Neoadjuvant cobimetinib and atezolizumab with or without vemurafenib for high-risk operable Stage III melanoma: the Phase II NeoACTIVATE trial.

Both targeted therapies and immunotherapies provide benefit in resected Stage III melanoma. We hypothesized that the combination of targeted and immunotherapy given prior to therapeutic lymph node dissection (TLND) would be tolerable and drive robust pathologic responses. In NeoACTIVATE (NCT03554083), a Phase II trial, patients with clinically evident resectable Stage III melanoma received either 12 weeks of neoadjuvant vemurafenib, cobimetinib, and atezolizumab (BRAF-mutated, Cohort A, n = 15), or cobimetinib and atezolizumab (BRAF-wild-type, Cohort B, n = 15) followed by TLND and 24 weeks of adjuvant atezolizumab. Here, we report outcomes from the neoadjuvant portion of the trial. Based on intent to treat analysis, pathologic response (≤50% viable tumor) and major pathologic response (complete or near-complete, ≤10% viable tumor) were observed in 86.7% and 66.7% of BRAF-mutated and 53.3% and 33.3% of BRAF-wild-type patients, respectively (primary outcome); these exceeded pre-specified benchmarks of 50% and 30% for major pathologic response. Grade 3 and higher toxicities, primarily dermatologic, occurred in 63% during neoadjuvant treatment (secondary outcome). No surgical delays nor progression to regional unresectability occurred (secondary outcome). Peripheral blood CD8 + TCM cell expansion associated with favorable pathologic responses (exploratory outcome).

A real-world experience of pembrolizumab monotherapy in microsatellite instability-high and/or tumor mutation burden-high metastatic castration-resistant prostate cancer: outcome analysis.

BACKGROUND: The efficacy of pembrolizumab monotherapy in metastatic castration-resistant prostate cancer patients (mCRPC) when stratified by MSI-H and/or TMB-H is poorly defined. Additionally, outcomes based on sequencing source (i.e., tissue or liquid biopsy) have not been well described. We sought to assess outcomes of pembrolizumab monotherapy in patients with mCRPC and compare efficacy based on MSI-H and/or TMB-H when identified by tissue or liquid biopsy. METHODS: A retrospective analysis was performed of mCRPC patients treated at Mayo Clinic with pembrolizumab monotherapy between 2018 and 2023. Objective response rates (ORR), median progression-free survival (mPFS), and overall survival (mOS), were determined by RECIST v1.1 criteria. RESULTS: Twenty-two patients with mCRPC received pembrolizumab monotherapy for at least 3 cycles for a MSI-H or TMB-H indication. All patients had next generation sequencing (NGS) performed via tissue (n = 11) or liquid (n = 10) biopsy source. The ORR was 50% (27.3% complete response and 22.7% had partial response). The mPFS for TMB 10-14.9 mut/Mb (n = 4), TMB 15-24.9 mut/Mb (n = 6), and TMB ≥ 25 mut/Mb (n = 10) was 2.1, not reached (NR), and NR, respectively (p = 0.0003). The mOS for these same groups was 5.1 months, 20.5 months, and not reached, respectively. Among patients with TMB-H without co-occurring MSI-H or CDK12 (n = 6), none experienced a response and only one patient had stable disease compared to patients with MSI-H (n = 12) for whom the ORR was 75%. Immunotherapy responsive alterations such as ATRX and PTCH1 mutations were frequently noticed among patients who had complete response (CR). CONCLUSIONS: Our hypothesis-generating study suggests that MSI-H drives the efficacy of pembrolizumab in mCRPC with better survival outcomes as TMB increases. Clinicians should consider alternative treatment strategies for advanced prostate cancer when TMB-H is present without co-occurring MSI-H or CDK12.

A phase I oncolytic virus trial with vesicular stomatitis virus expressing human interferon beta and tyrosinase related protein 1 administered intratumorally and intravenously in uveal melanoma: safety, efficacy, and T cell responses.

Introduction: Metastatic uveal melanoma (MUM) has a poor prognosis and treatment options are limited. These patients do not typically experience durable responses to immune checkpoint inhibitors (ICIs). Oncolytic viruses (OV) represent a novel approach to immunotherapy for patients with MUM. Methods: We developed an OV with a Vesicular Stomatitis Virus (VSV) vector modified to express interferon-beta (IFN-ß) and Tyrosinase Related Protein 1 (TYRP1) (VSV-IFNß-TYRP1), and conducted a Phase 1 clinical trial with a 3 + 3 design in patients with MUM. VSV-IFNß-TYRP1 was injected into a liver metastasis, then administered on the same day as a single intravenous (IV) infusion. The primary objective was safety. Efficacy was a secondary objective. Results: 12 patients with previously treated MUM were enrolled. Median follow up was 19.1 months. 4 dose levels (DLs) were evaluated. One patient at DL4 experienced dose limiting toxicities (DLTs), including decreased platelet count (grade 3), increased aspartate aminotransferase (AST), and cytokine release syndrome (CRS). 4 patients had stable disease (SD) and 8 patients had progressive disease (PD). Interferon gamma (IFNγ) ELIspot data showed that more patients developed a T cell response to virus encoded TYRP1 at higher DLs, and a subset of patients also had a response to other melanoma antigens, including gp100, suggesting epitope spreading. 3 of the patients who responded to additional melanoma antigens were next treated with ICIs, and 2 of these patients experienced durable responses. Discussion: Our study found that VSV-IFNß -TYRP1 can be safely administered via intratumoral (IT) and IV routes in a previously treated population of patients with MUM. Although there were no clear objective radiographic responses to VSV-IFNß-TYRP1, dose-dependent immunogenicity to TYRP1 and other melanoma antigens was seen.

Patient- and Provider-Level Factors Associated With Telehealth Utilization Across a Multisite, Multiregional Cancer Practice From 2019 to 2021.

PURPOSE: In response to the COVID-19 pandemic, many cancer practices rapidly adopted telehealth services. However, there is a paucity of data regarding ongoing telehealth visit utilization beyond this initial response. The purpose of this study was to assess changes in variables associated with telehealth visit utilization over time. METHODS: This is a cross-sectional, year-over-year, retrospective analysis of telehealth visits conducted across a multisite, multiregional cancer practice in the United States. Multivariable models examined the association of patient- and provider-level variables with telehealth utilization across outpatient visits conducted over three 8-week periods from July to August in 2019 (n = 32,537), 2020 (n = 33,399), and 2021 (n = 35,820). RESULTS: The rate of telehealth utilization increased from <0.01% (2019) to 11% (2020) to 14% (2021). The most significant patient-level factors associated with increased telehealth utilization included nonrural residence and age ≤65 years. Among patients residing in rural settings, video visit utilization rates were significantly lower and phone visit utilization rates were significantly higher compared with patients from nonrural residences. Regarding provider-level factors, widening differences in telehealth utilization were observed at tertiary versus community-based practice settings. Increased telehealth utilization was not associated with duplicative care as per-patient and per-physician visit volumes in 2021 remained consistent with prepandemic levels. CONCLUSION: We observed continuous expansion in telehealth visit utilization from 2020 to 2021. Our experiences suggest that telehealth can be integrated into cancer practices without evidence of duplicative care. Future work should examine sustainable reimbursement structures and policies to ensure accessibility of telehealth as a means to facilitate equitable, patient-centered cancer care.

NKG7 Is a T-cell-Intrinsic Therapeutic Target for Improving Antitumor Cytotoxicity and Cancer Immunotherapy.

Cytotoxic CD8+ T cells (CTL) are a crucial component of the immune system notable for their ability to eliminate rapidly proliferating malignant cells. However, the T-cell intrinsic factors required for human CTLs to accomplish highly efficient antitumor cytotoxicity are not well defined. By evaluating human CD8+ T cells from responders versus nonresponders to treatment with immune checkpoint inhibitors, we sought to identify key factors associated with effective CTL function. Single-cell RNA-sequencing analysis of peripheral CD8+ T cells from patients treated with anti-PD-1 therapy showed that cells from nonresponders exhibited decreased expression of the cytolytic granule-associated molecule natural killer cell granule protein-7 (NKG7). Functional assays revealed that reduced NKG7 expression altered cytolytic granule number, trafficking, and calcium release, resulting in decreased CD8+ T-cell-mediated killing of tumor cells. Transfection of T cells with NKG7 mRNA was sufficient to improve the tumor-cell killing ability of human T cells isolated from nonresponders and increase their response to anti-PD-1 or anti-PD-L1 therapy in vitro. NKG7 mRNA therapy also improved the antitumor activity of murine tumor antigen-specific CD8+ T cells in an in vivo model of adoptive cell therapy. Finally, we showed that the transcription factor ETS1 played a role in regulating NKG7 expression. Together, our results identify NKG7 as a necessary component for the cytotoxic function of CD8+ T cells and establish NKG7 as a T-cell-intrinsic therapeutic target for enhancing cancer immunotherapy.See related article by Li et al., p. 154.

Cancer Mortality Rates Increasing vs Cardiovascular Disease Mortality Decreasing in the World: Future Implications.

OBJECTIVE: To highlight the current global trends in mortality for cardiovascular disease and cancer. METHODS: The World Health Organization and the World Bank DataBank databases were used to analyze mortality rates for cancer and cardiovascular disease by calculating age-standardized mortality rates (ASRs) from 2000 to 2015 for high-income, upper-middle-income, and lower-middle-income countries. Data for cancer mortality and population for 43 countries representing 5 of the 7 continents (except Australia and Antarctica) were analyzed. RESULTS: From 2000 to 2015, there was an increase in the ASR for cancer for both men and women irrespective of a country's income status, representing an overall 7% increase in cancer ASR (Pearson r, +0.99; P<.00001). We report a higher ASR for cancer in high-income countries than in upper-middle-income and lower-middle-income countries specifically; high-income countries saw a 3% increase in cancer ASR vs +31% for upper-middle-income and +19% for lower-middle-income countries (P<.01). There has been a decrease in the ASR for cardiovascular disease for the 15 years analyzed (P<.00001). In addition, high-income countries had a higher ASR for cardiovascular disease than upper-middle-income countries during the 15-year period (P<.05). CONCLUSION: We suspect that because of early detection and targeted interventions, cardiovascular disease mortality rates have decreased during the past decade. On the basis of our results, cancer mortality rates continue to rise, with the projection of surpassing cardiovascular disease mortality rates in the near future.

Peptide vaccine with glucopyranosyl lipid A-stable oil-in-water emulsion for patients with resected melanoma.

Aim: We tested the safety and immunogenicity of a novel vaccine in patients with resected high-risk melanoma. Patients & methods: HLA-A2-positive patients with resected Stage II-IV melanoma were randomized to receive up to three vaccinations of melanoma-associated peptide (MART-1a) combined with a stable oil-in-water emulsion (SE) either with the Toll-like receptor 4 agonist glucopyranosyl lipid A (GLA-SE-Schedule 1) or alone (SE-Schedule 2). Safety and immunogenicity of the vaccines were monitored. Results: A total of 23 patients were registered. No treatment-related grade 3 or higher adverse events were observed. Increases in MART-1a-specific T cells were seen in 70 and 63% of Schedule 1 and Schedule 2 patients, respectively. Conclusion: Both vaccine schedules were well-tolerated and resulted in an increase in MART-1a-specific T cells. Clinical Trial registration: NCT02320305 (ClinicalTrials.gov).

Therapeutic plasma exchange clears circulating soluble PD-L1 and PD-L1-positive extracellular vesicles.

BACKGROUND: Trans-acting programmed death-ligand 1 (PD-L1) derives from malignant cells in three known forms. High levels of secreted splice variant PD-L1 (sPD-L1), ADAM10/ADAM17-shed sPD-L1, and PD-L1-positive extracellular vesicles (evPD-L1) each predict poor prognosis and limited response to PD-(L)1 checkpoint inhibitors in cancer. To our knowledge, no clinical intervention has reduced any of these circulating forms of extracellular PD-L1. Here, we explore therapeutic plasma exchange (TPE) as a treatment to reduce circulating extracellular PD-L1. RESULTS: In patients with melanoma, sPD-L1 levels above 0.277 ng/mL predicted inferior overall survival. In patients undergoing TPE for non-malignant indications, each TPE session removed a mean 70.8% sPD-L1 and 73.1% evPD-L1 detectable in plasma. TPE also reduced total and ADAM10-positive extracellular vesicles. CONCLUSION: Here, we report the first known clinical intervention to remove either sPD-L1 or evPD-L1 from plasma in vivo. TPE reduces plasma sPD-L1 and evPD-L1 in vivo and may have a role in treatment with immunotherapy. TPE may also prove useful in patients with other extracellular vesicle-related conditions.

Chemo-immunotherapy combination after PD-1 inhibitor failure improves clinical outcomes in metastatic melanoma patients.

Management of PD-1 blockade resistance in metastatic melanoma (MM) remains challenging. Immunotherapy or chemotherapy alone provides limited benefit in this setting. Chemo-immunotherapy (CIT) has demonstrated favorable efficacy and safety profiles in lung cancer. Our pre-clinical study showed that in MM patients who have failed PD-1 blockade, the addition of chemotherapy increases CX3CR1+ therapy-responsive CD8+ T-cells with enhanced anti-tumor activity, resulting in improved clinical response. Here, we examined the clinical outcomes of CIT in MM patients after PD-1 blockade failure and the treatment-related changes in CX3CR1+ therapy-responsive CD8+ T-cells. We reviewed MM patients seen between January 2012 and June 2018 who failed anti-PD-1-based therapy and received subsequent CIT, immune checkpoint inhibitors (ICI) or chemotherapy alone. Overall survival (OS), objective response rate (ORR), event-free survival (EFS), and toxicities were assessed. Among 60 patients, 33 received CIT upon disease progression on PD-1 blockade. At a median follow-up of 3.9 years, the CIT group had a median OS of 3.5 years [95% confidence interval (CI) 1.7-NR] vs. 1.8 years (95% CI 0.9-2; P = 0.002) for those who received subsequent ICI (n = 9) or chemotherapy alone (n = 18), with ORR of 59% vs. 15% (P = 0.0003), respectively. The median EFS was 7.6 months (95% CI 6-10) following CIT vs. 3.4 months (95% CI 2.8-4.1; P = 0.0005) following ICI or chemotherapy alone. Therapy-responsive CX3CR1+CD8+ T-cells showed dynamic increase with successful CIT. CIT showed favorable clinical outcomes and acceptable safety profile in PD-1 blockade-resistant patients. CX3CR1+CD8+ therapy-responsive T-cells can be potentially used for monitoring disease response to CIT.

ADAM10 and ADAM17 cleave PD-L1 to mediate PD-(L)1 inhibitor resistance.

ADAM10 and ADAM17 expression and soluble PD-L1 (sPD-L1) predict poor prognosis in many malignancies, including in patients treated with PD-(L)1 inhibitors. The mechanism of soluble PD-L1 production and its effects are unknown. Here we uncover a novel mechanism of ADAM10- and ADAM17-mediated resistance to PD-(L)1 inhibitors. ADAM10 and ADAM17 cleave PD-L1 from the surface of malignant cells and extracellular vesicles. This cleavage produces an active sPD-L1 fragment that induces apoptosis in CD8 + T cells and compromises the killing of tumor cells by CD8 + T cells. Reduced tumor site PD-L1 protein-to-mRNA ratios predict poor outcomes and are correlated with elevated ADAM10 and ADAM17 expression in multiple cancers. These results may explain the discordance between PD-L1 immunohistochemistry and PD-(L)1 inhibitor response. Thus, including ADAM10 and ADAM17 tissue staining may improve therapy selection. Furthermore, treatment with an ADAM10/ADAM17 inhibitor may abrogate PD-(L)1 inhibitor resistance and improve clinical responses to PD-(L)1 immunotherapy.

Assessment of clinical outcomes with immune checkpoint inhibitor therapy in melanoma patients with CDKN2A and TP53 pathogenic mutations.

BACKGROUND: CDKN2A and TP53 mutations are recurrent events in melanoma, occurring in 13.3% and 15.1% of cases respectively and are associated with poorer outcomes. It is unclear what effect CDKN2A and TP53 mutations have on the clinical outcomes of patients treated with checkpoint inhibitors. METHODS: All patients with cutaneous melanoma or melanoma of unknown primary who received checkpoint inhibitor therapy and underwent genomic profiling with the 50-gene Mayo Clinic solid tumor targeted cancer gene panel were included. Patients were stratified according to the presence or absence of mutations in BRAF, NRAS, CDKN2A, and TP53. Patients without mutations in any of these genes were termed quadruple wild type (QuadWT). Clinical outcomes including median time to progression (TTP), median overall survival (OS), 6-month and 12-month OS, 6-month and 12-month without progression, ORR and disease control rate (DCR) were analyzed according to the mutational status of CDKN2A, TP53 and QuadWT. RESULTS: A total of 102 patients were included in this study of which 14 had mutations of CDKN2A (CDKN2Amut), 21 had TP53 mutations (TP53mut), and 12 were QuadWT. TP53mut, CDKN2Amut and QuadWT mutational status did not impact clinical outcomes including median TTP, median OS, 6-month and 12-month OS, 6-month and 12-month without progression, ORR and DCR. There was a trend towards improved median TTP and DCR in CDKN2Amut cohort and a trend towards worsened median TTP in the QuadWT cohort. CONCLUSION: Cell cycle regulators such as TP53 and CDKN2A do not appear to significantly alter clinical outcomes when immune checkpoint inhibitors are used.

Sex-Based Differences in Melanoma Survival in a Contemporary Patient Cohort.

Background: A female survival advantage in cutaneous melanoma has been long recognized. However, whether this extends across all age groups, with risk stratification using the latest prognostic staging system or in the current era of efficacious systemic therapies is unknown. Therefore, we evaluated whether sex-based differences in melanoma survival persisted within a recent population-based patient cohort with consideration of these factors. Materials and Methods: We identified stage II-IV cutaneous melanoma patients from 2010 to 2014 Surveillance, Epidemiology, and End Results cancer registries data. We recalculated stage per American Joint Committee on Cancer 8th edition guidelines. Cancer-specific survival (CSS) was estimated by using the Kaplan-Meier method and multivariable Cox proportional hazards regression. Results: Of 16,807 patients (39.8% female), 8,990 were stage II, 4,826 stage III, and 2,991 stage IV at diagnosis. Unadjusted 3-/5-year CSS estimates for females versus males were 64.2% versus 59.7%, and 53.5% versus 49.9%, respectively, p ≤ 0.0001. Five-year CSS varied within each stage and across age strata of <45, 45 - 59, and ≥60 years. Within each stage, females <45 had better CSS than all other sex/age groups (p < 0.0001). In multivariable analysis of stage II/III patients, female sex, younger age, and lower mitotic index retained favorable CSS prognostic significance (p < 0.001). Conclusions: Sex-based differences in melanoma survival persist in a contemporary patient cohort staged with the latest prognostic system. These data may guide decision marking regarding adjuvant therapy, highlight the importance of including sex as a pre-specified clinical trial variable, and suggest that investigation of underlying biologic mechanisms may drive discovery of biomarkers and therapeutic targets to improve patient care.

Biomarkers of hyperprogression and pseudoprogression with immune checkpoint inhibitor therapy.

Hyperprogression and pseudoprogression are two atypical responses to immune checkpoint inhibitor therapy that affect therapeutic decisions and prognosis. Identification of predictive biomarkers for atypical responses either before or during treatment remains a huge unmet need in cancer immunotherapy. Many studies have looked at potential biomarkers, including clinical factors and laboratory findings (e.g., peripheral blood counts, circulating tumor DNA, cytokine levels). The results of these studies have been inconsistent, possibly due to small sample sizes, different tumor types and heterogeneity of the definition of these atypical responses.

Immune Checkpoint Inhibitor Toxicities.

Immune checkpoint inhibitors are molecules that increase the endogenous immune response against tumors. They have revolutionized the field of oncology. Since their initial approval for the treatment of advanced melanoma, their use has expanded to the treatment of several other advanced cancers. Unfortunately, immune checkpoint inhibitors have also been associated with the emergence of a new subset of autoimmune-like toxicities, known as immune-related adverse events. These toxicities differ depending on the agent, malignancy, and individual susceptibilities. Although the skin and colon are most commonly involved, any organ may be affected, including the liver, lungs, kidneys, and heart. Most of these toxicities are diagnosed by excluding other secondary infectious or inflammatory causes. Corticosteroids are commonly used for treatment of moderate and severe immune-related adverse events, although additional immunosuppressive therapy may occasionally be required. The occurrence of immune-related toxicities may require discontinuation of immunotherapy, depending on the specific toxicity and its severity. In this article, we provide a focused review to familiarize practicing clinicians with this important topic given that the use of immune checkpoint inhibitors continues to increase.

Sex Differences in Tolerability to Anti-Programmed Cell Death Protein 1 Therapy in Patients with Metastatic Melanoma and Non-Small Cell Lung Cancer: Are We All Equal?

BACKGROUND: Immune-related adverse events (irAEs) have emerged as a serious clinical issue in the use of immune checkpoint inhibitors (ICIs). Risk factors for irAEs remain controversial. Therefore, we studied sex differences in irAEs in patients treated with anti-programmed cell death protein 1 (PD-1) therapy. MATERIALS AND METHODS: All patients with metastatic melanoma and non-small cell lung cancer (NSCLC) treated with anti-PD-1 therapy at Mayo Clinic Rochester and Florida from 2015 to 2018 were reviewed. Kaplan-Meier method and log-rank test was used for time-to-event analysis. RESULTS: In 245 patients with metastatic melanoma, premenopausal women were more likely to experience irAEs (all grades) compared with postmenopausal women and men (67% vs. 60% vs. 46%), primarily because of an increase in endocrinopathies (33% vs. 12% vs. 10%, respectively). In patients with NSCLC (231 patients), women (all ages) were also more likely to develop irAEs of all grades (48% vs. 31%). Women with NSCLC were more likely to develop pneumonitis (11% vs. 4%) and endocrinopathies (14% vs. 5%). No differences in grade ≥3 toxicities were seen across sexes in both cohorts, but women were more likely to receive systemic steroids for the treatment of irAEs compared with men. Better progression-free-survival was observed in women with NSCLC and irAEs (10 months vs. 3.3 months) compared with women without irAEs. CONCLUSION: Women with metastatic melanoma and NSCLC are more likely to experience irAEs compared with men. We also observed differences between sexes in the frequency of certain irAEs. Larger studies are needed to investigate the mechanisms underlying these associations. IMPLICATIONS FOR PRACTICE: The results of this study suggest that women may be at a higher risk for immune-related adverse events (irAEs) compared with men when treated with anti-programmed cell death protein 1 therapy. In addition, women were more likely to develop certain irAEs, including endocrinopathies and pneumonitis. Close follow-up of women undergoing treatment with immune checkpoint inhibitors will allow clinicians to diagnose these treatment-related complications early, potentially reducing their associated morbidity and mortality. In addition, a possible association between irAEs and response to therapy was observed.

Prospective Immunophenotyping of CD8+ T Cells and Associated Clinical Outcomes of Patients With Oligometastatic Prostate Cancer Treated With Metastasis-Directed SBRT.

PURPOSE: This study examined the effects of metastasis-directed stereotactic body radiation therapy (mdSBRT) on CD8+ T-cell subpopulations and correlated post-mdSBRT immunophenotypic responses with clinical outcomes in patients with oligometastatic prostate cancer (OPCa). METHODS AND MATERIALS: Peripheral blood mononuclear cells were prospectively isolated from 37 patients with OPCa (≤3 metastases) who were treated with mdSBRT. Immunophenotyping identified circulating CD8+ T-cell subpopulations, including tumor-reactive (TTR), effector memory, central memory (TCM), effector, and naïve T cells from samples collected before and after mdSBRT. Univariate Cox proportional hazards regression was used to assess whether changes in these T-cell subpopulations were potential risk factors for death and/or progression. The Kaplan-Meier method was used for survival. Cumulative incidence for progression and new distant metastasis weas estimated, considering death as a competing risk. RESULTS: Median follow-up was 39 months (interquartile range, 34-43). Overall survival at 3 years was 78.2%. Cumulative incidence for local progression and new distant metastasis at 3 years was 16.5% and 67.6%, respectively. Between baseline and day 14 after mdSBRT, an increase in the TCM cell subpopulation was associated with the risk of death (hazard ratio, 1.22 [95% confidence interval, 1.02-1.47]; P = .033), and an increase in the TTR cell subpopulation was protective against the risk of local progression (hazard ratio, 0.80 [95% confidence interval, 0.65-0.98]; P = .032). CONCLUSIONS: An increase in the TTR cell subpopulation was protective against the risk of disease progression, and an increase in the TCM cell subpopulation was associated with the risk of death in patients with OPCa treated with mdSBRT. Disease control may be further improved by better understanding the CD8+ T-cell subpopulations and by enhancing their antitumor effect.

Paradox-driven adventures in the development of cancer immunology and immunotherapy.

After more than one hundred years of documented trials, immunotherapy has become a standard of care in the treatment of human cancer. Much of the knowledge that led to recent breakthroughs seems quite logical from today's point of view. However, what we now cite as facts were originally considered paradoxes, meaning something contrary to expectations or perceived opinion at the time. In order to make gains in the field of immunotherapy, one had to be willing to confront ideas and concepts that seemed to contradict one another, and reconcile how each could be true. This is what led to new knowledge and advances. Here, we highlight some of these paradoxes and the milestone discoveries that followed, each one critical for our understanding of immune checkpoint pathways. By outlining some of the steps that we took and the challenges that we overcame, we hope to inspire and encourage future generations of researchers to confront the paradoxes that still permeate the field.

Combining Immune Checkpoint Inhibitors With Conventional Cancer Therapy.

Immune checkpoint inhibitors (ICIs) have recently revolutionized cancer treatment, providing unprecedented clinical benefits. However, primary or acquired therapy resistance can affect up to two-thirds of patients receiving ICIs, underscoring the urgency to elucidate the mechanisms of treatment resistance and to design more effective therapeutic strategies. Conventional cancer treatments, including cytotoxic chemotherapy, radiation therapy, and targeted therapy, have immunomodulatory effects in addition to direct cancer cell-killing activities. Their clinical utilities in combination with ICIs have been explored, aiming to achieve synergetic effects with improved and durable clinical response. Here, we will review the immunomodulatory effects of chemotherapy, targeted therapy, and radiation therapy, in the setting of ICI, and their clinical implications in reshaping modern cancer immunotherapy.

CX3CR1 identifies PD-1 therapy-responsive CD8+ T cells that withstand chemotherapy during cancer chemoimmunotherapy.

Although immune checkpoint inhibitors have resulted in durable clinical benefits in a subset of patients with advanced cancer, some patients who did not respond to initial anti-PD-1 therapy have been found to benefit from the addition of salvage chemotherapy. However, the mechanism responsible for the successful chemoimmunotherapy is not completely understood. Here we show that a subset of circulating CD8+ T cells expressing the chemokine receptor CX3CR1 are able to withstand the toxicity of chemotherapy and are increased in patients with metastatic melanoma who responded to chemoimmunotherapy (paclitaxel and carboplatin plus PD-1 blockade). These CX3CR1+CD8+ T cells have effector memory phenotypes and the ability to efflux chemotherapy drugs via the ABCB1 transporter. In line with clinical observation, our preclinical models identified an optimal sequencing of chemoimmunotherapy that resulted in an increase of CX3CR1+CD8+ T cells. Taken together, we found a subset of PD-1 therapy-responsive CD8+ T cells that were capable of withstanding chemotherapy and executing tumor rejection with their unique abilities of drug efflux (ABCB1), cytolytic activity (granzyme B and perforin), and migration to and retention (CX3CR1 and CD11a) at tumor sites. Future strategies to monitor and increase the frequency of CX3CR1+CD8+ T cells may help to design effective chemoimmunotherapy to overcome cancer resistance to immune checkpoint blockade therapy.

Contraction of T cell richness in lung cancer brain metastases.

Very little is known about how the adaptive immune system responds to clonal evolution and tumor heterogeneity in non-small cell lung cancer. We profiled the T-cell receptor ß complementarity determining region 3 in 20 patients with fully resected non-small cell lung cancer primary lesions and paired brain metastases. We characterized the richness, abundance and overlap of T cell clones between pairs, in addition to the tumor mutation burden and predicted neoantigens. We found a significant contraction in the number of unique T cell clones in brain metastases compared to paired primary cancers. The vast majority of T cell clones were specific to a single lesion, and there was minimal overlap in T cell clones between paired lesions. Despite the contraction in the number of T cell clones, brain metastases had higher non-synonymous mutation burdens than primary lesions. Our results suggest that there is greater richness of T cell clones in primary lung cancers than their paired metastases despite the higher mutation burden observed in metastatic lesions. These results may have implications for immunotherapy.