Unravelling the immunological roles of dipeptidyl peptidase 4 (DPP4) activity and/or structure homologue (DASH) proteins

Dipeptidyl peptidase (DPP) 4 (CD26, DPP4) is a multi-functional protein involved in T cell activation by co-stimulation via its association with adenosine deaminase (ADA), caveolin-1, CARMA-1, CD45, mannose-6-phosphate/insulin growth factor-II receptor (M6P/IGFII-R) and C-X-C motif receptor 4 (CXC-R4). The proline-specific dipeptidyl peptidase also modulates the bioactivity of several chemokines. However, a number of enzymes displaying either DPP4-like activities or representing structural homologues have been discovered in the past two decades and are referred to as DPP4 activity and/or structure homologue (DASH) proteins. Apart from DPP4, DASH proteins include fibroblast activation protein alpha (FAP), DPP8, DPP9, DPP4-like protein 1 (DPL1, DPP6, DPPX L, DPPX S), DPP4-like protein 2 (DPL2, DPP10) from the DPP4-gene family S9b and structurally unrelated enzyme DPP2, displaying DPP4-like activity. In contrast, DPP6 and DPP10 lack enzymatic DPP4-like activity. These DASH proteins play important roles in the immune system involving quiescence (DPP2), proliferation (DPP8/DPP9), antigen-presenting (DPP9), co-stimulation (DPP4), T cell activation (DPP4), signal transduction (DPP4, DPP8 and DPP9), differentiation (DPP4, DPP8) and tissue remodelling (DPP4, FAP). Thus, they are involved in many pathophysiological processes and have therefore been proposed for potential biomarkers or even drug targets in various cancers (DPP4 and FAP) and inflammatory diseases (DPP4, DPP8/DPP9). However, they also pose the challenge of drug selectivity concerning other DASH members for better efficacy and/or avoidance of unwanted side effects. Therefore, this review unravels the complex roles of DASH proteins in immunology.

Abstract OT2-01-04: E2112: Randomized phase III trial of endocrine therapy plus entinostat/placebo in patients with hormone receptor-positive advanced breast cancer. A trial of the ECOG-ACRIN cancer research group

Background:

A potential mechanism of resistance to endocrine therapy in breast cancer involves changes in gene expression secondary to epigenetic modifications, which might be modulated with the use of histone deacetylase (HDAC) inhibitors such as entinostat. ENCORE 301, a phase II study evaluating the addition of entinostat to the steroidal aromatase inhibitor (AI) exemestane in patients with hormone receptor (HR)-positive advanced breast cancer who had experienced disease progression after a non-steroidal AI (NSAI), showed a significant improvement in progression-free survival (PFS), and overall survival (OS). Entinostat has been designated a Breakthrough Therapy by the FDA.

Methods:

E2112 is a multicenter randomized double-blind placebo-controlled phase III study (NCT02115282) enrolling patients with advanced HR-positive, HER2-negative breast cancer with prior disease progression on a NSAI (n=600). Patients receive exemestane 25mg po daily and entinostat/placebo 5mg po every week. Eligibility: Postmenopausal women and men, ECOG 0-1, locally advanced/metastatic invasive adenocarcinoma of the breast: ER/PR-positive, HER2-negative, measurable or non-measurable (20% cap) disease. Disease progression after NSAI use in the metastatic setting OR relapse while on or within ≤ 12 months of end of adjuvant NSAI therapy.

Statistics: Both PFS (central review) and OS are primary endpoints, and the study is designed to show an improvement in either PFS or OS. Secondary endpoints include: Safety and tolerability, objective response rate, changes in lysine acetylation status in peripheral blood mononuclear cells, patient-reported symptom burden and treatment toxicities, adherence. One-sided type 1 error 0.025 split between two hypotheses tests: 0.001 for PFS test and 0.024 for OS. PFS is tested in the first 360 pts, 88.5% power to detect 42% reduction in the hazard of PFS failure (median PFS 4.1 to 7.1 months); OS is tested in all 600 pts, 80% power to detect 25% reduction in the hazard of death (median OS 22 to 29.3 months).

E2112 was activated in March 2014 and accrual is anticipated to complete in 40 months.

Citation Format: Connolly R, Zhao F, Miller K, Tevaarwerk A, Wagner L, Lee M, Murray J, Gray R, Piekarz R, Zujewski JA, Sparano J. E2112: Randomized phase III trial of endocrine therapy plus entinostat/placebo in patients with hormone receptor-positive advanced breast cancer. A trial of the ECOG-ACRIN cancer research group. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr OT2-01-04.

Alternatives to HIST for acellular pertussis vaccines: progress and challenges in replacement

The 'International Workshop on Alternatives to the Murine Histamine Sensitization Test for Acellular Pertussis Vaccines: Progress and Challenges in the Replacement of HIST' was held on 24 August 2014, in Prague, Czech Republic, as a satellite meeting to the 9th World Congress on Alternatives and Animal Use in the Life Sciences. Participants discussed the progress and challenges associated with the development, validation, and implementation of in vitro assays as replacements for the histamine sensitisation test (HIST) for acellular pertussis vaccines. Discussions focused on the consistency approach, the necessary framework for regulatory acceptance of a harmonised method, and recent international efforts towards the development of in vitro assays to replace the HIST. Workshop participants agreed that acceptable alternatives to the HIST should be based on ADP ribosylation-mediated cell intoxication and therefore that the CHO cell clustering assay, which measures cell intoxication, should be further pursued and developed as a possible replacement for the HIST. Participants also agreed to continue ongoing multinational discussions involving national and international standardisation authorities to reach consensus and to organise collaborative studies in this context for assay characterisation and calibration of reference materials.

In search of acceptable alternatives to the murine histamine sensitisation test (HIST): what is possible and practical?

The 'International Workshop on Alternatives to the Murine Histamine Sensitization Test for Acellular Pertussis Vaccines: In Search of Acceptable Alternatives to the Murine Histamine Sensitization Test (HIST): What is Possible and Practical?' was held on 4 and 5 March 2015 in London, United Kingdom. Participants discussed the results of the data generated from an international collaborative study (BSP114 Phase 2) sponsored by the European Directorate for the Quality of Medicines & Health Care (EDQM) to determine if a modified Chinese hamster ovary (CHO) cell-based clustering assay is a suitable alternative to replace HIST. Workshop participants agreed that protocol transferability demonstrated in the collaborative study indicates that a standardised CHO cell assay is adequate for measuring pure PTx in reference preparations. However, vaccine manufacturers would still need to demonstrate that the method is valid to detect or measure residual PTx in their specific adjuvanted products. The 2 modified CHO cell protocols included in the study (the Direct and the Indirect Methods) deserve further consideration as alternatives to HIST. Using the CHO cell assay, an in vitro alternative, for acellular pertussis (aP) vaccine batch release testing would reduce the number of animals used for aP vaccine safety testing. A strategic, stepwise adoption plan was proposed, in which the alternative test would be used for release purposes first, and then, once sufficient confidence in its suitable performance has been gained, its use would be extended to stability testing.

Transferability study of CHO cell clustering assays for monitoring of pertussis toxin activity in acellular pertussis vaccines

Current regulations for acellular pertussis (aP) vaccines require that they are tested for the presence of residual or reversion-derived pertussis toxin (PTx) activity using the mouse histamine sensitisation test (HIST). Although a CHO cell clustering assay can be used by manufacturers to verify if sufficient inactivation of the substance has occurred in-process, this assay cannot be used at present for the final product due to the presence of aluminium adjuvants which interfere with mammalian cell cultures. Recently, 2 modified CHO cell clustering assays which accommodate for the adjuvant effects have been proposed as alternatives to the HIST. These modified assays eliminate the adjuvant-induced cytotoxicity either through dilution of the vaccine (called the Direct Method) or by introducing a porous barrier between the adjuvant and the cells (the Indirect Method). Transferability and suitability of these methods for testing of products present on the European market were investigated during a collaborative study organised by the European Directorate for the Quality of Medicines & HealthCare (EDQM). Thirteen laboratories participated in this study which included 4 aP-containing vaccines spiked by addition of PTx. This study also assessed the transferability of a standardised CHO cell clustering assay protocol for use with non-adjuvanted PTx preparations. Results showed that the majority of laboratories were able to detect the PTx spike in all 4 vaccines at concentrations of 4 IU/mL or lower using the Indirect Method. This sensitivity is in the range of the theoretical sensitivity of the HIST. The Direct Method however did not show the expected results and would need additional development work.

Survey About the Cancer Risk of Renal Transplant Recipients

INTRODUCTION

There is a greater risk of malignant tumors developing in kidney transplant patients. Due to this, early detection is of outmost importance, in which screening tests play an important role.

METHODS

We have conducted a survey among renal transplant recipients to assess individual risk factors.

RESULTS

Of 530 respondents, 55 developed post-transplantation tumors. Cutaneous tumors (36%) and kidney cancer (16%) were the most frequent. In total, 59% of recipients were over the age of 50, 61.7% were over the normal body-mass index range, 40.3% smoked or used to smoke, and 21.8% had diabetes. Five patients had hepatitis B virus and 11 were hepatitis C virus-positive. Malignancies developed significantly more frequent in men than in women (P = .04). The progressing of age (P = .0001) and the time elapsed after transplantation (P < .01) also were associated with a significant increase in the occurrence of post-transplantation tumors.

CONCLUSION

We have created a database to facilitate a more personalized and efficient screening program for immunocompromised patients.

[Intrinsic sphincter deficiency and female urinary incontinence]

OBJECTIVE

Stress urinary female incontinence (SUI) is primary due to intrinsic sphincter deficiency (ISD) and urethral hypermobility. Despite a lack of standardised international definition, ISD needs to be clearly diagnosed in order to be correctly treated. This work is an update about the female ISD produced from a review of a published article.

MATERIAL AND METHODS

This review of article published on this subject in the Medline (Pubmed database), selected according to their scientific relevants, of consensus conferences and published guidelines, has been performed by the committee for women pelvic floor surgery of the French Urological Association.

RESULTS

Although there is no international consensus definition, we can consider that the ISD is a composite concept combining urodynamic data (MUCP < 20 or 30 cmH20) and one or more clinical information (no urethral mobility, negative urethral support test, failure of a first surgery, leakage during abdominal straining, high stress incontinence scores). Imaging can provide additional evidence for intrinsic sphincter deficiency diagnosis, but the correlation between imaging and function remains low. By standardizing methodology and interpretations to better diagnose women with ISD, it may be possible to improve preoperative planning and outcomes for these patients. A retropubic midurethral sling can be performed as a first surgery. In case of a lack of urethral mobility, the artificial urinary sphincter (AUS) remains the gold standard. Adjustable continence therapy (ACT(®)) can be proposed as an alternative option. The efficacy and safety of muscle-derived cell therapy in ISD needs more studies. Injection of bulking agents may be an option according to the severity and the expectations of the patient. Bladder overactivity needs to be treated as first-line in case of mixed urinary incontinence. In elderly women, a careful evaluation of the bladder contractility and comorbidity must be performed. A geriatric evaluation can be necessary.

CONCLUSION

Clinical and paraclinical assessment allow to confirm the diagnosis of female ISD, to estimate its severity, and to identify associated mechanisms of incontinence (urethral hypermobility, bladder overactivity) to choose the most adapted treatment.

De novo Prograf versus de novo Advagraf: are trough level profile curves similar?

BACKGROUND

According to the clinical trials, Advagraf (ADV) has efficacy and safety profile similar to Prograf (PROG). The aim of this study was to compare the graft functions, dosages, and tacrolimus (TAC) trough level profile curves of patients on de novo PROG and ADV therapy.

METHODS

The ADV group included 39 de novo renal cases who had received initial immunosuppression (IS) with once-daily TAC (1 × 0.2 mg/kg from day1 after transplantation). We compared them with a PROG group of 38 transplant patients who received equivalent IS with twice-daily TAC (2 × 0.1 mg/kg from day1). In both groups, the IS was combined with antimetabolites and steroids. The mean follow-up time was similar (13.5 ± 7 days) in both groups after renal transplantation until the emission of the patients from our clinic.

RESULTS

TAC mean total daily dose was reduced and whole-blood trough levels decreased over the time in early postoperative days. Only on day 3 and day 4 after transplant, a significant higher adjustment in the ADV dosage was necessary to achieve sufficient TAC trough levels. The average TAC trough level profile curves were similar in PROG and ADV groups, but the individual curves were very different. Mainly in patients on ADV therapy, the initial concentrations were often >30 ng/mL, and in some cases on the 9th posttransplant day decreased to <5 ng/mL, then slowly increased into the required therapeutic range.

CONCLUSIONS

The results demonstrate that patients after renal transplantation can be safely treated de novo with ADV. Setting the required therapeutic TAC blood levels may require more attention to avoid the "fluctuations" of trough level profile curve during the early postoperative period. Our data suggest that dose adjustment of ADV can be carried out more carefully compared with PROG on the basis of clinical symptoms and the value of TAC blood levels to avoid acute rejection and toxicity.