Phase II study to determine the anti-tumor activity and safety of simlukafusp alfa (FAP-IL2v) combined with atezolizumab in esophageal cancer

PURPOSE

Reported here are results from the esophageal squamous cell carcinoma (SCC) cohort of a Phase II, non-comparative, basket study, evaluating the anti-tumor activity and safety of FAP-IL2v plus atezolizumab in patients with advanced/metastatic solid tumors (NCT03386721).

EXPERIMENTAL DESIGN

Eligible patients had an Eastern Cooperative Oncology Group performance status of 0-1; measurable metastatic, persistent, or recurrent esophageal SCC; progression on ≥1 prior therapy; and were checkpoint inhibitor naive. Patients received FAP-IL2v 10 mg plus atezolizumab 1200 mg intravenously every 3 weeks, or FAP-IL2v weekly for 4 weeks, then every 2 weeks, plus atezolizumab 840 mg intravenously every 2 weeks. Primary endpoint was investigator-assessed objective response rate (ORR).

RESULTS

In the response-evaluable population (N=34), best confirmed ORR was 20.6% (95% confidence interval [CI]: 10.4-36.8) with a complete response (CR) seen in one patient and partial responses (PR) in six patients. Disease control rate was 44.1% (CR=2.9%; PR=17.6%; stable disease [SD]=23.5%) and median duration of response was 10.1 months (95% CI: 5.6-26.7). Median progression-free survival was 1.9 months (95% CI: 1.8-3.7). Analysis of response by PD-L1 expression (Ventana SP263) resulted in an ORR of 26.7 % for patients with PD-L1-positive tumors (tumor area positivity [TAP] cut-off ≥1%; n=15) and 7.1% for patients with PD-L1-negative tumors (TAP cut-off <1%; n=14). Overall, the treatment combination was tolerable and adverse events were consistent with the known safety profiles of each drug.

CONCLUSIONS

FAP-IL2v plus atezolizumab demonstrated clinical activity and was tolerable in patients with previously treated esophageal SCC.

Phase 1 first-in-human dose-escalation study of ANV419 in patients with relapsed/refractory advanced solid tumors

Patients with advanced cancer, previously treated with immune checkpoint blockade therapy, may retain residual treatment when undergoing the initial infusion of experimental monotherapy in phase 1 clinical trials. ANV419, an antibody-cytokine fusion protein, combines interleukin-2 (IL-2) with an anti-IL-2 monoclonal antibody, aiming to stimulate the expansion of CD8 T and natural killer lymphocytes while restricting regulatory T lymphocytes. In the recent publication of the phase 1 dose escalation study of ANV419, a notable gap exists in detailed information regarding patients' prior antitumoral treatments, specifically programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) targeted monoclonal antibodies. Some patients likely retained residual anti-PD-1/PD-L1 monoclonal antibodies, potentially influencing the outcomes of ANV419. In a separate clinical cohort, we retrospectively measured the residual concentration of nivolumab and pembrolizumab, revealing persistent serum concentrations of anti-PD-1/PD-L1 antibodies even months after treatment cessation. This underscores the importance of comprehensively documenting prior immunotherapy details in clinical trials. Such information is crucial for understanding potential interactions that may impact both immunological and clinical effects.

Antibody drug conjugates in older patients: State of the art

More than half of cancer cases occur in patients aged 65 years or older. The efficacy and safety of antibody drug conjugates (ADCs) in older patients remains an unclear subject as available evidence is limited. Geriatric population is underrepresented in clinical trials. Consequently, most of our knowledge regarding innovative therapeutics was studied on a younger population. In this review of published literature, we report the available information on efficacy, safety and pharmacokinetics of FDA approved ADCs for hematologic malignancies and solid tumors in the geriatric population. We explore the results of clinical trials dedicated for older individuals as well as subgroup analyses of the geriatric population in major trials evaluating these drugs. Available data suggest a similar efficacy in older adults as compared to general population. However, older patients might be prone to a higher rate of adverse events in incidence with a potential impact on quality of life. We lack data to support primary dose reductions or schedule modifications in this category of patients. No pharmacokinetic differences were reported between age groups. It is crucial to encourage the development of clinical trials dedicated to older patients with geriatric parameters (G8 score, G-CODE…) so that results can be more representative of this population outside of clinical trials.

Profile and outcome of cancer patients enrolled in contemporary phase I trials

BACKGROUND

Phase I trials historically involved heavily pretreated patients (pts) with no more effective therapeutic options available and with poor expected outcomes. There are scare data regarding profile and outcomes of pts enrolled into modern phase I trials. Here, we sought to provide an overview of pts' profile and outcome into phase I trials at Gustave Roussy (GR).

METHODS

This is a monocentric retrospective study, including all pts enrolled into phase I trials at GR from 2017 to 2021. Data regarding pts' demographics, tumour types, investigational treatments and survival outcomes were collected.

RESULTS

In total, 9482 pts were referred for early phase trials; 2478 pts were screened, among which 449 (18.1%) failed screening; 1693 pts finally received at least one treatment dose as part of a phase I trial. Median age of pts was 59 years old (range, 18-88) and most common tumour types included gastrointestinal (25.3%), haematological (15%), lung (13.6%), genitourinary (10.5%) and gynaecologic cancers (9.4%). Amongst all pts treated and evaluable for response (1634 pts), objective response rate was 15.9% and disease control rate was 45.4%. Median progression-free survival and overall survival were, respectively, 2.6 months (95% confidence interval [95% CI], 2.3; 2.8) and 12.4 months (95% CI, 11.7; 13.6).

CONCLUSION

As compared with historical data, our study shows that outcomes of pts included into modern phase I trials have improved and that these trials constitute nowadays a valid and safe therapeutic option. These updated data provide facts for adapting the methodology, role and place of phase I trials over the next years.

Infections occurring following IL6 blockade for the management of cytokine release syndrome in onco-hematology patients

BACKGROUND

Cytokine release syndrome (CRS) is a common adverse event of CAR T cell or bispecific antibody (bsAb) therapy. Anti-IL6/IL6R drugs are used in the management of auto-immune diseases. Some reports showed increased risk of bacterial infection in this context. In onco-hematology, there are few data about the occurrence of infection after administration of an anti-IL6/IL6R for CRS.

METHODS

We retrospectively reviewed all consecutive patients treated in Gustave Roussy Cancer Campus between 2018 and 2021, who received anti-IL6/IL6R for CRS due to bsAb in phase I clinical trials or adoptive cellular therapy (ACT). We constituted a control group including all the patients treated in the same clinical trials or standard of care ACT, naïve of anti-IL6/IL6R.

RESULTS

Fifty-two patients have been included. In the anti-IL6/IL6R group (n = 26), five patients developed a grade 2 to 5 infection within a month after anti-IL6/IL6R treatment, including two grade 5 infections. In the control group (n = 26), only one patient had a grade 3 infection. The two patients who had grade 5 infections were treated for diffuse large B cell lymphoma (DLBCL), one with bsAb and the other with CAR T cell. Fifty percent (3/6) of DLBCL patients who received an anti-IL6/IL6R presented an infection, one of which was a grade 5. In solid tumor patients treated with bsAb and anti-IL6/IL6R, only one patient (/9, 11%) developed a grade 2 viral infection.

CONCLUSION

It seems that the use of anti-IL6/IL6R in CRS secondary to bsAb administration in solid tumors patients does not significantly increase the risk of infection, as opposed to DLBCL patients where secondary infection might be a concern.

Tarlatamab, a First-in-Class DLL3-Targeted Bispecific T-Cell Engager, in Recurrent Small-Cell Lung Cancer: An Open-Label, Phase I Study

PURPOSE

Small-cell lung cancer (SCLC) is an aggressive malignancy with limited treatments. Delta-like ligand 3 (DLL3) is aberrantly expressed in most SCLC. Tarlatamab (AMG 757), a bispecific T-cell engager molecule, binds both DLL3 and CD3 leading to T-cellb-mediated tumor lysis. Herein, we report phase I results of tarlatamab in patients with SCLC.

PATIENTS AND METHODS

This study evaluated tarlatamab in patients with relapsed/refractory SCLC. The primary end point was safety. Secondary end points included antitumor activity by modified RECIST 1.1, overall survival, and pharmacokinetics.

RESULTS

By July 19, 2022, 107 patients received tarlatamab in dose exploration (0.003 to 100 mg; n = 73) and expansion (100 mg; n = 34) cohorts. Median prior lines of anticancer therapy were 2 (range, 1-6); 49.5% received antiprogrammed death-1/programmed death ligand-1 therapy. Any-grade treatment-related adverse events occurred in 97 patients (90.7%) and grade b % 3 in 33 patients (30.8%). One patient (1%) had grade 5 pneumonitis. Cytokine release syndrome was the most common treatment-related adverse event, occurring in 56 patients (52%) including grade 3 in one patient (1%). Maximum tolerated dose was not reached. Objective response rate was 23.4% (95% CI, 15.7 to 32.5) including two complete and 23 partial responses. The median duration of response was 12.3 months (95% CI, 6.6 to 14.9). The disease control rate was 51.4% (95% CI, 41.5 to 61.2). The median progression-free survival and overall survival were 3.7 months (95% CI, 2.1 to 5.4) and 13.2 months (95% CI, 10.5 to not reached), respectively. Exploratory analysis suggests that selecting for increased DLL3 expression can result in increased clinical benefit.

CONCLUSION

In patients with heavily pretreated SCLC, tarlatamab demonstrated manageable safety with encouraging response durability. Further evaluation of this promising molecule is ongoing.

Society for Immunotherapy of Cancer (SITC) consensus definitions for immune checkpoint inhibitor-associated immune-related adverse events (irAEs) terminology

Immune-related adverse events (irAEs) associated with immune checkpoint inhibitor (ICI) therapy may vary substantially in their clinical presentation, including natural history, outcomes to treatment, and patterns. The application of clinical guidelines for irAE management can be challenging for practitioners due to a lack of common or consistently applied terminology. Furthermore, given the growing body of clinical experience and published data on irAEs, there is a greater appreciation for the heterogeneous natural histories, responses to treatment, and patterns of these toxicities, which is not currently reflected in irAE guidelines. Furthermore, there are no prospective trial data to inform the management of the distinct presentations of irAEs. Recognizing a need for uniform terminology for the natural history, response to treatment, and patterns of irAEs, the Society for Immunotherapy of Cancer (SITC) convened a consensus panel composed of leading international experts from academic medicine, industry, and regulatory agencies. Using a modified Delphi consensus process, the expert panel developed clinical definitions for irAE terminology used in the literature, encompassing terms related to irAE natural history (ie, re-emergent, chronic active, chronic inactive, delayed/late onset), response to treatment (ie, steroid unresponsive, steroid dependent), and patterns (ie, multisystem irAEs). SITC developed these definitions to support the adoption of a standardized vocabulary for irAEs, which will have implications for the uniform application of irAE clinical practice guidelines and to enable future irAE clinical trials.

First-in-human phase I study of the OX40 agonist GSK3174998 with or without pembrolizumab in patients with selected advanced solid tumors (ENGAGE-1)

BACKGROUND

The phase I first-in-human study ENGAGE-1 evaluated the humanized IgG1 OX40 agonistic monoclonal antibody GSK3174998 alone (Part 1 (P1)) or in combination with pembrolizumab (Part 2 (P2)) in patients with advanced solid tumors.

METHODS

GSK3174998 (0.003-10 mg/kg) ± pembrolizumab (200 mg) was administered intravenously every 3 weeks using a continuous reassessment method for dose escalation. Primary objectives were safety and tolerability; secondary objectives included pharmacokinetics, immunogenicity, pharmacodynamics, and clinical activity.

RESULTS

138 patients were enrolled (45 (P1) and 96 (P2, including 3 crossovers)). Treatment-related adverse events occurred in 51% (P1) and 64% (P2) of patients, fatigue being the most common (11% and 24%, respectively). No dose-toxicity relationship was observed, and maximum-tolerated dose was not reached. Dose-limiting toxicities (P2) included Grade 3 (G3) pleural effusion and G1 myocarditis with G3 increased troponin. GSK3174998 ≥0.3 mg/kg demonstrated pharmacokinetic linearity and >80% receptor occupancy on circulating T cells; 0.3 mg/kg was selected for further evaluation. Limited clinical activity was observed for GSK3174998 (P1: disease control rate (DCR) ≥24 weeks 9%) and was not greater than that expected for pembrolizumab alone (P2: overall response rate 8%, DCR ≥24 weeks 28%). Multiplexed immunofluorescence data from paired biopsies suggested that increased infiltration of natural killer (NK)/natural killer T (NKT) cells and decreased regulatory T cells (Tregs) in the tumor microenvironment may contribute to clinical responses: CD16+CD56-CD134+ NK /NKT cells and CD3+CD4+FOXP3+CD134+ Tregs exhibited the largest magnitude of change on treatment, whereas CD3+CD8+granzyme B+PD-1+CD134+ cytotoxic T cells were the least variable. Tumor gene expression profiling revealed an upregulation of inflammatory responses, T-cell proliferation, and NK cell function on treatment with some inflammatory cytokines upregulated in peripheral blood. However, target engagement, evidenced by pharmacologic activity in peripheral blood and tumor tissue, did not correlate with clinical efficacy. The low number of responses precluded identifying a robust biomarker signature predictive of response.

CONCLUSIONS

GSK3174998±pembrolizumab was well tolerated over the dose range tested and demonstrated target engagement. Limited clinical activity does not support further development of GSK3174998±pembrolizumab in advanced cancers.

TRIAL REGISTRATION NUMBER

NCT02528357.

Paradoxical cancer cell stimulation by IFNγ drives tumor hyperprogression upon checkpoint blockade immunotherapy

Hyperprogression is a paradoxical cancer acceleration observed in a minority of patients upon immunotherapy. In this issue of Cancer Cell, Li et al demonstrate that hyperprogressive tumors upregulate the Wnt/β-catenin pathway. This activation was subsequent to an oncogenic FGF2-mediated autocrine loop generated by the IFNγ released by CD8⁺ T cells upon PD-1/PD-L1 blockade.

Better than RECIST and faster than iRECIST: defining the Immunotherapy Progression Decision score to better manage progressive tumors on immunotherapy

PURPOSE

The objective of the study is to propose the immunotherapy progression decision (iPD) score, a practical tool based on patient features that are available at the first evaluation of immunotherapy treatment, to help oncologists decide whether to continue the treatment or switch rapidly to another therapeutic line when facing a progressive disease patient at the 1st evaluation.

METHODS

This retrospective study included 107 patients with progressive disease at first evaluation according to RECIST 1.1. Clinical, radiological, and biological data at baseline and 1st evaluation were analyzed. An external validation set consisting of 31 patients with similar baseline characteristics was used for the validation of the score.

RESULTS

Variables were analyzed in a univariate study. The iPD score was constructed using only independent variables, each considered as a worsening factor for the survival of patients. The patients were stratified in three groups: Good Prognosis (GP), Poor Prognosis (PP) and Critical Prognosis (CP). Each group showed significantly different survivals (GP: 11.4, PP: 4.4, CP: 2.3 months median OS, p<0.001 log-rank-test). Moreover, the iPD score was able to detect the pseudo-progressors better than other scores. On the validation set, CP patients had significantly worse survival than PP and GP patients (p<0.05, log-rank-test).

CONCLUSION

The iPD score provides oncologists with a new evaluation, computable at first-progression, to decide if treatment should be continued (for the GP group), or immediately changed for the PP and CP groups. Further validation on larger cohorts is needed to prove its efficacy in clinical practice.

Genomic Instability and Pro-Tumoral Inflammation are associated with Primary Resistance to Anti-PD1 + Anti-Angiogenesis in Malignant Pleural Mesothelioma

Cancer immunotherapy combinations have recently shown to improve the overall survival of advanced mesotheliomas especially for patients responding to those treatments. We aimed to characterize the biological correlates of malignant pleural mesotheliomas primary resistance to immunotherapy and anti-angiogenics by testing the combination of pembrolizumab, an anti-PD-1 antibody, and nintedanib, a pan anti-angiogenic tyrosine kinase inhibitor (TKI), in the multi-center PEMBIB trial (NCT02856425). Thirty patients with advanced malignant pleural mesothelioma were treated and explored. Unexpectedly, we found that refractory patients were actively recruiting CD3+CD8+ cytotoxic T-cells in their tumors through CXCL9 tumor release upon treatment. However, these patients displayed high levels of somatic copy number alterations in their tumors that correlated with high blood and tumor levels of IL-6 and CXCL8. Those pro-inflammatory cytokines resulted in higher tumor secretion of VEGF and tumor enrichment in regulatory T-cells. Advanced mesothelioma should further benefit from stratified combination therapies adapted to their tumor biology.

Protective effect of obesity on survival in cancers treated with immunotherapy vanishes when controlling for type of cancer, weight loss and reduced skeletal muscle

INTRODUCTION

Association of high body mass index (BMI) with longer survival has been reported in patients on immune checkpoint inhibitors (ICIs), but results are inconsistent. This 'obesity paradox' is potentially confounded by the effects of BMI change over time and of skeletal muscle depletion.

METHODS

We conducted a secondary analysis of a prospective cohort, including consecutive patients receiving ICI treatment for melanoma (n = 411) and non-small cell lung cancer (NSCLC) (n = 389) in routine care.

RESULTS

In the univariable analysis of the entire population, overweight/obesity (BMI ≥ 25 kg/m²) was associated with longer survival (p < 0.01); however, this effect was limited to NSCLC (p < 0.01) and was absent in melanoma. Weight loss (WL) and reduced skeletal muscle mass were observed in patients within all BMI categories. WL was associated with shorter survival in multivariable analysis in both tumour sites (p < 0.01), and for NSCLC, BMI lost significance when WL was included (p = 0.13). In models further adjusted for CT-defined skeletal muscle mass, WL retained significance for both tumour types (p < 0.01), and reduced skeletal muscle only for NSCLC (p = 0.02) was associated with shorter survival. WL retained significance when biomarkers (lactate dehydrogenase enzyme, albumin and derived neutrophil to lymphocyte ratio) were added to the multivariable model.

CONCLUSIONS

The so-called 'obesity paradox', counterintuitive association between high BMI and longer survival, vanished when controlling for confounders, such as type of cancer, and manifestations of depletion (WL and reduced skeletal muscle mass).

Synergizing liver systemic treatments with interventional oncology: friend or foe?

Interventional radiology techniques provide excellent local tumor control for small tumors in various organs, but several limitations can hamper the oncological outcomes such as the tumor size or the number of lesions. Technical improvements, optimal patient selection and combination with systemic therapies, including immune checkpoint inhibitors, have been successfully developed to overcome these barriers.In this setting, chemotherapy and targeted therapies aim to diminish the tumor burden in addition to local treatments, while immunotherapies may have a synergistic effect in terms of mechanism of action on the tumor cell as well as the immune environment, with multiple treatment combinations being available. Finally, interventional Rrdiology treatments often increase tumor antigen exposure to the immune system, and thus stimulate a specific antitumor immune response that can act beyond the treated site. Notwithstanding their many benefits, combination treatment may also result in complications, the most feared may be auto-immune-related adverse events.In early studies, several combined therapies have shown promising levels of safety and efficacy, particularly in hepatocellular carcinoma.This review provides a comprehensive and up-to-date overview of results of combined therapies for primary and secondary liver malignancies. Recent advances and future perspectives will be discussed.

PALLIA 10 score in phase I cancer studies

OBJECTIVE

Phase I clinical trials usually include patients with advanced disease who have failed standard therapies and should benefit from early palliative care. We try to assess whether PALLIA 10, a score developed in France to help identify patients who might benefit from a palliative care referral, could be used in a phase I department trial.

METHODS

We assessed PALLIA 10 score and other prognostic factors in patients enrolled in phase I trials at Gustave Roussy Cancer Center prospectively during two periods of time (cohort 1 (C1) and 2 (C2)). A double-blind assessment of the PALLIA 10 score was done in C2 by a palliative care specialist and a nurse.

RESULTS

From 1 July 2018 to 1 November 2018 (C1) and from 1 December 2020 to 16 April 2021 (C2), 86 patients were assessed in C1 and 302 in C2. Median PALLIA 10 was very low in both cohorts (median 1, range 1-5 in C1 and 1-8 in C2). On C1 and C2, 12% and 5% of patients had a dedicated palliative consultation. In C2, assessment of PALLIA 10 score was significantly different between palliative care physician (median 5, range 3-8), phase I physician (median 1, range 1-6) and phase I nurse (median 3, range 1-8) (p<0.001).

CONCLUSION

Median PALLIA 10 score was low when assessed by the phase I physician, which suggests the need for a better tool and appropriate clinician's education to implement early palliative care in clinical practice and trials.

Immunosenescence, inflammaging, and cancer immunotherapy efficacy

INTRODUCTION

Immunosenescence is a progressive remodeling of immune functions associated with a decreased ability of the immune system to set up an efficient immune response, both innate and adaptive, with an increase of highly differentiated T cells at the expense of naive T cells. The incidence and prevalence of most cancers increase with age, which can partly be explained by tumor escape mechanisms and decreased immunosurveillance. Aging is also associated with inflammaging, a low-grade proinflammatory state characterized by an increase in inflammatory mediators. Anti-cancer immunotherapy has profoundly changed the landscape of oncology therapy in the last 10 years. Modern T-cell targeted therapies such as bispecific T cell engagers, CAR-T cells, or immune checkpoint blockers may be theoretically affected by immunosenescence or inflammaging.

AREAS COVERED

A bibliographic review through PubMed and Embase was carried out using the following search terms: 'immunosenescence,' 'immunotherapy,' 'inflammaging,' 'bispecific antibodies,' 'CAR-T cells,' 'immune checkpoint blockers,' and 'older patients.'

EXPERT OPINION

This review explores the potential impact of immunosenescence and inflammaging on anti-cancer immunotherapy and therapeutic strategies that could counter immune senescence. A more dedicated research on immunosenescence biomarkers in future clinical trials is warranted for the development of new, more effective and safer therapies.

Abstract 1993: Biomarker analyses from the Phase I clinical trial of the first-in-class SIRPa immune checkpoint inhibitor BI765063 in patients with advanced solid tumors

Background: BI 765063 (OSE-172) is a humanised IgG4 monoclonal antibody which binds selectively to the V1 allele of Signal Regulatory Protein α [SIRPα] blocking the SIRPα/CD47 “don't eat me” pathway. Preclinical studies showed that SIRPα blockage led to macrophage and T-cell recruitment into tumor xenografts, and induced upregulation of chemokines, cytokines and adaptive immune function genes in human tumor explants (Gauttier et al., 2020). The goal of the biomarker analyses was to characterize the BI 765063 impact on peripheral blood immune cells (PBMCs) and the tumor microenvironment (TME).

Methods: Fifty patients (26 V1/V1, 24 V1/V2) received BI 765063 IV from 0.02 mg/kg to 36 mg/kg every 3 weeks. Paired tumor biopsies were collected before and 2 weeks after first BI 765063 infusion. PBMCs were collected before, then 4 h, 1, 14, and 21 days after first infusion. BI 765063 receptor occupancy (RO) was determined on peripheral CD14+ monocytes. Immunophenotyping of PBMCs was performed by flow-cytometry. TME was analysed with a Brightplex® IHC panel including CD8+ T-cells, CD68+ macrophages, SIRPα, CD47, and PD-L1. Tumor gene expression profiling was performed using the Pan Cancer Immune gene set.

Results: BI 765063 full RO saturation was achieved at trough levels (C2D1, pre-dose) in V1/V1 patients treated with doses of 6 mg/kg and higher, while V1/V2 patients showed a more heterogeneous RO ranging from 40-80%, reaching an apparent saturation at ≥ 12 mg/kg. An increase of activated CD80+/CD14+ and CD40+/CD14+ monocytes in PBMCs was observed at 24 h post-treatment in both, V1/V1 and V1/V2 patients. In paired tumor biopsies, IFNγ, MHCII antigen presentation gene pathways, and CCL7 transcripts appeared to be upregulated at C1D15 in patients with a systemic exposure of ≥ 100 µg/ml. One patient with hepatocellular carcinoma (HCC) and liver and lung metastases treated with BI 765063 monotherapy at 24 mg/kg achieved partial response (Champiat et al., ASCO, 2021). Baseline tumor biopsy of that patient showed that 66% of HCC tumor cells were CD47+ and 87% of CD68+ macrophages were SIRPα+. Furthermore, high levels of CD8+ T-cells were observed at baseline. At C1D15 increased CD68+ macrophage infiltration, sustained CD8 T-cell tumor accumulation and higher PD-L1 CPS (48% at baseline vs 75% at C1D15) were observed. Analysis of paired tumor biopsies in other patients showed that often, increased levels of tumor CD68+ macrophages were accompanied by CD8+ T-cell infiltration.

Conclusion: This early biomarker analysis in patients with a wide range of solid tumors and treated with the first-in-class SIRPa inhibitor BI 765063 show encouraging signs of potentially mode-of-action related changes, both in peripheral blood and the TME. These early signals will be further evaluated in similar samples from the ongoing expansion cohorts in more homogeneous patient populations.

Citation Format: Stephane Champiat, Philippe A. Cassier, Nuria Kotecki, Carlos Gomez-Roca, Aurélien Marabelle, Armelle Vinceneux, Christiane Jungels, Mabrouk Elgadi, Ralph Graeser, Thomas Vandewalle, Isabelle Girault, Nina Salabert-Le Guen, Nicolas Poirier, Bérangère Vasseur, Dominique Costantini, Claudia Fromond, Jean-Pierre Delord. Biomarker analyses from the Phase I clinical trial of the first-in-class SIRPa immune checkpoint inhibitor BI765063 in patients with advanced solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1993.

Abstract CT188: ICT01, an anti-butyrophilin 3A targeted mAb activating g9d2 T cells, induces immune remodeling of the tumor microenvironment and clinical responses in combination with pembrolizumab in patients with advanced solid tumors who failed prior checkpoint inhibitor therapy: EVICTION Trial

Background: γ9δ2 T cells are part of the innate-like immune response to malignancies and have the ability to bridge to the adaptive immune response via cytokine release (e.g., IFNγ and TNFα). Butyrophilin 3A is a novel checkpoint molecule required to activate γ9δ2 T cells highly expressed on immune and malignant cells, and the target of a monoclonal antibody ICT01. ICT01 induces activation/migration of γ9δ2 T cells from the blood to induce immune remodeling of the tumor microenvironment at doses ≥700 μg being tested in the ongoing EVICTION clinical trial (NCT04243499) (AACR 2021, CT034). In vitro studies showed that ICT01 induces upregulation of PD-1 on γ9δ2 T cells and that the combination with pembrolizumab leads to enhanced cancer cell killing, providing scientific rationale for evaluating this combination.

Methods: EVICTION is an ongoing Phase 1/2a, international, open-label trial with Group C assessing ICT01 (IV Q3W) plus pembrolizumab (200mg IV Q3W) in patients with bladder cancer, HNSCC, melanoma, or NSCLC who failed ≥1 CPI. Pharmacodynamic activity was monitored by immunophenotyping and cytokine level analysis. Tumor biopsies (baseline, Day 28) were used for immunohistochemistry of BTN3A and tumor-infiltrating lymphocytes, and gene expression profiling. Efficacy evaluations by i/RECIST 1.1 were conducted every 8 weeks.

Results: Five Group C patient cohorts have been enrolled and treated with ICT01 doses of 700μg, 2mg, 7mg, 20mg or 75mg (n=30) plus pembrolizumab, with the 200mg ICT01 cohort enrolling currently. To date, no DLTs have been observed with the combination. First-dose fever and chills (Grade 1/2) were the most common AEs that increased in frequency up to 75mg (100%, n=6), without any increase in severity, and rarely recur with subsequent dosing. ICT01+pembrolizumab induced trafficking of &gt;95% of circulating γ9δ2 T cells within 30 min post ICT01 (≥700 μg), which was sustained for 21 days at 75mg. Transient, dose-dependent increases in serum cytokines at 30 min (TNFα) or 4h (IFNγ) post-dose were correlated with baseline γ9δ2 T cell counts and returned to baseline by 24 hrs post dose. Baseline γ9δ2 T cell count also correlated with increases in tumor infiltration of γδ, CD3, and CD8 T cells, confirming the ability to remodel the TME, and the potential to select/enrich patients with higher baseline γ9δ2 T cell counts. Sixteen patients (9/16 pembro-experienced, 5/16 received &gt;1 prior CPI) were efficacy-evaluable at ≥Week 8 by RECIST1.1 at ICT01 doses up to 20 mg, with an observed disease control rate of 44% including 3 confirmed PRs beyond 6 months: bladder (2mg), melanoma (2mg), NSCLC (7mg). The Ipi/Nivo-refractory melanoma patient with PR also achieving a CR on their non-target lesion brain metastasis at 6 months. Data from the 75 and 200mg cohorts will be presented.

Conclusion: The immune remodeling of the TME by ICT01-activated γ9δ2 T cells is associated with clinical benefit in CPI-experienced patients when used in combination with pembrolizumab. The selection of patients with higher baseline γ9δ2 T cells may improve the response profile to this novel therapeutic combination in CPI-failure patients, which will be tested in the Phase 2a portion of EVICTION starting in Q2 2022.

Citation Format: Stephane Champiat, Martin Wermke, Johann de Bono, Aurelien Marabelle, Christiane Jungels, Cécile Vicier, Norbert Vey, Catrin List, Katrin Wetzko, Leo Ruhnke, Elena Garralda, Vladimir Galvão de Aguiar, Patricia LoRusso, Nuria Kotecki, Aude De Gassart, Emmanuel Valentin, Patrick Brune, Marina Iché, Céline Leparquier, Daniel Olive, Paul Frohna. ICT01, an anti-butyrophilin 3A targeted mAb activating g9d2 T cells, induces immune remodeling of the tumor microenvironment and clinical responses in combination with pembrolizumab in patients with advanced solid tumors who failed prior checkpoint inhibitor therapy: EVICTION Trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT188.

PD-1 Blockade in Solid Tumors with Defects in Polymerase Epsilon

Missense mutations in the polymerase epsilon (POLE) gene have been reported to generate proofreading defects resulting in an ultramutated genome and to sensitize tumors to checkpoint blockade immunotherapy. However, many POLE-mutated tumors do not respond to such treatment. To better understand the link between POLE mutation variants and response to immunotherapy, we prospectively assessed the efficacy of nivolumab in a multicenter clinical trial in patients bearing advanced mismatch repair-proficient POLE-mutated solid tumors. We found that only tumors harboring selective POLE pathogenic mutations in the DNA binding or catalytic site of the exonuclease domain presented high mutational burden with a specific single-base substitution signature, high T-cell infiltrates, and a high response rate to anti-PD-1 monotherapy. This study illustrates how specific DNA repair defects sensitize to immunotherapy. POLE proofreading deficiency represents a novel agnostic biomarker for response to PD-1 checkpoint blockade therapy.

SIGNIFICANCE

POLE proofreading deficiency leads to high tumor mutational burden with high tumor-infiltrating lymphocytes and predicts anti-PD-1 efficacy in mismatch repair-proficient tumors. Conversely, tumors harboring POLE mutations not affecting proofreading derived no benefit from PD-1 blockade. POLE proofreading deficiency is a new tissue-agnostic biomarker for cancer immunotherapy. This article is highlighted in the In This Issue feature, p. 1397.

Interim safety and efficacy results from AURELIO-03: A phase 1 dose escalation study of the IL-2/IL-15 receptor βγ superagonist SOT101 as a single agent and in combination with pembrolizumab in patients with advanced solid tumors

2502

Background: SOT101 (previously SO-C101) is a fusion protein of IL-15 and the IL-15 receptor α sushi+ domain. Synergistic effects of SOT101 and an anti-programmed cell death protein 1 antibody have been validated in various tumor mouse models inducing a protective memory response. Methods: In this phase 1 study, safety, tolerability, pharmacokinetics, pharmacodynamics, and preliminary efficacy of increasing doses of SOT101 administered subcutaneously were investigated in patients (pts) with advanced solid tumors as monotherapy (Part A) and in combination with pembrolizumab every 3-week cycle (Part B). Dose escalation followed a standard 3+3 design. Data cut-off was 26 January 2022. Results: Overall, 51 pts were treated: 30 in Part A monotherapy at 0.25 to 15 μg/kg SOT101 and 21 in Part B combination therapy (Tx) at 1.5 to 12 μg/kg SOT101. The median (range) number of previous lines of Tx was 3 (1-9) in Part A and 2 (1-6) in Part B. In Part A, 19 (63.3%) pts had previous check-point inhibitor (CPI) Tx, of whom 9 (30 %) were refractory, 5 (16.7%) relapsed. In Part B, 11 pts (52.4%) had previous CPI Tx, and the outcome was 9 (42.9%) pts relapsed, 1 (4.8%) refractory. The most common treatment-emergent adverse events (TEAEs) were transient, and included pyrexia, chills, lymphopenia, anemia, transaminase elevation and vomiting. Most TEAEs were ≤ Grade 2. No treatment-related death was reported. For both monotherapy and combination Tx, the recommended phase 2 dose of SOT101 was determined to be 12 μg/kg. In Part A, in 13 pts at 6 to 12 μg/kg SOT101, the observed clinical benefit rate was 38%. A partial response (PR) was confirmed in 1 pt with skin squamous cell carcinoma, CPI refractory, PR duration 46 days (d), on treatment 154 d. Four pts (all CPI pretreated) had stable disease (SD), range 33-183 d. Final median duration on treatment was 84 d, range 43-183 d. The median duration of clinical benefit was 190 d. In Part B, the observed clinical benefit rate across all SOT101 doses was 63%. A complete response (CR) was confirmed in 1 pt with mesothelioma, CPI naïve, starting at the first tumor assessment, and the pt is ongoing in cycle 5. Three pts, 2 CPI pretreated, had a PR, range 51-232 d, 2 ongoing with PR, and 1 Tx discontinuation while still on PR. Five pts, 3 CPI pretreated, had SD, range 92-340 d, 2 ongoing with SD. The 3 CPI pretreated pts had SD range 41-340 d, 1 pt ongoing. The preliminary median duration on combination Tx was 113 d, range 7-429 d. The preliminary median duration of clinical benefit was 131 d. Conclusions: SOT101 as monotherapy and in combination with pembrolizumab showed a favorable safety profile. Highly promising efficacy signals with one ongoing CR and several long-lasting PRs were reported in CPI-naïve and CPI pretreated pts, including CPI-resistant tumors. Clinical trial information: NCT04234113.

Anti-CSF-1R emactuzumab in combination with anti-PD-L1 atezolizumab in advanced solid tumor patients naïve or experienced for immune checkpoint blockade

BACKGROUND

This phase 1b study (NCT02323191) evaluated the safety, antitumor activity, pharmacokinetics, and pharmacodynamics of colony-stimulating factor-1 receptor-blocking monoclonal antibody (mAb) emactuzumab in combination with the programmed cell death-1 ligand (PD-L1)-blocking mAb atezolizumab in patients with advanced solid tumors naïve or experienced for immune checkpoint blockers (ICBs).

METHODS

Emactuzumab (500-1350 mg flat) and atezolizumab (1200 mg flat) were administered intravenously every 3 weeks. Dose escalation of emactuzumab was conducted using the 3+3 design up to the maximum tolerated dose (MTD) or optimal biological dose (OBD). Extension cohorts to evaluate pharmacodynamics and clinical activity were conducted in metastatic ICB-naive urothelial bladder cancer (UBC) and ICB-pretreated melanoma (MEL), non-small cell lung cancer (NSCLC) and UBC patients.

RESULTS

Overall, 221 patients were treated. No MTD was reached and the OBD was determined at 1000 mg of emactuzumab in combination with 1200 mg of atezolizumab. Grade ≥3 treatment-related adverse events occurred in 25 (11.3%) patients of which fatigue and rash were the most common (14 patients (6.3%) each). The confirmed objective response rate (ORR) was 9.8% for ICB-naïve UBC, 12.5% for ICB-experienced NSCLC, 8.3% for ICB-experienced UBC and 5.6% for ICB-experienced MEL patients, respectively. Tumor biopsy analyses demonstrated increased activated CD8 +tumor infiltrating T lymphocytes (TILs) associated with clinical benefit in ICB-naïve UBC patients and less tumor-associated macrophage (TAM) reduction in ICB-experienced compared with ICB-naïve patients.

CONCLUSION

Emactuzumab in combination with atezolizumab demonstrated a manageable safety profile with increased fatigue and skin rash over usual atezolizumab monotherapy. A considerable ORR was particularly seen in ICB-experienced NSCLC patients. Increase ofCD8 +TILs under therapy appeared to be associated with persistence of a TAM subpopulation.

503 Clinical activity of ICT01, an anti-BTN3A-targeted, γ9δ2-activating mAb, alone and in combination with pembrolizumab in patients with advanced/refractory solid tumors: EVICTION trial

Background

We presented EVICTION Trial data from patients with solid tumors that showed microgram doses of ICT01 rapidly activate γ9δ2 T cells that release inflammatory cytokines (e.g., IFNγ) and traffic from the circulation (Abstract #316, SITC 2020). Confirming tumor infiltration of activated γ9δ2 T cells and the subsequent clinical benefit are the next steps in characterizing the therapeutic potential of ICT01.

Methods

EVICTION is an ongoing Phase 1/2a, EU and US trial assessing ICT01 monotherapy (IV Q3W) in advanced/refractory solid and hematologic cancers, and ICT01 in combination with pembrolizumab (200mg IV Q3W) in solid tumor patients who failed ≥1 CPI. Pharmacodynamic activity was monitored by immunophenotyping and cytokine level analysis. Tumor biopsies (baseline, Day 28) were used for immunohistochemistry of BTN3A and tumor-infiltrating lymphocytes, and gene expression profiling. Efficacy evaluations were conducted every 8 weeks.

Results

ICT01 monotherapy dose escalation (20µg to 200mg IV ICT01 Q3W) in solid tumor patients (Group A, n=32) has been completed, and 3 dose cohorts of ICT01 (700µg, 2 and 7 mg) plus Pembro (Group C, n=12) were completed; both without any DLTs. First-dose fever and chills (Grade 1/2) were the most common AEs that increased in frequency but not severity with dose and did not recur.ICT01 induced trafficking of >95% of circulating γ9δ2 T cells within 30 min post ICT01 (≥2mg), which was sustained for 21 days at doses ≥75mg. Transient, dose-dependent increases in serum cytokines at 30 min (TNFα) or 4h (IFNγ) post-dose were correlated with baseline γ9δ2 T cell counts and with activation and migration of NK and CD8 T cells out of the blood at doses ≥7mg. Higher baseline circulating γ9δ2 T cells and lower TILs were associated with more robust intra-tumoral increases in total γδ(3–34x increase), CD3 (3–55x increase) and CD8 T cells (1.3–66x increase), which demonstrated the potential to transform an immune desert tumor phenotype. Disease control by ITT analysis of RECIST1.1 data was observed in 6/32 (SD) and 4/7 patients (3 SD (bladder, melanoma, NSCLC), 1 PR (bladder)) in Groups A and C, respectively, with 5/6 patients at 7mg in Group C not yet evaluable.

Conclusions

These results show a broad antitumor immune response in the blood and tumors comprising γ9δ2, CD8 T cell, and NK cell activation and tumor-infiltration following ICT01 alone and in combination with pembrolizumab. Preliminary efficacy data suggest low-dose ICT01 plus pembrolizumab may be more effective than ICT01 monotherapy for advanced/refractory solid tumors, which requires confirmation.

Acknowledgements

Lena Daher for her medical/scientific writing support.

Trial Registration www.clinicaltrials.gov NCT04243499; EudraCT Number: 2019-003847-31

Ethics Approval

This study was approved by the following Ethics Committees: COMITE DE PROTECTION DES PERSONNES, Sud-Méditerranée V (Gustave Roussy, IPC, Nantes), Comité d’Ethique Institut Jules Bordet, COMITÉ DE ÉTICA DE INVESTIGACIÓN CLÍNICA CON MEDICAMENTOS del Hospital Universitari Vall d’Hebron, Ethikkommission an der TU Dresden, HRA London-Surrey Borders Research Ethics Committee.

Consent

Written informed consent was obtained from the patient for publication of this abstract and any accompanying images. A copy of the written consent is available for review by the Editor of this journal.

484 Preliminary efficacy of the IL-15 superagonist SO-C101 in combination with pembrolizumab in patients with advanced/metastatic solid tumors

Background

SO-C101 (IL 15/IL-15Rα sushi + domain fusion protein) was investigated in a multicenter, open-label, dose escalation study as monotherapy and in combination with pembrolizumab in patients with selected advanced/metastatic tumors (NCT04234113). Synergistic effects of SO-C101 and an anti-programmed cell death protein 1 (PD-1) antibody have been validated in various tumor mouse models inducing a protective memory response.

Methods

The combination part of the study follows a classical 3+3 dose escalation design. Study objectives are to determine the maximum tolerated dose (MTD) and the recommended phase 2 dose (RP2D). The evaluation period for dose-limiting toxicities in each dose step is 21 days. The RP2D is defined as MTD or a dose below, taking into consideration pharmacokinetic and pharmacodynamic parameters.The study is ongoing (data cut-off 21 June 2021).

Results

A total of 12 patients with a median of 2 (range 1–6) lines of previous systemic therapies were treated at SO-C101 dose levels 1.5 µg/kg (3 patients), 3.0 µg/kg (3 patients), and 6.0 µg/kg (6 patients) together with 200 mg of pembrolizumab. One dose-limiting toxicity of grade (G) 3 cytokine release syndrome (CRS) was observed in one patient at 6.0 µg/kg. The MTD has not yet been reached.Of the treated patients, 2 had long-term stable disease (anal squamous cell carcinoma patient at 1.5 µg/kg, duration 25 weeks; gastric carcinoma patient at 3.0 µg/kg, duration 14 weeks) and 3 achieved a partial response (thyroid gland cancer patient at 3.0 µg/kg, target lesion decrease by 36%; skin squamous cell carcinoma patient at 6.0 µg/kg, target lesion decrease by 40%; and melanoma patient at 6.0 µg/kg, target lesion decrease by 58%). The patients with skin squamous cell carcinoma and melanoma had previously progressed on anti-PD-1 therapy, while the patient with thyroid cancer was anti-PD-1 naïve.The most common study drug-related adverse events were lymphopenia, local injection site reactions, transaminase increase, fever, chills as well as CRS-related symptoms (all mainly G1 or G2 and resolved). The only study drug-related adverse event >G2 that occurred in more than one patient was lymphopenia. No treatment-related death was reported.

Conclusions

Although the MTD of SO-C101 in combination with pembrolizumab has not been reached yet, clinical efficacy signals were already observed in 5 patients. Available safety data indicate good tolerability. SO-C101 in combination with pembrolizumab has already shown the potential to provide an additional clinical benefit to patients with solid tumors.

Trial Registration

NCT04234113

Ethics Approval

This study was approved by the FDA (IND 140011) and by the Ethics Boards of participating institutions

Intratumoural administration and tumour tissue targeting of cancer immunotherapies

Immune-checkpoint inhibitors and chimeric antigen receptor (CAR) T cells are revolutionizing oncology and haematology practice. With these and other immunotherapies, however, systemic biodistribution raises safety issues, potentially requiring the use of suboptimal doses or even precluding their clinical development. Delivering or attracting immune cells or immunomodulatory factors directly to the tumour and/or draining lymph nodes might overcome these problems. Hence, intratumoural delivery and tumour tissue-targeted compounds are attractive options to increase the in situ bioavailability and, thus, the efficacy of immunotherapies. In mouse models, intratumoural administration of immunostimulatory monoclonal antibodies, pattern recognition receptor agonists, genetically engineered viruses, bacteria, cytokines or immune cells can exert powerful effects not only against the injected tumours but also often against uninjected lesions (abscopal or anenestic effects). Alternatively, or additionally, biotechnology strategies are being used to achieve higher functional concentrations of immune mediators in tumour tissues, either by targeting locally overexpressed moieties or engineering 'unmaskable' agents to be activated by elements enriched within tumour tissues. Clinical trials evaluating these strategies are ongoing, but their development faces issues relating to the administration methodology, pharmacokinetic parameters, pharmacodynamic end points, and immunobiological and clinical response assessments. Herein, we discuss these approaches in the context of their historical development and describe the current landscape of intratumoural or tumour tissue-targeted immunotherapies.

Role of Cardiac Imaging in the Diagnosis of Immune Checkpoints Inhibitors Related Myocarditis

Immune checkpoint inhibitors (ICI) have constituted a paradigm shift in the management of patients with cancer. Their administration is associated with a new spectrum of immune-related toxicities that can affect any organ. In patients treated with ICI, cardiovascular toxicities, particularly myocarditis, occur with a low incidence (<1%) but with a high fatality rate (30-50%). ICI-related myocarditis has been attributed to an immune infiltration, comprising of T-cells that are positive for CD3+, CD4+, CD8+, and macrophages that are positive for CD68. The diagnosis remains challenging and is made based on clinical syndrome, an electrocardiogram (ECG), biomarker data, and imaging criteria. In most clinical scenarios, endomyocardial biopsy plays a pivotal role in diagnosis, while cardiac magnetic resonance imaging (cMRI) has limitations that should be acknowledged. In this review, we discuss the role of medical imaging in optimizing the management of ICI related myocarditis, including diagnosis, prognostication, and treatment decisions.

Interventional Radiology for Local Immunotherapy in Oncology

Human intratumoral immunotherapy (HIT-IT) is under rapid development, with promising preliminary results and high expectations for current phase III trials. While outcomes remain paramount for patients and the referring oncologists, the technical aspects of drug injection are critical to the interventional radiologist to ensure optimal and reproducible outcomes. The technical considerations for HIT-IT affect the safety, efficacy, and further development of this treatment option. Image-guided access to the tumor allows the therapeutic index of a treatment to be enhanced by increasing the intratumoral drug concentration while minimizing its systemic exposure and associated on-target off-tumor adverse events. Direct access to the tumor also enables the acquisition of cancer tissue for sequential sampling to better understand the pharmacodynamics of the injected immunotherapy and its efficacy through correlation of immune responses, pathologic responses, and imaging tumor response. The aim of this article is to share the technical insights of HIT-IT, with particular consideration for patient selection, lesion assessment, image guidance, and technical injection options. In addition, the organization of a standard patient workflow is discussed, so as to optimize HIT-IT outcome and the patient experience.

Comparison of Fast-Progression, Hyperprogressive Disease, and Early Deaths in Advanced Non–Small-Cell Lung Cancer Treated With PD-1/PD-L1 Inhibitors or Chemotherapy

PURPOSE

Hyperprogressive disease (HPD), fast progression (FP), and early death (ED) have been described in 13.8%, 4.7%, and 5.6% and in 5.1%, 2.8%, and 6.8%, respectively, of patients with non–small-cell lung cancer (NSCLC) treated with single-agent programmed cell death ligand 1 inhibitors (ICI) or chemotherapy, respectively. Whether FP/ED and HPD represent overlapping patterns is unknown.

PATIENTS AND METHODS

FP, ED, and HPD were retrospectively assessed in patients with NSCLC treated with single-agent ICI or chemotherapy. Eligibility required 2 computed tomography (CT) scans before and 1 CT scan during treatment. (1) HPD, (2) FP, (3) ED were defined as (1) RECIST version 1.1 progression at first CT scan and tumor growth rate variation per month > 50%, (2) ≥ 50% increase in the sum of the longest diameters of target lesions within 6 weeks from baseline, and (3) death as a result of radiologic progression within 12 weeks from baseline CT scan, respectively.

RESULTS

Of 406 ICI-treated NSCLC, 56 patients (13.8%), 9 patients (2.2%), and 36 patients (8.8%) were HPD, FP, and ED, respectively. Eight (14.2%) and 20 (35.7%) of 56 patients with HPD were also FP and ED. ED significantly correlated with baseline Eastern Cooperative Oncology Group performance status ≥ 2 compared with HPD (33% v 13%, P = .02). Overall survival was significantly longer for HPD (3.4 months [95% CI, 2.7 to 4.0 months]) compared with FP (0.7 months [95% CI, 0.6 to 0.8 months]); HR, 0.18 [95% CI, 0.08 to 0.42]; P < .0001) and ED (1.4 months [95% CI, 1.3 to 1.6 months]); HR, 0.19 [95% CI, 0.11 to 0.34]); P < .0001), whereas it did not differ between FP and ED (HR, 1.3 [95% CI, 0.56 to 3.0]; P = .55). Of 59 patients with NSCLC treated with single-agent chemotherapy, the HPD, FP, and ED rates were 5.1%, 1.7%, and 6.7%, respectively.

CONCLUSION

FP, ED, and HPD represent distinct progression patterns with limited overlap and different survival outcomes.

Human Endogenous Retrovirus Expression Is Upregulated in the Breast Cancer Microenvironment of HIV Infected Women: A Pilot Study

In people living with HIV (PLWH), chronic inflammation can lead to cancer initiation and progression, besides driving a dysregulated and diminished immune responsiveness. HIV infection also leads to increased transcription of Human Endogenous Retroviruses (HERVs), which could increase an inflammatory environment and create a tumor growth suppressive environment with high expression of pro-inflammatory cytokines. In order to determine the impact of HIV infection to HERV expression on the breast cancer microenvironment, we sequenced total RNA from formalin-fixed paraffin-embedded (FFPE) breast cancer samples of women HIV-negative and HIV-positive for transcriptome and retrotranscriptome analyses. We performed RNA extraction from FFPE samples, library preparation and total RNA sequencing (RNA-seq). The RNA-seq analysis shows 185 differentially expressed genes: 181 host genes (178 upregulated and three downregulated) and four upregulated HERV transcripts in HIV-positive samples. We also explored the impact of HERV expression in its neighboring breast cancer development genes (BRCA1, CCND1, NBS1/NBN, RAD50, KRAS, PI3K/PIK3CA) and in long non-coding RNA expression (AC060780.1, also known as RP11-242D8.1). We found a significant positive association of HERV expression with RAD50 and with AC060780.1, which suggest a possible role of HERV in regulating breast cancer genes from PLWH with breast cancer. In addition, we found immune system, extracellular matrix organization and metabolic signaling genes upregulated in HIV-positive breast cancer. In conclusion, our findings provide evidence of transcriptional and retrotranscriptional changes in breast cancer from PLWH compared to non-HIV breast cancer, including dysregulation of HERVs, suggesting an indirect effect of the virus on the breast cancer microenvironment.

Abstract CT150: A first-in-human phase I study of the OX40 agonist GSK3174998 (GSK998) +/- pembrolizumab in patients (Pts) with selected advanced solid tumors (ENGAGE-1)

Background: OX40 is a costimulatory receptor transiently expressed on the surface of activated T cells and some innate immune cells (e.g. NK cells). OX40 agonists have been shown to increase antitumor immunity and improve tumor-free survival in preclinical models, demonstrating increased efficacy when given in combination with a PD-1 inhibitor. GSK998 is a humanized IgG1 agonistic OX40 monoclonal antibody. Methods: ENGAGE-1 (NCT02528357) is a Phase 1 dose escalation study evaluating safety, PK, PD, and clinical activity of GSK998 (0.003-10 mg/kg IV Q3W) alone (Part 1) and in combination with pembrolizumab 200 mg IV Q3W (Part 2) in pts with previously treated advanced solid tumors: non-small cell lung cancer (NSCLC), squamous cell carcinoma of the head and neck, renal cell carcinoma, melanoma (MEL), bladder cancer, soft tissue sarcoma (STS), triple-negative breast cancer, and MSI-high colorectal carcinoma. Dose escalation used a continuous reassessment method and 4-week DLT period. Results: A total of 138 pts were enrolled (45 Part 1, 96 Part 2; 3 crossed over from Part 1). Two DLTs occurred in Part 2 only (G3 non-malignant pleural effusion 0.03 mg/kg; G1 myocarditis 10 mg/kg); MTD was not established. Most common (≥10%) treatment-related AEs (mostly G1-2) were diarrhea, fatigue (Part 1) and fatigue, nausea (Part 2). GSK998 demonstrated target engagement in the periphery as evidenced by PK and receptor occupancy (RO); a dose of 0.3 mg/kg was the threshold for linear PK & peripheral RO saturation over the 3-wk dose interval and was selected for further clinical evaluation in MEL, STS, and NSCLC in Part 2 expansion. Clinical responses and SD ≥24 weeks were observed in both PD-1/L1 naïve and experienced pts: Part 1 (1 PR, 1 SD; both 0.3 mg/kg) and Part 2 (2 CR, 7 PR, 9 SD; 0.01-3 mg/kg); Part 2 clinical responses were not correlated with baseline tumor PD-L1 expression levels; including one MEL pt with PD-L1 TPS=0 who progressed on prior CTLA-4/PD-1 treatment and had a CR (&gt;18mo). Overall, peripheral and tumor expression of OX40 was low (&lt;2% total cells in tumor were OX40 +ve). MultiOmyxTM data from tumor biopsies suggested increased NK/decreased Treg involvement in some responders. Conclusions: GSK998 +/- pembrolizumab was well tolerated, with evidence of target engagement; monotherapy clinical activity was limited. While combination responses may not be significantly greater than expected for pembrolizumab alone, responses were observed in some PD-1/L1 experienced pts and some with low PD-L1 expression. Given the low OX40 expression observed and preclinical evidence that increased expression improves activity of OX40 agonism, ongoing clinical evaluation of GSK998 will assess whether concurrent immune-stimulation or immunogenic cell death impacts OX40 expression and increases the efficacy of this agent. Combinations with TLR4 and ICOS agonists and an anti-BCMA antibody-drug conjugate are ongoing.

Citation Format: Sophie Postel-Vinay, Vincent K. Lam, Willeke Ros, Todd M. Bauer, Aaron R. Hansen, Daniel C. Cho, F. Stephen Hodi, Jan H.M. Schellens, Jennifer K. Litton, Sandrine Aspeslagh, Karen A. Autio, Frans L. Opdam, Meredith McKean, Neeta Somaiah, Stephane Champiat, Mehmet Altan, Anna Spreafico, Osama Rahma, Elaine M. Paul, Christoph M. Ahlers, Helen Zhou, Herbert Struemper, Shelby A. Gorman, Maura Watmuff, Kaitlin M. Yablonski, Niranjan Yanamandra, Michael J. Chisamore, Emmett V. Schmidt, Axel Hoos, Aurélien Marabelle, Jeffrey S. Weber, John V. Heymach. A first-in-human phase I study of the OX40 agonist GSK3174998 (GSK998) +/- pembrolizumab in patients (Pts) with selected advanced solid tumors (ENGAGE-1) [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT150.

Chemotherapy beyond immune checkpoint inhibitors in patients with metastatic colorectal cancer

BACKGROUND

Immune checkpoint inhibitors (ICIs) alone or in combination with chemotherapy (CT) are the current standard of therapy in several cancer types. Patients (pts) with lung cancer display higher response rates to CT when given after ICIs. Although ICIs have failed to demonstrate antitumour activity in microsatellite stable (MSS) metastatic colorectal cancer (mCRC), little is known about CT effect after ICIs. We aimed to assess whether sequential ICIs followed by CT may be an alternative therapeutic approach in a population of pts with mCRC.

MATERIAL AND METHODS

We retrospectively assessed CT after ICI (CAICI) failure in pts with mCRC. The ICI regimen consisted of anti-PD(L)1 alone or in combination. The primary end-point was objective response rate. Progression-free survival (PFS) and overall survival (OS) were secondary end-points.

RESULTS

Between 2014 and 2018, 29 pts with mCRC received CAICI (MSS tumours, 27 pts [86%]). The median number of previous lines was 4 (range, 2-7). Regimens included TAS-102 (n = 14), FOLFIRI (irinotecan, leucovorin, and fluorouracil; n = 6) or FOLFOX (oxaliplatin, leucovorin, and fluorouracil; n = 4), regorafenib (n = 3) and carboplatin (1 pt with BRCA mutation). Partial response and stable disease were observed in 4 (19%) and 9 (43%) pts, respectively (disease control rate, 62%). The median PFS and OS were 3.8 months (95% confidence interval [CI] = 1.5-5.4) and 8.0 months (95% CI = 4.2-14.0), respectively.

CONCLUSION

ICIs administered before CT might enhance cytotoxic effects even in pts with immunorefractory MSS mCRC. The results of this small cohort need to be validated in independent prospective cohorts. The role of ICIs as modifiers of both tumour cells and microenvironment in mCRC deserves further research.