Anish Suri
Analyst · Stephen Willey with Stifel. Please proceed with your question
Thanks Ken and thank you to everyone listening in. I hope all of you and your families are safe and well through these times. I'd like to remind everyone of the scientific version that has underscored our focus and efforts from the very start. A vision that was centered on a singular all important question which is how does one take advantage of the selectivity and specificity of the immune response while not breaching patient safety. We believe our Immuno-STAT framework as exemplified by the CUE-100 series, as shown in Slide 9, of which Cue-101 is representative is a rational solution anchored on sophisticated protein engineering. From an elegant perspective, the best map of the landscape is the landscape itself. To that end, the landscape of T cell modulation and cancer immunotherapy can involve many elements. However, the key fundamental signals for specificity coupled with controlled activation are what ultimately govern the outcome of the immune reaction. These very core elements are incorporated into the molecular framework of the CUE-100 series. The two key signals on the 100 series as shown in Slide 9 consist of stabilized peptide HLA molecules to engage the tumor specific T cells via the T cell receptor, thereby locking in the specificity combined with rationally engineered IL-2 molecules that selectively act upon those T cells to control their activation. We believe this control mechanism is an obligatory prerequisite for T cells and cancer immunity. In other words, an absence of the appropriate anti-tumor T cell repertoire the application of a T cell modulating approach via a singular cytokine therapy like IL-2 or its variants, or antibodies targeting checkpoint molecules is likely going to be suboptimal or futile endeavor. From the earliest approval of Proleukin and IL-2 has been a validated target for T cell activation. The challenge for broad application of Il-2 has pertained to safety liabilities, due to cytokine release and vascular leakage and indiscriminate activation of immune cells in broad T cell subsets, including regulatory T cells, or Treg. We evaluated the incorporation of IL-2 in the CUE-100 series guided by structure based rational protein engineering solutions. From the very beginning, we sought to achieve two key objectives. One was to generate an IL-2 that avoids the safety liabilities, and Treg engagement properties of wild type IL-2 and two, ensuring that the IL-2 was selectively delivered to tumor relevant T cells. The output of these efforts resulted in the generation of the CUE-100 series framework, as you see here in Slide 9. The top-down view of the ribbon diagram of the Cue-100 series, as shown here provides a good contextual perspective for the spatial engagement of these molecules by tumor specific T cells. Note there are two modifications to the IL-2 molecule that are important for specificity and selectivity. The first is abrogation of binding to IL_2 receptor alpha subunit in order to avoid Treg engagement. The second modification is the attenuated binding to the IL-2 receptor beta subunit, such that the IL-2 activity is biased to those T cells that are docked to the specific peptide HLA complex via the T cell receptors or TCRs. We believe this engineered biologic framework allows us to maintain specificity and selectivity while avoiding the systemic toxicities associated with indiscriminate IL-2 dependent activation of many different cell types. And indeed, as you've heard from Ken, and as you've seen the dose cohorts, the initial clinical data sets suddenly appeared to support this thesis. Several key points should be emphasized. First we have a normal biologic scaffold that demonstrates exposure and dose proportionality in line with projections, which is highly encouraging. Furthermore, we have not seen major safety liabilities that doses were in a molar content comparison IL-2 were significantly higher than the approved dose of Proleukin. For example, at the dose level in the fourth cohort, CUE-101 has approximately eight times the molar content of IL-2 compared to Proleukin. In addition, the early PD data seems to suggest that we have activity in engaging and expanding the targeted T cells based on Tetramer and ELISpot analysis. These are early data at early time points that will be confirmed and extended as we obtain additional patient samples. But perhaps most encouraging is the composite view from the clinical experience thus far. We design a novel biologics platform that appears to possess favorable properties pertaining to drug exposure in PD and also appears to be demonstrating mono-therapy clinical activity. As we continue to obtain further supporting data from CUE-101. We are highly enthusiastic about the broad possible applications of the CUE-100 series. The data generated from CUE-101 clinical experience has the potential to de-risk the entire CUE-100 series since the core IL-2 elements coupled to the peptide HLA framework remain constant. Okay, I'd like to now move on to Slide 10 to remind you of the key features that we believe underscore the superior differentiation of the IL-2 based CUE-100 series over other IL-2 modalities that are out there. This slide has been presented before as a part of our corporate deck and highlights the important fact that the CUE-100 series can selectively deliver IL-2 to the relevant T cells that is the tumor specific T-cells, while minimizing the safety liabilities and broad effects and other types of subsets, both the Tregs and the vast majority of the non-tumor reactive, effective T cell repertoire that all of us harbor. This is in stark contrast to the not alpha IL-2 variants that minimize the activity in Tregs but still act with equal opportunity on all other T cells, the vast majority of them have no relevance to tumor specificity. Furthermore, the core framework of the CUE-100 series can prime and expand T cells from a naive T cell repertoire, as also reported in our recent publication in Clinical Cancer Research last month. While the not alpha IL-2 variants rely upon a pre-existing anti-tumor T cell repertoire that must be present within the patient to derive benefit. The next slide, Slide 11 highlights our immune-oncology development strategy to exploit the fullest potential of the CUE-100 framework. The present clinical trial with CUE-101 provides us with a foundational proof of concept in an indication of unmet medical need, and as mentioned previously, 101 is positioned to potentially de-risk the entire 100 series. We have thus positioned ourselves to maximize success for the CUE-100 series by exploiting the key strength of the Immuno-STAT platform, which is modularity and flexibility that allows us to target different tumor antigens, along with distinct HLA alleles for global patient populations. This strategic growth opportunities is exemplified from our current ongoing work with CUE-102 and beyond where we have focused on tumor antigens like Wilms Tumor 1 or WT-1 and KRAS and have initiated programs with additional alleles besides HLA-A02. These include HLA-A24 and A11, both being dominant in Asia, which was the primary reason for our LG Chem partnership for our first three programs. We have made strong progress with our CUE-102 programs and have generated pilot data demonstrating ex vivo expansion of human T cells, poly functionality and the killing of target cells. These data were recently presented at an invited talk at the frontiers in cancer immunotherapy meeting, organized by the New York Academy of Sciences on May 12. We will also look forward to other avenues and forums to disclose these promising datasets, including the upcoming AACR Virtual Conference on June 22, where we will be presenting a poster. Okay, so based upon the foundational work of our Immuno-STAT platform, we have further developed our next generation platform referred to as Neo-STAT, which greatly accelerates our scalability in generating new clinical candidates. The Neo-STAT framework specifically enhances the productivities and efficiencies, both from a time and cost perspective and builds upon a versatility to target multiple tumor antigens including post translational modifications and personalized Neo antigens in the future. The next slide, Slide 12 focuses a bit more on the Neo-STAT platform, a key intellectual leap here was to design a platform enhancement that significantly expanded the reach into diverse tumor antigens. To remind you, the current Immuno-STAT platform incorporates singular primary tumor driver antigens. This is great for examples like the HPV16, E7 protein, as in our lead molecule CUE-101 or targets like WT1 or KRAS and such. In these cases, the immune assault to a dominant human driver antigen is likely to provide meaningful clinical benefit. Indeed, with all of the examples mentioned above data from cell therapy based clinical studies utilizing either TCR T cell therapy or TIL based adoptive cell therapy have demonstrated clinical responses. However, looking into the future, we want to be positioned to capture the vast landscape of available tumor antigens. Tumor sequencing and profiling data emerging in real time is providing us a continual source of new antigens that can be effectively deployed using our CUE-100 series. This is the thinking that – is what propelled the Neo stock platform, wherein we can generate the entire CUE-100 series scaffold without any specific peptide attached to the HLA molecule. And again, this is in stark contrast to the current minister platform where each T cell epitope is an integral part of the Immuno-STAT, meaning it's incorporated into the molecule as a fusion protein at the time of synthesis. Immuno-STATs are synthesized without a peptide epitope. Instead, the peptide epitope is actually attached subsequently using sophisticated attachment chemistry, as shown in the current figure with examples of three different peptides bound to the Neo-STAT scaffold. This advance allows us to generate the co-generic scaffold for any HLA allele via a single cell line and then use the same product to conjugate to different tumor antigens to expand our reach. The fact that only a single scaffold needs to be generated will save us significant resources and both time and cost, but generation of clinical grade material, and in doing so, provides us essentially with an off the shelf biologic to target T cells directly in the patient. We have generated early proof of concept data supporting the biological activity of molecules generated via the Neo-STAT platform. And an example of one such data set is shown in the following Slide 13. Additional data underscoring the protein engineering efforts were disclosed at a talk at the World Vaccine and Immunotherapy Congress meeting about six months ago, in December 2019 in San Francisco. So moving on to Slide 13, the top panel here shows the expansion of CMV specific T cells from three human donors. The bottom panel shows expansion of MART-1 specific T cells. From additional three human donors, MART-1 is a known antigen in melanoma. In each case, the PBMCs from human donors were expanded with Immuno-STATs were in the CMV or MART-1 T cell epitope is made as a fusion protein or with Neo-STATs within the respective T cell antigen is chemically conjugated to the scaffold. As you can know, the expansion of relevant T cells specific CMV or MART-1 one was very comparable. The Immuno-STAT expanded T cells are shown in solid lines, while the NEOs that expanded T cells for each specificity are shown in dotted lines. These data provide enormous confidence that the Neo-STAT platform can be developed for future therapeutic applications, and will complement and extend the current application of the Immuno-STAT platform. Note that the scaffold of the Neo-STAT described in the current slide is essentially the CUE-100 series without an antigenic peptide, but the same core configuration and valency of IL-2 molecules. Next slide. Slide 14 highlights our pipeline progress. We've made significant progress with CUE-101 in the mono-therapy trial, as discussed by Ken and Dan, and are positioned well for the combination study with pembrolizumab for later this year. CUE-102 with WT1 continues to make strong progress. To remind you this program is being prosecuted with two different HLA alleles, HLA-AO2 and HLA-A24, which is a dominant allele in Asian populations. CUE-103 is being bettered currently with LG Chem our Asia partner and will be disclosed in the near future. And as listed here, we've also made meaningful progress with our KRAS programs for the CUE-100 series. We will hopefully find an appropriate forum to share those data in the near future. We continue to extend the application of our platform with the CUE-200 series wherein we have early datasets with cell surface receptors like CD80, which is B71 that binds to CD28 in T cells and 4-1BB Ligand. And finally, as disclosed recently, we continue to make strong progress in autoimmunity in our alliance with Merck using the CUE-300 series, wherein we have successfully generated Immuno-STATs incorporating class two HLA molecules to selectively target or reactive CD4 positive T cells in human patients. Select the modulation of an apparent immune response and autoimmune diseases without broad immunosuppression, as is the case with current therapies is likely to bring superior clinical benefits to patients. We believe this goal can be achieved with a platform like ours. In conclusion, and as I've stated in prior presentations, the Immuno-STAT and by extension the Neo-STAT platform address that fundamental immunological challenge which is how does one maintain selectivity and specificity of a desirable immune response without breaching patient safety or creating toxicities. We believe our approach that is built upon rational protein engineering and is bolstered by supporting data sets may offer a unique solution to patients suffering from cancers, autoimmune diseases and threats from chronic pathogenic infections. Okay with that I'll now turn the call over to Carrie to review our financial results. Kerrie.