Pneumonitis After Chemoradiotherapy and Adjuvant Durvalumab in Stage III Non-Small Cell Lung Cancer

PURPOSE

Adjuvant durvalumab after definitive chemoradiotherapy (CRT) for unresectable stage III non-small cell lung cancer (NSCLC) is well-tolerated in clinical trials. However, pneumonitis rates outside of clinical trials remain poorly defined with CRT followed by durvalumab. We aimed to describe the influence of durvalumab on pneumonitis rates among a large cohort of patients with stage III NSCLC.

METHODS AND MATERIALS

We studied patients with stage III NSCLC in the national Veterans Health Administration from 2015 to 2021 who received concurrent CRT alone or with adjuvant durvalumab. We defined pneumonitis as worsening respiratory symptoms with radiographic changes within 2 years of CRT and graded events according to National Cancer Institute Common Terminology Criteria for Adverse Events version 4.03. We used Cox regression to analyze risk factors for pneumonitis and the effect of postbaseline pneumonitis on overall survival.

RESULTS

Among 1994 patients (989 CRT alone, 1005 CRT followed by adjuvant durvalumab), the 2-year incidence of grade 2 or higher pneumonitis was 13.9% for CRT alone versus 22.1% for CRT plus durvalumab (unadjusted P < .001). On multivariable analysis, durvalumab was associated with higher risk of grade 2 pneumonitis (hazard ratio, 1.45; 95% CI, 1.09-1.93; P = .012) but not grade 3 to 5 pneumonitis (P = .2). Grade 3 pneumonitis conferred worse overall survival (hazard ratio, 2.51; 95% CI, 2.06-3.05; P < .001) but grade 2 pneumonitis did not (P = .4).

CONCLUSIONS

Adjuvant durvalumab use was associated with increased risk of low-grade but not higher-grade pneumonitis. Reassuringly, low-grade pneumonitis did not increase mortality risk. We observed increased rates of high-grade pneumonitis relative to clinical trials; the reasons for this require further study.

PIKfyve controls dendritic cell function and tumor immunity

The modern armamentarium for cancer treatment includes immunotherapy and targeted therapy, such as protein kinase inhibitors. However, the mechanisms that allow cancer-targeting drugs to effectively mobilize dendritic cells (DCs) and affect immunotherapy are poorly understood. Here, we report that among shared gene targets of clinically relevant protein kinase inhibitors, high PIKFYVE expression was least predictive of complete response in patients who received immune checkpoint blockade (ICB). In immune cells, high PIKFYVE expression in DCs was associated with worse response to ICB. Genetic and pharmacological studies demonstrated that PIKfyve ablation enhanced DC function via selectively altering the alternate/non-canonical NF-κB pathway. Both loss of Pikfyve in DCs and treatment with apilimod, a potent and specific PIKfyve inhibitor, restrained tumor growth, enhanced DC-dependent T cell immunity, and potentiated ICB efficacy in tumor-bearing mouse models. Furthermore, the combination of a vaccine adjuvant and apilimod reduced tumor progression in vivo. Thus, PIKfyve negatively controls DCs, and PIKfyve inhibition has promise for cancer immunotherapy and vaccine treatment strategies.

Potentiating the radiation-induced type I interferon antitumoral immune response by ATM inhibition in pancreatic cancer

Radiotherapy induces a type I interferon-mediated (T1IFN-mediated) antitumoral immune response that we hypothesized could be potentiated by a first-in-class ataxia telangiectasia mutated (ATM) inhibitor, leading to enhanced innate immune signaling, T1IFN expression, and sensitization to immunotherapy in pancreatic cancer. We evaluated the effects of AZD1390 or a structurally related compound, AZD0156, on innate immune signaling and found that both inhibitors enhanced radiation-induced T1IFN expression via the POLIII/RIG-I/MAVS pathway. In immunocompetent syngeneic mouse models of pancreatic cancer, ATM inhibitor enhanced radiation-induced antitumoral immune responses and sensitized tumors to anti-PD-L1, producing immunogenic memory and durable tumor control. Therapeutic responses were associated with increased intratumoral CD8+ T cell frequency and effector function. Tumor control was dependent on CD8+ T cells, as therapeutic efficacy was blunted in CD8+ T cell-depleted mice. Adaptive immune responses to combination therapy provided systemic control of contralateral tumors outside of the radiation field. Taken together, we show that a clinical candidate ATM inhibitor enhances radiation-induced T1IFN, leading to both innate and subsequent adaptive antitumoral immune responses and sensitization of otherwise resistant pancreatic cancer to immunotherapy.

Class II HLA-DRB4 is a predictive biomarker for survival following immunotherapy in metastatic non-small cell lung cancer

Immune checkpoint inhibitors (ICI) are important treatment options for metastatic non-small cell lung cancer (mNSCLC). However, not all patients benefit from ICIs and can experience immune-related adverse events (irAEs). Limited understanding exists for germline determinants of ICI efficacy and toxicity, but Human Leukocyte Antigen (HLA) genes have emerged as a potential predictive biomarker. We performed HLA typing on 85 patients with mNSCLC, on ICI therapy and analyzed the impact of HLA Class II genotype on progression free survival (PFS), overall survival (OS), and irAEs. Most patients received pembrolizumab (83.5%). HLA-DRB4 genotype was seen in 34/85 (40%) and its presence correlated with improved OS in both univariate (p = 0.022; 26.3 months vs 10.2 months) and multivariate analysis (p = 0.011, HR 0.49, 95% CI [0.29, 0.85]). PFS did not reach significance (univariate, p = 0.12, 8.2 months vs 5.1 months). Eleven patients developed endocrine irAEs. HLA-DRB4 was the predominant genotype among these patients (9/11, 81.8%). Cumulative incidence of endocrine irAEs was higher in patients with HLA-DRB4 (p = 0.0139). Our study is the first to suggest that patients with metastatic NSCLC patients on ICI therapy with HLA-DRB4 genotype experience improved survival outcomes. Patients with HLA-DRB4 had the longest median OS (26.3 months). Additionally, we found a correlation between HLA-DRB4 and the occurrence of endocrine irAEs.

Targeting the lipid kinase PIKfyve upregulates surface expression of MHC class I to augment cancer immunotherapy

Despite the remarkable clinical success of immunotherapies in a subset of cancer patients, many fail to respond to treatment and exhibit resistance. Here, we found that genetic or pharmacologic inhibition of the lipid kinase PIKfyve, a regulator of autophagic flux and lysosomal biogenesis, upregulated surface expression of major histocompatibility complex class I (MHC-I) in cancer cells via impairing autophagic flux, resulting in enhanced cancer cell killing mediated by CD8+ T cells. Genetic depletion or pharmacologic inhibition of PIKfyve elevated tumor-specific MHC-I surface expression, increased intratumoral functional CD8+ T cells, and slowed tumor progression in multiple syngeneic mouse models. Importantly, enhanced antitumor responses by Pikfyve-depletion were CD8+ T cell- and MHC-I-dependent, as CD8+ T cell depletion or B2m knockout rescued tumor growth. Furthermore, PIKfyve inhibition improved response to immune checkpoint blockade (ICB), adoptive cell therapy, and a therapeutic vaccine. High expression of PIKFYVE was also predictive of poor response to ICB and prognostic of poor survival in ICB-treated cohorts. Collectively, our findings show that targeting PIKfyve enhances immunotherapies by elevating surface expression of MHC-I in cancer cells, and PIKfyve inhibitors have potential as agents to increase immunotherapy response in cancer patients.

Evaluation of the Prognostic Role of Liver Metastases on Patient Outcomes: Systematic Review and Meta-analysis

ABSTRACT

The liver is a common site of metastasis for many primary malignancies, but the quantitative impact on survival is unknown. We performed a systematic review and meta-analysis of 83 studies (604,853 patients) assessing the overall hazard associated with liver metastases by primary tumor type and treatment regimen. The pooled overall survival hazard ratio (HR) for all included studies was 1.77 (95% confidence interval [CI], 1.62-1.93). Patients with breast cancer primaries fared the worst (HR, 2.37; 95% CI, 1.64-3.44), as did patients treated with immunotherapies (HR, 1.86; 95% CI, 1.42-2.42). Liver metastases negatively impact survival, necessitating new approaches to disease management.

Adopting Weight-Based Dosing With Pharmacy-Level Stewardship Strategies Could Reduce Cancer Drug Spending By Millions

Immune checkpoint inhibitors, a class of drugs used in approximately forty unique cancer indications, are a sizable component of the economic burden of cancer care in the US. Instead of personalized weight-based dosing, immune checkpoint inhibitors are most commonly administered at "one-size-fits-all" flat doses that are higher than necessary for the vast majority of patients. We hypothesized that personalized weight-based dosing along with common stewardship efforts at the pharmacy level, such as dose rounding and vial sharing, would lead to reductions in immune checkpoint inhibitor use and lower spending. Using data from the Veterans Health Administration (VHA) and Medicare drug prices, we estimated reductions in immune checkpoint inhibitor use and spending that would be associated with pharmacy-level stewardship strategies, in a case-control simulation study of individual patient-level immune checkpoint inhibitor administration events. We identified baseline annual VHA spending for these drugs of approximately $537 million. Combining weight-based dosing, dose rounding, and pharmacy-level vial sharing would generate expected annual VHA health system savings of $74 million (13.7 percent). We conclude that adoption of pharmacologically justified immune checkpoint inhibitor stewardship measures would generate sizable reductions in spending for these drugs. Combining these operational innovations with value-based drug price negotiation enabled by recent policy changes may improve the long-term financial viability of cancer care in the US.

Impact of immune tolerance mechanisms on the efficacy of immunotherapy in primary and secondary liver cancers

The liver is a functionally unique organ with an immunosuppressive microenvironment. The liver is the sixth most common site of primary cancer in humans and is a frequent site of metastasis from other solid tumors. The development of effective therapies for primary and metastatic liver cancer has been challenging due to the complex metabolic and immune microenvironment of the liver. The liver tumor microenvironment (TME) in primary and secondary (metastatic) liver cancers is heterogenous and consists of unique immune and stromal cell populations. Crosstalk between these cell populations and tumor cells creates an immunosuppressive microenvironment within the liver which potentiates cancer progression. Immune checkpoint inhibitors (ICIs) are now clinically approved for the management of primary and secondary liver cancer and can partially overcome liver immune tolerance, but their efficacy is limited. In this review, we describe the liver microenvironment and the use of immunotherapy in primary and secondary liver cancer. We discuss emerging combination strategies utilizing locoregional and systemic therapy approaches which may enhance efficacy of immunotherapy in primary and secondary liver cancer. A deeper understanding of the immunosuppressive microenvironment of the liver will inform novel therapies and therapeutic combinations in order to improve outcomes of patients with primary and secondary liver cancer.

Abstract 2823: Targeting monopolar spindle kinase I (TTK) as a radiosensitizing strategy in syngeneic murine models of triple negative breast cancer (TNBC) and its implications on the tumor immune microenvironment

Purpose: Triple negative breast cancer (TNBC) is an aggressive breast cancer subset with poor outcomes. Since TNBC is resistant to hormone therapies, there are few effective therapies available for TNBC patients. One potential therapeutic strategy exists in targeting specific molecular components of an individual patient’s cancer. Prior work in our group has nominated monopolar spindle kinase I (TTK) as a gene upregulated in breast cancer patients. Specifically, TTK expression was found to be increased in cancerous breast tissue compared to healthy tissue and correlated with cancer recurrence following radiotherapy. Importantly, the implications of TTK inhibition and radiotherapy on the immune system is not well understood. In this study, we aimed to elucidate the role of combined TTK inhibition and radiotherapy in syngeneic murine mouse models. We hypothesize that TTK inhibition will radiosensitize murine TNBC models to radiotherapy both in vitro and in vivo and modulate the immune tumor microenvironment.

Methods: Cell viability assays were implemented to determine the half-maximal inhibitory concentrations (IC50) of TTK inhibitor. Clonogenic survival assays were used to determine the radiation enhancement ratios (rERs) of TTK inhibition in vitro. Syngeneic murine mouse models were used to assess therapeutic effects of TTK inhibition and RT in vivo. 4T1 TNBC cells were injected bilaterally into the flanks of BALB/c mice and treated with combinations of radiotherapy and TTK inhibition. Tumor growth was monitored and, following the completion of the study, final tumor weights were recorded and tumor tissue was collected to perform immunofluorescent microscopy.

Results: Single-agent TTK inhibition via treatment with the ATP-competitive inhibitor empesertib inhibits the growth of murine TNBC cell lines with IC50 values up to 30nM. Sub-IC50 values of TTK inhibitor induced radiosensitization in the murine TNBC cells 4T1 (rERs ≤ 2.4) and Py8119 (rERs ≤ 1.6). TTK knockdown also resulted in changes in radiosensitization in vitro. Furthermore, we also observed a similar phenotype in vivo. In our 4T1 model system, mice receiving combined treatment had significantly decreased tumor growth compared to mice that receiving single-agent therapies or vehicle control alone. Quantities of monocyte derived suppressor cells and CD8+ T cells were altered with radiotherapy and TTK inhibition.

Conclusion: Our data suggests that TTK inhibition and radiotherapy is synergistic in murine TNBC and alters the tumor immune microenvironment. This combined therapy suggests that changes in the underlying immune mechanisms as a result of the synergistic treatment efficacy are important in TNBC. Future work will examine the underlying mechanisms of TTK inhibition and radiotherapy on systemic and tumoral immune changes.

Citation Format: Kassidy M. Jungles, Zhuwen Wang, Caroline R. Bishop, Kalli R. Jungles, Cydnee Wilson, Meilan Liu, Ashley N. Pearson, Erin A. Holcomb, Ben Chandler, Jadyn James, Amanda Huber, Lori J. Pierce, Corey Speers, James M. Rae, Michael D. Green. Targeting monopolar spindle kinase I (TTK) as a radiosensitizing strategy in syngeneic murine models of triple negative breast cancer (TNBC) and its implications on the tumor immune microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2823.

Public reporting of black participation in anti-hypertensive drug clinical trials

BACKGROUND

Non-Hispanic Black people in the United States have the highest prevalence of essential hypertension. Unfortunately, clinical trials often underrepresent Black patients. We aim to understand whether trial sponsorship type is associated with representation of Black participants in anti-hypertensive drug clinical trials. Then, we contextualize our findings amongst current efforts to improve diversity in clinical research populations.

METHODS

We searched ClinicalTrials.gov in May 2022 for antihypertensive drug trials. Of n = 408 trials in our initial search, n = 97 (23.77%) met inclusion criteria and were stratified by sponsorship type (industry vs non-industry). Standardized tests of difference were employed to compare characteristics of these trials, and linear regression was used to model change over time.

RESULTS

Of 97 trials reporting results from 2010 to 2020, there were minimal differences in the percent of Black patients enrolled in anti-hypertensive clinical trials by sponsorship type. Both industry and non-industry sponsored studies had high rates of non-reporting, with slightly more non-reporting for industry (73.2%) vs non-industry (66.67%) studies. Industry funded studies reported results to ClinicalTrials.gov within 23.3 ± 15.0 months from completing studies, while non-industry funded trials reported within 18.9 ± 10.8 months.

CONCLUSIONS

Despite Black Americans carrying the highest burden of disease for essential hypertension, they are underrepresented in anti-hypertension clinical trials and their overall participation has decreased between 2010 and 2020. In addition, there is major underreporting of trial participant race. We implore researchers and funders to establish clear, meaningful targets for anti-hypertensive drug trial diversity, and improve transparency in reporting of study characteristics.

Intersection of immune and oncometabolic pathways drives cancer hyperprogression during immunotherapy

Immune checkpoint blockade (ICB) can produce durable responses against cancer. We and others have found that a subset of patients experiences paradoxical rapid cancer progression during immunotherapy. It is poorly understood how tumors can accelerate their progression during ICB. In some preclinical models, ICB causes hyperprogressive disease (HPD). While immune exclusion drives resistance to ICB, counterintuitively, patients with HPD and complete response (CR) following ICB manifest comparable levels of tumor-infiltrating CD8+ T cells and interferon γ (IFNγ) gene signature. Interestingly, patients with HPD but not CR exhibit elevated tumoral fibroblast growth factor 2 (FGF2) and β-catenin signaling. In animal models, T cell-derived IFNγ promotes tumor FGF2 signaling, thereby suppressing PKM2 activity and decreasing NAD+, resulting in reduction of SIRT1-mediated β-catenin deacetylation and enhanced β-catenin acetylation, consequently reprograming tumor stemness. Targeting the IFNγ-PKM2-β-catenin axis prevents HPD in preclinical models. Thus, the crosstalk of core immunogenic, metabolic, and oncogenic pathways via the IFNγ-PKM2-β-catenin cascade underlies ICB-associated HPD.

Fat Fuels the Fire in Cervical Cancer

Cervical cancer is the second most common cause of cancer mortality among young women and disproportionately impacts underserved patient populations. An obesity paradox has been observed in cervical cancer wherein patients with higher body mass indices benefit more from standard-of-care chemoradiation. However, the molecular pathways through which obesity modulates treatment response are poorly defined. In exciting work in this issue of Cancer Research, Muhammad and colleagues have shown that monounsaturated and diunsaturated free fatty acids released by adipocytes activate β-oxidation within tumor cells, which potentiates radiotherapy. This work extends our understanding of the metabolic vulnerabilities of cervical cancer. See related article by Muhammad et al., p. 4515.

Association of Prostate-Specific Antigen Screening Rates With Subsequent Metastatic Prostate Cancer Incidence at US Veterans Health Administration Facilities

Importance

There is controversy about the benefit of prostate-specific antigen (PSA) screening. Prostate-specific antigen screening rates have decreased since 2008 in the US, and the incidence of metastatic prostate cancer has increased. However, there is no direct epidemiologic evidence of a correlation between population PSA screening rates and subsequent metastatic prostate cancer rates.

Objective

To assess whether facility-level variation in PSA screening rates is associated with subsequent facility-level metastatic prostate cancer incidence.

Design, Setting, and Participants

This retrospective cohort used data for all men aged 40 years or older with an encounter at 128 facilities in the US Veterans Health Administration (VHA) from January 1, 2005, to December 31, 2019.

Exposures

Yearly facility-level PSA screening rates, defined as the proportion of men aged 40 years or older with a PSA test in each year, and long-term nonscreening rates, defined as the proportion of men aged 40 years or older without a PSA test in the prior 3 years, from January 1, 2005, to December 31, 2014.

Main Outcomes and Measures

The main outcomes were facility-level yearly counts of incident metastatic prostate cancer diagnoses and age-adjusted yearly metastatic prostate cancer incidence rates (per 100 000 men) 5 years after each PSA screening exposure year.

Results

The cohort included 4 678 412 men in 2005 and 5 371 701 men in 2019. Prostate-specific antigen screening rates decreased from 47.2% in 2005 to 37.0% in 2019, and metastatic prostate cancer incidence increased from 5.2 per 100 000 men in 2005 to 7.9 per 100 000 men in 2019. Higher facility-level PSA screening rates were associated with lower metastatic prostate cancer incidence 5 years later (incidence rate ratio [IRR], 0.91 per 10% increase in PSA screening rate; 95% CI, 0.87-0.96; P < .001). Higher long-term nonscreening rates were associated with higher metastatic prostate cancer incidence 5 years later (IRR, 1.11 per 10% increase in long-term nonscreening rate; 95% CI, 1.03-1.19; P = .01).

Conclusions and Relevance

From 2005 to 2019, PSA screening rates decreased in the national VHA system. Facilities with higher PSA screening rates had lower subsequent rates of metastatic prostate cancer. These data may be used to inform shared decision-making about the potential benefits of PSA screening among men who wish to reduce their risk of metastatic prostate cancer.

High-content CRISPR screening in tumor immunology

CRISPR screening is a powerful tool that links specific genetic alterations to corresponding phenotypes, thus allowing for high-throughput identification of novel gene functions. Pooled CRISPR screens have enabled discovery of innate and adaptive immune response regulators in the setting of viral infection and cancer. Emerging methods couple pooled CRISPR screens with parallel high-content readouts at the transcriptomic, epigenetic, proteomic, and optical levels. These approaches are illuminating cancer immune evasion mechanisms as well as nominating novel targets that augment T cell activation, increase T cell infiltration into tumors, and promote enhanced T cell cytotoxicity. This review details recent methodological advances in high-content CRISPR screens and highlights the impact this technology is having on tumor immunology.

Updates in combined approaches of radiotherapy and immune checkpoint inhibitors for the treatment of breast cancer

Breast cancer is the most prevalent non-skin cancer diagnosed in females and developing novel therapeutic strategies to improve patient outcomes is crucial. The immune system plays an integral role in the body’s response to breast cancer and modulating this immune response through immunotherapy is a promising therapeutic option. Although immune checkpoint inhibitors were recently approved for the treatment of breast cancer patients, not all patients respond to immune checkpoint inhibitors as a monotherapy, highlighting the need to better understand the biology underlying patient response. Additionally, as radiotherapy is a critical component of breast cancer treatment, understanding the interplay of radiation and immune checkpoint inhibitors will be vital as recent studies suggest that combined therapies may induce synergistic effects in preclinical models of breast cancer. This review will discuss the mechanisms supporting combined approaches with radiotherapy and immune checkpoint inhibitors for the treatment of breast cancer. Moreover, this review will analyze the current clinical trials examining combined approaches of radiotherapy, immunotherapy, chemotherapy, and targeted therapy. Finally, this review will evaluate data regarding treatment tolerance and potential biomarkers for these emerging therapies aimed at improving breast cancer outcomes.

De-escalating adjuvant durvalumab treatment duration in stage III non-small cell lung cancer

BACKGROUND

One year of adjuvant durvalumab following concurrent chemoradiotherapy significantly improves progression-free survival (PFS) and overall survival (OS) for patients with stage III non-small cell lung cancer (NSCLC). However, the optimal length of adjuvant therapy has not been determined.

METHODS

We identified patients with stage III NSCLC treated with definitive chemoradiation and adjuvant durvalumab from November 2017 to April 2021 from the United States Veterans Affairs system. Predictors of early durvalumab discontinuation were evaluated with Cox proportional hazards regression. The effect of differing durations of durvalumab treatment (up to 6, 9, and 12 months) on PFS and OS were compared with a marginal structural model and time-dependent Cox modelling.

RESULTS

We included 1006 patients with stage III non-small cell lung cancer who received concurrent chemoradiotherapy and at least one dose of adjuvant durvalumab. The median duration of durvalumab treatment was 7 months (interquartile range 2.8-11.5) and 31% completed the intended durvalumab course. The most common reasons for early discontinuation were tumour progression (22%), immune-related adverse events (15%), and non-immune-related toxicity (6.0%), Marginal structural models suggested similar PFS for 9 months versus 12 months of durvalumab treatment and inferior PFS for 6 months versus 12 months.

CONCLUSIONS

A substantial proportion of patients undergoing adjuvant durvalumab discontinue therapy early due to toxicity, and shorter durvalumab treatment durations may provide similar disease control to 12 months of therapy. Prospective randomised controlled studies are needed to characterise the optimal durvalumab treatment duration in locally advanced NSCLC patients.

Prognostic and Predictive Role of PD-L1 Expression in Stage III Non-small Cell Lung Cancer Treated With Definitive Chemoradiation and Adjuvant Durvalumab

PURPOSE

It is unclear whether programmed death ligand 1 (PD-L1) expression is prognostic or predictive of immunotherapy benefit among patients with stage III non-small cell lung cancer (NSCLC) treated with definitive chemoradiation and adjuvant durvalumab.

METHODS AND MATERIALS

We determined pretreatment tumor PD-L1 expression for 312 patients with stage III NSCLC treated with definitive chemoradiation and at least 1 dose of adjuvant durvalumab between November 2017 and April 2021 across the national Veterans Health Administration. Progression-free survival (PFS) and overall survival (OS) in PD-L1 expression subgroups (<1%, 1%-49%, and 50%-100%) were compared with 994 patients with stage III NSCLC treated without adjuvant durvalumab from 2015 to 2016.

RESULTS

PD-L1 expression was <1%, 1% to 49%, and 50% to 100% in 109 (34.9%), 96 (30.7%), and 107 (34.3%) patients, respectively. Increasing PD-L1 expression was associated with longer PFS (adjusted hazard ratio [aHR], 0.84 per 25% absolute increase in expression; 95% confidence interval [CI], 0.75-0.94; P = .003) and OS (aHR, 0.86 per 25% absolute increase in expression; 95% CI, 0.74-0.99; P = .036). Compared with the no-durvalumab group, PFS was longer for PD-L1 50% to 100% (aHR, 0.44; 95% CI, 0.32-0.60; P < .001) and PD-L1 1% to 49% (aHR, 0.64; 95% CI, 0.47-0.86; P = .003) but not PD-L1 <1% (aHR, 0.84; 95% CI, 0.64-1.10; P = .19). Similar results were found for OS, with no significant difference between the no-durvalumab group and PD-L1 <1% (aHR, 0.81; 95% CI, 0.58-1.13; P = .22).

CONCLUSIONS

Increasing tumor PD-L1 expression is prognostic for PFS and OS among patients with stage III NSCLC treated with adjuvant durvalumab, and patients with PD-L1 expression <1% may have limited benefit from adjuvant durvalumab.

Early Response Assessment in Advanced Stage Melanoma Treated with Combination Ipilimumab/Nivolumab

Background

Standard combination ipilimumab/nivolumab (I/N) is given as 4 induction doses for advanced stage melanoma followed by nivolumab single-agent maintenance therapy. While many patients receive less than 4 doses due to immune-related toxicities, it is unclear if fewer doses of I/N may still provide long term clinical benefit. Our aim is to determine if response assessment after 1 or 2 doses of I/N can predict long-term survival and assess if fewer doses of I/N can lead to similar survival outcomes.

Methods

We performed a retrospective analysis on a cohort of patients with advanced melanoma who w0ere treated with standard I/N. Cox regression of progression-free survival (PFS) and overall survival (OS) models were performed to assess the relationship between response after 1 or 2 doses of I/N and risk of progression and/or death. Clinical benefit response (CBR) was assessed, defined as SD (stable disease) + PR (partial response) + CR (complete response) by imaging. Among patients who achieved a CBR after 1 or 2 doses of I/N, a multivariable Cox regression of survival was used to compare 1 or 2 vs 3 or 4 doses of I/N adjusted by known prognostic variables in advanced melanoma.

Results

199 patients were evaluated. Patients with CBR after 1 dose of I/N had improved PFS (HR: 0.16, 95% CI 0.08-0.33; p<0.001) and OS (HR: 0.12, 0.05-0.32; p<0.001) compared to progressive disease (PD). Patients with CBR (vs PD) after 2 doses of I/N also had improved PFS (HR: 0.09, 0.05-0.16; p<0.001) and OS (HR: 0.07, 0.03-0.14; p<0.001). There was no survival risk difference comparing 1 or 2 vs 3 or 4 doses of I/N for PFS (HR: 0.95, 0.37-2.48; p=0.921) and OS (HR: 1.04, 0.22-4.78; p=0.965).

Conclusions

Early interval imaging with response during induction with I/N may be predictive of long-term survival in advanced stage melanoma. CBR after 1 or 2 doses of I/N is associated with favorable survival outcomes, even in the setting of fewer I/N doses received. Further studies are warranted to evaluate if electively administering fewer combination I/N doses despite tolerance in select patients may balance the benefits of therapy while decreasing toxicities.

DNA-PK Inhibition and Radiation Promote Antitumoral Immunity through RNA Polymerase III in Pancreatic Cancer

Targeting the DNA damage response in combination with radiation enhances type I interferon (T1IFN)-driven innate immune signaling. It is not understood, however, whether DNA-dependent protein kinase (DNA-PK), the kinase critical for repairing the majority of radiation-induced DNA double-strand breaks in cancer cells, is immunomodulatory. We show that combining radiation with DNA-PK inhibition increases cytosolic double-stranded DNA and tumoral T1IFN signaling in a cyclic GMP-AMP synthase (cGAS)- and stimulator of interferon genes (STING)-independent, but an RNA polymerase III (POL III), retinoic acid-inducible gene I (RIG-I), and antiviral-signaling protein (MAVS)-dependent manner. Although DNA-PK inhibition and radiation also promote programmed death-ligand 1 (PD-L1) expression, the use of anti-PD-L1 in combination with radiation and DNA-PK inhibitor potentiates antitumor immunity in pancreatic cancer models. Our findings demonstrate a novel mechanism for the antitumoral immune effects of DNA-PK inhibitor and radiation that leads to increased sensitivity to anti-PD-L1 in poorly immunogenic pancreatic cancers.

IMPLICATIONS

Our work nominates a novel therapeutic strategy as well as its cellular mechanisms pertinent for future clinical trials combining M3814, radiation, and anti-PD-L1 antibody in patients with pancreatic cancer.

Harnessing the DNA Repair Pathway in Breast Cancer: Germline Mutations/Polymorphisms in Breast Radiation

Molecular profiling facilitates opportunities for personalization of breast cancer management. Increasing availability of germline and somatic sequencing provides insight into predictors of treatment efficacy and treatment tolerance of patients with breast cancer. The presence of pathologic mutations can guide patient selection for breast conserving surgery vs mastectomy. However, our understanding of the interplay between genetic variants and radiotherapy responses and side effects remains incomplete. Here we review the available data on germline mutations and polymorphisms in breast cancer. We also outline their association with treatment tolerance, locoregional outcomes, and ongoing efforts to transform these insights into more effective treatment strategies in combination with radiotherapy.

Improved prediction of radiation pneumonitis by combining biological and radiobiological parameters using a data-driven Bayesian network analysis

Grade 2 and higher radiation pneumonitis (RP2) is a potentially fatal toxicity that limits efficacy of radiation therapy (RT). We wished to identify a combined biomarker signature of circulating miRNAs and cytokines which, along with radiobiological and clinical parameters, may better predict a targetable RP2 pathway. In a prospective clinical trial of response-adapted RT for patients (n = 39) with locally advanced non-small cell lung cancer, we analyzed patients' plasma, collected pre- and during RT, for microRNAs (miRNAs) and cytokines using array and multiplex enzyme linked immunosorbent assay (ELISA), respectively. Interactions between candidate biomarkers, radiobiological, and clinical parameters were analyzed using data-driven Bayesian network (DD-BN) analysis. We identified alterations in specific miRNAs (miR-532, -99b and -495, let-7c, -451 and -139-3p) correlating with lung toxicity. High levels of soluble tumor necrosis factor alpha receptor 1 (sTNFR1) were detected in a majority of lung cancer patients. However, among RP patients, within 2 weeks of RT initiation, we noted a trend of temporary decline in sTNFR1 (a physiological scavenger of TNFα) and ADAM17 (a shedding protease that cleaves both membrane-bound TNFα and TNFR1) levels. Cytokine signature identified activation of inflammatory pathway. Using DD-BN we combined miRNA and cytokine data along with generalized equivalent uniform dose (gEUD) to identify pathways with better accuracy of predicting RP2 as compared to either miRNA or cytokines alone. This signature suggests that activation of the TNFα-NFκB inflammatory pathway plays a key role in RP which could be specifically ameliorated by etanercept rather than current therapy of non-specific leukotoxic corticosteroids.

A random survey of the prevalence of falsified and substandard antibiotics in the Lao PDR

OBJECTIVES

In 2012, a stratified random survey, using mystery shoppers, was conducted to investigate the availability and quality of antibiotics sold to patients in the private sector in five southern provinces of the Lao People's Democratic Republic (Laos).

METHODS

A total of 147 outlets were sampled in 10 districts. The active pharmaceutical ingredient (API) content measurements for 909 samples, including nine APIs (amoxicillin, ampicillin, ceftriaxone, ciprofloxacin, doxycycline, ofloxacin, sulfamethoxazole, tetracycline and trimethoprim), were determined using HPLC.

RESULTS

All the analysed samples contained the stated API and we found no evidence for falsification. All except one sample had all the units tested with %API values between 75% and 125% of the content stated on the label. However, we identified the presence of substandard antibiotics: 19.6% (201/1025) of samples had their units outside the 90%-110% content of the label claim and 18.3% (188/1025) of the samples had units outside the International Pharmacopoeia/United States Pharmacopoeia assay (percentage of label claim) specifications. Trimethoprim had a high number of samples [51.6% (64)] with units below the limit range, followed by ceftriaxone [42.9% (3)] and sulfamethoxazole [34.7% (43)]. Doxycycline, ofloxacin and ciprofloxacin had the highest number of samples with high API content: 43.7% (38), 14.7% (10) and 11.8% (2), respectively. Significant differences in %API were found between stated countries of manufacture and stated manufacturers.

CONCLUSIONS

With the global threat of antimicrobial resistance on patient outcomes, greater understanding of the role of poor-quality antibiotics is needed. Substandard antibiotics will have reduced therapeutic efficacy, impacting public health and control of bacterial infections.

Metabolism drives macrophage heterogeneity in the tumor microenvironment

Tumor-associated macrophages (TAMs) are a major cellular component in the tumor microenvironment (TME). However, the relationship between the phenotype and metabolic pattern of TAMs remains poorly understood. We performed single-cell transcriptome profiling on hepatic TAMs from mice bearing liver metastatic tumors. We find that TAMs manifest high heterogeneity at the levels of transcription, development, metabolism, and function. Integrative analyses and validation experiments indicate that increased purine metabolism is a feature of TAMs with pro-tumor and terminal differentiation phenotypes. Like mouse TAMs, human TAMs are highly heterogeneous. Human TAMs with increased purine metabolism exhibit a pro-tumor phenotype and correlate with poor therapeutic efficacy to immune checkpoint blockade. Altogether, our work demonstrates that TAMs are developmentally, metabolically, and functionally heterogeneous and purine metabolism may be a key metabolic feature of a pro-tumor macrophage population.

Timing of Adjuvant Durvalumab Initiation Is Not Associated With Outcomes in Stage III Non-small Cell Lung Cancer

PURPOSE

It is unclear whether time from radiation therapy (RT) completion to durvalumab initiation influences the outcomes of stage III non-small cell lung cancer (NSCLC) treated with definitive chemoradiation and adjuvant durvalumab.

METHODS AND MATERIALS

Using the US Veterans Health Administration database, we retrospectively identified 728 patients with stage III NSCLC treated with definitive chemoradiation who started durvalumab within 120 days of radiation completion. Time between the last radiation treatment and first durvalumab infusion was analyzed in multivariable Cox regression models for the primary outcomes of progression-free survival (PFS) and overall survival (OS), adjusting for baseline patient and disease characteristics. The primary analysis used a 120-day landmark, measuring OS and PFS from 120 days after radiation completion.

RESULTS

Among 728 patients, the median time from RT completion to durvalumab start was 41 days (interquartile range 30-58). In multivariable Cox regression, time from RT completion to durvalumab start showed no association with PFS (adjusted hazard ratio [aHR] 1.01 per week, 95% confidence interval [CI] 0.98-1.04, P = .4) or OS (aHR 1.02 per week, 95% CI 0.98-1.06, P = .3). Starting durvalumab ≤14 days after RT was also not associated with improved PFS or OS. Results were robust in sensitivity analyses varying analytical technique.

CONCLUSIONS

Timing of durvalumab initiation up to 120 days after RT completion is not associated with PFS or OS in this real-world patient cohort.

Real World Outcomes versus Clinical Trial Results of Durvalumab Maintenance in Veterans with Stage III Non-Small Cell Lung Cancer

Simple Summary

The standard of care for patients with stage III non-small cell lung cancer is concurrent chemoradiotherapy followed by maintenance durvalumab based on outcomes from the PACIFIC trial. The efficacy of this regimen in a real-world population has not been extensively studied. We found that the addition of durvalumab has significantly improved both progression-free and overall survival in veterans with stage III non-small cell lung cancer as compared to veterans who received concurrent chemoradiotherapy alone, but overall survival of veterans is reduced compared to patients in the PACIFIC trial. Additional studies will need to be performed to understand this efficacy-effectiveness gap.

Abstract

One year of durvalumab following concurrent chemoradiotherapy improves progression-free (PFS) and overall survival (OS) for patients with stage III non-small cell lung cancer (NSCLC). However, the real-world efficacy of durvalumab has not been determined. We conducted a multi-center observational cohort study across the Veterans Health Administration, including patients with stage III NSCLC who received concurrent chemoradiotherapy and durvalumab, compared to patients who received concurrent chemoradiotherapy alone. Kaplan–Meier and Cox regression approaches were used to identify factors associated with PFS and OS. We calculated a hazard ratio and efficacy-effectiveness factor to compare OS of veterans to the referenced clinical trial population. A total of 1006 patients with stage III NSCLC who received concurrent chemoradiotherapy and at least one dose of durvalumab from November 2017 to April 2021 were compared to 989 patients who received concurrent chemoradiotherapy alone from January 2015 to December 2016. Adjuvant durvalumab was associated with higher PFS (HR 0.62, 95% CI 0.55–0.70, p < 0.001) and OS (HR 0.57, 95% CI 0.50–0.66, p < 0.001). OS was shorter in veterans compared to PACIFIC (HR 1.24, 95% CI 1.03–1.48, p = 0.02: EE gap 0.73). OS of veterans with stage III NSCLC treated with adjuvant durvalumab is improved compared to a modern comparator but is reduced compared to the PACIFIC population.

Prognostic and predictive value of neutrophil-to-lymphocyte ratio with adjuvant immunotherapy in stage III non-small-cell lung cancer

BACKGROUND

Elevated pre-treatment neutrophil-to-lymphocyte ratio (NLR) may reflect immune dysfunction and is negatively prognostic in cancer patients treated with immunotherapy, but it is unclear if NLR is predictive of immunotherapy benefit.

METHODS

We identified stage III non-small-cell lung cancer (NSCLC) patients treated with definitive chemoradiation and adjuvant durvalumab within the national Veterans Affairs system from 2017 to 2021. We compared the prognostic value of NLR measured before durvalumab start to a control group of stage III NSCLC patients treated with definitive chemoradiation alone from 2015 to 2016 (no-durvalumab group) before the approval of adjuvant durvalumab. We estimated the predictive value of NLR through the statistical interaction of durvalumab group by NLR level. Outcomes included progression-free survival (PFS) and overall survival (OS).

RESULTS

The primary analysis for NLR included 821 durvalumab patients and 445 no-durvalumab patients. Higher NLR was associated with inferior PFS in both groups (no-durvalumab: adjusted HR [aHR] 1.14 per 7.43 unit increase in NLR, 95% confidence interval [CI] 1.06-1.23; durvalumab: aHR 1.42, 95% CI 1.23-1.64), though this effect was greater in durvalumab patients (p for interaction = 0.009). Similar results were found for OS (no-durvalumab: aHR 1.16, 95% CI 1.09-1.24; durvalumab: aHR 1.48, 95% CI 1.25-1.76; p for interaction = 0.010). Absolute lymphocytes, eosinophils, and basophils were not prognostic in either group. Estimates of durvalumab treatment efficacy suggested declining efficacy with higher NLR.

CONCLUSION

Pre-treatment NLR is especially prognostic among stage III NSCLC patients treated with adjuvant immunotherapy compared to control patients treated without immunotherapy and may be a predictive biomarker of immunotherapy benefit.

Tissue-specific Tregs in cancer metastasis: opportunities for precision immunotherapy

Decades of advancements in immuno-oncology have enabled the development of current immunotherapies, which provide long-term treatment responses in certain metastatic cancer patients. However, cures remain infrequent, and most patients ultimately succumb to treatment-refractory metastatic disease. Recent insights suggest that tumors at certain organ sites exhibit distinctive response patterns to immunotherapy and can even reduce antitumor immunity within anatomically distant tumors, suggesting the activation of tissue-specific immune tolerogenic mechanisms in some cases of therapy resistance. Specialized immune cells known as regulatory T cells (Tregs) are present within all tissues in the body and coordinate the suppression of excessive immune activation to curb autoimmunity and maintain immune homeostasis. Despite the high volume of research on Tregs, the findings have failed to reconcile tissue-specific Treg functions in organs, such as tolerance, tissue repair, and regeneration, with their suppression of local and systemic tumor immunity in the context of immunotherapy resistance. To improve the understanding of how the tissue-specific functions of Tregs impact cancer immunotherapy, we review the specialized role of Tregs in clinically common and challenging organ sites of cancer metastasis, highlight research that describes Treg impacts on tissue-specific and systemic immune regulation in the context of immunotherapy, and summarize ongoing work reporting clinically feasible strategies that combine the specific targeting of Tregs with systemic cancer immunotherapy. Improved knowledge of Tregs in the framework of their tissue-specific biology and clinical sites of organ metastasis will enable more precise targeting of immunotherapy and have profound implications for treating patients with metastatic cancer.

The Liver-Immunity Nexus and Cancer Immunotherapy

The impact of liver metastases on immune checkpoint-inhibitor effectiveness in patients with solid-tumor malignancies has been the focus of several recent clinical and translational studies. We review the literature describing the immune functions of the liver and particularly the mechanistic observations in these studies. The initial clinical observation was that pembrolizumab appeared to be much less effective in melanoma and non-small cell lung cancer (NSCLC) patients with liver metastasis. Subsequently other clinical studies have extended and reported similar findings with programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1) inhibitors in many cancers. Two recent translational studies in animal models have dissected the mechanism of this systemic immune suppression. In both studies CD11b⁺ suppressive macrophages generated by liver metastasis in a two-site MC38 model appear to delete CD8⁺ T cells in a FasL-dependent manner. In addition, regulatory T-cell (Treg) activation was observed and contributed to the distal immunosuppression. Finally, we discuss some of the interventions reported to address liver immune suppression, such as radiation therapy, combination checkpoint blockade, and Treg depletion.

Translation of DNA Damage Response Inhibitors as Chemoradiation Sensitizers From the Laboratory to the Clinic

Combination therapies with agents targeting the DNA damage response (DDR) offer an opportunity to selectively enhance the therapeutic index of chemoradiation or eliminate use of chemotherapy altogether. The successful translation of DDR inhibitors to clinical use requires investigating both their direct actions as (chemo)radiosensitizers and their potential to stimulate tumor immunogenicity. Beginning with high-throughput screening using both viability and DNA damage-reporter assays, followed by validation in gold-standard radiation colony-forming assays and in vitro assessment of mechanistic effects on the DDR, we describe proven strategies and methods leading to the clinical development of DDR inhibitors both with radiation alone and in combination with chemoradiation. Beyond these in vitro studies, we discuss the impact of key features of human xenograft and syngeneic mouse models on the relevance of in vivo tumor efficacy studies, particularly with regard to the immunogenic effects of combined therapy with radiation and DDR inhibitors. Finally, we describe recent technological advances in radiation delivery (using the small animal radiation research platform) that allow for conformal, clinically relevant radiation therapy in mouse models. This overall approach is critical to the successful clinical development and ultimate Food and Drug Administration approval of DDR inhibitors as (chemo)radiation sensitizers.

Tim-4+ cavity-resident macrophages impair anti-tumor CD8+ T cell immunity

Immune checkpoint blockade (ICB) has been a remarkable clinical advance for cancer; however, the majority of patients do not respond to ICB therapy. We show that metastatic disease in the pleural and peritoneal cavities is associated with poor clinical outcomes after ICB therapy. Cavity-resident macrophages express high levels of Tim-4, a receptor for phosphatidylserine (PS), and this is associated with reduced numbers of CD8+ T cells with tumor-reactive features in pleural effusions and peritoneal ascites from patients with cancer. We mechanistically demonstrate that viable and cytotoxic anti-tumor CD8+ T cells upregulate PS and this renders them susceptible to sequestration away from tumor targets and proliferation suppression by Tim-4+ macrophages. Tim-4 blockade abrogates this sequestration and proliferation suppression and enhances anti-tumor efficacy in models of anti-PD-1 therapy and adoptive T cell therapy in mice. Thus, Tim-4+ cavity-resident macrophages limit the efficacy of immunotherapies in these microenvironments.

Cytidine Deaminase APOBEC3A Regulates PD-L1 Expression in Cancer Cells in a JNK/c-JUN-Dependent Manner

Programmed death-ligand 1 (PD-L1) promotes tumor immune evasion by engaging the PD-1 receptor and inhibiting T-cell activity. While the regulation of PD-L1 expression is not fully understood, its expression is associated with tumor mutational burden and response to immune checkpoint therapy. Here, we report that Apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like 3A (APOBEC3A) is an important regulator of PD-L1 expression. Using an APOBEC3A inducible expression system as well as siRNA against endogenous APOBEC3A, we found that APOBEC3A regulates PD-L1 mRNA and protein levels as well as PD-L1 cell surface expression in cancer. Mechanistically, APOBEC3A-induced PD-L1 expression was dependent on APOBEC3A catalytic activity as catalytically dead APOBEC3A mutant (E72A) failed to induce PD-L1 expression. Furthermore, APOBEC3A-induced PD-L1 expression was dependent on replication-associated DNA damage and JNK/c-JUN signaling but not interferon signaling. In addition, we confirmed the relevance of these finding in patient tumors as APOBEC3A expression and mutational signature correlated with PD-L1 expression in multiple patient cancer types. These data provide a novel link between APOBEC3A, its DNA mutagenic activity and PD-L1-mediated antitumoral immunity. This work nominates APOBEC3A as a mechanism of immune evasion and a potential biomarker for the therapeutic efficacy of immune checkpoint blockade. IMPLICATIONS: APOBEC3A catalytic activity induces replication-associated DNA damage to promote PD-L1 expression implying that APOBEC3A-driven mutagenesis represents both a mechanism of tumor immune evasion and a therapeutically targetable vulnerability in cancer cells.

Bone Metastases, Skeletal-Related Events, and Survival in Patients With Metastatic Non-Small Cell Lung Cancer Treated With Immune Checkpoint Inhibitors

BACKGROUND

Bone metastases and skeletal-related events (SREs) are a frequent cause of morbidity in patients with metastatic non-small cell lung cancer (mNSCLC). Data are limited on bone metastases and SREs in patients with mNSCLC treated using immune checkpoint inhibitors (ICIs), and on the efficacy of bone-modifying agents (BMAs) in this setting. Here we report the incidence, impact on survival, risk factors for bone metastases and SREs, and impact of BMAs in patients with mNSCLC treated with ICIs in a multi-institutional cohort.

PATIENTS AND METHODS

We conducted a retrospective study of patients with mNSCLC treated with ICIs at 2 tertiary care centers from 2014 through 2017. Overall survival (OS) was compared between patients with and without baseline bone metastases using a log-rank test. A Cox regression model was used to evaluate the association between OS and the presence of bone metastases at ICI initiation, controlling for other confounding factors.

RESULTS

We identified a cohort of 330 patients who had received ICIs for metastatic disease. Median patient age was 63 years, most patients were treated in the second line or beyond (n=259; 78%), and nivolumab was the most common ICI (n=211; 64%). Median OS was 10 months (95% CI, 8.4-12.0). In our cohort, 124 patients (38%) had baseline bone metastases, and 43 (13%) developed SREs during or after ICI treatment. Patients with bone metastases had a higher hazard of death after controlling for performance status, histology, line of therapy, and disease burden (hazard ratio, 1.57; 95% CI, 1.19-2.08; P=.001). Use of BMAs was not associated with OS or a decreased risk of SREs.

CONCLUSIONS

Presence of bone metastases at baseline was associated with a worse prognosis for patients with mNSCLC treated with ICI after controlling for multiple clinical characteristics. Use of BMAs was not associated with reduced SREs or a difference in survival.

Abstract PO-046: Combining PARP inhibition with radiation to sensitize homologous recombination proficient pancreatic cancer to immunotherapy

Pancreatic cancer is notoriously resistant to most cancer therapeutics including immunotherapy. We have previously shown that inhibition of the DNA damage response (DDR) enhances radiation-induced Type I interferon (T1IFN) and sensitizes pancreatic cancers to immunotherapy. In this study, we investigated the efficacy of radiation in combination with the poly (ADP-ribose) polymerase (PARP)inhibitor olaparib and programmed death ligand 1 (PD-L1) immune checkpoint blockade in otherwise resistant homologous recombination (HR) proficient pancreatic cancer. Initial studies demonstrated, in contrast to olaparib alone, that the combination of olaparib and radiation induced innate immune signaling in HR proficient pancreatic cancer cells marked by increases in pTBK1, T1IFN and pSTAT1. In animal tumor models, we found that the therapeutic efficacy of olaparib and radiation was greater in immune competent versus immune deficient hosts. In addition to the positive immune effects of olaparib and radiation, we also observed increased expression of PD-L1, a negative immune regulatory mechanism that likely restrains T1IFN-mediated innate immunity. We therefore went on to test the combined efficacy of PD-L1 blocking antibody with olaparib and radiation in syngeneic pancreatic tumor models. We found that monotherapy was ineffective in controlling tumor growth while doublet therapy with olaparib and radiation produced an intermediate tumor growth response. Importantly, maximal tumor growth inhibition was achieved following combined treatment with olaparib, radiation, and anti-PD-L1 which was significant relative to doublet therapy with olaparib-radiation or anti-PD-L1-radiation, and associated with a 20% complete response rate. Given that advances in therapy of pancreatic cancer require improvements in both local and systemic disease control, we examined the efficacy of combined therapy against tumors outside of the radiation field. In addition to the effects on tumors in the radiation field, we found that combined therapy with olaparib, radiation and anti-PD-L1 significantly delayed the growth of contralateral tumors outside of the radiation field, suggesting an adaptive immune response. Taken together, these studies illustrate the potential efficacy of combined therapy with olaparib, radiation, and anti-PD-L1 on both local and systemic pancreatic cancer and support our proposed clinical trial in patients with pancreatic cancer.

Citation Format: Qiang Zhang, Long Jiang, Yawen Zheng, Theodore Lawrence, Vaibhav Sahai, Michael D. Green, Meredith Morgan. Combining PARP inhibition with radiation to sensitize homologous recombination proficient pancreatic cancer to immunotherapy [abstract]. In: Proceedings of the AACR Virtual Special Conference on Radiation Science and Medicine; 2021 Mar 2-3. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(8_Suppl):Abstract nr PO-046.

Stanniocalcin 1 is a phagocytosis checkpoint driving tumor immune resistance

Immunotherapy induces durable clinical responses in a fraction of patients with cancer. However, therapeutic resistance poses a major challenge to current immunotherapies. Here, we identify that expression of tumor stanniocalcin 1 (STC1) correlates with immunotherapy efficacy and is negatively associated with patient survival across diverse cancer types. Gain- and loss-of-function experiments demonstrate that tumor STC1 supports tumor progression and enables tumor resistance to checkpoint blockade in murine tumor models. Mechanistically, tumor STC1 interacts with calreticulin (CRT), an "eat-me" signal, and minimizes CRT membrane exposure, thereby abrogating membrane CRT-directed phagocytosis by antigen-presenting cells (APCs), including macrophages and dendritic cells. Consequently, this impairs APC capacity of antigen presentation and T cell activation. Thus, tumor STC1 inhibits APC phagocytosis and contributes to tumor immune evasion and immunotherapy resistance. We suggest that STC1 is a previously unappreciated phagocytosis checkpoint and targeting STC1 and its interaction with CRT may sensitize to cancer immunotherapy.

Validation of the American Joint Committee on Cancer Eighth Edition Staging of Patients With Metastatic Cutaneous Melanoma Treated With Immune Checkpoint Inhibitors

IMPORTANCE

Immune checkpoint inhibitors (ICIs) have transformed the survival of patients with metastatic melanoma. Patient prognosis is reflected by the American Joint Committee on Cancer (AJCC) staging system; however, it is unknown whether the metastatic (M) stage categories for cutaneous melanoma remain informative of prognosis in patients who have received ICIs.

OBJECTIVES

To evaluate the outcomes of patients with metastatic cutaneous melanoma based on the M stage category from the AJCC eighth edition and to determine whether these designations continue to inform the prognosis of patients who have received ICIs.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study included patients with metastatic cutaneous melanoma who were treated between August 2006 and August 2019 at the University of Michigan. The estimated median follow-up time was 35.5 months. Patient data were collected via the electronic medical record system. Critical findings were externally validated in a multicenter nationwide cohort of patients treated within the Veterans Affairs health care system. Data analysis was conducted from February 2020 to January 2021.

EXPOSURES

All patients were treated with dual-agent concurrent ipilimumab and nivolumab followed by maintenance nivolumab or single-agent ipilimumab, nivolumab, or pembrolizumab therapy. Patients were staged using the AJCC eighth edition.

MAIN OUTCOMES AND MEASURES

Univariable and multivariable analyses were used to assess the prognostic value of predefined clinicopathologic baseline factors on survival.

RESULTS

In a discovery cohort of 357 patients (mean [SD] age, 62.6 [14.2] years; 254 [71.1%] men) with metastatic cutaneous melanoma treated with ICIs, the M category in the AJCC eighth edition showed limited prognostic stratification by both univariable and multivariable analyses. The presence of liver metastases and elevated levels of serum lactate dehydrogenase (LDH) offered superior prognostic separation compared with the M category (liver metastases: hazard ratio, 2.22; 95% CI, 1.48-3.33; P < .001; elevated serum LDH: hazard ratio, 1.73; 95% CI, 1.16-2.58; P = .007). An updated staging system based on these factors was externally validated in a cohort of 652 patients (mean [SD] age, 67.9 [11.6] years; 630 [96.6%] men), with patients without liver metastases or elevated LDH levels having the longest survival (median overall survival, 30.7 months).

CONCLUSIONS AND RELEVANCE

This study found that the AJCC eighth edition M category was poorly reflective of prognosis in patients receiving ICIs. Future staging systems could consider emphasizing the presence of liver metastases and elevated LDH levels. Additional studies are needed to confirm the importance of these and other prognostic biomarkers.

Characterization of outcomes in patients with advanced genitourinary malignancies treated with immune checkpoint inhibitors

PURPOSE

Several immune checkpoint inhibitors (ICIs) are FDA approved for treatment of genitourinary (GU) malignancies. We aim to determine demographic and clinicopathologic characteristics that significantly affect clinical outcomes in patients with advanced stage GU malignancies treated with ICIs.

MATERIALS AND METHODS

We performed a single-center, consecutive, retrospective cohort analysis on patients with metastatic or unresectable GU malignancies who were treated with ICIs at the University of Michigan. Immune-related adverse events (irAEs), putative immune-mediated allergies, and overall response rates (ORR) were assessed. Comorbidity index scores were calculated. Survival analysis was performed to evaluate progression-free survival (PFS) and overall survival (OS), stratifying and controlling for a variety of clinicopathologic baseline factors including site of metastases.

RESULTS

A total of 160 patients were identified with advanced renal cell carcinoma (RCC) or urothelial carcinoma. Median PFS and OS were 5.0 and 23.6 months for RCC, and 2.8 and 9.6 months for urothelial carcinoma, respectively. Patients who experienced increased frequency and higher grade irAEs had better ICI treatment response (P < 0.0001). Presence of liver metastases was associated with poor response to ICI therapy (P = 0.001). Multivariable modeling demonstrates that patients with urothelial carcinoma and liver metastases had statistically worse PFS and OS compared to patients with RCC or other sites of metastases, respectively.

CONCLUSION

Greater frequency and higher grades of irAEs are associated with better treatment response in patients with RCC and urothelial malignancy receiving ICI therapy. The presence of liver metastases denotes a negative predictive marker for immunotherapy efficacy.

SUMMARY

Immune checkpoint inhibitors (ICI) are increasingly used to treat genitourinary (GU) malignancies. However, clinical data regarding patients with advanced-stage GU malignancies treated with ICI is lacking. Thus, we performed a single-center, retrospective cohort study on patients with metastatic and unresectable renal cell carcinoma (RCC) and urothelial carcinoma who were treated with ICIs at the University of Michigan to provide demographic and clinicopathologic data regarding this population. We specifically focused on immune-related adverse events (irAEs), immune-mediated allergies, and the associated overall response rates (ORR). To better assess performance status, we calculated comorbidity scores for all patients. Finally, survival analyses for progression-free survival (PFS) and overall survival (OS) were performed using Kaplan-Meier analysis and Cox proportional hazards modeling, stratifying and controlling for clinicopathologic baseline factors, including sites of metastases, in our multivariable analysis. A total of 160 patients were identified with advanced RCC or urothelial carcinoma. We found decreased PFS (2.8 vs. 5.0 months) and decreased OS (9.8 vs. 23.6 months) for urothelial carcinoma compared to RCC patients. We noted that patients who experienced increased frequency and higher grades of irAEs had better treatment ORR with ICI therapy (P ≤ 0.0001). The presence of liver metastases was associated with worse ORR (P = 0.001), PFS (P = 0.0014), and OS (P = 0.0028) compared to other sites of metastases including lymph node, lung, and CNS/bone. The poor PFS and OS associated with urothelial carcinoma and liver metastases were preserved in our multivariable modeling after controlling for pertinent clinical factors. We conclude that greater frequency and higher grades of irAEs are associated with better treatment response in GU malignancy patients receiving ICI, a finding that is consistent with published studies in other cancers. The presence of liver metastases represents a significantly poor predictive marker in GU malignancy treated with ICI. Our findings contribute to the growing body of literature that seeks to understand the clinicopathologic variables and outcomes associated with ICI therapy.

639. Short Course Therapy for Urinary Tract Infections (SCOUT) in Children

Background

The AAP recommends 7 to 14-days of antimicrobials for the treatment of urinary tract infections (UTIs), one of the most common bacterial infections of childhood. However, most physicians routinely prescribe at least 10 days of therapy. Prior observational studies suggest that courses shorter than 10 days might be effective.

Methods

The primary objective was to determine if halting antimicrobial therapy in children who improved clinically after 5 days of therapy (short course therapy) results in a similar failure rate as children who continue antimicrobials for an additional 5 days (standard course therapy).

This was a multi-center, randomized, double-blind, placebo-controlled non-inferiority clinical trial of children ages 2 to 10 years with UTI. Subjects treated with 1 of 5 antibiotics (trimethoprim-sulfamethoxazole, amoxicillin-clavulanate, cefixime, cefdinir or cephalexin) were eligible. Children were stratified by presence or absence of fever and were enrolled if they had clinical improvement before Day 5 of treatment. The a priori equivalence interval was set at 0.05 for a one-sided analysis. The primary outcome was development of a symptomatic UTI defined as the presence of symptoms, pyuria, and a positive urine culture. The Intent-to-Treat population included children who took at least one dose of study medication.

Results

A total of 693 children were randomized, 345 to short course and 348 to standard course. Median age was 4 years old (IQR; 2-6), 652 (96.3%) were female and 255 were febrile (37%). Treatment success rate was 322/336 (96%) for short course and 326/328 (99%) for standard course. The 95% upper CI limit for the difference was 0.054. Treatment failure was not related to age group, fever at presentation, antibiotic type, or study site. There were no significant differences between groups the in the rates of adverse events, recurrent infection, clinical symptoms that may have been related to UTI, or emergent antibiotic resistance.

Conclusion

In children aged 2 months to 10 years with UTI, halting antimicrobial therapy in children who had exhibited clinical improvement after 5 days and continuing for an additional 5 days both resulted in high success rates. However, short course was inferior to treatment for 10 days.

Disclosures

Kevin J. Downes, MD, Merck, Inc. (Grant/Research Support) Brian T. Fisher, DO, MPH, MSCE, Astellas (Advisor or Review Panel member)Merck (Grant/Research Support)Pfizer (Grant/Research Support)

163. Automation of an Inpatient Provider Specific Antimicrobial Use Report

Background

The use of individual prescriber report cards has shown to be an effective strategy in optimizing antimicrobial use in the pediatric outpatient setting. This is more difficult in an inpatient setting with prescribing often being done by a resident, but the decisions regarding antimicrobials are often made by the attending physician. This concept was tackled at a tertiary children’s hospital but was a manual and time-consuming process. The purpose of this review is to compare provider specific antimicrobial use between a manual chart review and an automated report.

Methods

An automatic report was developed that calculates antimicrobial days of therapy per 1000 patient days for each Pediatric Intensive Care Unit (PICU) attending provider. The software used was Business Objects that interfaces with the Electronic Medical Record. The provider is attached to daily antimicrobial use based on the attending to write a note that day. The provider was attached to patient days based on the number of days per patient they wrote notes.

Results

One week including 96 patients was chart reviewed and compared to the automated report prospectively. The automatic report days of therapy and patient days per PICU provider were within 10% of the chart review. Two months of the previous manual chart review was compared to the same two months with the automated report, which was also within 10%. Average quarterly hospital PICU antimicrobial days of therapy per 1000 patient days during the calendar year of 2019 in the Pediatric Health Information System (PHIS) were compared quarterly to the automated report, which was also within 10%.

Conclusion

An automated report that connects the attending to antimicrobial orders by attaching it to the note writer was found to be comparable to manual chart review as well as an average of use for the PICU compared to the national database PHIS. This automation can help decrease workload and optimize efforts for specific interventions and education that can be distributed with the PICU attending antimicrobial use report.

Disclosures

All Authors: No reported disclosures

The impact of BRAF mutation status on clinical outcomes with anti-PD-1 monotherapy versus combination ipilimumab/nivolumab in treatment-naïve advanced stage melanoma

Nearly half of all metastatic melanoma patients possess the BRAF V600 mutation. Several therapies are approved for advanced stage melanoma, but it is unclear if there is a differential outcome to various immunotherapy regimens based on BRAF mutation status. We retrospectively analyzed a cohort of metastatic or unresectable melanoma patients who were treated with combination ipilimumab/nivolumab (ipi/nivo) or anti-PD-1 monotherapy, nivolumab, or pembrolizumab, as first-line treatment. 235 previously untreated patients were identified in our study. Our univariate analysis showed no statistical difference in progression-free survival (PFS) or overall survival (OS) with ipi/nivo versus anti-PD-1 monotherapy in the BRAF V600 mutant cohort, but there was improved PFS [HR: 0.48, 95% CI, 0.28-0.80] and OS [HR: 0.50, 95% CI, 0.26-0.96] with ipi/nivo compared to anti-PD-1 monotherapy in the BRAF WT group. After adjusting for known prognostic variables in our multivariable analysis, the BRAF WT cohort continued to show PFS and OS benefit with ipi/nivo compared to anti-PD-1 monotherapy. Our single-institution analysis suggests ipi/nivo should be considered over anti-PD-1 monotherapy as the initial immunotherapy regimen for metastatic melanoma patients regardless of BRAF mutation status, but possibly with greater benefit in BRAF WT.

Cardiac Biomarkers Associated With Hospital Length of Stay After Pediatric Congenital Heart Surgery

BACKGROUND

Prolonged hospital length of stay after congenital heart surgery is a significant cost burden and is associated with postoperative morbidity. Our goal was to evaluate the association between pre- and postoperative biomarker levels and in-hospital length of stay for children after congenital heart surgery.

METHODS

We enrolled patients <18 years of age who underwent at least 1 congenital heart operation at Johns Hopkins Hospital from 2010 to 2014. Blood samples were collected before the index operation and at the end of the bypass. ST2 and N-terminal pro-brain natriuretic peptide (NT-proBNP) measurements were evaluated as log-transformed, median, and tercile cut-points. We evaluated the association between pre- and postoperative NT-proBNP and ST2 measurements with in-hospital postoperative length of stay using multivariate logistic regression. We adjusted for covariates used in The Society of Thoracic Surgeons Congenital Heart Surgery Mortality Risk Model.

RESULTS

In our cohort 45% of our patients had an in-hospital postoperative length of stay longer than the median. Before adjustment preoperative NT-proBNP above the population median and the highest tercile exhibited a significantly longer in-hospital length of stay. After adjustment for covariates in the risk model, pre- and postoperative ST2 and NT-proBNP demonstrated a significantly longer length of stay.

CONCLUSIONS

Perioperative ST2 and NT-proBNP had a significant association with increased postoperative in-hospital length of stay before and after adjustment. ST2 in particular could be used to guide an earlier assessment of patient risk for complications that may lead to adverse outcomes.

Tumor Immune Microenvironment Clusters in Localized Prostate Adenocarcinoma: Prognostic Impact of Macrophage Enriched/Plasma Cell Non-Enriched Subtypes

Background: Prostate cancer (PCa) is characterized by significant heterogeneity in its molecular, genomic, and immunologic characteristics. Methods: Whole transcriptome RNAseq data from The Cancer Genome Atlas of prostate adenocarcinomas (n = 492) was utilized. The immune microenvironment was characterized using the CIBERSORTX tool to identify immune cell type composition. Unsupervised hierarchical clustering was performed based on immune cell type content. Analyses of progression-free survival (PFS), distant metastases, and overall survival (OS) were performed using Kaplan–Meier estimates and Cox regression multivariable analyses. Results: Four immune clusters were identified, largely defined by plasma cell, CD4⁺ Memory Resting T Cells (CD4 MR), and M0 and M2 macrophage content (CD4 MR^HighPlasma Cell^HighM0^LowM2^Mid, CD4 MR^LowPlasma Cell^HighM0^LowM2^Low, CD4 MR^HighPlasma Cell^LowM0^HighM2^Low, and CD4 MR^HighPlasma Cell^LowM0^LowM2^High). The two macrophage-enriched/plasma cell non-enriched clusters (3 and 4) demonstrated worse PFS (HR 2.24, 95% CI 1.46–3.45, p = 0.0002) than the clusters 1 and 2. No metastatic events occurred in the plasma cell enriched, non-macrophage-enriched clusters. Comparing clusters 3 vs. 4, in patients treated by surgery alone, cluster 3 had zero progression events (p < 0.0001). However, cluster 3 patients had worse outcomes after post-operative radiotherapy (p = 0.018). Conclusion: Distinct tumor immune clusters with a macrophage-enriched, plasma cell non-enriched phenotype and reduced plasma cell enrichment independently characterize an aggressive phenotype in localized prostate cancer that may differentially respond to treatment.

Epigenetic driver mutations in ARID1A shape cancer immune phenotype and immunotherapy

Whether mutations in cancer driver genes directly affect cancer immune phenotype and T cell immunity remains a standing question. ARID1A is a core member of the polymorphic BRG/BRM-associated factor chromatin remodeling complex. ARID1A mutations occur in human cancers and drive cancer development. Here, we studied the molecular, cellular, and clinical impact of ARID1A aberrations on cancer immunity. We demonstrated that ARID1A aberrations resulted in limited chromatin accessibility to IFN-responsive genes, impaired IFN gene expression, anemic T cell tumor infiltration, poor tumor immunity, and shortened host survival in many human cancer histologies and in murine cancer models. Impaired IFN signaling was associated with poor immunotherapy response. Mechanistically, ARID1A interacted with EZH2 via its carboxyl terminal and antagonized EZH2-mediated IFN responsiveness. Thus, the interaction between ARID1A and EZH2 defines cancer IFN responsiveness and immune evasion. Our work indicates that cancer epigenetic driver mutations can shape cancer immune phenotype and immunotherapy.

Radiotherapy in the Multidisciplinary Management of Merkel Cell Carcinoma

The management of Merkel cell carcinoma (MCC) requires multidisciplinary care for optimal patient outcomes. Radiotherapy (RT) is most commonly used as adjuvant therapy to improve locoregional control in patients with MCC who undergo surgery. Additionally, it can sometimes be used as definitive monotherapy for patients who decline or are not candidates for surgery and as palliative treatment in those with metastatic MCC. This article discusses the indications, treatment considerations, and recommended dose prescriptions for RT in the management of early- and advanced-stage disease. Considerable hope exists that immunotherapy advances will synergize with RT to further enhance clinical outcomes.

Radiotherapy and Immunotherapy Promote Tumoral Lipid Oxidation and Ferroptosis via Synergistic Repression of SLC7A11

A challenge in oncology is to rationally and effectively integrate immunotherapy with traditional modalities, including radiotherapy. Here, we demonstrate that radiotherapy induces tumor-cell ferroptosis. Ferroptosis agonists augment and ferroptosis antagonists limit radiotherapy efficacy in tumor models. Immunotherapy sensitizes tumors to radiotherapy by promoting tumor-cell ferroptosis. Mechanistically, IFNγ derived from immunotherapy-activated CD8⁺ T cells and radiotherapy-activated ATM independently, yet synergistically, suppresses SLC7A11, a unit of the glutamate-cystine antiporter xc^-, resulting in reduced cystine uptake, enhanced tumor lipid oxidation and ferroptosis, and improved tumor control. Thus, ferroptosis is an unappreciated mechanism and focus for the development of effective combinatorial cancer therapy. SIGNIFICANCE: This article describes ferroptosis as a previously unappreciated mechanism of action for radiotherapy. Further, it shows that ferroptosis is a novel point of synergy between immunotherapy and radiotherapy. Finally, it nominates SLC7A11, a critical regulator of ferroptosis, as a mechanistic determinant of synergy between radiotherapy and immunotherapy.This article is highlighted in the In This Issue feature, p. 1631.

Integrating radiomics into clinical trial design

In radiomics, quantitative features that describe phenotypic tumor characteristics are derived from radiographic images. Because radiomics generates information from routine medical images, it is a powerful way to non-invasively examine the spatial and temporal heterogeneity of disease, and thus has potential to significantly impact clinical trial design, execution, and ultimately patient care. The aim of this review article is to discuss how radiomics may address some of the current challenges in clinical randomized control trials, and the difficulties of integrating robust and repeatable radiomics analysis into trial design. Each step of the radiomics process, including image acquisition and reconstruction, image segmentation, feature extraction, and computational analysis, requires extensive standardization in order to be successfully incorporated into clinical trials and inform clinical decision making. By addressing these challenges, the potential of radiomics may be realized.

Monitoring and Predicting Net Longevity by Measuring Surface Levels of Insecticide: Implementing a Faster, Cost Effective, Nondestructive, and Field-Ready Alternative to the World Health Organization Cone Test Bioassay

An important component of malaria control programs is the ability to assess the effectiveness of the insecticide in insecticide-treated nets (ITNs) during normal usage. The standard technique to measure insecticidal activity is the World Health Organization (WHO) cone test, which in many circumstances, may be difficult to implement. We have evaluated an alternative technique, the colorimetric field test (CFT) on a group of 24-month-old Permanet^® 2.0 (Vestergaard-Frandsen, Denmark) nets collected in Colombia. The CFT, which measures surface levels (SL) of deltamethrin is compared with standard high-performance liquid chromatography (HPLC) and the WHO cone test. Effective concentrations of deltamethrin for 80% mortality (EC₈₀) were determined from the CFT and HPLC results. Distribution of insecticide SL after 24 months of use reveal that sampling of the midsection best represents the condition of the entire net. We conclude that the CFT is a practical alternative to the WHO cone test for assessing ITN efficacy.

Adjuvant Radiation Improves Recurrence-Free Survival and Overall Survival in Adrenocortical Carcinoma

CONTEXT

Adrenocortical carcinoma (ACC) is a rare malignancy with high rates of recurrence and poor prognosis. The role of radiotherapy (RT) in localized ACC has been controversial, and RT is not routinely offered.

OBJECTIVE

To evaluate the benefit of adjuvant RT on outcomes in ACC.

DESIGN

This is a retrospective propensity-matched analysis.

SETTING

All patients were seen through the University of Michigan's Endocrine Oncology program, and all those who underwent RT were treated at the University of Michigan.

PARTICIPANTS

Of 424 patients with ACC, 78 were selected; 39 patients underwent adjuvant radiation.

INTERVENTION

Adjuvant RT to the tumor bed and adjacent lymph nodes.

MAIN OUTCOMES MEASURES

Time to local failure, distant failure, or death.

RESULTS

Median follow-up time was 4.21 years (95% CI, 2.79 to 4.94). The median radiation dose was 55 Gy (range, 45 to 60). The 3-year overall survival estimate for patients improved from 48.6% for patients without RT (95% CI, 29.7 to 65.2) to 77.7% (95% CI, 56.3 to 89.5) with RT, with a hazard ratio (HR) of 3.59 (95% CI, 1.60 to 8.09; P = 0.002). RT improved local recurrence-free survival (RFS) from 34.2% (95% CI, 18.8 to 50.3) to 59.5% (95% CI, 39.0 to 75.0), with an HR of 2.67 (95% CI, 1.38 to 5.19; P = 0.0035). RT improved all RFS from 18.3% (95% CI, 6.7 to 34.3) to 46.7% (95% CI, 26.9 to 64.3), with an HR 2.59 (95% CI, 1.40 to 4.79; P = 0.0024).

CONCLUSIONS

In the largest single institution study to date, adjuvant RT after gross resection of ACC improved local RFS, all RFS, and overall survival in this propensity-matched analysis. Adjuvant RT should be considered a part of multidisciplinary management for patients with ACC.