Blockade Of Programmed Death-ligand 1 Research Articles

Non-comparative, open-label, international, multicenter phase I/II study of nivolumab (NIVO) ± ipilimumab (IPI) in patients (pts) with recurrent/metastatic merkel cell carcinoma (MCC) (CheckMate 358).

9506 Background: MCC is a rare and aggressive skin cancer. Programmed death-ligand 1 (PD-L1) is often upregulated in MCC and blockade of PD-L1 or its receptor, PD-1, has improved survival for patients with metastatic MCC. Anti–PD-1 combined with anti–CTLA-4 has been reported to improve outcomes over anti–PD-1 monotherapy (NCT03071406; Kim S et al., Lancet 2022), however further investigation is needed. CheckMate 358 (NCT02488759) assessed NIVO ± IPI in 2 non-randomized MCC cohorts. Methods: Eligible pts had recurrent or metastatic MCC, ≤ 2 prior therapies, ECOG performance status (PS) 0–1, and no prior immune checkpoint inhibitor (ICI) therapy. Pts were eligible regardless of PD-(L)1 status. Pts received NIVO 240 mg Q2W or NIVO 3 mg/kg Q2W + IPI 1 mg/kg Q6W for ≤ 24 months (m) or until disease progression, unacceptable toxicity, or consent withdrawal. Imaging was conducted Q8W in year 1 and Q12W thereafter. Planned sample sizes were 23 pts for NIVO and 40 pts for NIVO + IPI. The primary endpoint was investigator-assessed objective response rate (ORR). Secondary endpoints included duration of response (DOR), investigator-assessed progression-free survival (PFS), and overall survival (OS). Results: 68 pts received NIVO (n = 25) or NIVO + IPI (n = 43) with ≥ 24 m follow-up (median: NIVO, 62.5 m; NIVO + IPI, 24.4 m). In the NIVO arm, median age was 66 yrs (range, 27–88), 10 (40.0%) pts had ECOG PS of 1, and 15 (60.0%) were treatment-naive. In the NIVO + IPI arm, median age was 70 yrs (range, 48–85), 27 (62.8%) pts had ECOG PS of 1, and 33 (76.7%) were treatment-naive. Treatment duration was 15.8 m in the NIVO arm, and 7.9 m for NIVO and 6.0 m for IPI in the NIVO + IPI arm. Efficacy and safety outcomes are summarized in the table. ORR was 60.0% (95% CI, 38.7–78.9) in the NIVO arm and 58.1% (95% CI, 42.1–73.0) in the NIVO + IPI arm. The most common reasons for treatment discontinuation were disease progression (NIVO, 28.0%; NIVO + IPI, 32.6%) or study-drug toxicity (NIVO, 20.0%; NIVO + IPI, 25.6%). There was 1 study drug-related death in each arm (NIVO, pneumonitis; NIVO + IPI, gastrointestinal motility disorder). Conclusions: Both NIVO and NIVO + IPI show durable clinical efficacy in advanced MCC. While the non-randomized trial design limits comparisons between the arms, results do not suggest additional efficacy benefit with IPI added to NIVO. Higher incidence of grade 3/4 TRAEs observed in the combination arm could have resulted in shorter treatment duration. Clinical trial information: NCT02488759 . [Table: see text]

Gold Nanorod–mesoporous silica core shell nanocomposites for NIR-II photothermal ablation and dual PD-L1/VEGF blockade therapy in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a common malignancy often associated with high angiogenesis and immune suppression in the tumor microenvironment (TME). Targeting of the tumor immune microenvironment via the dual blockade of vascular endothelial growth factor (VEGF) and programmed death-ligand 1 (PD-L1) offers longer progression-free survival as a first-line treatment for patients with unresectable HCC. However, certain critical factors limit the clinical success of this therapy, including low stability of antibody, poor tumor penetration, weak immunogenicity, uncontrollable biological activity, short internal half-life, and failures in lasting antitumor immune response. Nanoparticle-based photothermal therapy (PTT) offers the possibility to amplify anti-tumor immune responses, although some issues still limit the expansion of this strategy, such as limited tumor penetration depth for the activation of immune cells and a weak immune response in a powerful immunosuppressive TME. Here, we designed a nanoplatform (GSBVVP) for combined use with PTT and dual blockade of VEGF and PD-L1 to achieve an enhanced PTT-mediated immune response for the treatment of HCC. This nanoplatform is composed of a gold nanorod/mesoporous silica core-shell nanoparticle, which demonstrated excellent photothermal conversion efficiency and could ablate tumor cells under 1208-nm laser irradiation (NIR-II). GSBVVP was loaded with a small-molecule inhibitor of PD-L1, released by NIR-II triggering. This increased the number of infiltrating CD8+ T cells via the inhibition of T cell PD-1 binding to PD-L1 on tumor cells. A peptide vaccine on the surface of GSBVVP induced anti-VEGF antibody production, thereby blocking the secretion of VEGF by tumor cells in the TME and suppressing the angiogenesis signaling pathway. Animal studies verified that GSBVVP-mediated photothermal immunotherapy significantly inhibited primary tumor growth, suppressed metastasis and prevented tumor recurrence. Our strategy of bridging photothermal ablation with dual blockade VEGF and PD-L1 by nanotechnology may have a great potential for clinical translation, and it is promising for cancer immunotherapy.

Bispecific Aptamer-Based Recognition-then-Conjugation Strategy for PD1/PDL1 Axis Blockade and Enhanced Immunotherapy.

Cytotoxic T cells initiate antitumor effects mainly through direct interactions with tumor cells. As a counter to this, tumor cells can put the brakes on such T-cell activity via specific linkage between programmed death ligand 1 (PDL1) and its receptor programmed cell death protein 1 (PD1). Bispecific inhibitors that enabled synchronous blockade of PD1 and PDL1, thereby releasing the brakes on T-cell antitumor activity, should significantly improve the efficacy of immune checkpoint blockade (ICB) therapy. In this work, we identified a DNA aptamer, Ap3, that could specifically recognize PDL1 on tumor cells and competed with the binding of PD1. By integrating Ap3 with an anti-PD1 aptamer, the bispecific aptamer Ap3-7c was constructed, and it showed promise for improving the T-cell immune response. We further designed a dibenzocyclooctyne (DBCO)-labeled bispecific aptamer, D-Ap3-7c, allowing covalent conjugation of aptamers onto PD1 and PDL1 after specific cell recognition. Our in vivo studies showed that this recognition-then-conjugation strategy could induce a potent immunological effect against tumors. This work is expected to provide clues for antitumor immunotherapy.

Synergism of 64Cu-Labeled RGD with Anti-PD-L1 Immunotherapy for the Long-Acting Antitumor Effect.

We put forward a novel targeting-triggering-therapy (TTT) scheme that combines 64Cu-based targeted radionuclide therapy (TRT) with programmed death-ligand 1 (PD-L1)-based immunotherapy for enhancing therapeutic efficacy. The αvβ3 integrin-targeted 64Cu-DOTA-EB-cRGDfK (64Cu-DER) was synthesized. Flow cytometry, immunofluorescence staining, and RT-qPCR were performed to verify PD-L1 upregulation after irradiation with 64Cu-DER. Positron emission tomography imaging was performed to investigate the prominent tumor retention property of 64Cu-DER. In the MC38 tumor model, anti-PD-L1 antibody (αPD-L1 mAb) was delivered in a concurrent or sequential manner after 64Cu-DER was injected, followed by the testing of changes in tumor microenvironment (TME). PD-L1 was upregulated in a time- and dose-dependent manner after being induced by 64Cu-DER. The combination of 64Cu-DER TRT (925 MBq/kg) and αPD-L1 mAb (10 mg/kg) resulted in significant delay in tumor growth and protected against tumor rechallenge. Blockade of PD-L1 at 4 h after 64Cu-DER TRT (64Cu-DER + αPD-L1 mAb @ 4 h combination group) was able to achieve 100% survival rate, prevent tumor relapse, and evidently prolong the survival of mice. In summary, the combination of 64Cu-DER and αPD-L1 mAb in a time-dependent manner could be a promising approach to improve therapeutic efficacy. Understandably, this strategy has the potential to extend the scope of 64Cu-based TTT and merits translation into clinical practice for the better management of immune checkpoint blockade immunotherapy.

Pathologic complete response (pCR) to neoadjuvant treatment with or without atezolizumab in triple-negative, early high-risk and locally advanced breast cancer: NeoTRIP Michelangelo randomized study

High-risk triple-negative breast cancers (TNBCs) are characterized by poor prognosis, rapid progression to metastatic stage and onset of resistance to chemotherapy, thus representing an area in need of new therapeutic approaches. Programmed death-ligand 1 (PD-L1) expression is an adaptive mechanism of tumour resistance to tumour-infiltrating lymphocytes, which in turn are needed for response to chemotherapy. Overall, available data support the concept that blockade of PD-L1/programmed cell death protein 1 checkpoint may improve efficacy of classical chemotherapy. Two hundred and eighty patients with TNBC were enrolled in this multicentre study (NCT002620280) and randomized to neoadjuvant carboplatin area under the curve 2 and nab-paclitaxel 125 mg/m2 intravenously (i.v.) on days 1 and 8, without (n= 142) or with (n= 138) atezolizumab 1200 mg i.v. on day 1. Both regimens were given q3 weeks for eight cycles before surgery followed by four cycles of an adjuvant anthracycline regimen. The primary aim of the study was to compare event-free survival (EFS), and an important secondary aim was the rate of pathological complete response (pCR defined as the absence of invasive cells in breast and lymph nodes). The primary population for all efficacy endpoints is the intention-to-treat (ITT) population. The ITT analysis revealed that pCR rate after treatment with atezolizumab (48.6%) did not reach statistical significance compared to no atezolizumab [44.4%: odds ratio (OR) 1.18; 95% confidence interval 0.74-1.89; P= 0.48]. Treatment-related adverse events were similar with either regimen except for a significantly higher overall incidence of serious adverse events and liver transaminase abnormalities with atezolizumab. The addition of atezolizumab to nab-paclitaxel and carboplatin did not significantly increase the rate of pCR in women with TNBC. In multivariate analysis, the presence of PD-L1 expression was the most significant factor influencing the rate of pCR (OR 2.08). Continuing follow-up for the EFS is ongoing, and molecular studies are under way.

T cell-mediated elimination of cancer cells by blocking CEACAM6–CEACAM1 interaction

ABSTRACT Carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6), a cell surface receptor, is expressed on normal epithelial tissue and highly expressed in cancers of high unmet medical need, such as non-small cell lung, pancreatic, and colorectal cancer. CEACAM receptors undergo homo- and heterophilic interactions thereby regulating normal tissue homeostasis and angiogenesis, and in cancer, tumor invasion and metastasis. CEACAM6 expression on malignant plasma cells inhibits antitumor activity of T cells, and we hypothesize a similar function on epithelial cancer cells. The interactions between CEACAM6 and its suggested partner CEACAM1 on T cells were studied. A humanized CEACAM6-blocking antibody, BAY 1834942, was developed and characterized for its immunomodulating effects in co-culture experiments with T cells and solid cancer cells and in comparison to antibodies targeting the immune checkpoints programmed cell death protein 1 (PD-1), programmed death-ligand 1 (PD-L1), and T cell immunoglobulin mucin-3 (TIM-3). The immunosuppressive activity of CEACAM6 was mediated by binding to CEACAM1 expressed by activated tumor-specific T cells. BAY 1834942 increased cytokine secretion by T cells and T cell-mediated killing of cancer cells. The in vitro efficacy of BAY 1834942 correlated with the degree of CEACAM6 expression on cancer cells, suggesting potential in guiding patient selection. BAY 1834942 was equally or more efficacious compared to blockade of PD-L1, and at least an additive efficacy was observed in combination with anti-PD-1 or anti-TIM-3 antibodies, suggesting an efficacy independent of the PD-1/PD-L1 axis. In summary, CEACAM6 blockade by BAY 1834942 reactivates the antitumor response of T cells. This warrants clinical evaluation.

Potential PD-L1 expressing cytotoxic T-cell immunopathology in Alzheimer disease.

Growing evidence suggested that adaptive immunity involved Alzheimer's disease (AD). Peripheral blood mononuclear cell (PBMC) subpopulations and expression of immune checkpoints such as programmed death-ligand 1(PD-L1) and programmed cell death protein-1 (PD-1) could play roles in Alzheimer disease. The interaction of PD-L1/PD-1 lead PD-1 expressing T cells to attenuate T cell-activating signals. Recent studies had demonstrated the blockade of PD-L1/PD-1 axis modified brain pathology and restored cognitive performance in tauopathy murine model. However similar human experiment suggested controversial results in AD patients. To observe the changes of PBMC subpopulations and PD-L1/PD-1 expression in AD and healthy controls, we utilized flow cytometry, and applied t-distributed stochastic neighbor embedding (t-SNE) algorithm as a new approach to analyze results. AD patients (n=16) with different disease severity (CDR= 1 - 2) and healthy controls (n=16) were enrolled. Expression levels of PD-L1/PD-1 in AD patients and healthy controls were derived by flow cytometric analysis parameters. Moreover, a dimensionality reduction algorithm for visualized t-SNE, was implemented to analyze the PD-L1/PD-1 expressing cell clusters between AD patients and healthy controls. We found no significant PD-1 expression intensity difference between cytotoxic T lymphocytes (CTL) of AD patients and healthy controls. In AD patients, subpopulation of CTL expressing PD-L1 was elevated by 85.53%. Further, PD-L1 expressing CTL clusters between AD patients and healthy controls were compared. We observed that densities of PD-L1high CTL clusters are significantly higher than the healthy controls. Upregulation of PD-L1 and PD-L1 expressing CTL were increased in peripheral blood of AD patients, linking to newly found strong correlation between the level of PD-L1 positive CTL and markers which indicated negative immune climate. Abnormal adaptive immune response of CTL might associate with concurrent viral infection, intracellular bacterial infection, and underlying cancer in AD patients. Our results suggested a novel strategy to prevent AD progression with regulation of PD-L1 expressing CTL, and notation of underlying intracellular infection and malignancy for which could relate to dementia progression.

Rejuvenation of tumour-specific T cells through bispecific antibodies targeting PD-L1 on dendritic cells.

Bispecific T-cell engagers (BiTEs) preferentially targeting tumour-associated antigens and stimulating CD3-mediated signalling are being used in patients to treat acute B-cell lymphoblastic leukemia. However, the potency of BiTEs in solid tumours is limited by their short half-life and their severe toxicity at relevant therapeutic doses. Here we report the design and in vivo performance of a bispecific antibody that simultaneously targets the murine T-cell co-receptor CD3ε and the murine immune checkpoint programmed-death ligand 1 (PD-L1). In multiple syngeneic tumour models, the bispecific antibody generated higher antitumour immune responses than conventional BiTEs targeting tumour-associated antigens and CD3ε. We found that the durable antigen-specific T-cell responses resulted from the rejuvenation of CD8 T cells, owing to the blockade of PD-L1 on dendritic cells (but not on tumour cells) and co-stimulation by B7-1&2 (a peripheral membrane protein on dendritic cells). Bispecific T-cell engagers targeting dendritic cells rather than tumour cells may represent a general means of T-cell rejuvenation for durable cancer immunotherapy.

Dual checkpoint blockade of CD47 and PD-L1 using an affinity-tuned bispecific antibody maximizes antitumor immunity

BackgroundT cell checkpoint immunotherapies have shown promising results in the clinic, but most patients remain non-responsive. CD47-signal regulatory protein alpha (SIRPα) myeloid checkpoint blockade has shown early clinical activity in...

Avelumab in relapsed/refractory classical Hodgkin lymphoma: phase 1b results from the JAVELIN Hodgkins trial

AbstractThe 9p24.1 chromosomal alteration in classical Hodgkin lymphoma (cHL) is associated with increased expression of programmed death ligand 1 (PD-L1)/PD-L2 and an immunosuppressive tumor microenvironment. Blockade of PD-L1/PD-1 interactions with avelumab (anti–PD-L1) is hypothesized to restore antitumor immunity. JAVELIN Hodgkins was a phase 1b, multiple-dose, open-label, randomized, parallel-arm trial of avelumab in patients with relapsed/refractory (R/R) cHL. Primary end points included avelumab target occupancy by dose/schedule in peripheral blood immune cells and pharmacokinetic parameters. Secondary end points included safety and antitumor activity. Four dose levels and 2 dosing schedules were investigated: 70, 350, and 500 mg administered every 2 weeks; 500 mg every 3 weeks; and 10 mg/kg every 2 weeks. Thirty-one patients with R/R cHL were randomized; 9 (29.0%) and 20 (64.5%) had received 3 or ≥4 prior anticancer treatments, respectively. Target occupancy of >90% was observed across all treatment arms, throughout the dosing interval. Avelumab pharmacokinetic data were similar to those previously reported. The most common treatment-related adverse events of any grade were infusion-related reaction (30.0%), nausea (20.0%), increased alanine aminotransferase and rash (16.7% each), and fatigue (13.3%). The objective response rate (ORR) in all randomized patients was 41.9%, with a complete response rate of 19.4%; ORR in those with prior allogeneic hematopoietic stem cell transplant (allo-HSCT) was 55.6%. Due to decreased use of allo-HSCT in patients with R/R cHL, the expansion phase enrolling post–allo-HSCT patients was terminated. Avelumab was tolerable and demonstrated antitumor activity in heavily pretreated patients with cHL, suggesting that PD-L1 blockade may be sufficient for therapeutic benefit in cHL. This trial was registered at www.clinicaltrials.gov as #NCT02603419.

Programmed Death Ligand 1 Is Overexpressed in Liver Macrophages in Chronic Liver Diseases, and Its Blockade Improves the Antibacterial Activity Against Infections

Background and AimsBacterial infections are common and severe in cirrhosis, but their pathogenesis is poorly understood. Dysfunction of liver macrophages may play a role, but information about their function in cirrhosis is limited. Our aims were to investigate the specific profile and function of liver macrophages in cirrhosis and their contribution to infections. Macrophages from human cirrhotic livers were characterized phenotypically by transcriptome analysis and flow cytometry; function was assessed in vivo by single photon emission computerized tomography in patients with cirrhosis. Serum levels of specific proteins and expression in peripheral monocytes were determined by ELISA and flow cytometry. In vivo phagocytic activity of liver macrophages was measured by spinning disk intravital microscopy in a mouse model of chronic liver injury.Approach and ResultsLiver macrophages from patients with cirrhosis overexpressed proteins related to immune exhaustion, such as programmed death ligand 1 (PD‐L1), macrophage receptor with collagenous structure (MARCO), and CD163. In vivo phagocytic activity of liver macrophages in patients with cirrhosis was markedly impaired. Monocytes from patients with cirrhosis showed overexpression of PD‐L1 that paralleled disease severity, correlated with its serum levels, and was associated with increased risk of infections. Blockade of PD‐L1 with anti‐PD‐L1 antibody caused a shift in macrophage phenotype toward a less immunosuppressive profile, restored liver macrophage in vivo phagocytic activity, and reduced bacterial dissemination.ConclusionLiver cirrhosis is characterized by a remarkable impairment of phagocytic function of macrophages associated with an immunosuppressive transcriptome profile. The programmed cell death receptor 1/PD‐L1 axis plays a major role in the impaired activity of liver macrophages. PD‐L1 blockade reverses the immune suppressive profile and increases antimicrobial activity of liver macrophages in cirrhosis.

Abstract IA23: Marker-guided targeted therapy, PARP inhibitors, and novel post-translational modification of PD-L1

Abstract Poly (ADP-ribose) polymerase (PARP) inhibitors have emerged as promising therapeutics for many diseases, including cancer, in clinical trials. Three PARP inhibitors have been approved by the FDA to treat ovarian cancer with (olaparib and rucaparib) or without BRCA mutations (niraparib). BRCA1 and BRCA2 play essential roles in repairing DNA double-strand breaks, and a deficiency of BRCA proteins sensitizes cancer cells to PARP inhibition. My group recently demonstrated that receptor tyrosine kinase c-Met associates with and phosphorylates PARP1 at Tyr907. Phosphorylation of PARP1 Tyr907 increases PARP1 enzymatic activity and reduces binding to a PARP inhibitor, thereby rendering cancer cells resistant to PARP inhibition. Combining c-Met and PARP1 inhibitors synergized to suppress growth of breast cancer cells in vitro and xenograft tumor models. Similar synergistic effects were observed in a lung cancer xenograft tumor model. These results suggest that PARP1 pTyr907 abundance may predict tumor resistance to PARP inhibitors, and that treatment with a combination of c-Met and PARP inhibitors may benefit patients bearing tumors with high c-Met expression who do not respond to PARP inhibition alone (Nature Medicine 2016;22:194). We are working with clinicians at MD Anderson to initiate marker-guided clinical trials using combinational therapy of PARP and c-MET inhibitors. Extracellular interaction between programmed death ligand-1 (PD-L1) and programmed cell death protein-1 (PD-1) leads to tumor-associated immune escape. We further explored whether a cross-talk exists between PARP inhibition and PD-L1/PD-1 immune checkpoint axis and determined whether blockade of PD-L1/PD-1 potentiates PARP inhibitor (PARPi) in tumor suppression. PARP inhibitor (PARPi) treatment upregulates tumor cell PD-L1 expression, which attenuates PARPi efficacy via cancer-associated immunosuppression. The blockade of PD-L1 can restore the attenuated antitumor immunity and potentiate PARPi in tumor suppression (Clinical Cancer Res 2017;23:3711). My group also conducted a highly translational study, which identified a link between the ubiquitination and glycosylation pathways that regulate the immunosuppressive activity of PD-L1 (Nature Communications 2016;7:12632). We showed that glycosylation of PD-L1 is required for its protein stability and interaction with PD-1. In addition, we demonstrated that metformin-activated AMPK kinase downregulates PD-L1 through phosphorylation of Ser-195, which alters glycosylation of PD-L1 and functionally mimics anti-PD-L1 to block PD-L1/PD-1 interaction. It exhibited a highly potent synergistic effect of combination therapy of metformin, a drug that has been used to treat patients with diabetes and anti-CTLA4. The therapeutic efficacy could reach to survival rate of 50-70% in different syngeneic mouse models, which were treated by this combination therapy (Molecular Cell 2018;71:606). We also demonstrated that epithelial-mesenchymal transition (EMT) enhances PD-L1 in cancer stem-like cells (CSCs) by the EMT/β-catenin/STT3-PD-L1 signaling axis. Etoposide, a commonly used anticancer chemotherapy drug, is able to suppress this signaling axis, resulting in downregulation of PD-L1 to sensitize cancer cells to anti-Tim 3 therapy (Nature Communications 2018;9:1908). These findings provide potential therapeutic strategies to enhance cancer immune therapy efficacy by targeting PD-L1 stabilization to combat multiple cancer types. We identified TNFα as a major factor triggering cancer cell immunosuppression against T-cell surveillance via stabilization of programmed cell death-ligand 1 (PD-L1) (Cancer Cell 2016;30:925). To this end, in collaboration with StCube Pharmaceuticals Inc., we have developed monoclonal antibodies against glycosylation-specific PD-L1. Impressive therapeutic effect was observed through antibody-drug-conjugate approach (Cancer Cell 2018;33:187). Most recently, we unraveled an active defense system of PD-L1, previously known to only associate with passive defense activity. We discovered that cancer cells that express PD-L1 can secrete exosomes containing PD-L1 (exosome-PD-L1). The exosome-PD-L1 is able to directly interact with PD-1 to inhibit T-cell activation as well as T-cell killing activity (Cell Res 2018;28:862). Our new discoveries provide a new means to enhance therapeutic efficacy of immune checkpoint therapy. Citation Format: Mien-Chie Hung. Marker-guided targeted therapy, PARP inhibitors, and novel post-translational modification of PD-L1 [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr IA23.

Safety and Anti-Tumor Activity Study of Loncastuximab Tesirine and Durvalumab in Diffuse Large B-Cell, Mantle Cell, or Follicular Lymphoma

Introduction: Loncastuximab tesirine (Lonca) is an antibody-drug conjugate (ADC) comprising a humanized anti-CD19 antibody (Ab) conjugated to a pyrrolobenzodiazepine dimer toxin. In a Phase 1, first-in-human ADCT-402-101 clinical study, Lonca demonstrated single-agent anti-tumor activity with manageable toxicity in patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL), mantle cell lymphoma (MCL) and follicular lymphoma (FL). Durvalumab is a human monoclonal Ab of the immunoglobulin G-1 kappa subclass that blocks the interaction of programmed death-ligand 1 (PD-L1) with PD-1 on T-cells and with CD80 (B7.1) on other immune cells. Blockade of PD-L1/PD-1 and PD-L1/CD80 interactions releases the inhibition of immune responses, including those that may result in tumor elimination. Preclinical data, as well as early results from clinical trials combining ADCs and checkpoint inhibitors, show potentially increased effectiveness of these therapeutics when used in combination and provide the rationale for the current trial. Study Design and Methods: This is a Phase 1b, open-label, dose escalation (Part 1) and expansion (Part 2) trial of Lonca combined with durvalumab in patients with R/R DLBCL, MCL, or FL (NCT03685344). The key inclusion and exclusion criteria for the ADCT-402-104 study are reported in Table 1, and the dosing schema is presented in Figure 1. This trial will evaluate the safety and tolerability, preliminary anti-tumor activity, pharmacokinetics, pharmacodynamics, and immunogenicity of Lonca combined with durvalumab. Patients will receive Lonca once every 3 weeks for 2 doses in total, and durvalumab every 4 weeks for up to 1 year. Patients with only partial response or stable disease at the second disease evaluation may receive 2 additional doses of Lonca given once every 3 weeks. During Part 1, the dose of Lonca will be escalated using a classic 3+3 design with a fixed dose of durvalumab. Part 2 will consist of up to 3 expansion cohorts, one for each of the DLBCL, MCL, and FL populations. All patients in Part 2 will receive the dose of Lonca determined in Part 1, with a fixed dose of durvalumab. The trial opened in February 2019 and recruitment is ongoing. Study sponsored by ADC Therapeutics SA with the support of MedImmune Limited, a wholly-owned subsidiary of AstraZeneca Pharmaceuticals PLC, which supplies durvalumab (http://clinicaltrials.gov/show/NCT03685344). Disclosures Moskowitz: ADC Therapeutics: Research Funding; Merck: Consultancy, Research Funding; Celgene: Consultancy; Pharmacyclics: Research Funding; Seattle Genetics, Inc.: Consultancy, Research Funding; Genentech: Consultancy, Research Funding. Ungar:ADC Therapeutics: Employment, Other: Stock options. equity interest. Dautaj:ADC Therapeutics: Employment, Other: Stock options.

Abstract 2399: LAG-3/PD-L1 mAb2 can overcome PD-L1-mediated compensatory upregulation of LAG-3 induced by single-agent checkpoint blockade

Abstract FS118, currently tested in Phase I clinical trial in patients with advanced malignancies (NCT03440437), is a first-in-class bispecific antagonistic antibody (known as mAb2) targeting LAG-3 (Lymphocyte-Activation Gene 3) and PD-L1 (Programmed Death-Ligand 1), two immune checkpoint molecules that promote tumour escape from immune surveillance. Resistance to anti-PD-1 treatment is associated with upregulation of other checkpoint inhibitor receptors such as LAG-3. Dual targeting in immune checkpoint blockade (ICB) using bispecific monoclonal antibodies could potentially overcome this resistance, further increase the clinical benefit of ICB therapy and prevent relapse or resistance after immunotherapy. In a syngeneic model we used a surrogate mAb2 of FS118 (blocking both mPD-L1 and mLAG-3 binding to their receptors) to determine the effect of dual checkpoint blockade on tumour growth and to elucidate the modulation of the underlying immune mechanisms following treatment with the mAb2. Dual blockade of LAG-3 and PD-L1 with the surrogate mAb2 in the MC38 tumour-bearing mice model resulted in an increased anti-tumour activity comparable to a combination of the single agents targeting LAG-3 and PD-L1. Moreover, the mAb2 and single agent combination resulted in distinct modulations of LAG-3 and PD-L1 cell surface expression within the spleen and tumour microenvironment (TME). While both the mAb2 and combination therapy significantly reduced the number of free PD-L1 binding sites on CD4+ and CD8+ T cells in spleen and TME, total LAG-3 cell surface expression increased following treatment with the combination, whereas it reduced with mAb2 treatment. In addition, analysis of serum samples collected at various timepoints confirmed evidence of drug target engagement with increasing levels of both soluble LAG-3 (sLAG-3) and soluble PD-L1 (sPD-L1) in the mAb2 treated animals. Modulation of sPD-L1 levels in the serum of treated animals was also observed in cynomolgus monkeys treated with FS118. These data provide a strong rationale for investigating both cell surface and soluble LAG-3 and PD-L1 levels as potential pharmacodynamic biomarkers in further clinical development. Citation Format: Mustapha Faroudi, Matthew Kraman, Natalie Fosh, Claire Reader, Daniel Gliddon, Claire Seal, Christa Lucas, Alexander Koers, Mateusz Wydro, Michelle Morrow, Neil Brewis. LAG-3/PD-L1 mAb2 can overcome PD-L1-mediated compensatory upregulation of LAG-3 induced by single-agent checkpoint blockade [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 2399.

Neddylation inhibition upregulates PD-L1 expression and enhances the efficacy of immune checkpoint blockade in glioblastoma.

Pevonedistat (MLN4924), a specific NEDD8-activating enzyme inhibitor, has been considered as a promising treatment for glioblastoma, which is currently in Phase I/II clinical trials. On the other hand, inhibition of neddylation pathway substantially upregulates the expression of T cell negative regulator programmed death-ligand 1 (PD-L1), which might account for the potential resistance via evasion of immune surveillance checkpoints. Whether administration of anti-PD-L1 enhances the efficacy of pevonedistat through a cytotoxic T cell-dependent mechanism in glioblastoma needs to be investigated. Here, we report that depletion of neddylation pathway key enzymes markedly elevates PD-L1 expression in glioblastoma cancer cells. Consistently, neddylation inhibitor pevonedistat significantly enhances PD-L1 expression in both glioblastoma cancer cell lines and animal models. Mechanistically, pevonedistat increases PD-L1 mRNA levels mainly through inhibiting Cullin1-F-box and WD repeat domain-containing 7 E3 ligase activity and accumulating c-MYC proteins, a direct transcriptional activator of PD-L1 gene expression. In addition, inhibition of Cullin3 activity by pevonedistat also blocks PD-L1 protein degradation. Importantly, pevonedistat attenuates T cell killing through PD-L1 induction, and blockade of PD-L1 restores the sensitivity of pevonedistat-treated glioblastoma cancer cells to T cell killing. The combination of pevonedistat and anti-PD-L1 therapy compared to each agent alone significantly increased the therapeutic efficacy in vivo. Our study demonstrates inhibition of neddylation pathway suppresses cancer-associated immunity and provides solid evidence to support the combination of pevonedistat and PD-L1/programmed cell death protein 1 immune checkpoint blockade as a potential therapeutic strategy to treat glioblastoma.

Combined Inhibition of TGF-β Signaling and the PD-L1 Immune Checkpoint Is Differentially Effective in Tumor Models.

Antibodies blocking the programmed death-ligand 1 (PD-L1) have shown impressive and durable responses in clinical studies. However, this type of immunotherapy is only effective in a subset of patients and not sufficient for rejection of all tumor types. In this study, we explored in two mouse tumor models whether the antitumor effect could be enhanced by the combined blockade of PD-L1 and transforming growth factor-β (TGF-β), a potent immunosuppressive cytokine. The effect of anti-PD-L1 mouse monoclonal (mAb) and a TGF-β type I receptor small molecule kinase inhibitor (LY364947) was evaluated in the highly immunogenic mouse MC38 colon adenocarcinoma and the poorly immunogenic mouse KPC1 pancreatic tumor model. In the MC38 tumor model, LY364947 monotherapy did not show any antitumor effect, whereas treatment with anti-PD-L1 mAb significantly delayed tumor outgrowth. However, combination therapy showed the strongest therapeutic efficacy, resulting in improved long-term survival compared with anti-PD-L1 mAb monotherapy. This improved survival was associated with an increased influx of CD8+ T cells in the tumor microenvironment. In the KPC1 tumor model, LY364947 did not enhance the antitumor effect of anti-PD-L1 mAb. Despite this, delayed KPC1 tumor outgrowth was observed in the LY364947-treated group and this treatment led to a significant reduction of CD4+ T cells in the tumor microenvironment. Together, our data indicate that an additive anti-tumor response of dual targeting PD-L1 and TGF-β is dependent on the tumor model used, highlighting the importance of selecting appropriate cancer types, using in-depth analysis of the tumor microenvironment, which can benefit from combinatorial immunotherapy regimens.

Enhancement of Cytomegalovirus-Specific Cytokine Production after Modulation of the Costimulation in Kidney Transplant Patients.

Kidney transplantation is the therapy of choice for patients with end stage renal disease. Due to immunosuppressive treatment, patients are at risk for opportunistic infections. Cytomegalovirus (CMV) reactivation is highly relevant in kidney transplant recipients because it occurs—depending on the serological constellation of the donor and recipient—in more than half of the patients and influences patient outcome. Patients with CMV reactivation show decreased allograft and overall survival. Previous studies could demonstrate that transplant patients often show weak CMV-specific immunity. Besides immunosuppressive treatment, additional mechanisms may reduce CMV-specific immunocompetence such as enhanced negative costimulation. Hence, the aim of this study was to investigate if the function of CMV-specific cells of kidney transplant recipients could be restored by a modulation of costimulatory molecules. To address this question, lymphocytes of kidney transplant patients were stimulated with CMV-specific antigens and incubated with programmed death-ligand 1 (PD-L1), programmed cell death protein 1 (PD-1), or B- and T-lymphocyte attenuator (BTLA) antibodies. Afterwards, the IFN-γ, IL-21, and IL-17A production was measured by the ELISpot assay. It could be shown that a blockade of the ligand PD-L1 resulted in an increased CMV-specific IFN-γ, IL-21, and IL-17A secretion. The blockade of the receptor PD-1 distinctly enhanced the production of IL-21. BTLA antibodies, however, led only to a marginal increase of CMV-specific IFN-γ and of IL-21 production. Experiments in healthy controls could confirm the results of the kidney transplant recipients. Furthermore, they could demonstrate that treatment with the immunosuppressive drug tacrolimus resulted in decreased CMV-specific IFN-γ and of IL-21 production. Thus, our study could show for the first time that the blockade of the PD-L1/PD-1 pathway also modulates CMV-specific Th21 and Th17 cell function in kidney transplant recipients. Further studies are mandatory to clarify the role of Th21 and Th17 cells in CMV control of these patients.

Cancer Immunotherapy of TLR4 Agonist-Antigen Constructs Enhanced with Pathogen-Mimicking Magnetite Nanoparticles and Checkpoint Blockade of PD-L1.

Despite the tremendous potential of Toll-like receptor 4 (TLR4) agonists in vaccines, their efficacy as monotherapy to treat cancer has been limited. Only some lipopolysaccharides (LPS) isolated from particular bacterial strains or structures like monophosphoryl lipid A (MPLA) derived from lipooligosaccharide (LOS), avoid toxic overactivation of innate immune responses while retaining adequate immunogenicity to act as adjuvants. Here, different LOS structures are incorporated into nanoparticle-filled phospholipid micelles for efficient vaccine delivery and more potent cancer immunotherapy. The structurally unique LOS of the plant pathogen Xcc is incorporated into phospholipid micelles encapsulating iron oxide nanoparticles, producing stable pathogen-mimicking nanostructures suitable for targeting antigen presenting cells in the lymph nodes. The antigen is conjugated via a hydrazone bond, enabling rapid, easy-to-monitor and high-yield antigen ligation at low concentrations. The protective effect of these constructs is investigated against a highly aggressive model for tumor immunotherapy. The results show that the nanovaccines lead to a higher-level antigen-specific cytotoxic T lymphocyte (CTL) effector and memory responses, which when combined with abrogation of the immunosuppressive programmed death-ligand 1 (PD-L1), provide 100% long-term protection against repeated tumor challenge. This nanovaccine platform in combination with checkpoint inhibition of PD-L1 represents a promising approach to improve the cancer immunotherapy of TLR4 agonists.

Modulation of Gut Microbiota: A Novel Paradigm of Enhancing the Efficacy of Programmed Death-1 and Programmed Death Ligand-1 Blockade Therapy.

Blockade of programmed death 1 (PD-1) protein and its ligand programmed death ligand 1 (PD-L1) has been used as cancer immunotherapy in recent years, with the blockade of PD-1 being more widely used than blockade of PD-L1. PD-1 and PD-L1 blockade therapy showed benefits in patients with various types of cancer; however, such beneficial effects were seen only in a subgroup of patients. Improving the efficacy of PD-1 and PD-L1 blockade therapy is clearly needed. In this review, we summarize the recent studies on the effects of gut microbiota on PD-1 and PD-L1 blockade and discuss the new perspectives on improving efficacy of PD-1 and PD-L1 blockade therapy in cancer treatment through modulating gut microbiota. We also discuss the possibility that chronic infections or inflammation may impact on PD-1 and PD-L1 blockade therapy.

Cancer vaccine formulation dictates synergy with CTLA-4 and PD-L1 checkpoint blockade therapy

Anticancer vaccination is a promising approach to increase the efficacy of cytotoxic T lymphocyte-associated protein 4 (CTLA-4) and programmed death ligand 1 (PD-L1) checkpoint blockade therapies. However, the landmark FDA registration trial for anti-CTLA-4 therapy (ipilimumab) revealed a complete lack of benefit of adding vaccination with gp100 peptide formulated in incomplete Freund's adjuvant (IFA). Here, using a mouse model of melanoma, we found that gp100 vaccination induced gp100-specific effector T cells (Teffs), which dominantly forced trafficking of anti-CTLA-4-induced, non-gp100-specific Teffs away from the tumor, reducing tumor control. The inflamed vaccination site subsequently also sequestered and destroyed anti-CTLA-4-induced Teffs with specificities for tumor antigens other than gp100, reducing the antitumor efficacy of anti-CTLA-4 therapy. Mechanistically, Teffs at the vaccination site recruited inflammatory monocytes, which in turn attracted additional Teffs in a vicious cycle mediated by IFN-γ, CXCR3, ICAM-1, and CCL2, dependent on IFA formulation. In contrast, nonpersistent vaccine formulations based on dendritic cells, viral vectors, or water-soluble peptides potently synergized with checkpoint blockade of both CTLA-4 and PD-L1 and induced complete tumor regression, including in settings of primary resistance to dual checkpoint blockade. We conclude that cancer vaccine formulation can dominantly determine synergy, or lack thereof, with CTLA-4 and PD-L1 checkpoint blockade therapy for cancer.