A soluble LAG-3 protein (eftilagimod alpha) and an anti-PD-L1 antibody (avelumab) tested in a phase I trial: a new combination in immuno-oncology

BACKGROUND

Eftilagimod alpha (efti) is a major histocompatibility complex class II agonist activating antigen-presenting cells which leads to greater systemic type 1 T helper response and more cytotoxic CD8+ T-cell activation. This phase I trial evaluated the administration of efti, a soluble lymphocyte activation gene-3 (LAG-3) protein, combined with the anti-programmed death-ligand 1 (PD-L1) antibody avelumab in advanced solid tumors.

PATIENTS AND METHODS

Patients with heavily pretreated metastatic solid tumors received intravenous avelumab (800 mg) combined with subcutaneously administered efti (6 or 30 mg) for up to 12 cycles, followed by avelumab monotherapy. The primary endpoint was the assessment of the recommended phase II dose (RP2D) of efti in combination with avelumab.

RESULTS

Twelve patients with different tumor entities were enrolled (six patients in each cohort). During treatment, no dose-limiting toxicities occurred, and the severity of most adverse events was grade 1 or 2. In total, nine serious adverse events were documented, resulting in a fatal outcome in two cases, but none of them were assessed to be treatment related. Five patients (42%) achieved partial response. The median progression-free survival was 1.96 months and the median overall survival was not reached, with a 12-month survival rate of 75%.

CONCLUSION

Subcutaneously administered efti plus avelumab was well tolerated, and efti of 30 mg was determined to be RP2D. The activity is promising and warrants further investigation in future phase II trials.

Antibody-mediated depletion of lymphocyte-activation gene-3 (LAG-3(+) )-activated T lymphocytes prevents delayed-type hypersensitivity in non-human primates

Lymphocyte-activation gene-3 (LAG-3, CD223) is a marker for recently activated effector T cells. Activated T lymphocytes are of major importance in many autoimmune diseases and organ transplant rejection. Therefore, specifically depleting LAG-3(+) T cells might lead to targeted immunosuppression that would spare resting T cells while eliminating pathogenic activated T cells. We have shown previously that anti-LAG-3 antibodies sharing depleting as well as modulating activities inhibit heart allograft rejection in rats. Here, we have developed and characterized a cytotoxic LAG-3 chimeric antibody (chimeric A9H12), and evaluated its potential as a selective therapeutic depleting agent in a non-human primate model of delayed-type hypersensitivity (DTH). Chimeric A9H12 showed a high affinity to its antigen and depleted both cytomegalovirus (CMV)-activated CD4(+) and CD8(+) human T lymphocytes in vitro. In vivo, a single intravenous injection at either 1 or 0·1 mg/kg was sufficient to deplete LAG-3(+) -activated T cells in lymph nodes and to prevent the T helper type 1 (Th1)-driven skin inflammation in a tuberculin-induced DTH model in baboons. T lymphocyte and macrophage infiltration into the skin was also reduced. The in vivo effect was long-lasting, as several weeks to months were required after injection to restore a positive reaction after antigen challenge. Our data confirm that LAG-3 is a promising therapeutic target for depleting antibodies that might lead to higher therapeutic indexes compared to traditional immunosuppressive agents in autoimmune diseases and transplantation.

Early stratification of patients with chest pain and suspected acute coronary syndrome in the Emergency Department

AIM

The aim of this study was to investigate the accuracy of a critical pathway in the early stratification and management of patients with chest pain and suspected acute coronary syndrome (ACS) in the Emergency Department (ED).

METHODS

An observational study was performed enrolling all patients with non-traumatic chest pain and suspected ACS who presented during a one-year period in the ED, where a critical pathway with five-level risk stratification, based on risk factors, characteristics of pain and ECG, was implemented. Patients were prospectively evaluated for rates of death, unstable angina, myocardial infarction or revascularization procedure occurring during admission or in the 30 days following discharge from the ED. Receiver-Operating Characteristics (ROC) curve was used to measure the accuracy of the stratification method.

RESULTS

Overall, 1813 patients were enrolled: 475 patients (26.1%, 95% CI: 24.0-28.1 ) were admitted and 1338 (73.8%, 95% CI: 71.7-75.8) were discharged. Main outcomes occurred in 233 (49.9%, 95% CI: 47.5-52.2) of patients admitted and in 6 (0.4%, 95% CI: 0.06-0.7) of those discharged. The risk stratification system showed a good accuracy with an AUC-ROC curve of 0.90 (95% CI: 0.88-0.93). A total of 1541 (85%) patients were managed according to critical pathway. Adverse events were significantly fewer in patients discharged according to pathway criteria than in those who were not (0.27% vs. 1.37%, difference: 1.1% CI 95%: 0.06-2.1), without significant increase of inappropriate admissions.

CONCLUSION

A critical pathway, based on clinical and ECG features, is a safe and accurate tool to stratify and manage the patients with non-traumatic chest pain and suspected ACS in the ED.

Vertebroplasty in the treatment of osteoporosis vertebral fractures: report on 52 cases

BACKGROUND

Percutaneous vertebroplasty (PV) is largely employed in vertebral body compression fractures (VCF).

PURPOSE

To evaluate the efficacy of PV on pain relief and functional status, and its complications rate.

MATERIALS AND METHODS

A prospective observational study was conducted by the Division of Internal Medicine of St. Croce and Carle Hospital.

INCLUSION CRITERIA

Diagnosis of osteoporosis, intense back pain, unresponsive to conservative treatment, associated with radiological evidence of recent VCF. Pain control and functional improvement were respectively assessed using Visual Analogue Scale (VAS) and Activity of Daily Living scale (ADL) on admission, 24 h after PV and at follow-up. PV complications were detected by an immediate computed tomography (CT) scan on the vertebra treated as well as the vertebrae above and below the treated level(s) and by CT chest scan to exclude pulmonary emboli. A magnetic resonance imaging (MRI) follow-up at 6 or 12 months was performed.

RESULTS

Fifty-two (46 with primary osteoporosis) patients were enrolled (mean age 73.18 yr, range 44-92). Median follow-up was 20.4 months (range 6-24). Treated vertebrae were 124. VAS, mean value was 9.05 (range 6-10) before treatment, 5.95 (range 2-8) at 24 h after PV and 4.94 (range 2-9) at follow-up (p<0.001). Before PV, 18 patients (34.6%) were functionally impaired vs 8 patients (15.3%) at follow-up (p<0.003). Control MRI evidenced 9 (17.3%) new VCF adjacent and 13 (25%) non-adjacent to treated vertebras. There was one case of discitis. Seven cases (13%) of cement leakage in para-vertebral space were observed.

CONCLUSION

PV is safe and effective in immediate pain reduction and functional improvement and at a median term follow-up.

hHR23B is required for genotoxic-specific activation of p53 and apoptosis

Rad23 proteins function in both DNA repair and protein stability regulation. As ubiquitinated forms of p53 are stabilized after DNA damage in concert with p53 functional activation, and human Rad23 proteins (hHR23A and B) regulate p53 stability in unstressed cells, the role of hHR23B in post-genotoxin regulation of p53 was investigated. Depletion of hHR23B by specific short interfering RNA before genotoxic exposure attenuated p53, p21 and bax induction, abrogated the accumulation of ubiquitinated p53 and suppressed apoptosis. Expression of ubiquitin derivatives with all lysines mutated except K48 or K63 demonstrated that K48-linked p53-ubiquitin conjugates were specifically induced after DNA damage. hHR23B, along with native and ubiquitinated p53, accumulated in chromatin after genotoxic exposure, and the accumulation of ubiquitinated p53 in chromatin was prevented by hHR23B depletion. Chromatin immunoprecipitation analysis demonstrated that hHR23B and p53 both localized to the p21 promoter shortly after DNA damage. hHR23B thus plays a critical role in the activation and function of p53 after specific genotoxic exposures.

Proteases produced by activated neutrophils are able to release soluble CD23 fragments endowed with proinflammatory effects

Polymorphonuclear neutrophils (PMNs) are the major source of proteolytic activities involved mainly in tissue injuries observed in chronic inflammatory disorders. High levels of soluble forms of CD23 (the low-affinity receptor for IgE) were found in biological fluids from these patients, and recent reports focused on a CD23-mediated regulation of inflammatory response. In this context, we show here that co-culture of activated PMN with CD23+ B cells resulted in a drastic release of soluble CD23 fragments from the cell surface. This cleavage was inhibited by serine proteases inhibitors, including a1-antitrypsin. We next demonstrated that purified human leukocyte elastase or cathepsin G efficiently cleaved membrane CD23 on B cells with a high specificity. Soluble fragments released by serine proteases-mediated CD23 proteolysis stimulated resting monocytes to produce oxidative burst and proinflammatory cytokine without any co-stimulatory signal. This work strongly supports the idea that the capacity of PMN-derived proteases to release soluble forms of CD23 participates in the inflammatory process mediated by these cells.

Binding of anti-CD23 monoclonal antibody to the leucine zipper motif of FcepsilonRII/CD23 on B cell membrane promotes its proteolytic cleavage. Evidence for an effect on the oligomer/monomer equilibrium

In the present study we have compared the binding of two monoclonal antibodies to CD23, EBVCS1 and mAb25, which recognize the stalk and the lectin domain, respectively, on the CD23 molecule. At 4 degreesC, EBVCS1 binds to about 10% of the receptors recognized by mAb25 on the B cell surface. At 37 degreesC, whereas mAb25 reaches its maximal binding within a few seconds, EBVCS1 requires 60 min to bind to the same extent. Stabilization of the oligomeric structure of CD23 with IgE strongly affects in a dose-dependent fashion the number of binding sites seen by EBVCS1 but not the t1/2 to reach them, suggesting that EBVCS1 binds to the coiled coil region through an allosteric mechanism. EBVCS1 rapidly down-modulates the membrane CD23 expression with a coincident increase of CD23-soluble fragments in the culture medium, an effect that is inhibited by IgE. In contrast, mAb25, as well as IgE, protects CD23 from proteolytic cleavage and stimulates its endocytosis. These results suggest that EBVCS1 unravels the coiled coil structure of CD23, rendering it more susceptible to proteolytic attack. This supports the oligomeric model proposed previously (Gould, H., Sutton, B., Edmeades, R., and Beavil, A. (1991) Monogr. Allergy 29, 28-49). The biological significance of these observations is discussed.