Ervin Griffin

Most new cancer diagnoses occur in patients over the age of 65. The composition and function of the immune system changes with age, but how the aged immune system affects responses to immune checkpoint inhibitor (ICI) cancer therapies remains incompletely understood. Here, using multiplex cytokine assay and high-parameter mass cytometry, we analyze prospectively collected blood samples from 104 cancer patients receiving ICIs. We find aged patients ( ≥ 65-years-old; n = 54) derive similar clinical outcomes as younger patients (n = 50). However, aged, compared to young, patients have divergent immune phenotypes at baseline that persist during ICI therapy, including diminished cytokine responses, reduced pools of naïve T cells with increased relative expression of immune checkpoint molecules, and more robust effector T cell expansion in responders compared to non-responders. Our study provides insights into age-stratified mechanisms of ICI effects while also implying the utility of age-tailored immunotherapeutic approaches.

BACKGROUNDImmune-related adverse events (irAEs) and their associated morbidity/mortality are a key concern for patients receiving immune checkpoint inhibitors (ICIs). Prospective evaluation of the drivers of irAEs in a diverse pan-tumor cohort is needed to identify patients at greatest risk and to develop rational treatment and interception strategies.METHODSIn an observational study, we prospectively collected blood samples and performed regular clinical evaluations for irAEs in patients receiving ICI therapy as standard of care for solid tumors. We performed in-parallel analysis of cytokines by Luminex immunoassay and circulating immune cells by cytometry by time-of-flight (CyTOF) at baseline and on treatment to investigate mechanisms of irAEs.RESULTSWe enrolled 111 patients, of whom 40.5% developed a symptomatic irAE (grade ≥ 2). Development of a grade ≥ 2 irAE was positively associated with the use of combination ICI and a history of an autoimmune disorder. Early changes in T helper 17 (Th17) (IL-6, IL-17f), type 2 (IL-5, IL-13, IL-25), and type 1 (TNF-α) cytokine signatures and congruent on-treatment expansions of Th17 and Th2 effector memory (Th2EM) T cell populations in peripheral blood were positively associated with the development of grade ≥2 irAEs. IL-6 levels were also associated with inferior cancer-specific survival and overall survival.CONCLUSIONSIn a diverse, prospective pan-tumor cohort, Th17 and Th2 skewing during early ICI treatment was associated with the development of clinically relevant irAEs but not antitumor responses, providing possible targets for monitoring and therapeutic interventions.FUNDINGJohns Hopkins Bloomberg-Kimmel Institute for Cancer Immunotherapy, the NCI SPORE in Gastrointestinal Cancers (P50 CA062924), NCI grant (R50CA243627 to LD), the NIH Center Core Grant (P30 CA006973), Swim Across America (to MY), NIAMS (K23AR075872 to LC), and imCORE-Genentech grant 137515 (to Johns Hopkins Medicine on behalf of MY).

BACKGROUND: Obesity is a risk factor for developing cancer but is also associated with improved outcomes after treatment with immune checkpoint inhibitors (ICIs), a phenomenon called the obesity paradox. To interrogate mechanisms of divergent immune responses in obese and non-obese patients, we examined the relationship among obesity status, clinical responses, and immune profiles from a diverse, pan-tumor cohort of patients treated with ICI-based therapy. METHODS: From June 2021 to March 2023, we prospectively collected serial peripheral blood samples from patients with advanced or metastatic solid tumors who received ICI as standard of care at Johns Hopkins. Patients were stratified by obesity status at treatment initiation, with obesity defined as body mass index (BMI)≥30 at treatment initiation and BMI≥18.5 and <30 considered non-obese; underweight patients (BMI<18.5) were excluded. We evaluated the concentration of 37 cytokines and used cytometry by time of flight to characterize immune cell clusters and cell-surface expression markers at baseline and on-treatment. RESULTS: We enrolled 94 patients, of whom 30 (32%) were obese and 64 (68%) were non-obese. Compared with non-obese patients, obese patients had superior progression-free survival (HR: 0.44 (95% CI: 0.24 to 0.81), p=0.01) and overall survival (OS) (HR: 0.24 (95% CI: 0.07 to 0.80), p=0.02). Obese patients had lower serum IL-15 levels at treatment baseline and lower on-treatment levels of IL-6, IL-8, and IL-15. Low on-treatment IL-6 was associated with improved OS (HR: 0.27 (95% CI: 0.08 to 0.88), p=0.03), as was low on-treatment IL-8 (HR: 0.19 (95% CI: 0.05 to 0.70), p=0.01). Obese patients demonstrated lower levels of T effector cells with reduced expression of cytotoxicity markers and higher expression of exhaustion markers at baseline and on-treatment. CONCLUSIONS: Obese and non-obese patients with cancer have divergent immunological responses to ICIs. Obesity is associated with reduced levels of certain inhibitory cytokines and higher expression of T-cell exhaustion markers. ICI-based therapy may more effectively reverse T-cell dysfunction in obese patients, potentially contributing to the paradoxically improved responses in this population.

The systemic immunologic effects of combining anti-cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA4) therapy with PDL1 blockade remain incompletely characterized despite the widespread use of this combination in treating various solid tumors across multiple stages of disease. In this study, we investigated the additive impact of anti-CTLA4 on peripheral immune signatures in patients undergoing PDL1 blockade, using blood samples from a cohort of patients receiving checkpoint inhibitor therapy for advanced solid tumors. We performed in-parallel analysis of peripheral blood mononuclear cells using cytometry by time of flight and plasma cytokines using Luminex immunoassay. Our study cohort included 104 patients: 54 received anti-PDL1 alone and 50 received anti-PDL1 in combination with anti-CTLA4. As compared with single-agent anti-PDL1, combination therapy was associated with a greater expansion of CD4+ Th cell subsets, including Th17 (adjusted P = 0.04) and regulatory T cells (adjusted P = 0.02), after multivariable and multiple testing adjustment. In patients receiving anti-CTLA4, examination of functional marker expression within the Th17 subset revealed an increase in the expression of the Th1-related transcription factor TBET (P = 0.003). Assessment of the peripheral cytokine signatures showed an increase in Th1-associated cytokines (P = 0.002) in recipients of combination anti-PDL1 and anti-CTLA4, particularly the IFNγ-inducible cytokines MIG (adjusted P = 0.05) and IP-10 (adjusted P = 0.05). Our results confirm prior reports that anti-CTLA4 therapy is associated with the augmentation of Th17 cell subsets, and they also show that anti-CTLA4 may reshape CD4+ T-cell responses through Th17-to-Th1 plasticity, revealing a potential mechanism for enhanced antitumor immunity with broader implications for immune modulation in immunotherapy.

Fatigue is a common and often debilitating adverse event among patients receiving immune checkpoint inhibitor (ICI) therapy, yet its underlying immunologic mechanisms remain poorly defined. We prospectively collected clinical data and blood samples from patients with solid tumors receiving ICI therapy. Patients were prospectively surveyed at month 2, 4, or 6 on treatment to assess for the presence and severity of fatigue as compared with treatment baseline. We analyzed peripheral lymphocyte populations by cytometry by time of flight and peripheral levels of 39 cytokines with a Luminex multiplex assay to identify dynamic immune changes associated with ICI-related fatigue. Of 53 patients enrolled, 31 (58.5%) reported worsening fatigue during ICI therapy. Patients reporting fatigue exhibited broad early-treatment elevations in circulating cytokines, with the most prominent increases observed in the Th1-associated cytokine cluster, including IFN-γ, IL-2, and IL-12. In parallel, several clusters of cytotoxic effector CD8+ T cells expanded significantly from baseline in the fatigued group. Fatigue was not associated with objective tumor response or with the development of other clinically meaningful immune-related adverse events. In a pan-tumor cohort treated with ICIs, increases in clusters of cytotoxic effector CD8+ T cells in parallel with related Th1-associated cytokines were associated with ICI-related fatigue, implicating fatigue as a potential marker of immune activation in this population. SIGNIFICANCE: This study illuminates dynamic changes in peripheral cytokines and immune cell clusters that are associated with ICI-related fatigue. Namely, this study implicates the Th1 pathway as a novel contributor to ICI-related fatigue and identifies ICI-related fatigue as a clinical surrogate for immune activation in patients receiving ICI therapy. Recognizing that fatigue may be a biomarker of heightened immune activity influences monitoring strategies and informs supportive care interventions during immunotherapy.