scholarly journals Safety and Immunogenicity of ChAd63/MVA Pfs25-IMX313 in a Phase I First-in-Human Trial

2021 ◽  
Vol 12 ◽  
Author(s):  
Hans de Graaf ◽  
Ruth O. Payne ◽  
Iona Taylor ◽  
Kazutoyo Miura ◽  
Carol A. Long ◽  
...  
Keyword(s):  
Viral Vectors ◽  
Safety Data ◽  
Mosquito Vector ◽  
Cell Responses ◽  
Modified Vaccinia Virus Ankara ◽  
Membrane Feeding ◽  
Reducing Activity ◽  
Favorable Safety ◽  
Immunogenicity Assays ◽  
First Time

BackgroundTransmission blocking vaccines targeting the sexual-stages of the malaria parasite could play a major role to achieve elimination and eradication of malaria. The Plasmodium falciparum Pfs25 protein (Pfs25) is the most clinically advanced candidate sexual-stage antigen. IMX313, a complement inhibitor C4b-binding protein that forms heptamers with the antigen fused to it, improve antibody responses. This is the first time that viral vectors have been used to induce antibodies in humans against an antigen that is expressed only in the mosquito vector.MethodsClinical trial looking at safety and immunogenicity of two recombinant viral vectored vaccines encoding Pfs25-IMX313 in healthy malaria-naive adults. Replication-deficient chimpanzee adenovirus serotype 63 (ChAd63) and the attenuated orthopoxvirus modified vaccinia virus Ankara (MVA), encoding Pfs25-IMX313, were delivered by the intramuscular route in a heterologous prime-boost regimen using an 8-week interval. Safety data and samples for immunogenicity assays were taken at various time-points.ResultsThe reactogenicity of the vaccines was similar to that seen in previous trials using the same viral vectors encoding other antigens. The vaccines were immunogenic and induced both antibody and T cell responses against Pfs25, but significant transmission reducing activity (TRA) was not observed in most volunteers by standard membrane feeding assay.ConclusionBoth vaccines were well tolerated and demonstrated a favorable safety profile in malaria-naive adults. However, the transmission reducing activity of the antibodies generated were weak, suggesting the need for an alternative vaccine formulation.Trial RegistrationClinicaltrials.gov NCT02532049.

scholarly journals Poor CD4+ T Cell Immunogenicity Limits Humoral Immunity to P. falciparum Transmission-Blocking Candidate Pfs25 in Humans

2021 ◽  
Vol 12 ◽  
Author(s):  
Marija Zaric ◽  
Arianna Marini ◽  
Carolyn M. Nielsen ◽  
Gaurav Gupta ◽  
David Mekhaiel ◽  
...  
Keyword(s):  
T Cell ◽  
Viral Vectors ◽  
Transmission Blocking ◽  
Peptide Epitopes ◽  
Cell Responses ◽  
Follicular Helper ◽  
Specific Memory ◽  
Modified Vaccinia Virus Ankara ◽  
Specific Igg ◽  
Transmission Blocking Vaccines

Plasmodium falciparum transmission-blocking vaccines (TBVs) targeting the Pfs25 antigen have shown promise in mice but the same efficacy has never been achieved in humans. We have previously published pre-clinical data related to a TBV candidate Pfs25-IMX313 encoded in viral vectors which was very promising and hence progressed to human clinical trials. The results from the clinical trial of this vaccine were very modest. Here we unravel why, contrary to mice, this vaccine has failed to induce robust antibody (Ab) titres in humans to elicit transmission-blocking activity. We examined Pfs25-specific B cell and T follicular helper (Tfh) cell responses in mice and humans after vaccination with Pfs25-IMX313 encoded by replication-deficient chimpanzee adenovirus serotype 63 (ChAd63) and the attenuated orthopoxvirus modified vaccinia virus Ankara (MVA) delivered in the heterologous prime-boost regimen via intramuscular route. We found that after vaccination, the Pfs25-IMX313 was immunologically suboptimal in humans compared to mice in terms of serum Ab production and antigen-specific B, CD4+ and Tfh cell responses. We identified that the key determinant for the poor anti-Pfs25 Ab formation in humans was the lack of CD4+ T cell recognition of Pfs25-IMX313 derived peptide epitopes. This is supported by correlations established between the ratio of proliferated antigen-specific CD4+/Tfh-like T cells, CXCL13 sera levels, and the corresponding numbers of circulating Pfs25-specific memory B cells, that consequently reflected on antigen-specific IgG sera levels. These correlations can inform the design of next-generation Pfs25-based vaccines for robust and durable blocking of malaria transmission.

scholarly journals Immediate-Early Expression of a Recombinant Antigen by Modified Vaccinia Virus Ankara Breaks the Immunodominance of Strong Vector-Specific B8R Antigen in Acute and Memory CD8 T-Cell Responses

2010 ◽  
Vol 84 (17) ◽  
pp. 8743-8752 ◽  
Author(s):  
Karen Baur ◽  
Kay Brinkmann ◽  
Marc Schweneker ◽  
Juliane Pätzold ◽  
Christine Meisinger-Henschel ◽  
...  
Keyword(s):  
T Cell ◽  
Vaccinia Virus ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Immediate Early ◽  
Egfp Expression ◽  
Cell Responses ◽  
Modified Vaccinia Virus Ankara ◽  
Memory Cd8 T Cell ◽  
Early Late

ABSTRACT Efficient T-cell responses against recombinant antigens expressed by vaccinia virus vectors require expression of these antigens in the early phase of the virus replication cycle. The kinetics of recombinant gene expression in poxviruses are largely determined by the promoter chosen. We used the highly attenuated modified vaccinia virus Ankara (MVA) to determine the role of promoters in the induction of CD8 T-cell responses. We constructed MVA recombinants expressing either enhanced green fluorescent protein (EGFP) or chicken ovalbumin (OVA), each under the control of a hybrid early-late promoter (pHyb) containing five copies of a strong early element or the well-known early-late p7.5 or pS promoter for comparison. In primary or cultured cells, EGFP expression under the control of pHyb was detected within 30 min, as an immediate-early protein, and remained higher over the first 6 h of infection than p7.5- or pS-driven EGFP expression. Repeated immunizations of mice with recombinant MVA expressing OVA under the control of the pHyb promoter led to superior acute and memory CD8 T-cell responses compared to those to p7.5- and pS-driven OVA. Moreover, OVA expressed under the control of pHyb replaced the MVA-derived B8R protein as the immunodominant CD8 T-cell antigen after three or more immunizations. This is the first demonstration of an immediate-early neoantigen expressed by a poxviral vector resulting in superior induction of neoantigen-specific CD8 T-cell responses.

scholarly journals Prediction of IL4 Inducing Peptides

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Sandeep Kumar Dhanda ◽  
Sudheer Gupta ◽  
Pooja Vir ◽  
G. P. S. Raghava
Keyword(s):  
Mhc Class Ii ◽  
Critical Role ◽  
Interleukin 4 ◽  
Th2 Response ◽  
Data Set ◽  
T Helper 2 ◽  
Cell Responses ◽  
Antibody Class ◽  
First Time ◽  
Motif Information

The secretion of Interleukin-4 (IL4) is the characteristic of T-helper 2 responses. IL4 is a cytokine produced by CD4+ T cells in response to helminthes and other extracellular parasites. It has a critical role in guiding antibody class switching, hematopoiesis and inflammation, and the development of appropriate effector T-cell responses. In this study, it is the first time an attempt has been made to understand whether it is possible to predict IL4 inducing peptides. The data set used in this study comprises 904 experimentally validated IL4 inducing and 742 noninducing MHC class II binders. Our analysis revealed that certain types of residues are preferred at certain positions in IL4 inducing peptides. It was also observed that IL4 inducing and noninducing epitopes differ in compositional and motif pattern. Based on our analysis we developed classification models where the hybrid method of amino acid pairs and motif information performed the best with maximum accuracy of 75.76% and MCC of 0.51. These results indicate that it is possible to predict IL4 inducing peptides with reasonable precession. These models would be useful in designing the peptides that may induce desired Th2 response.

scholarly journals Novel Recombinant Mycobacterium bovis BCG, Ovine Atadenovirus, and Modified Vaccinia Virus Ankara Vaccines Combine To Induce Robust Human Immunodeficiency Virus-Specific CD4 and CD8 T-Cell Responses in Rhesus Macaques

2010 ◽  
Vol 84 (12) ◽  
pp. 5898-5908 ◽  
Author(s):  
Maximillian Rosario ◽  
Richard Hopkins ◽  
John Fulkerson ◽  
Nicola Borthwick ◽  
Máire F. Quigley ◽  
...  
Keyword(s):  
T Cell ◽  
Vaccinia Virus ◽  
Mycobacterium Bovis ◽  
Ex Vivo ◽  
Rhesus Macaques ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Cell Responses ◽  
Modified Vaccinia Virus Ankara ◽  
Hiv 1

ABSTRACT Mycobacterium bovis bacillus Calmette-Guérin (BCG), which elicits a degree of protective immunity against tuberculosis, is the most widely used vaccine in the world. Due to its persistence and immunogenicity, BCG has been proposed as a vector for vaccines against other infections, including HIV-1. BCG has a very good safety record, although it can cause disseminated disease in immunocompromised individuals. Here, we constructed a recombinant BCG vector expressing HIV-1 clade A-derived immunogen HIVA using the recently described safer and more immunogenic BCG strain AERAS-401 as the parental mycobacterium. Using routine ex vivo T-cell assays, BCG.HIVA401 as a stand-alone vaccine induced undetectable and weak CD8 T-cell responses in BALB/c mice and rhesus macaques, respectively. However, when BCG.HIVA401 was used as a priming component in heterologous vaccination regimens together with recombinant modified vaccinia virus Ankara-vectored MVA.HIVA and ovine atadenovirus-vectored OAdV.HIVA vaccines, robust HIV-1-specific T-cell responses were elicited. These high-frequency T-cell responses were broadly directed and capable of proliferation in response to recall antigen. Furthermore, multiple antigen-specific T-cell clonotypes were efficiently recruited into the memory pool. These desirable features are thought to be associated with good control of HIV-1 infection. In addition, strong and persistent T-cell responses specific for the BCG-derived purified protein derivative (PPD) antigen were induced. This work is the first demonstration of immunogenicity for two novel vaccine vectors and the corresponding candidate HIV-1 vaccines BCG.HIVA401 and OAdV.HIVA in nonhuman primates. These results strongly support their further exploration.

scholarly journals Single dose of BNT162b2 mRNA vaccine against SARS-CoV-2 induces high frequency of neutralising antibody and polyfunctional T-cell responses in patients with myeloproliferative neoplasms

2021 ◽  
Author(s):  
Patrick Harrington ◽  
Hugues de Lavallade ◽  
Katie Doores ◽  
Amy O'Reilly ◽  
Jeffrey Seow ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Response ◽  
Myeloproliferative Neoplasms ◽  
T Cell Response ◽  
The Novel ◽  
Neutralising Antibodies ◽  
Cell Responses ◽  
Disease Subtype ◽  
Immune Defects ◽  
First Time

Encouraging results have been observed from initial studies evaluating vaccines targeting the novel beta coronavirus which causes severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, concerns have been raised around the efficacy of these vaccines in immunosuppressed populations, including patients with haematological malignancy. Myeloproliferative neoplasms (MPN), in particular myelofibrosis (MF), are associated with heterogenous immune defects which are influenced by patient age, disease subtype and the use of cytoreductive therapies. Patients with a WHO defined diagnosis of an MPN presenting to our clinic were recruited following first injection of 30μg BNT162b2. A positive anti-S IgG ELISA was seen in 76.1% (16) of patients following vaccination with positive neutralising antibodies detected in 85.7% (18) of patients. A memory T cell response was observed in 80% (16) of patients, with a CD4+ T cell response in 75% (15) and a CD8+ T cell response in 35% (7). These results, for the first time, provide some reassurance regarding the initial immune response to the BNT162b2 vaccine amongst patients with MPN, with response rates similar to that observed in the general population.

Three-year follow-up of ATTRACTION-3: A phase III study of nivolumab (Nivo) in patients with advanced esophageal squamous cell carcinoma (ESCC) that is refractory or intolerant to previous chemotherapy.

2021 ◽  
Vol 39 (3_suppl) ◽  
pp. 204-204
Author(s):  
Keisho Chin ◽  
Ken Kato ◽  
Byoung Chul Cho ◽  
Masanobu Takahashi ◽  
Morihito Okada ◽  
...  
Keyword(s):  
Overall Survival ◽  
Subgroup Analysis ◽  
Survival Data ◽  
Special Interest ◽  
Safety Data ◽  
Phase Iii ◽  
Taxane Chemotherapy ◽  
Favorable Safety ◽  
Safety Signals

204 Background: Previous results from the ATTRACTION-3 phase 3 trial demonstrated a significant improvement in overall survival and a favorable safety profile compared with taxane chemotherapy (CT) in previously-treated ESCC patients. To our knowledge, no long-term efficacy and safety data of this immune checkpoint inhibitor has been reported in ESCC. Herein, we report the three-year survival data of Nivo in ESCC. Methods: In ATTRACTION-3, 419 patients with unresectable advanced or recurrent ESCC refractory or intolerant to 1 prior fluoropyrimidine/platinum-based CT were randomized in a 1:1 ratio to receive Nivo (N = 210) or the investigator’s choice of CT (paclitaxel or docetaxel) (N = 209) until disease progression or unacceptable toxicity. The primary endpoint was overall survival (OS). A subgroup analysis of OS according to the best overall response (BOR) was performed. The onset of treatment-related adverse events of special interest over time in the Nivo arm was also evaluated. Results: As of data cut-off on 25 May 2020, 3 years after the last patient was enrolled, the median OS (mOS) was 10.91 months with Nivo versus 8.51 months with CT [hazard ratio (HR) 0.79; 95% confidence interval (CI) 0.64-0.97]. The OS rates of patients with Nivo and CT were 20.2 % and 13.5 % at 24 months, and 15.3% and 8.7% at 36 months, respectively. In the subgroup analysis of OS by BOR, mOS in CR/PR patients were 19.91 and 15.41 months (HR 0.84, 95%CI 0.46-1.54) and that in SD patients were 17.38 and 9.36 months (HR 0.45, 95%CI 0.26-0.78) in the Nivo and CT arm, respectively. Furthermore, mOS in PD patients were 10.91 and 6.18 months (HR 0.56, 95%CI 0.33-0.95) in the Nivo and CT arm, respectively. No new safety signals were detected during the three-year follow-up. Time to onset of the event of special interest was within the range of events previously observed in other indications. Conclusions: At three-year follow up, Nivo continued to show improved OS over CT in pretreated patients with advanced ESCC patients. Nivo showed a longer mOS than CT regardless of BOR. During the three-year follow-up, no new safety signals were observed. Clinical trial information: NCT02569242.

Safety of darolutamide (DARO) for nonmetastatic castration-resistant prostate cancer (nmCRPC) from extended follow-up in the phase III ARAMIS trial.

2021 ◽  
Vol 39 (6_suppl) ◽  
pp. 239-239
Author(s):  
Matthew Raymond Smith ◽  
Karim Fizazi ◽  
Teuvo L. J. Tammela ◽  
Felipe Melo Cruz ◽  
Luke T. Nordquist ◽  
...  
Keyword(s):  
Safety Profile ◽  
Safety Data ◽  
Final Analysis ◽  
Phase Iii ◽  
Prolonged Treatment ◽  
Fracture Rate ◽  
Castration Resistant Prostate Cancer ◽  
Favorable Safety Profile ◽  
Risk Of Death ◽  
Favorable Safety

239 Background: DARO is a structurally distinct androgen receptor inhibitor (ARI) approved for treating nmCRPC. In ARAMIS, DARO significantly reduced the risk of death by 31% (HR = 0.69; 95% CI: 0.53-0.88; p = 0.003) and prolonged median metastasis-free survival vs placebo (PBO; 40.4 months vs 18.4 months; HR = 0.41; 95% CI: 0.34-0.50; p < 0.001). Adverse events (AEs) of interest commonly associated with ARI therapy, such as fatigue, falls, fractures, rash, mental impairment, and hypertension, as well as interactions between ARIs and concomitantly administered drugs, can impact patient daily life. In the final analysis of the double-blind (DB) period of the ARAMIS trial, DARO had a favorable safety profile, showing ≤2% difference vs PBO for most AEs of interest. Fatigue was the only AE with > 10% incidence with DARO. The incidence of permanent discontinuation due to AEs was also similar between DARO and PBO (8.9% vs 8.7%). Here we present safety data for prolonged treatment with DARO from the final analysis of the DB + open-label (OL) period of ARAMIS. Methods: Patients (pts) with nmCRPC (N = 1509) were randomized 2:1 to DARO or matched PBO while continuing androgen deprivation therapy. The data cut-off for the primary analysis of the DB period was September 3, 2018. Study unblinding occurred on November 30, 2018, after which pts in the DARO arm still receiving study treatment continued with OL DARO. The data cut-off for final analysis of the DB+OL period was November 15, 2019. Results: At the final analysis, the median treatment duration for pts randomized to DARO was 18.5 months for the DB period and 25.8 months for the DB+OL period. At the final cut-off date, 48.8% of patients in the DARO DB+OL group were still receiving DARO treatment. The increase in the incidence of any-grade AEs (85.7% vs 89.8%) and serious AEs (26.1% vs 32.1%) between the DB and DB+OL period was small. Between the DB and DB+OL periods, only minor numerical changes for ARI-associated AEs were observed. When the incidences were corrected for exposure, there were minimal differences between the DB and DB+OL period, e.g., the fracture rate was 3.4 vs 4.0 per 100 patient-years for the DB vs DB+OL periods, respectively. Fatigue was the only ARI-associated AE of interest that exhibited > 10% incidence in the DARO arm during the DB+OL period. The incidence of permanent discontinuation of DARO due to AEs increased slightly from 8.9% during the DB period to 10.5% during the DB+OL period; the incidence of discontinuation of PBO due to AEs during the DB period was 8.7%. Conclusions: With longer treatment exposure, DARO remained well-tolerated. In the DB+OL period, no new safety signals were observed. The expected increases in incidence of AEs between the DB and DB+OL periods largely disappeared when adjusted for the longer exposure, confirming the favorable safety profile of DARO with prolonged treatment. Clinical trial information: NCT02200614.

scholarly journals Optimising T cell (re)boosting strategies for adenoviral and modified vaccinia Ankara vaccine regimens in humans

npj Vaccines ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Stefania Capone ◽  
Anthony Brown ◽  
Felicity Hartnell ◽  
Mariarosaria Del Sorbo ◽  
Cinzia Traboni ◽  
...  
Keyword(s):  
T Cells ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
T Cell ◽  
Viral Vectors ◽  
Standard Dose ◽  
T Cell Responses ◽  
Effector Memory ◽  
Cell Responses ◽  
Wide Range

Abstract Simian adenoviral and modified vaccinia Ankara (MVA) viral vectors used in heterologous prime-boost strategies are potent inducers of T cells against encoded antigens and are in advanced testing as vaccine carriers for a wide range of infectious agents and cancers. It is unclear if these responses can be further enhanced or sustained with reboosting strategies. Furthermore, despite the challenges involved in MVA manufacture dose de-escalation has not been performed in humans. In this study, healthy volunteers received chimpanzee-derived adenovirus-3 and MVA vaccines encoding the non-structural region of hepatitis C virus (ChAd3-NSmut/MVA-NSmut) 8 weeks apart. Volunteers were then reboosted with a second round of ChAd3-NSmut/MVA-NSmut or MVA-NSmut vaccines 8 weeks or 1-year later. We also determined the capacity of reduced doses of MVA-NSmut to boost ChAd3-NSmut primed T cells. Reboosting was safe, with no enhanced reactogenicity. Reboosting after an 8-week interval led to minimal re-expansion of transgene-specific T cells. However, after a longer interval, T cell responses expanded efficiently and memory responses were enhanced. The 8-week interval regimen induced a higher percentage of terminally differentiated and effector memory T cells. Reboosting with MVA-NSmut alone was as effective as with ChAd3-NSmut/MVA-NSmut. A ten-fold lower dose of MVA (2 × 107pfu) induced high-magnitude, sustained, broad, and functional Hepatitis C virus (HCV)-specific T cell responses, equivalent to standard doses (2 × 108 pfu). Overall, we show that following Ad/MVA prime-boost vaccination reboosting is most effective after a prolonged interval and is productive with MVA alone. Importantly, we also show that a ten-fold lower dose of MVA is as potent in humans as the standard dose.

scholarly journals Potent HIV-1-Specific CD8 T Cell Responses Induced in Mice after Priming with a Multiepitopic DNA-TMEP and Boosting with the HIV Vaccine MVA-B

Viruses ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 424 ◽  
Author(s):  
Beatriz Perdiguero ◽  
Suresh C. Raman ◽  
Cristina Sánchez-Corzo ◽  
Carlos Oscar S. Sorzano ◽  
José Ramón Valverde ◽  
...  
Keyword(s):  
T Cell ◽  
Immune Responses ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Effective Vaccine ◽  
T Cell Epitopes ◽  
Cell Responses ◽  
Modified Vaccinia Virus Ankara ◽  
Hiv 1

An effective vaccine against Human Immunodeficiency Virus (HIV) still remains the best solution to provide a sustainable control and/or eradication of the virus. We have previously generated the HIV-1 vaccine modified vaccinia virus Ankara (MVA)-B, which exhibited good immunogenicity profile in phase I prophylactic and therapeutic clinical trials, but was unable to prevent viral rebound after antiretroviral (ART) removal. To potentiate the immunogenicity of MVA-B, here we described the design and immune responses elicited in mice by a new T cell multi-epitopic B (TMEP-B) immunogen, vectored by DNA, when administered in homologous or heterologous prime/boost regimens in combination with MVA-B. The TMEP-B protein contained conserved regions from Gag, Pol, and Nef proteins including multiple CD4 and CD8 T cell epitopes functionally associated with HIV control. Heterologous DNA-TMEP/MVA-B regimen induced higher HIV-1-specific CD8 T cell responses with broader epitope recognition and higher polyfunctional profile than the homologous DNA-TMEP/DNA-TMEP or the heterologous DNA-GPN/MVA-B combinations. Moreover, higher HIV-1-specific CD4 and Tfh immune responses were also detected using this regimen. After MVA-B boost, the magnitude of the anti-VACV CD8 T cell response was significantly compromised in DNA-TMEP-primed animals. Our results revealed the immunological potential of DNA-TMEP prime/MVA-B boost regimen and supported the application of these combined vectors in HIV-1 prevention and/or therapy.

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