, including atopic dermatitis, alopecia areata and others. In October, we initiated the Phase 2b study of REZPEG in biologic-naive atopic dermatitis patients. Our goal is to enroll roughly 400 patients with three different regimens of REZPEG versus placebo, evaluated over a 16-week induction period. After the induction period, patients that meet a threshold to advance from induction to maintenance will be rerandomized into one of two maintenance regimens at different dosages at either once a month or once every 3-month dosing schedule that will continue for another 28 weeks. We expect this study will take approximately 54 weeks to conduct, and we expect data in the first half of 2025. We also plan to initiate a Phase 2b study of REZPEG and alopecia areata later and early next year. Alopecia areata is an indication with a high clinical unmet need for a biologic as the only approved agents or JAK inhibitors, which come with a black box warning and lack durability after cessation of dosing. For these reasons, we believe there's an opportunity for REZPEG to become a novel biologic therapy in alopecia areata. And as I just mentioned, we believe that REZPEG and its Treg mechanism of action is great potential for addressing this indication, which is essentially a dermal disease of the scalp. Across all of our studies, with nearly 600 people treated, REZPEG demonstrates a consistent and highly predictable Treg cell pharmacodynamic profile in different autoimmune disease pathologies and even in healthy volunteers. Taken together, we believe there is strong rationale for REZPEG for the treatment of alopecia. The Phase 2b study plans to recruit roughly 80 patients with moderate-to-severe alopecia that will be randomized to REZPEG or placebo. As Howard mentioned, while it was previously our plan to run a Phase 2a trial with roughly 40 patients after reviewing historical trials in this indication, we decided to increase the size of our study to achieve a Phase 2b design at minimal incremental cost. Patients will be treated for a period of 36 weeks and observed up to 48 weeks in total. Our primary endpoint for this study is mean percent improvement in salt or the severity of alopecia tool at week 36, which is very standard in the field. We will also be looking at a number of other secondary endpoints, including proportion of patients who saw a reduction in salt. Now turning to our lead immunology research program, a TNFR2 agonist antibody program. TNFR2 is highly expressed on Tregs, neuronal cells and others, and TNFR2 agonism has been shown to potentiate the suppressive effect in overall functional properties of Tregs. If TNFR2 is absent, it is associated with autoimmunity and other genetic conditions resembling FoxP3 loss of function. In contrast, its presence has been associated with immunoregulatory function and protective effects for multiple cell populations and tissues in the body. Building upon what we know the potential of regulatory T cell mechanisms, this makes this program incredibly exciting to us. Nektar has identified two lead antibodies that we have now validated for selected TNFR2 binding, cell type specificity in TNFR2 agonism in primary human cell-based assays. We believe that a selective TNFR2 agonist holds great promise for the treatment of multiple autoimmune diseases and are aggressively pursuing this program and on track to submit our IND in 2024. And now I'd like to turn the call over to Mary to provide a brief update on our NKTR-255 program in oncology and our recent collaboration with CBMG. Mary?