Anti-PD-1 Antibody Administration following Hip Fracture Surgery Reverses Immune Dysfunction and Decreases Susceptibility to Infection

Immune checkpoint inhibitors for the treatment of sepsis:insights from preclinical and clinical development

INTRODUCTION

Sepsis represents one-fifth of all deaths worldwide and is associated with huge costs. Regarding disease progression, it is now well established that sepsis induces a state of acquired immunosuppression, with an increased risk of secondary infections that contributes to patients' worsening. Thus, tackling sepsis-induced immunosuppression represents a promising perspective.

AREAS COVERED

Of mechanisms responsible for sepsis-induced immunosuppression, the increased expression of co-inhibitory receptors (aka immune checkpoint) such as PD-1, CTLA4, TIM-3, LAG-3 or BTLA and their ligands recently received considerable interest since their inhibition, thanks to the so-called checkpoint inhibitors (CPI), provided astonishing results in cancer by rebooting immune functions. This review reports on the first landmarks of these molecules in sepsis. We introduce them in terms of basic immunology in line with sepsis pathophysiology both in experimental models and observational works and assess the first human clinical studies.

EXPERT OPINION

Preclinical results are positive and the first human clinical trials, although currently limited to the early phase, showed a beneficial effect on immunological functions and/or markers and suggested that tolerance of CPIs side effects, mainly auto-immune disorders, is acceptable in sepsis. Elsewhere, in some specific infections leading to ICU admission (or occurring during ICU stay), such as fungal infections, preliminary convincing case reports have been published. Overall, the first results regarding CPIs in sepsis appear encouraging. However, further efforts are warranted, especially in defining the right patients to be treated (i.e., in an individualized approach) and establishing the optimal time to start an immune restoration. Larger trials are now mandatory to confirm CPIs' potential in sepsis.

Hip Fracture Leads to Transitory Immune Imprint in Older Patients

Background: Hip fracture (HF) is common in the geriatric population and is associated with a poor vital and functional prognosis which could be impacted by immunological changes. The objective here is to decipher immune changes occurring in the 1st days following HF and determine how phenotype, function, and regulation of innate and adaptive compartments adapt during acute stress event.

Methods: We included HF patients, aged over 75 years. For each patient, blood samples were taken at five different timepoints: four in the perioperative period (day 0 to hospital discharge) and one at long term (6–12 months). Phenotypical and functional analysis were performed longitudinally on fresh blood or cryopreserved PBMCs. Clinical data were prospectively collected.

Results: One-hundred HF patients and 60 age-matched controls were included. Innate compartment exhibits pro-inflammatory phenotypes (hyperleukocytosis, increase of CD14+ CD16+ proportion and CCR2 expression), maintaining its ability to produce pro-inflammatory cytokines. Adaptive compartment extends toward a transitory immunosuppressive profile (leucopenia) associated with an active T-cell proliferation. Furthermore, increases of LAG-3 and PD-1 and a decrease of 2-B4 expression are observed on T-cells, reinforcing their transitory suppressive status. Of note, these immune changes are transitory and sequential but may participate to a regulation loop necessary for homeostatic immune control at long term.

Conclusion: HF is associated with several transitory immunological changes including pro-inflammatory phenotype in innate compartment and immunosuppressive profile in adaptive compartment. A comprehensive assessment of immune mechanisms implicated in the patient's prognosis after HF could pave the way to develop new immune therapeutics strategies.

Phase II Study of Pembrolizumab As First-Line, Single-Drug Therapy for Patients With Unresectable Cutaneous Squamous Cell Carcinomas

PURPOSE

To evaluate first-line pembrolizumab monotherapy efficacy and safety in patients with unresectable cutaneous squamous cell carcinomas (CSCCs).

PATIENTS AND METHODS

Patients, predominantly men, with their CSSCs' immunohistochemically determined programmed cell death-ligand 1 (PD-L1) status determined (tumor proportion score threshold, 1%), received pembrolizumab (200 mg every 3 weeks). The primary endpoint was the 39-patient primary cohort's objective response rate at week 15 (ORR_W15). Secondary objectives were best ORR, overall survival (OS), progression-free survival (PFS), duration of response (DOR), safety, ORR according to PD-L1 status and health-related quality of life using Functional Assessment of Cancer Therapy-General (FACT-G) score. An 18-patient expansion cohort, recruited to power the study to evaluate the ORR_W15 difference between PD-L1+ and PD-L1- patients, was assessed for ORR, disease control rate, and safety, but not survival.

RESULTS

Median age of all patients was 79 years. The primary cohort's ORR_W15 was 41% (95% CI, 26% to 58%), including 13 partial and 3 complete responses. Best responses were 8 partial and 8 complete responses. At a median follow-up of 22.4 months, respective median PFS, DOR, and OS were 6.7 months, not reached, and 25.3 months, respectively. Pembrolizumab-related adverse events affected 71% of the patients, and 4 (7%) were grade ≥ 3. One death was related to rapid CSCC progression; another resulted from a fatal second aggressive head and neck squamous cell carcinoma diagnosed 15 weeks postinclusion. ORR_W15 for the entire population was 42%; it was significantly higher for PD-L1+ patients (55%) versus PD-L1- patients (17%; P = .02). Responders' W15 total FACT-G score had improved (P = .025) compared with nonresponders.

CONCLUSION

First-line pembrolizumab monotherapy exhibited promising anti-CSCC activity, with durable responses and manageable safety. PD-L1 positivity appears to be predictive of pembrolizumab efficacy.

Potential diagnostic value of PD-1 in peripheral blood mononuclear cells of postmenopausal osteoporosis patients

BACKGROUND

Postmenopausal osteoporosis (PMOP) is an estrogen deficiency-induced skeletal disorder. Bone mineral density (BMD) testing is the gold standard for diagnosing osteoporosis. However, its sensitivity for fracture risk assessment is low. Programmed cell death protein 1 (PD-1) is a key immune checkpoint molecule implicated in the pathophysiology of bone remodeling, but its role in osteoporosis has not yet been explored. Thus, this study aimed to assess the expression and diagnostic utility of PD-1 in PMOP.

METHODS

A total of 56 patients with PMOP and 37 postmenopausal healthy controls (NC) were enrolled in the study. Peripheral blood mononuclear cells (PBMCs) were isolated by Ficoll density gradient centrifugation, and PD-1 expression was measured by quantitative polymerase chain reaction (qPCR). Pearson's correlation test was performed to explore the associations between PD-1 level and clinical variables, while receiver operating characteristic (ROC) curve analysis was used to evaluate the potential diagnostic value of PD-1 in patients with PMOP.

RESULTS

We found that PD-1 level was significantly upregulated in the PBMCs of PMOP patients than those of NC (P = .016). PD-1 expression was positively correlated with C-reactive protein (CRP) levels. ROC curve analysis showed that PD-1 had certain diagnostic value for PMOP (area under the curve = 0.65, standard error = 0.06, 95% confidence interval [0.53,0.76], P = .016), with a sensitivity and specificity of 44.64% and 81.08%, respectively.

CONCLUSION

Programmed cell death protein 1 is significantly upregulated in the PBMCs of PMOP patients and has certain diagnostic value for PMOP.