Integration of external control data, with patient-level information, in clinical trials has the potential to accelerate the development of new treatments in neuro-oncology by contextualising ...single-arm studies and improving decision making (eg, early stopping decisions). Based on a series of presentations at the 2020 Clinical Trials Think Tank hosted by the Society of Neuro-Oncology, we provide an overview on the use of external control data representative of the standard of care in the design and analysis of clinical trials. High-quality patient-level records, rigorous methods, and validation analyses are necessary to effectively leverage external data. We review study designs, statistical methods, risks, and potential distortions in using external data from completed trials and real-world data, as well as data sources, data sharing models, ongoing work, and applications in glioblastoma.
BackgroundThe novel T-MASK (Targeted Metallo/protease Activated SuperKine) platform involves fusion of a dual tumor-targeting/masking domain to potent immune modulator(s) via a metallo-protease (MMP) ...sensitive linker (PSL) to achieve the following objectives: (1) reduce/fine-tune the potency of the immune modulator by steric hindrance to increase systemic tolerability and (2) promote retention in the tumor microenvironment (TME) to maximize MMP cleavage and restore full potency at the intended target site. As proof of concept, we selected as the tumor-targeting/masking domain an IL-13 superkine (MDNA213) with high selectivity and affinity for the IL-13 decoy receptor IL-13Ra2, a tumor associated antigen expressed in many aggressive solid tumors. MDNA213 is fused via a PSL to MDNA11 and MDNA223, both containing a not-alpha, beta-enhanced IL-2 fused with albumin or anti-PD1 antibody respectively. We present preliminary results on characterization of both T-MASK constructs demonstrating conditional fine-tuning of IL-2R agonism.MethodsT-MASK optimization included assessment of PSL linker and orientation of the tumor-targeting/masking domain. In vitro IL-2 and PD-1/PDL-1 reporter assays were performed to evaluate IL-2R stimulation and anti-PD1 blockade respectively. In vitro MMP assay was used to validate cleavage of T-MASK constructs and restoration of full potency.ResultsT-MASK constructs showed approximately 10–40 fold reduction in potency compared to respective non-masked versions in IL-2R induced p-STAT5 reporter cell assay. Extent of fine-tuning can be adjusted by length and composition of PSL and orientation of the domains, providing versatility to the T-MASK platform and potential to engage the complete repertoire of peripherally circulating immune cells. In the case of MDNA223 (anti-PD1-IL-2Superkine), fusion of MDNA213 to generate the T-MASK construct MDNA113 resulted in reduced IL-2R agonism but had no effect on potency of PD1/PDL-1 blockade as expected. Unmasking of MDNA113 by MMP-mediated cleavage fully restored its IL-2R signaling activity to the same level as the non-masked MDNA223 construct. Similar data were obtained with the masked version of MDNA11, demonstrating robustness of the T-MASK platform. In vivo studies are ongoing to evaluate the effect of T-MASK constructs on peripheral immune cell expansion (systemic response), tumor retention (maximize activation) and tumor growth inhibition (targeted response).ConclusionsMDNA113 is a novel T-MASK construct designed to increase tolerability while leveraging the synergy between PD1/PDL-1 blockade and IL-2R agonism for immunotherapy. Ongoing studies investigate alternative tumor-targeting/masking domains and immune modulators, including other cytokines and potent therapeutic agents, to potentially broaden the utility of the T-MASK platform.Ethics ApprovalAnimal studies are conducted in concordance with institutional guideline and approval.
BackgroundRecombinant human interleukin-2 (rhIL-2, aldesleukin) is Food and Drug Administration approved for the treatment of metastatic melanoma and renal cell carcinoma and has achieved durable ...response in a subset of patients. However, its utility as an immunotherapeutic drug is limited by undesirable activation of immune suppressive regulatory T cells (Tregs) and a short half-life requiring frequent high dose administration, leading to unacceptable toxicities. We have engineered MDNA11, a long-acting IL-2 superkine, to overcome these limitations by (1) modifying receptor selectivity in favor of anti-cancer immune cells to increase therapeutic efficacy and (2) fusion to human albumin to extend the pharmacokinetic (PK) profile, circumventing the need for frequent dosing.MethodsMDNA11 was evaluated using in vitro and in vivo studies including: binding analyses to measure receptor affinity, IL-2 pathway signaling, PK studies in mice, and efficacy studies in syngeneic tumor models as single agent and in combination with immune checkpoint inhibitors. Finally, the safety and pharmacodynamic profile of MDNA11 was assessed in non-human primate (NHP).ResultsBinding studies with MDNA11 demonstrated increased affinity for IL-2Rβ (CD122) and no binding to IL-2Rα (CD25). As a result, MDNA11 exhibits reduced/limited Treg stimulation while triggering an enhanced activation of natural killer and naïve CD8 T cells compared with rhIL-2. When administered to animals with pre-established tumors, MDNA11 controlled tumor growth in a monotherapy setting and in combination with anti-PD1 or anti-CTLA4 to induce durable tumor clearance with a once weekly dosing regimen. In a NHP model, MDNA11 was well tolerated while triggering durable and potent immune responses including expansion of lymphocytes without significant effect on Tregs and eosinophils, the latter been linked to an increased risk of vascular leak syndrome.ConclusionMDNA11 is a next generation long-acting IL-2 immunotherapeutic with a highly favorable pharmacodynamic profile that translates to a strong therapeutic efficacy in preclinical tumor models and a strong and durable immune response in NHP.
In certain indications, it is well understood that randomized controlled trials lead to slow enrollment and high differential drop-out rate in the standard of care control arm when the standard of ...care is undesirable to patients. This not only impacts the pace of drug development but may also render a randomized trial uninterpretable if drop-out from the control arm is common. Single-arm trials are common in such indications. An external control arm (ECA) built using a propensity score method (Rosenbaum and Rubin, Biometrika 70:41–55, 1983) from subjects outside the current trial but who meet the same eligibility criteria as the subjects of the current trial, is valuable in assessing treatment effect of a new drug that cannot be otherwise assessed with a single-arm trial, or an unintentionally under-powered and arguably biased randomized controlled trial. Propensity score methods have increasingly gained importance in observational medical research, paving the way for the use of these methods in non-randomized clinical trials. In this paper, we describe our experience with building an ECA for drug development related to regulatory activities associated with a new molecular entity (NME). Through analysis of a phase 2 study, we show how best practices from causal statistical methods can be used to build an ECA for a non-randomized drug trial—a novel application of a well-studied method. To prevent selection bias, the selection of subjects for the ECA was carried out by an independent group of statisticians who were blinded to all patient outcome data. We share lessons learnt from our regulatory interactions that provide helpful suggestions on how to advance ECA-based drug development. There has been interest in confirmatory trials that use reduced control arm randomization along with an ECA. We present a design for such a hybrid trial using a propensity score weighting method and describe how a standard propensity score analysis can be used to analyze data resulting from a composite hybrid randomized and external control arm.
Abstract
Introduction: The IL-2 pathway plays a vital role in stimulating a pro-inflammatory (Th1) response against cancer through expansion and activation of effector CD8 T and NK cells. In ...contrast, the IL-4/IL-13 pathway stimulates myeloid derived suppressor cells (MDSCs) and M2 skewing of tumor associated macrophage (TAM) to foster an anti-inflammatory (Th2) response that is often exploited by cancers as a means to dampen the effects of the Th1 pathway. Therefore, suppression of MDSC and M2 TAM through inhibition of the IL-4/IL-13 pathway together with stimulation of effector immune cells through activation of the IL-2 pathway have the potential to invigorate a pro-inflammatory response in an otherwise immune suppressive tumor microenvironment (TME). To achieve this goal, we leveraged the versatility of our IL-2 and IL-13 superkine platforms to engineer long-acting bi-specific constructs to co-target surface receptors of these respective pathways.
Experimental Procedure: Studies included binding analyses by BLI/Octet and Biacore/SPR, signaling analyses using IL-2 and IL-4/IL-13 reporter assays, signaling analysis in human PBMC, and in vitro M1/M2 macrophage polarization assay.
Summary of Data: sIL2M-Fc-sIL13M is a bi-specific superkine composed of an IL-2 super-agonist (sIL2M) and IL-13 super-antagonist (sIL13M) linked together by human IgG1 Fc. sIL2M binds CD122 with superior affinity over IL-2 but does not engage CD25, which is expressed on immune-suppressive Tregs. sIL13M has higher affinity than IL-13 for IL13Rα1, which together with IL-4Rα forms a functional receptor complex. In pSTAT5 assay using primary human PBMCs, sIL2M-Fc-sIL13M showed enhanced potency over IL-2 in the activation of CD8 T-cells and NK cells while exhibiting limited activity on Treg. In an IL-4/IL-13 dependent pSTAT6 reporter assay, sIL2M-Fc-sIL13M demonstrated dose-dependent antagonism against stimulatory activity of both IL-4 and IL-13. This antagonistic effect was further validated with inhibition of IL-13 induced M2 polarization of macrophages in vitro.
Conclusion: sIL2M-Fc-sIL13M is a bi-specific superkine capable of concomitantly stimulating a Th1 response through activation of the IL-2 pathway and suppressing a Th2 response through inhibition of the IL-4/IL-13 pathway. Additional bi-specific superkine constructs are currently under testing, including those designed to enable accumulation in TME by engaging the decoy IL-13Rα2 that is overexpressed on a number of different tumor types.
Citation Format: Fahar Merchant, Minh To. Modulation of immune responses to cancer by bi-specific IL-2/IL-13 superkines abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1734.
BackgroundMDNA11 is an albumin-fused long-acting IL-2 agonist with enhanced affinity for IL-2Rb and no binding to IL-2Ra, resulting in potent CD8+ T and NK cell activation, limited Treg increase and ...reduced toxicities.1 ABILITY (A Beta-only IL-2 ImmunoTherapY) is a Phase 1/2 study evaluating the safety, pharmacokinetic (PK), pharmacodynamic (PD) and preliminary clinical activity of MDNA11 as monotherapy and in combination with Prembrolizumab in pre-treated patients with advanced solid tumors.MethodsThe dose-escalation phase of ABILITY uses a modified 3+3 design to determine the recommended dose for expansion (RDE). Patients received a fixed dose of 3, 10 or 30 μg/kg (dose levels 1–3; DL1–3) by intravenous infusion on a Q2W schedule. Step-up dosing was implemented starting at DL4 where patients received 2 or 3 priming doses prior to the target dose of 60 μg/kg (DL4), 90 μg/kg (DL5) or 120 μg/kg (DL6). Primary endpoints include incidence and severity of adverse events (AEs). Secondary endpoints include assessment of PK, PD and tumor response per RECISTv1.1 and iRECISTResultsAs of June 22, 2023, twenty dose limiting toxicity (DLT)-evaluable patients have been dosed with MDNA11 during monotherapy dose escalation (3–120 μg/kg). Tumor types enrolled included melanoma (n=11), renal cell carcinoma (n=2), pancreatic ductal adenocarcinoma (PDAC; n=2), sarcoma (n=2), tonsillar squamous cell carcinoma (n=1), gastro-esophageal adenocarcinoma (n=1) and lung adenocarcinoma (n=1). PK analysis showed dose-dependent increase in MDNA11 exposure. Immune profiling showed robust lymphocyte expansion, including increase in CD8+ T and NK cells and limited change in Tregs. There were no DLTs observed. The most common AEs were infusion related reaction (65%) comprising pyrexia (50%), nausea (45%), chills (35%), fatigue (30%) and diarrhea (25%), with the majority being grade 1–2 and resolved within 48–72 hours. Transient (~ 1week duration) transaminases increase was seen in 25% of patients. Tumor response was evaluated in 19 patients. Single-agent activity included stable disease (SD) observed in 6 patients, including a melanoma patient with SD beyond 1.5 year, and an ongoing partial response (PR) in a PDAC patient who had previously progressed on immune checkpoint inhibitor and is currently continuing on MDNA11 for > 1 year.ConclusionsMDNA11 is well tolerated with no DLTs up to target dose of 120 μg/kg on a Q2W schedule. Evidence of clinical activity includes SD in 6 of 19 patients in addition to a durable PR in a PDAC patient. Data analysis is ongoing to inform RDE selection.AcknowledgementsWe are grateful to all patients participating in this study.Trial RegistrationNCT: 05086692ReferenceMerchant R, Galligan C, Munegowda MA, et al. Fine-tuned long-acting interleukin-2 superkine potentiates durable immune responses in mice and non-human primate. 2022;10:e003155.Ethics ApprovalThe study was conducted with approval from institutional ethics committee and informed consent from participants.
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Background: The efficacy and safety of recombinant human IL-2 (rhIL-2; Proleukin) to treat certain cancers is limited by a short half-life, marked toxicity and selective high ...affinity binding to IL2Ra over IL2Rb, resulting in preferential activation of suppressive Tregs. In contrast, MDNA11 has been engineered as a long-acting IL-2 superkine with high affinity IL2Rb receptor selectivity, resulting in preferential anti-cancer effector immune cell activation. Methods: MDNA11 was characterized in both in vitro and in vivo studies including assessment of receptor binding kinetics using BLI/Octet, receptor-mediated signaling in human PMBCs, efficacy in syngeneic mouse tumor models including memory response, as well as safety and PK/PD assessments in non-human primates (NHP). Results: Unlike rhIL-2, MDNA11 does not bind to human IL2Ra but demonstrates a 30-fold higher affinity binding to human IL2Rb. This selectivity resulted in enhanced in vitro STAT5 signaling in human NK and resting CD8 T cells with diminished signaling in Tregs; validation studies in humanized mice are ongoing. In CT26 and MC38 syngeneic tumor models, MDNA11 demonstrates potent and durable efficacy as monotherapy following a Q1W dose schedule for 2 weeks. Synergy with anti-PD1 and anti-CTLA4 immune checkpoint inhibitors (ICIs) was observed and a robust immune memory response developed in all mice with complete tumor clearance. These mice were protected against relapse and tumor re-challenges for up to 8 months without any further treatment, and showed the presence of antigen-specific CD8 T cells. In binding studies with IL-2 receptors of different species, MDNA11 showed highly similar affinity towards human and cynomolgus IL2Rb, confirming the latter as a highly relevant model for toxicology study. MDNA11 was well tolerated in cynomolgus monkeys up to 0.6 mg/kg, while inducing durable (≥10 days) proliferation and expansion of NK and CD8 T cells. Effects on Tregs were minimal and there was no eosinophilia and hypotension (associated with vascular leak syndrome). At high doses of MDNA11, the most common clinical observations were transient loss of appetite and diarrhea. There was modest increase in levels of IFNg and TNFa, but no sign of cytokine release syndrome. Dosing did not trigger development of anti-drug antibodies or histopathologic evidence of pulmonary edema (a major IL-2 induced toxicity). Conclusions: MDNA11 is a long-acting IL-2 superkine that exhibits robust efficacy in mouse tumor models as a single agent and was synergistic in combination with ICIs (anti-CTLA4 and anti-PD1). In NHP, MDNA11 demonstrates selective immune effector cell activation and a favorable safety profile. These data constitute a strong framework for the design of a pivotal GLP toxicology study to further support the planned clinical study of MDNA11 either as a single agent or in combination with ICIs.
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Background: Use of IL-2 (Proleukin) remains limited due to its short half-life, toxicity, and its ability to preferentially activate Tregs resulting in unwanted immune suppression. ...Approaches to reduce binding to CD25 (IL2α), such as pegylation techniques, also results in reduced affinity to CD122 (IL2β). To bypass these limitations, we engineered MDNA11, an IL-2 Superkine containing core mutations to diminish binding to CD25 while increasing affinity to CD122. To increase half-life, MDNA11 was fused to an albumin scaffold, which is known to allow accumulation at the tumor site. Methods: MDNA11 was evaluated using in vitro and in vivo studies that included: IL-2 signaling in human PBMCs, Biacore binding analyses, PK studies in mice, and efficacy studies in syngeneic tumor models with or without immune checkpoint inhibitors (ICIs). In addition, dose-range finding studies in cynomolgus monkeys (NHP) were performed to characterize the safety and PK/PD profiles of MDNA11. Results: MDNA11 displayed enhanced STAT5 signaling in human NK and naïve CD8 T-cells with diminished Treg activity. In mice, the terminal half-life of MDNA11 was 24-fold longer than IL-2. As a result, MDNA11 triggered effective tumor growth control, as monotherapy or in combination with ICI, in multiple tumor models in spite of q1wk dosing for two weeks. MDNA11 administration to mice with pre-established CT26 colon cancer resulted in tumor-free animals and induced strong memory response and protection against subsequent re-challenges. MDNA11 also inhibited the growth of B16F10 melanomas, which translated into a durable increase in tumor infiltrating CD8 T-cells. When tested in NHP, MDNA11 led to increased circulating CD8 T-cells lasting for almost 14 days with limited effects on Tregs and eosinophils (the latter being a source of IL-5 causing vascular leak syndrome). High doses resulted in mild side effects that were transient and reversible even following repeated dosing. Conclusions: The long-acting MDNA11 Superkine has superior potency over IL-2 at activating naïve CD8 T-cells and NK cells, while exhibiting diminished Treg activation. This molecule potently inhibited tumor growth and induced durable regression and long-term memory response. Studies in NHP showed prolonged proliferation of immune effector cells lasting almost two weeks post-MDNA11 administration. The sum of these data underscores the potency of MDNA11 to trigger the host’s immune response to control or eradicate established tumors.
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e14220
Background: Proleukin (a cysteine-modified variant of interleukin (IL)-2) is the only common-γc cytokine approved for the treatment of metastatic melanoma and renal cell ...carcinoma. Its therapeutic use is however hampered by its short half-life and severe toxicity. At low doses, Proleukin administration leads to preferential activation of regulatory T cells (Tregs) due to their expression of the high affinity trimeric IL-2 receptor (IL-2R) consisting of CD25, CD122 and CD132 instead of cytotoxic CD8 T cells expressing the intermediate affinity IL-2R (CD122 and CD132). Methods: To bypass these limitations, we evaluated engineered variants of IL-2 (MDNA109 superkine) exhibiting enhanced affinity towards CD122 including their long-acting and bispecific superkine fusions. This approach allows preferential activation of CD8 T cells while displaying reduced adverse effects in vivo. Results: Both Biacore analysis and signaling studies on human peripheral blood mononuclear cells confirmed enhanced binding of MDNA109 to CD122 and STAT5 activation, respectively. When tested in vivo, MDNA109 co-administration with the immune-checkpoint blockers anti-programmed cell death (PD)-1 or anti-cytotoxic T-Lymphocyte-Associated Protein (CTLA)4 cured mice with pre-established MC38 or CT26 colon cancers respectively. In addition, bi-weekly administration of the long-acting MDNA109-Fc fusion led to similar therapeutic outcomes in the B16F10 model when compared to MDNA109 administered daily. Finally, in vitro and in-vivo results using (a) MDNA109 muteins with completely impaired CD25 binding activity and (b) novel bispecific superkine fusions consisting of MDNA109 and a dual IL-4/IL-13 super-antagonist capable of selective CD8 T-cell activation while mitigating the suppressive functions of myeloid-derived suppressor cells and tumor-associated macrophages will be presented. Conclusions: Altogether, these data demonstrate that both MDNA109 and MDNA109-Fc are therapeutically superior to Proleukin. Furthermore, use of MDNA109-based strategies will not only ensure complete abrogation of adverse effects, but will in addition eliminate immunosuppression caused by both Tregs and myeloid cells.
Abstract
INTRODUCTION
The current study compared the modified response assessment in neuro-oncology (mRANO)(1), iRANO (2), and standard RANO criteria (3) as well as quantified the association between ...progression-free (PFS) and overall survival (OS) in an immunotherapy trial in recurrent glioblastoma (rGBM).
METHODS
A total of 47 patients with rGBM were enrolled in a phase II convection-enhanced delivery of an IL4R-targeted immunotoxin (MDNA55-05, NCT02858895). Bidirectional tumor measurements were created by local sites and an independent radiologic faculty (IRF), then standard RANO, iRANO, and mRANO criteria were applied. Differences of PFS and the association between PFS and OS were evaluated.
RESULTS
41 of 47 patients were evaluable for response. Both local site and IRF-determined PFS was significantly shorter using standard RANO compared to iRANO (log-rank, P< 0.0001; HR=0.3) and mRANO (P< 0.0001; HR=0.3). No difference in PFS was observed between iRANO and mRANO (Local, P=0.67; IRF, P=0.59). In patients who died and had confirmed progression on standard RANO, no correlation was observed between PFS and OS (Local, P=0.47; IRF, P=0.34). Using the iRANO, a weak association driven by a few outliers was observed between confirmed PFS and OS via local site measurements (P=0.017), but not central IRF measurements (P=0.18). Importantly, 24 of 41 patients (59%) were censored using iRANO and not included because they did not have confirmation of progression 3 months after initial progression. A strong correlation was observed between mRANO PFS and OS for both local (R2=0.66, P< 0.0001) and IRF-determined reads (R2=0.57, P=0.0007).
CONCLUSION
No correlation between PFS and OS was observed for standard RANO or iRANO, but a strong correlation was identified between both locally-determined and centrally-determined PFS and OS using the mRANO criteria. Also, the iRANO criteria was difficult to implement due to need to confirm progression 3 months after initial progression, censoring more than half the patients.
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