Comparing anti-tumor and anti-self immunity in a patient with melanoma receiving immune checkpoint blockade

BACKGROUND

Tumor regression following immune checkpoint blockade (ICB) is often associated with immune-related adverse events (irAEs), marked by inflammation in non-cancerous tissues. This study was undertaken to investigate the functional relationship between anti-tumor and anti-self immunity, to facilitate irAE management while promoting anti-tumor immunity.

METHODS

Multiple biopsies from tumor and inflamed tissues were collected from a patient with melanoma experiencing both tumor regression and irAEs on ICB, who underwent rapid autopsy. Immune cells infiltrating melanoma lesions and inflamed normal tissues were subjected to gene expression profiling with multiplex qRT-PCR for 122 candidate genes. Subsequently, immunohistochemistry was conducted to assess the expression of 14 candidate markers of immune cell subsets and checkpoints. TCR-beta sequencing was used to explore T cell clonal repertoires across specimens.

RESULTS

While genes involved in MHC I/II antigen presentation, IFN signaling, innate immunity and immunosuppression were abundantly expressed across specimens, irAE tissues over-expressed certain genes associated with immunosuppression (CSF1R, IL10RA, IL27/EBI3, FOXP3, KLRG1, SOCS1, TGFB1), including those in the COX-2/PGE2 pathway (IL1B, PTGER1/EP1 and PTGER4/EP4). Immunohistochemistry revealed similar proportions of immunosuppressive cell subsets and checkpoint molecules across samples. TCRseq did not indicate common TCR repertoires across tumor and inflammation sites, arguing against shared antigen recognition between anti-tumor and anti-self immunity in this patient.

CONCLUSIONS

This comprehensive study of a single patient with melanoma experiencing both tumor regression and irAEs on ICB explores the immune landscape across these tissues, revealing similarities between anti-tumor and anti-self immunity. Further, it highlights expression of the COX-2/PGE2 pathway, which is known to be immunosuppressive and potentially mediates ICB resistance. Ongoing clinical trials of COX-2/PGE2 pathway inhibitors targeting the major COX-2 inducer IL-1B, COX-2 itself, or the PGE2 receptors EP2 and EP4 present new opportunities to promote anti-tumor activity, but may also have the potential to enhance the severity of ICB-induced irAEs.

288 The COX-2 pathway as a mediator of resistance to anti-PD-1 therapy

Background

We previously found upregulation of the cyclooxygenase-2/prostaglandin E2 (COX-2/PGE2) pathway in the tumor microenvironment (TME) of cancers that respond poorly to anti-PD-1 therapy.1–2 The potential functional role of this pathway in anti-PD-1 resistance is unknown. We therefore studied modulation of COX-2 expression in cultured human tumor and immune cells, PGE2-mediated effects on myeloid cells and their reversal with prostaglandin (EP) receptor inhibitors.

Methods

Nineteen tumor lines representing 6 histologies were treated with cytokines reported to induce COX-2 (IL-1B, IL-17A, TNF-a). Peripheral blood monocytes (Monos) were treated with toll-like receptor (TLR) agonists or TME-resident cytokines associated with high PD-L1 expression (IL-1A, IL-10, IL-27, IL-32g, IFN-g).3–4 COX-2 protein was detected by Western blotting and flow cytometry. In some experiments, Monos were pre-incubated with EP2i (PF-04418948) and/or EP4i (ONO-AE3-208), then treated with PGE2 ± TLR4 (LPS) or TLR7 (imiquimod) agonists. IL-6, IL-10, TNF-a, and VEGF secretion were detected by ELISA. Monocytic DCs generated with GM-CSF+IL-4 were matured with CD40L, ± PGE2, then phenotyped.

Results

Among 19 tumor cell lines, 6 expressed COX-2 constitutively, and 13 were induced to express COX-2 by 1-day exposure to IL-1B, IL-17A, or TNF-a. In Monos, COX-2 was induced by IL-1A and IL-1B, but not IFN-g or IL-27. TLR 1-9 agonists induced COX-2, with TLR2/4/5 agonists being the strongest inducers. COX-2 induction by these factors was non-overlapping with PD-L1 induction in tumor cells and Monos, suggesting non-redundant pathways of immune resistance. PGE2 had context-dependent effects in Monos, depending on the cytokines, TLR agonists, and donors assayed: PGE2 increased VEGF secretion by resting Monos from 4/4 donors tested, but increased IL-6, IL-10 and TNF-a secretion in only 1/4 donors; PGE2 increased imiquimod-induced TNF-a secretion, but decreased LPS-induced TNF-a secretion. EP2 and EP4 inhibitors counteracted PGE2-mediated cytokine modulation, and showed synergistic effects when combined in the context of high dose of PGE2 (500nM). Additionally, PGE2 suppressed the in vitro generation of mature DCs, reducing CD80 and CD83 expression and increasing CD16.

Conclusions

Understanding and preventing anti-PD-1 treatment resistance is a critical goal. Our results suggest that the COX-2/PGE2 pathway is expressed in tumor and immune cells, and modulates myeloid cell functions in a context-dependent manner. COX-2 expression is non-redundant with PD-L1 expression, providing a rationale to test COX-2 pathway inhibition in conjunction with anti-PD-1. Available drugs targeting this pathway, including IL-1R and IL-1B inhibitors, NSAIDs, and EP2 and EP4 inhibitors, will enable the clinical development of combination treatment regimens.

Acknowledgements

We gratefully acknowledge support from NCI R01-CA142779, Bristol Myers Squibb, and the Johns Hopkins Bloomberg~Kimmel Institute for Cancer Immunotherapy.

References

Duffield AS, Ascierto ML, Anders RA, et al. The immunosuppressive tumor microenvironment (TME) in nasopharyngeal carcinoma: implications for immunotherapy. AACR 2018;Abstract 4750.

Besharati S, McMiller T, Yarchoan M, et al. The immunosuppressive tumor microenvironment (TME) in epstein-barr virus (EBV)-positive and EBV-negative gastric cancers: implications for immunotherapy. SITC 2018;P541 (abstr).

Taube JM, Young GD, McMiller TL, et al. Differential expression of immune-regulatory genes associated with PD-L1 display in melanoma: implications for PD-1 pathway blockade. Clin Cancer Res 2015;21:3969–76.

Duffield AS, Ascierto ML, Anders RA, et al. Th17 immune microenvironment in epstein-barr virus negative Hodgkin lymphoma: implications for immunotherapy. Blood Advances 2017;1:1324–34.

Attenuating CD3 affinity in a PSMAxCD3 bispecific antibody enables killing of prostate tumor cells with reduced cytokine release

BACKGROUND

Therapeutic options currently available for metastatic castration-resistant prostate cancer (mCRPC) do not extend median overall survival >6 months. Therefore, the development of novel and effective therapies for mCRPC represents an urgent medical need. T cell engagers (TCEs) have emerged as a promising approach for the treatment of mCRPC due to their targeted mechanism of action. However, challenges remain in the clinic due to the limited efficacy of TCEs observed thus far in solid tumors as well as the toxicities associated with cytokine release syndrome (CRS) due to the usage of high-affinity anti-CD3 moieties such as OKT3.

METHODS

Using genetically engineered transgenic rats (UniRat and OmniFlic) that express fully human IgG antibodies together with an NGS-based antibody discovery pipeline, we developed TNB-585, an anti-CD3xPSMA TCE for the treatment of mCRPC. TNB-585 pairs a tumor-targeting anti-PSMA arm together with a unique, low-affinity anti-CD3 arm in bispecific format. We tested TNB-585 in T cell-redirected cytotoxicity assays against PSMA+ tumor cells in both two-dimensional (2D) cultures and three-dimensional (3D) spheroids as well as against patient-derived prostate tumor cells. Cytokines were measured in culture supernatants to assess the ability of TNB-585 to induce tumor killing with low cytokine release. TNB-585-mediated T cell activation, proliferation, and cytotoxic granule formation were measured to investigate the mechanism of action. Additionally, TNB-585 efficacy was evaluated in vivo against C4-2 tumor-bearing NCG mice.

RESULTS

In vitro, TNB-585 induced activation and proliferation of human T cells resulting in the killing of PSMA+ prostate tumor cells in both 2D cultures and 3D spheroids with minimal cytokine release and reduced regulatory T cell activation compared with a positive control antibody that contains the same anti-PSMA arm but a higher affinity anti-CD3 arm (comparable with OKT3). In addition, TNB-585 demonstrated potent efficacy against patient-derived prostate tumors ex vivo and induced immune cell infiltration and dose-dependent tumor regression in vivo.

CONCLUSIONS

Our data suggest that TNB-585, with its low-affinity anti-CD3, may be efficacious while inducing a lower incidence and severity of CRS in patients with prostate cancer compared with TCEs that incorporate high-affinity anti-CD3 domains.

A bispecific antibody agonist of the IL-2 heterodimeric receptor preferentially promotes in vivo expansion of CD8 and NK cells

The use of recombinant interleukin-2 (IL-2) as a therapeutic protein has been limited by significant toxicities despite its demonstrated ability to induce durable tumor-regression in cancer patients. The adverse events and limited efficacy of IL-2 treatment are due to the preferential binding of IL-2 to cells that express the high-affinity, trimeric receptor, IL-2Rαβγ such as endothelial cells and T-regulatory cells, respectively. Here, we describe a novel bispecific heavy-chain only antibody which binds to and activates signaling through the heterodimeric IL-2Rβγ receptor complex that is expressed on resting T-cells and NK cells. By avoiding binding to IL-2Rα, this molecule circumvents the preferential T-reg activation of native IL-2, while maintaining the robust stimulatory effects on T-cells and NK-cells in vitro. In vivo studies in both mice and cynomolgus monkeys confirm the molecule's in vivo biological activity, extended pharmacodynamics due to the Fc portion of the molecule, and enhanced safety profile. Together, these results demonstrate that the bispecific antibody is a safe and effective IL-2R agonist that harnesses the benefits of the IL-2 signaling pathway as a potential anti-cancer therapy.

Effect of modulation of CD3 binding in a PSMAxCD3 T-cell engaging bispecific antibody on maintenance of efficient tumor cell kill and cytokine release

e17583

Background: Castration resistant prostate cancer (CRPC) is an incurable disease and represents a significant unmet need. Prostate specific membrane antigen (PSMA) is a protein highly expressed on the surface of prostate cancer cells; expression has been shown to increase with disease progression. Therapies targeting PSMA, such as anti-PSMA radioligand conjugates, have shown promise in clinical trials, validating this target for CRPC. T-cell recruiting bispecific antibodies (T-BsAbs) have demonstrated potent tumor killing activity against multiple tumor types, but immune-mediated toxicities have hampered T-cell redirecting therapies to date. Using Teneobio’s unique antibody discovery platform, we have developed a CD3xPSMA bispecific antibody (TNB-585) that retains the potent cytotoxicity of other T-BsAbs but with significantly reduced cytokine release. Methods: Antibodies targeting CD3 and PSMA were generated via immunization of our proprietary transgenic animals. Candidate antibodies were selected by repertoire deep sequencing of B-cells from draining lymph nodes, followed by high-throughput gene assembly and recombinant expression. Multiple bispecific antibodies targeting CD3 and PSMA were assembled and evaluated for their ability to selectively activate primary human T-cells and mediate killing of PSMA+ tumor cells in vitro, ex vivo, and in vivo. T-cell activation surface markers, cytokine production, and tumor cell cytotoxicity were measured. Results: In co-culture experiments, primary human T-cells were activated only in the presence of both the bispecifics and PSMA+ cells. These bispecifics mediated potent and selective cytotoxicity against PSMA-positive tumor cells, prostate tumor cell lines, or primary human prostate tumor cells isolated from patients. From among these we identified TNB-585, which showed attenuated binding to CD3. TNB-585 mediated comparable tumor cell cytotoxicity to CD3xPSMA T-BsAbs containing a high affinity anti-CD3 domain but with significantly reduced cytokine production. TNB-585 also showed tumor growth inhibition in xenograft models of prostate cancer in vivo. Conclusions: We have developed a novel CD3xPSMA T-BsAb that mediates T-cell killing of PSMA+ tumor cells with minimal production of cytokines. This molecule may improve safety, efficacy, and offer opportunities for combination therapy to treat CRPC. A Phase 1 clinical trial of this compound in CRPC is scheduled to begin in Q1 2021.

Abstract 1554: Uncoupling tumor-cell cytotoxicity from cytokine release with novel T-cell engaging bispecific antibodies

T-cell recruiting bispecific antibody (T-BsAb) treatment is an emerging cancer immunotherapy notable for its highly-specific tumor killing activity in humans. However, the success of T-BsAbs in the clinic has been limited due to cytokine-release related toxicities. In order for this technology to reach its potential, the next generation of T-BsAbs must avoid this unintended toxicity by uncoupling cytokine-release from tumor-cell killing. To this end, we used a sequence-based discovery method on CD3-immunized OmniFlic rats, which express human fixed light-chain antibodies, to identify several novel anti-CD3 antibodies. These antibodies bind to multiple CD3 epitopes, each with varying affinities and degrees of T-cell activation. Furthermore, when placed in the context of a T-BsAb, these novel anti-CD3 antibodies achieve similar levels of T-cell mediated tumor-specific lysis, but with a thousand-fold range in potency. Among these antibodies, we identified one lead with particularly favorable properties, in that it stimulates very low levels of cytokine production without sacrificing its potent antigen-specific tumor lysis in vitro, in mouse xenograft assays, as well as ex vivo patient sample studies. This unique behavior gives our novel anti-CD3 antibody the potential to widen the therapeutic window when treating patients and ultimately usher in the next generation of T-BsAbs.

Citation Format: Kyle Lorentsen, Preethi Sankaran, Nathan D. Trinklein, Duy Pham, Ute Schellenberger, Ben Buelow, Andrew Boudreau, Priya Choudhry, Starlynn C. Clarke, Kevin Dang, Katherine E. Harris, Suhasini Iyer, Brett Jorgensen, Payal Pratap, Udaya S. Rangaswamy, Harshad S. Ugamraj, Omid Vafa, Arun P. Wiita, Wim van Schooten, Roland Buelow, Shelley Force Aldred. Uncoupling tumor-cell cytotoxicity from cytokine release with novel T-cell engaging bispecific antibodies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1554.

Evaluation of monovalent versus biparatopic CD3xPSMA bispecific antibodies for t-cell mediated killing of prostate tumor cells with minimal cytokine release

e16519

Background: Castration resistant prostate cancer (CRPC) remains an incurable disease and new treatments are needed. Therapies directed against Prostate specific membrane antigen (PSMA) -such as radiolabeled antibodies, chimeric antigen receptor T cells (CAR-Ts) and T-cell engaging bispecific antibodies (T-BsAbs)- have shown promising efficacy but also induce significant toxicity. In particular T-cell redirection leads to efficient killing of tumor cells but induces cytokine release-related toxicities. We have developed a panel of monovalent and biparatopic CD3xPSMA bispecific antibodies that eliminate prostate tumor cells while minimizing cytokine release. Methods: Antibodies targeting CD3 and PSMA were generated in transgenic rats (UniRat™, OmniFlic™) followed by deep sequencing of the antibody repertoire from draining lymph nodes in immunized animals, and high-throughput gene assembly/expression. PSMA x CD3 T-BsAbs were assembled and evaluated for stability, pharmacokinetics, and T cell activation and ability to eliminate PSMA+ tumor cells in vitro and in vivo. Results: Bispecific CD3xPSMA Abs. incorporating either monovalent or biparatopic anti-PSMA binding domains activated T-cells in the presence of PSMA (plate-bound or cell surface), while no T cell activation occurred in the absence of either PSMA antigen or bispecific antibody. Potent/selective cytotoxicity against PSMA+ cells was observed in co-cultures of primary human T cells and tumor cells treated with CD3xPSMA T-BsAbs. Similar results were observed in in vivo Xenograft models of prostate cancer. Strikingly, CD3xPSMA bispecifics containing a novel low affinity anti-CD3 domain produced similar levels of tumor cytotoxicity compared to those with a traditional high affinity anti-CD3 domain, but with reduced cytokine production. Conclusions: We have created novel CD3xPSMA bispecific antibodies incorporating both monovalent and biparatopic anti-PSMA binding domains that mediate T-cell killing of PSMA+ tumor cells with minimal production of cytokines. Such T-BsAbs may improve safety, efficacy, and opportunities for combination therapy to treat CRPC.

A novel CD3xPSMA bispecific antibody for efficient T cell mediated killing of prostate tumor cells with minimal cytokine release

324

Background: Castration resistant prostate cancer (CRPC) remains an incurable disease and new therapeutics are urgently needed. Prostate specific membrane antigen (PSMA) is expressed on the surface of prostate cancer cells and expression increases with disease progression. Therapies directed against PSMA such as radiolabeled antibodies and T cell redirecting therapies including chimeric antigen receptor T cells (CAR-Ts) and T-cell engaging bispecific antibodies (T-BsAbs) have shown promising efficacy in clinical trials but also induce significant toxicity. In particular CAR-Ts and T-BsAbs potently kill tumor cells but induce cytokine release-related toxicities. Novel anti-CD3 engaging domains may be required to create T-BsAbs with a broader therapeutic window. We have developed fully human CD3xPSMA bispecific antibodies that efficiently eliminate prostate tumor cells while minimizing cytokine release. Methods: Antibodies targeting CD3 and PSMA were generated in transgenic rats that produce human antibodies (UniRat, OmniFlic) followed by repertoire deep sequencing of lymph nodes isolated from immunized animals and high-throughput gene assembly/expression. CD3xPSMA T-BsAbs were assembled and evaluated for T cell activation and ability to eliminate PSMA+ tumor cells in vitro. Results: Primary human T cells were activated only in the presence of both bispecific CD3xPSMA antibodies and PSMA (either plate-bound or on the surface of tumor cells). Potent and selective cytotoxicity against PSMA+ prostate tumor cells was observed in co-cultures of primary human T cells and tumor cells treated with CD3xPSMA bispecific antibodies. Strikingly, CD3xPSMA bispecifics containing a novel low affinity anti-CD3 domain produced similar levels of tumor cell cytotoxicity compared to CD3xPSMA bispecifics containing a traditional high affinity anti-CD3 domain, but with reduced cytokine production. Conclusions: We have created novel CD3xPSMA bispecific antibodies that mediate T-cell killing of PSMA+ tumor cells with minimal production of cytokines. Such T-BsAbs may improve safety, efficacy, and opportunities for combination therapy to treat CRPC.

Multispecific Antibody Development Platform Based on Human Heavy Chain Antibodies

Heavy chain-only antibodies (HCAbs) do not associate with light chains and their V_H regions are functional as single domains, forming the smallest active antibody fragment. These V_H regions are ideal building blocks for a variety of antibody-based biologics because they tolerate fusion to other molecules and may also be attached in series to construct multispecific antibodies without the need for protein engineering to ensure proper heavy and light chain pairing. Production of human HCAbs has been impeded by the fact that natural human V_H regions require light chain association and display poor biophysical characteristics when expressed in the absence of light chains. Here, we present an innovative platform for the rapid development of diverse sets of human HCAbs that have been selected in vivo. Our unique approach combines antibody repertoire analysis with immunization of transgenic rats, called UniRats, that produce chimeric HCAbs with fully human V_H domains in response to an antigen challenge. UniRats express HCAbs from large transgenic loci representing the entire productive human heavy chain V(D)J repertoire, mount robust immune responses to a wide array of antigens, exhibit diverse V gene usage and generate large panels of stable, high affinity, antigen-specific molecules.

Chronic obstructive pulmonary disease and mortality from pneumonia: meta-analysis

BACKGROUND

We aimed to determine whether patients with concomitant community-acquired pneumonia (CAP) and chronic obstructive pulmonary disease (COPD) are at greater risk of death when compared with those with CAP or acute COPD exacerbation alone. We also assessed the effect of inhaled corticosteroids (ICS) on pneumonia mortality in COPD.

METHODS

We searched MEDLINE and EMBASE from inception to March 2012 for studies reporting on mortality in patients with COPD and CAP. We assessed ascertainment of disease, mortality, drug exposure and adjustment for confounders. Data were pooled using random effects meta-analysis, and heterogeneity was estimated using I².

RESULTS

We identified 24 eligible articles overall. Evaluation of 13 studies revealed considerable heterogeneity and a non-significant mortality risk associated with concomitant COPD and CAP as compared with CAP in five studies that reported adjusted or severity-matched data, pooled RR 1.44 (95% CI 0.97-2.16, I² = 50%). There was also considerable inconsistency amongst the effect estimates from five studies that reported on the associated mortality with concomitant CAP and COPD as compared with acute COPD exacerbations alone. Evaluation of six datasets found that ICS use in COPD was not consistently associated with lower mortality in CAP. Reports of reduced mortality with prior ICS use stemmed from three studies that enrolled participants from the same healthcare database.

CONCLUSIONS

Evidence on associated mortality risk with concomitant CAP and COPD (as opposed to CAP alone, or COPD exacerbation alone) is weak and heterogeneous. ICS use was not consistently associated with reduced mortality from pneumonia.

Performance of CURB-65 and CURB-age in community-acquired pneumonia

BACKGROUND

Community-acquired pneumonia (CAP) is common and associated with significant mortality. In this study, we validated a newly proposed severity assessment rule for CAP, CURB-age, and also compared with to the currently recommended criteria in UK, CURB-65.

METHODS

We conducted a prospective study in three hospitals in Norfolk and Suffolk, UK. One hundred and ninety patients were included and followed up for 6 weeks.

RESULTS

Of 190 patients, 100 were men (53%). The age range was 18-101 years (median 76 years). Sixty-five (34%) had severe pneumonia by CURB-65 and 54 (28%) had severe pneumonia by CURB-age. There were 54 deaths during follow-up. There were 32 deaths (50%) in severe and 22 deaths (18%) in non-severe group by CURB-65. There were 27 deaths each in both the groups by CURB-age (50% of severe cases and 20% of non-severe cases). For CURB-65, sensitivity, specificity, and positive and negative predictive values were 59.3% (45.0-72.4), 75.7% (67.6-82.7), 49.2% (36.6-61.9) and 82.4% (74.6-88.6), respectively. For CURB-age, the respective values were 50.0% (31.1-63.9), 80.1% (72.4-86.5), 50.0% (36.1-63.9) and 80.1% (72.4-86.5). Exclusion of patients aged < 65 years did not alter the results.

CONCLUSIONS

Despite better specificity in correctly identifying 6-week mortality for CAP, CURB-age appears to be less sensitive than CURB-65. Our findings further assure the usefulness of CURB-65 for predicting mortality in CAP.

Closing the diarrhoea diagnostic gap in Indian children by the application of molecular techniques

A large proportion of diarrhoeal illnesses in children in developing countries are ascribed to an unknown aetiology because the only available methods, such as microscopy and culture, have low sensitivity. This study was aimed at decreasing the diagnostic gap in diarrhoeal disease by the application of molecular techniques. Faecal samples from 158 children with and 99 children without diarrhoea in a hospital in South India were tested for enteric pathogens using conventional diagnostic methods (culture, microscopy and enzyme immunoassays) and molecular methods (six PCR-based assays). The additional use of molecular techniques increased identification to at least one aetiological agent in 76.5 % of diarrhoeal specimens, compared with 40.5 % using conventional methods. Rotavirus (43.3 %), enteropathogenic Escherichia coli (15.8 %), norovirus (15.8 %) and Cryptosporidium spp. (15.2 %) are currently the most common causes of diarrhoea in hospitalized children in Vellore, in contrast to a study conducted two decades earlier in the same hospital, where bacterial pathogens such as Shigella spp., Campylobacter spp. and enterotoxigenic E. coli were more prevalent. Molecular techniques significantly increased the detection rates of pathogens in children with diarrhoea, but a more intensive study, testing for a wider range of infectious agents and including more information on non-infectious causes of diarrhoea, is required to close the diagnostic gap in diarrhoeal disease.

Fiber sensor for the simultaneous measurement of current and voltage in a high-voltage system

A sensor employing a single monomode low-birefringence fiber, excited with a 632.8-nm He-Ne laser, has been developed for the simultaneous measurement of current and voltage in an energy system. The piezoelectric effect for the voltage and the magnetic stress for the current are utilized. The current and voltage signals are separated at the detector end by suitable self-tracking tuned filters. Experimental results from a laboratory model demonstrate the feasibility of the sensor for field application in high-voltage systems.