Epidermal growth factor receptor variant III (EGFRvIII) vaccine (CDX-110) in GBM

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. 2021-2021
Author(s):  
A. B. Heimberger ◽  
G. E. Archer ◽  
D. A. Mitchell ◽  
D. D. Bigner ◽  
R. J. Schmittling ◽  
...  
Keyword(s):  
Immune Responses ◽  
Phase Ii ◽  
Drug Hypersensitivity ◽  
Growth Factor Receptor ◽  
Gene Mutations ◽  
Keyhole Limpet Hemocyanin ◽  
Peptide Sequence ◽  
Control Group ◽  
Specific Gene ◽  
Normal Tissues

2021 Background: Unlike conventional therapies for GBM, immunologic targeting of tumor-specific gene mutations allows precise eradication of neoplastic cells with reduced toxicity. EGFRvIII is a constitutively activated and immunogenic mutation not expressed in normal tissues, but widely expressed in GBM and other neoplasms. The cancer vaccine CDX-110 is comprised of an EGFRvIII-specific peptide sequence linked to keyhole limpet hemocyanin (KLH). Methods: A phase II multi-center trial assessed the immunogenicity and efficacy of CDX-110 in patients with newly-diagnosed, EGFRvIII+ GBM. After resection and radiation / TMZ, patients received CDX-110 vaccinations biweekly x 3, then monthly until tumor progression. Sequential cohorts received CDX-110 alone [ACTIVATE (n = 18)] or in combination with TMZ (200 mg/m2 x 5/28 days [ACT II A (n = 13)]) or (100 mg/m2 x 21/28 days [ACT II B (n=10)]). Results: Reversible systemic drug hypersensitivity reactions were seen in 1 ACTIVATE and 4 ACT II patients. Two patients had non-specific changes on MRI which were possibly due to the vaccine but which resolved. Despite grade 2 or 3 lymphopenia in all ACT II patients, EGFRvIII-specific immune responses were generated in all patients, and all immune responses were sustained or enhanced during subsequent TMZ cycles. Although ACT II B patients had more severe TMZ-induced lymphopenia, they developed greater EGFRvIII-specific immune responses (p = 0.028) when compared to ACT II A. EGFRvIII-specific IgG1 also increased in avidity with vaccination (Ka>>2x109M-1) in a randomly selected subset of 4 patients (p = 0.000068). Of the 23 recurrent tumors studied, 18 lost EGFRvIII expression (p = 0.001). There are no significant differences between ACT II A and B in estimated median TTP (18.5 vs. 14.9 months, p = 0.31) and OS (23.6 vs. 19.9 months, p = 0.75). ACTIVATE TTP (14.2 months) and OS (26.0 months) and ACT II TTP (15.2 months) and OS (23.6 months) compare favorably to a TMZ-treated, matched historical control group (TTP: 6.3 months; OS: 15.0 months). Conclusions: CDX-110 vaccination in patients with GBM appears very promising. TMZ enhances immune responses despite lymphodepletion. CDX-110 with simultaneous TMZ is under further investigation in a larger phase II trial. [Table: see text]

REACT: A phase II study of rindopepimut (CDX-110) plus bevacizumab (BV) in relapsed glioblastoma (GB).

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. TPS2103-TPS2103 ◽  
Author(s):  
David A. Reardon ◽  
James J. Vredenburgh ◽  
Annick Desjardins ◽  
Ronald G. Steis ◽  
Erin M. Dunbar ◽  
...  
Keyword(s):  
Immune Responses ◽  
Phase Ii ◽  
Phase Ii Study ◽  
Objective Response ◽  
Peptide Sequence ◽  
Phase Iii ◽  
Open Label ◽  
Term Survival ◽  
Gm Csf ◽  
Phase Ii Studies

TPS2103 Background: EGFRvIII is a constitutively active tumorigenic deletion mutation of EGFR. It is expressed in ~30% of primary GB where it is linked to poor long-term survival (Pelloski 2007). The investigational vaccine rindopepimut consists of the unique EGFRvIII peptide sequence conjugated to keyhole limpet hemocyanin (KLH), delivered intradermally (500ug with 150ug GM-CSF as an adjuvant). Remarkably consistent and promising results across 3 phase II studies in newly diagnosed, resected EGFRvIII+ GB (Lai 2011) represent a statistically significant improvement over a historical control cohort matched for major eligibility criteria (median overall survival [OS] = 24.4 - 24.6 vs. 15.2 months from diagnosis [m] and median progression-free survival [PFS] = 12.3 - 15.3 vs. 6.4 m). ACT IV, a phase III trial in this population, is ongoing. The immunosuppressive influence of residual/advanced GB presents a challenge to activation of efficacious antitumor immune responses. Anecdotal evidence (compassionate use cases, Sampson 2008) suggests that rindopepimut may induce specific immune responses and regression in multifocal and bulky residual tumors. Rindopepimut with BV, which inhibits VEGF and its immunosuppressive properties (including impaired maturation of dendritic cells and disruption of tumoral T cell infiltration [Johnson 2007, Shrimali 2010]) may further optimize EGFRvIII-specific immune response and antitumor activity. Methods: ReACT is a Phase II study of rindopepimut plus BV in patients (pts) with 1st or 2nd relapse of EGFRvIII+ GB. BV-naïve pts will be enrolled to Group 1 (n=70: randomized 1:1 to BV plus either rindopepimut/GM-CSF or control injection [low-dose KLH]) while BV-refractory patients will enter Group 2 (n=25: to receive BV plus open-label rindopepimut/GM-CSF). Concurrent with BV (10 mg/kg, q 2 wks), blinded treatment or open-label vaccine is given in priming phase (days 1, 15 and 29), then monthly until PD. Tumor response is assessed every 8 weeks, and patients are followed for survival after PD. Objectives are PFS at 6 months (primary), objective response rate, PFS, OS, safety, immunogenicity and elimination of EGFRvIII. ReACT opened to accrual in December 2011 (NCT01498328).

Effect of daclizumab on TReg counts and EGFRvIII-specific immune responses in GBM

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. 2034-2034
Author(s):  
J. H. Sampson ◽  
G. E. Archer ◽  
D. D. Bigner ◽  
R. J. Schmittling ◽  
J. E. Herndon ◽  
...  
Keyword(s):  
Immune Responses ◽  
Preliminary Analysis ◽  
Interleukin 2 ◽  
Treated Group ◽  
T Test ◽  
Peptide Sequence ◽  
Normal Tissues ◽  
Cell Counts ◽  
Randomized Phase Ii ◽  
Double Blinded

2034 Background: TRegs are increased in patients with GBM and constitutively express the high affinity interleukin-2 receptor (IL-2Rα). Treatment with an antibody that blocks IL-2Rα signaling functionally inactivates and eliminates TRegs without inducing autoimmune toxicity in murine models. We hypothesized that daclizumab, a commercially-available, IL-2Rα-specific antibody would function identically.Methods: A randomized phase II clinical trial assessed the effects of daclizumab in the context of the cancer vaccine, CDX-110, which is comprised of an EGFRvIII-specific peptide sequence linked to KLH. EGFRvIII is a constitutively activated and immunogenic mutation not expressed in normal tissues, but widely expressed in GBMs and other neoplasms. In patients with newly-diagnosed, EGFRvIII+ GBM, after resection and radiation/TMZ, patients received CDX-110 vaccinations biweekly x 3, then monthly until tumor progression in combination with TMZ (200 mg/m2 x 5/28 days). Half the patients were randomized to receive daclizumab (1mg/Kg x1) at the first vaccine. The others received saline in a double-blinded fashion.Results: There were no drug related SAEs. EGFRvIII-specific immune responses were generated in all patients, and all immune responses were sustained or enhanced during subsequent TMZ cycles. Preliminary analysis (n = 4) suggests that daclizumab reduces Treg (CD4+CD25+CD45RO+FOXP3+) numbers [change 82.4 ± 7.1% from baseline (p = 0.011; t-test)] without reducing overall CD8+ or CD4+ T-cell counts. Tregs decreased only 3.7 + 11.0% after vaccination in the saline treated group during the same interval. Preliminary analysis (n = 4) also suggest that daclizumab enhanced EGFRvIII-specific immune responses (p = 0.01; t-test) and enhanced the titer of cytotoxic EGFRvIII-specific IgG1 isotype antibodies compared to the saline treated group (p = 0.003; t-test) and compared to previously vaccinated patients who did not receive daclizumab (p = 0.0015; t-test). TTP and OS survival in both arms has not been reached. Conclusions: Daclizumab may reduce Treg counts in patients with GBM. TMZ and daclizumab may enhance EGFRvIII-targeted immune responses despite lymphodepletion. These combinations are currently under further investigation. [Table: see text]

Booster inoculations of the AE37 peptide vaccine enhance immunological responses in a phase II study.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. 3095-3095
Author(s):  
Eleftheria A Anastasopoulou ◽  
Efi Pappou ◽  
Panagiotis Tzonis ◽  
Alexandros Ardavanis ◽  
Sathibalan Ponniah ◽  
...  
Keyword(s):  
High Risk ◽  
Immune Responses ◽  
Phase Ii ◽  
Clinical Efficacy ◽  
Peptide Vaccine ◽  
Significant Risk ◽  
Control Group ◽  
Gm Csf ◽  
Ifn Γ ◽  
Disease Free

3095 Background: We are conducting a multicenter randomized phase II trial of AE37, the Ii-Key hybrid peptide of HER2 776-790 (AE36). The purpose of the study is to determine if the AE37 vaccine can prevent recurrence in disease-free conventionally treated node-positive (NP) and high-risk node-negative (NN) breast cancer patients at significant risk for recurrence. Since clinical efficacy is anticipated to occur as the result of long lasting memory immune responses induced by vaccination, repeated booster inoculations were scheduled as part of the trial. Here we present data on immune responses in patients who received boosters up to 24 months after completion of the primary vaccination series (PVS). Methods: The trial is enrolling NP or high-risk NN patients with any degree of HER2 expression (IHC 1-3+ or FISH > 1.2) rendered disease-free following standard of care therapy. The vaccine group (VG) received AE37+GM-CSF and control group (CG) GM-CSF alone in 6 monthly i.d. inoculations followed by boosters administered every 6 months x 4. Immunologic responses were assessed in vivo by dermal reactions at the inoculation site, and in vitro, against the AE36 peptide, with proliferation and IFN-γ ELISPOT assays. Results: 25 patients in the VG and 23 in the CG have completed their boosters. After the last booster (BRC24), 100%, 54% and 54% in the VG (vs. 9%, 18% and 27% in the CG) responded by dermal reaction, proliferation and IFN-γ ELISPOT, respectively. Mean dermal reactions (orthogonal mean in mm) in vaccinated patients was 25.9±3.13 at completion of the PVS (R6) and increased to 35.47±4.35 at BRC24 (p=0.01). VG patients increased their proliferation response (stimulation index, SI) to AE36 from 0.97±0.046 at baseline (R0) before vaccination to 2.27±0.57 at R6 (p=0.0003) which was maintained until BRC24 (SI 2.21±0,33, p<0.0001). The number of IFN-γ specific spots/106 PBMC increased from 26.88±12.36 at R0 to 40.35±17.02 (p=0.07) at R6, up to 62±16.82 (p=0.0076) at BRC24. Conclusions: Our data demonstrate that AE37 vaccine boosters enhance the immune responses against HER elicited during the PVS, thus sustaining long lasting immunity, a prerequisite for possible clinical efficacy which is currently being evaluated. Clinical trial information: NCT00524277.

scholarly journals Wilms’ tumour antigen 1 Immunity via DNA fusion gene vaccination in haematological malignancies by intramuscular injection followed by intramuscular electroporation: a Phase II non-randomised clinical trial (WIN)

2016 ◽  
Vol 3 (3) ◽  
pp. 1-80 ◽  
Author(s):  
Christian Ottensmeier ◽  
Megan Bowers ◽  
Debbie Hamid ◽  
Tom Maishman ◽  
Scott Regan ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Phase Ii ◽  
Intramuscular Injection ◽  
Fusion Gene ◽  
Control Group ◽  
Cell Responses ◽  
Gene Vaccination ◽  
Epitope Sequence

BackgroundIn the UK almost 7000 people are diagnosed with leukaemia each year, but despite continuing advances in diagnosis and treatment with new drugs, such as the tyrosine kinase inhibitors, the majority of these patients will eventually die from their disease. Until quite recently, the only treatment to offer the possibility of long-term disease-free survival was allogeneic stem cell transplantation. However, this carries a substantial risk of mortality and is available to only a minority of patients.ObjectivesThe aim of the study was to test the hypothesis that molecular and clinical responses, induced by T lymphocytes (T cells), can be predicted by increases in the number of CD8+ (cluster of differentiation 8-positive) T cells specific for the vaccine-encoded T-cell epitopes. This project also aimed to build on the established programme of deoxyribonucleic acid (DNA) fusion-gene vaccination delivered by intramuscular injection, exploiting a unique experience with electroporation, to induce durable immune responses with the aim of controlling disease by precision attack of the tumour by CD8+ T cells.MethodA non-randomised, open-label, single-dose-level Phase II clinical trial in two patient groups [chronic myeloid leukaemia (CML) and acute myeloid leukaemia (AML)] on stable doses of imatinib. Human leucocyte antigen A2-positive (HLA A2+) patients were vaccinated with two DNA vaccines: (1) p.DOM–WT1-37 (epitope sequence: VLDFAPPGA); and (2) p.DOM–WT1-126 (epitope sequence: RMFPNAPYL). The HLA A2-negative patients formed an unvaccinated control group. The sample size for the HLA A2+ group was originally determined following Simon’s optimal Phase II trial design (Simon R. Optimal two-stage designs for phase II clinical trials.Control Clin Trials1989;10:1–10). This was changed to A’Hern’s single-stage design during the course of the trial (A’Hern RP. Sample size tables for single-stage phase II designs.Stat Med2001;20:859–66), which was endorsed by the trial’s independent oversight committees.ResultsThe study included 12 patients with CML who were vaccinated and nine patients with CML who were unvaccinated as the control group. Both the vaccines and the electroporation were safe, with no new or unexpected toxicities. The evaluation adverse events of special interest (heart, bone marrow, renal) did not reveal safety concerns. TwoBCR–ABL(breakpoint cluster region–Abelson murine leukaemia viral oncogene homolog 1) responses were observed, both of which were defined as a major response, with one in each group. Two Wilms’ tumour antigen 1 (WT1) molecular responses were observed in the vaccinated group and one was observed in the control group. At an immunological level, the vaccine performed as expected.ConclusionsThe study met its primary decision-making target with one major molecular response inBCR–ABLtranscript levels. Overall, the data showed, in this clinical setting, the immunogenicity and safety of the vaccine.LimitationsThe study did not complete recruitment and there were multiple hurdles that contributed to this failure. This is disappointing given the robust induction immune responses againstWT1T-cell responses in 7 out of 10 evaluable patients.Future workEvaluation of the p.DOM–WT1 vaccines in AML remains attractive clinically, but it is unlikely to be feasible at this time. Combination of the DNA vaccine approach with strategies to expand T-cell responses with immunomodulatory antibodies is in development.Funding detailsThis project was funded by the Efficacy and Mechanism Evaluation (EME) programme, a Medical Research Council (MRC) and National Institute for Health Research (NIHR) partnership, and Bloodwise.

scholarly journals Effects of Green Alga, Chaetomorpha aerea Extract on Non-Specific Immune Responses and Disease Resistance against Edwardsiella tarda Infection in Labeo rohita

2021 ◽  
Vol 11 (10) ◽  
pp. 4325
Author(s):  
Govindharajan Sattanathan ◽  
Vairakannu Tamizhazhagan ◽  
Nadeem Raza ◽  
Syed Qaswar Ali Shah ◽  
Muhammad Zubair Hussain ◽  
...  
Keyword(s):  
Immune Responses ◽  
Green Alga ◽  
Labeo Rohita ◽  
Virulent Strain ◽  
Edwardsiella Tarda ◽  
Fish Mortality ◽  
Control Group ◽  
Physiological Salt Solution ◽  
Myeloperoxidase Activity ◽  
Chaetomorpha Aerea

The current study evaluated the effects of a methanol extract from Chaetomorpha aerea (a green alga) on non-specific immune responses and resistance against Edwardsiella tarda infection in Labeo rohita. Different doses of the extract (5, 50 and 500 mg/kg of body weight) were injected into the fish intraperitoneally while a control group was injected with 0.2 mL of sterile physiological salt solution. Variations in several immunostimulatory parameters (i.e., neutrophil, serum lysozyme, myeloperoxidase, serum antiprotease, and ceruloplasmin activity), reactive oxygen species (ROS) and reactive nitrogen species (RNS) were assessed after 7, 14, 21, and 28 days of post stimulation. E. tarda culture was injected into the fish after 28 days of post stimulation to induce infection to monitor fish mortality within 14 days. Interestingly, all doses of methanolic extract enhanced neutrophil, lysozyme, and myeloperoxidase activity, ROS and RNS, while a dose of 50 mg/kg was the most effective. Fish injected with this optimal dose were also protected against infection with virulent strain of E. tarda. The results of the study suggest that C. aerea extract is a potential prophylactic agent against bacterial infections in finfish.

scholarly journals The identification of novel gene mutations for degenerative lumbar spinal stenosis using whole-exome sequencing in a Chinese cohort

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Xin Jiang ◽  
Dong Chen
Keyword(s):  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Spinal Stenosis ◽  
Lumbar Spinal Stenosis ◽  
Gene Mutations ◽  
Specific Gene ◽  
Single Nucleotide ◽  
Degenerative Lumbar Spinal Stenosis ◽  
Whole Exome ◽  
Lumbar Spinal

Abstract Background Degenerative lumbar spinal stenosis (DLSS) is a common lumbar disease that requires surgery. Previous studies have indicated that genetic mutations are implicated in DLSS. However, studies on specific gene mutations are scarce. Whole-exome sequencing (WES) is a valuable research tool that identifies disease-causing genes and could become an effective strategy to investigate DLSS pathogenesis. Methods From January 2016 to December 2017, we recruited 50 unrelated patients with symptoms consistent with DLSS and 25 unrelated healthy controls. We conducted WES and exome data analysis to identify susceptible genes. Allele mutations firstly identified potential DLSS variants in controls to the patients’ group. We conducted a site-based association analysis to identify pathogenic variants using PolyPhen2, SIFT, Mutation Taster, Combined Annotation Dependent Depletion, and Phenolyzer algorithms. Potential variants were further confirmed using manual curation and validated using Sanger sequencing. Results In this cohort, the major classification variant was missense_mutation, the major variant type was single nucleotide polymorphism (SNP), and the major single nucleotide variation was C > T. Multiple SNPs in 34 genes were identified when filtered allele mutations in controls to retain only patient mutations. Pathway enrichment analyses revealed that mutated genes were mainly enriched for immune response-related signaling pathways. Using the Novegene database, site-based associations revealed several novel variants, including HLA-DRB1, PARK2, ACTR8, AOAH, BCORL1, MKRN2, NRG4, NUP205 genes, etc., were DLSS related. Conclusions Our study revealed that deleterious mutations in several genes might contribute to DLSS etiology. By screening and confirming susceptibility genes using WES, we provided more information on disease pathogenesis. Further WES studies incorporating larger DLSS patient cohorts are required to comprehend the genetic landscape of DLSS pathophysiology fully.

scholarly journals FGFR3 overexpression is a useful detection tool for FGFR3 fusions and sequence variations in glioma

2020 ◽  
Author(s):  
Jens Schittenhelm ◽  
Lukas Ziegler ◽  
Jan Sperveslage ◽  
Michel Mittelbronn ◽  
David Capper ◽  
...  
Keyword(s):  
Coiled Coil ◽  
Growth Factor Receptor ◽  
Gene Mutations ◽  
Diagnostic Tools ◽  
Wild Type ◽  
Rt Pcr ◽  
Fgfr3 Gene ◽  
Detection Tool ◽  
Sequence Variations ◽  
Gene Panel Sequencing

Abstract Background Fibroblast growth factor receptor (FGFR) inhibitors are currently used in clinical development. A subset of glioblastomas carries gene fusion of FGFR3 and transforming acidic coiled-coil protein 3. The prevalence of other FGFR3 alterations in glioma is currently unclear. Methods We performed RT-PCR in 101 glioblastoma samples to detect FGFR3-TACC3 fusions (“RT-PCR cohort”) and correlated results with FGFR3 immunohistochemistry (IHC). Further, we applied FGFR3 IHC in 552 tissue microarray glioma samples (“TMA cohort”) and validated these results in two external cohorts with 319 patients. Gene panel sequencing was carried out in 88 samples (“NGS cohort”) to identify other possible FGFR3 alterations. Molecular modeling was performed on newly detected mutations. Results In the “RT-PCR cohort,” we identified FGFR3-TACC3 fusions in 2/101 glioblastomas. Positive IHC staining was observed in 73/1024 tumor samples of which 10 were strongly positive. In the “NGS cohort,” we identified FGFR3 fusions in 9/88 cases, FGFR3 amplification in 2/88 cases, and FGFR3 gene mutations in 7/88 cases in targeted sequencing. All FGFR3 fusions and amplifications and a novel FGFR3 K649R missense mutation were associated with FGFR3 overexpression (sensitivity and specificity of 93% and 95%, respectively, at cutoff IHC score &gt; 7). Modeling of these data indicated that Tyr647, a residue phosphorylated as a part of FGFR3 activation, is affected by the K649R mutation. Conclusions FGFR3 IHC is a useful screening tool for the detection of FGFR3 alterations and could be included in the workflow for isocitrate dehydrogenase (IDH) wild-type glioma diagnostics. Samples with positive FGFR3 staining could then be selected for NGS-based diagnostic tools.

scholarly journals NFB-08. PHASE II STUDY OF AXITINIB IN PATIENTS WITH NEUROFIBROMATOSIS TYPE 2 AND PROGRESSIVE VESTIBULAR SCHWANNOMAS

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii419-iii419
Author(s):  
Sheetal Phadnis ◽  
Mari Hagiwara ◽  
Anna Yaffe ◽  
Carole Mitchell ◽  
Theodore Nicolaides ◽  
...  
Keyword(s):  
Growth Factor ◽  
Phase Ii ◽  
Kinase Inhibitor ◽  
Phase Ii Study ◽  
Growth Factor Receptor ◽  
Neurofibromatosis Type ◽  
Neurofibromatosis Type 2 ◽  
Vestibular Schwannomas ◽  
Volumetric Response

Abstract INTRODUCTION Vascular endothelial growth factor receptor (VEGFR), platelet derived growth factor receptor (PDGFR), and c-KIT represent clinically and/or preclinically validated molecular targets in vestibular schwannomas. We conducted a single institution, prospective, open-label, two-stage phase II study (ClinicalTrials.gov identifier NCT02129647) to estimate the response rate to axitinib, an oral multi-receptor tyrosine kinase inhibitor targeting VEGFR, PDGFR and c-KIT, in neurofibromatosis type 2 (NF2) patients with progressive vestibular schwannomas (VS). METHODS NF2 patients older than 5 years with at least one volumetrically measurable, progressive VS were eligible. The primary endpoint was to estimate the objective volumetric response rates to axitinib. Axitinib was given continuously in 28-day cycles for up to of 12 cycles. Response was assessed every 3 months with MRI using 3-D volumetric tumor analysis and audiograms. Volumetric response and progression were defined as ≥20% decrease or increase in VS volume, respectively. RESULTS Twelve eligible patients (ages: 14–56 years) were enrolled on this study. Seven of twelve patients completed 12 cycles (range: 2 to 12 cycles). We observed two imaging and three hearing responses. Best volumetric response was -53.9% after nine months on axitinib. All patients experienced drug-related toxicities, the most common adverse events were diarrhea, hematuria and skin toxicity, not exceeding grade 2 and hypertension, not exceeding grade 3. CONCLUSIONS While axitinib has modest anti-tumor activity in NF2 patients, it is more toxic and appears to be less effective compared to bevacizumab. Based on these findings, further clinical development of axitinib for this indication does not appear warranted.

scholarly journals Determination of Efficacy of Single and Double 4.7 mg Deslorelin Acetate Implant on the Reproductive Activity of Female Pond Sliders (Trachemys scripta)

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 660
Author(s):  
Edoardo Bardi ◽  
Martina Manfredi ◽  
Raffaella Capitelli ◽  
Emanuele Lubian ◽  
Alessandro Vetere ◽  
...  
Keyword(s):  
Phase Ii ◽  
Egg Production ◽  
Reproductive Activity ◽  
Trachemys Scripta ◽  
Phase Iii ◽  
Control Group ◽  
Sexual Hormones ◽  
Significant Difference ◽  
Group 6 ◽  
Plasmatic Concentration

The use of long-acting gonadotropin-releasing hormone (GnRH) agonists to suppress fertility has been poorly investigated in reptiles, and the few available studies show inconsistent results. The efficacy of single and double intramuscular 4.7 mg deslorelin acetate implants in captive pond sliders (Trachemys scripta) was investigated, with 20 animals divided into three groups: a single-implant group (6 animals), a double-implant group (6 animals), and a control group (no implant). During one reproductive season (March to October), plasmatic concentration of sexual hormones (estradiol, progesterone, and testosterone) and ovarian morphometric activity via computed tomography were monitored about every 30 days. A significative decrease in the number of phase II ovarian follicles was detected in the double-implant group compared with the control group, but no significant difference was noted in the number of phase III and phase IV follicles, egg production, and plasmatic concentration of sexual hormones. Results show that neither a single nor a double deslorelin acetate implant can successfully inhibit reproduction in female pond sliders during the ongoing season, but the lower number of phase II follicles in the double-implant group can possibly be associated with reduced fertility in the following seasons.

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