Dataset Information

A Phase 2 Extension Study Evaluating the Immunogenicity, Safety, and Tolerability of 3 or 4 Doses of a Clostridioides difficile Vaccine in Healthy US Adults Aged 65 to 85 Years.

ABSTRACT:

Background

This phase 2 extension explored the long-term antibody persistence of an investigational Clostridioides difficile vaccine and the safety, tolerability, and immunogenicity of dose 4 approximately 12 months post-dose 3.

Methods

One year post-dose 3, healthy US 65- to 85-year-olds (N = 300) were randomized to dose 4 of vaccine at previously received antigen levels (100 or 200 μg) or placebo. Assessments included safety and percentages of participants achieving neutralizing antibody titers above prespecified thresholds (≥219 and ≥2586 neutralization units/mL for toxins A and B, respectively).

Results

In participants previously given three 200-µg doses and placebo in the extension, toxin A and B neutralizing antibodies were above prevaccination levels 48 months post-dose 3 (36 months after placebo); 24.0% and 26.0% had toxin A and B antibodies at or above prespecified thresholds, respectively. Neutralizing antibodies increased post-dose 4 (12 months post-dose 3) and persisted to 36 months post-dose 4. Thirty days post-dose 4, all participants had toxin A and 86.5% to 100% had toxin B titers at or above prespecified thresholds. Local reactions were more frequent in vaccine recipients. Systemic and adverse event frequencies were similar across groups.

Conclusions

C difficile vaccine immune responses persisted 48 months post-dose 3. Dose 4 was immunogenic and well tolerated, supporting continued development. Clinical Trials Registration. ClinicalTrials.gov NCT02561195.

SUBMITTER: Remich S

PROVIDER: S-EPMC10873164 | biostudies-literature | 2024 Feb

REPOSITORIES: biostudies-literature

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Publications

A Phase 2 Extension Study Evaluating the Immunogenicity, Safety, and Tolerability of 3 or 4 Doses of a Clostridioides difficile Vaccine in Healthy US Adults Aged 65 to 85 Years.

Remich Shon S Kitchin Nicholas N Peterson James J Li Ping P Pride Michael W MW Brock Linda L Anderson Annaliesa S AS Gruber William C WC Jansen Kathrin U KU Lockhart Stephen P SP Webber Chris C

The Journal of infectious diseases 20240201 2

<h4>Background</h4>This phase 2 extension explored the long-term antibody persistence of an investigational Clostridioides difficile vaccine and the safety, tolerability, and immunogenicity of dose 4 approximately 12 months post-dose 3.<h4>Methods</h4>One year post-dose 3, healthy US 65- to 85-year-olds (N = 300) were randomized to dose 4 of vaccine at previously received antigen levels (100 or 200 μg) or placebo. Assessments included safety and percentages of participants achieving neutralizing ...[more]

PMID: 37531657

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Project description:Abstract Background Disruptions to gut microbiota composition can result in dysbiosis and subsequent intestinal colonization by opportunistic pathogens such as Clostridioides difficile.1,2 The incidence of Clostridioides difficile infection (CDI) in persons ≥ 65 years old is greater than in those < 65 years old,3 with 1 in 11 CDI patients ≥ 65 years old dying within 1 month of diagnosis.4 We report the efficacy and safety of RBX2660, a microbiota-based live biotherapeutic, in patients with recurrent CDI (rCDI) who were ≥ 65 years old with comorbidities. This is a subgroup analysis of the PUNCH CD3 trial (NCT03244644), a prospective, multicenter, randomized, double-blind, placebo-controlled phase 3 trial. Methods Participants enrolled in PUNCH CD3 were ≥ 18 years old with documented rCDI who completed standard-of-care antibiotic therapy prior to treatment with RBX2660 or placebo. Treatment success was defined as remaining recurrence-free 8 weeks after intervention. In this subgroup analysis, we assessed outcomes of participants ≥ 65 years old with underlying cardiac disorders, chronic kidney disease (CKD), and gastrointestinal (GI) disorders. The treatment-emergent adverse events (TEAEs) were summarized for the double-blind treatment period within 8 weeks and censored if a patient received open-label RBX2660 after CDI recurrence. Results In the modified intent-to-treat population, 119 of 262 participants (45%) were ≥ 65 years old. Of these 119 participants, 42% had a cardiac disorder, 19% had CKD, and 61% had a GI disorder; the respective RBX2660 treatment success rates were 69%, 68%, and 67% (Figure 1). In the total safety population, the overall incidence of TEAEs was 52% with RBX2660 treatment compared to 44% with placebo treatment; mild events accounted for most of the difference (40% vs 30%) (Table 1). The overall incidence of TEAEs was 51% in RBX2660-treated participants ≥ 65 years old and 61%, 68%, and 51% in those participants with a cardiac disorder, CKD, or GI disorder, respectively. Most TEAEs were mild or moderate in severity and related to a pre-existing condition. Conclusion RBX2660 is safe and efficacious across a range of medically complex patients and consistently reduced rCDI in adults ≥ 65 years old, regardless of baseline comorbidities. Disclosures Glenn S. Tillotson, PhD, Ferring Pharmaceuticals: Advisor/Consultant|Paratek Pharmaceuticals: Grant/Research Support|Spero Pharmaceuticals: Advisor/Consultant|Taro Pharmaceuticals: Advisor/Consultant Paul Feuerstadt, MD, FACG, AGAF, Ferring/Rebiotix Pharmaceuticals: Advisor/Consultant|Ferring/Rebiotix Pharmaceuticals: Grant/Research Support|Merck and Co: Advisor/Consultant|SERES Therapeutics: Advisor/Consultant|SERES Therapeutics: Grant/Research Support|Takeda Pharmaceuticals: Advisor/Consultant Stuart Johnson, M.D., Ferring Pharmaceuticals: Membership on Ferring Publication Steering Committee|Ferring Pharmaceuticals: Employee|Summit Plc: Advisor/Consultant Adam Harvey, PhD, Ferring Pharmaceuticals: Employment.

Project description:IntroductionRespiratory syncytial virus (RSV) and influenza pose major disease burdens in older adults due to an aging immune system and comorbidities; seasonal overlap exists between these infections. In 2023, the RSV prefusion protein F3 older adult (RSVPreF3 OA) vaccine was first approved in the USA as a single dose for prevention of lower respiratory tract disease due to RSV in adults aged ≥ 60 years. The vaccine has since been approved in the European Union and elsewhere. RSVPreF3 OA and FLU-QIV-HD could be coadministered if immunogenicity, safety, and reactogenicity are not affected.MethodsThis open-label, randomized (1:1), controlled, phase 3 study in 1029 adults aged ≥ 65 years in the USA evaluated the immunogenicity (up to 1 month after last vaccine dose) and safety (up to 6 months after last vaccine dose) of RSVPreF3 OA coadministered with FLU-QIV-HD (co-ad group) versus FLU-QIV-HD alone followed by RSVPreF3 OA at a separate visit 1 month later (control group). Non-inferiority criterion was defined as an upper limit of the two-sided 95% confidence interval of the geometric mean titer (GMT) group ratio (control/co-ad) ≤ 1.5. Secondary endpoints included safety and reactogenicity.ResultsProportions of participants across age categories between groups and proportions of male (50.4%) and female (49.6%) participants were well balanced; most participants were white (68.7%). Group GMT ratios for RSV-A neutralizing titers, hemagglutination inhibition titers for four influenza vaccine strains, and RSV-B neutralizing titers were non-inferior in the co-ad group versus the control group. No clinically meaningful differences in local or systemic solicited and unsolicited adverse events (AEs), serious AEs, and potential immune-mediated diseases were identified. The most common solicited AEs in both groups were injection-site pain and myalgia.ConclusionIn adults aged ≥ 65 years, coadministration of RSVPreF3 OA and FLU-QIV-HD was immunogenically non-inferior to the sequential administration of both vaccines 1 month apart, and had clinically acceptable safety and reactogenicity profile.Trial registrationClinicalTrials.gov identifier, NCT05559476.

Project description:The response to iron limitation of several bacteria is regulated by the ferric uptake regulator (Fur). The Fur-regulated transcriptional, translational and metabolic networks of the Gram-positive, pathogen Clostridioides difficile were investigated by a combined RNA sequencing, proteomic, metabolomic and electron microscopy approach. At high iron conditions (760 g/l) the C. difficile fur mutant displayed a growth deficiency compared to wild type C. difficile cells. Several iron transporters were found induced by Fur regulation during low iron (11 g/l) conditions. The major adaptation to low iron conditions was observed for the central energy metabolism. Most ferredoxin-dependent amino acid fermentations were found significantly down regulated (had, etf, acd, grd, trx, bdc, hbd). The substrates of these pathways phenylalanine, leucine, glycine and some initial intermediates (phenylpyruvate, oxo-isocaproate, 3-hydroxy-butanoyl-CoA, crotonyl-CoA) were found accumulated, while some end product like isocaproate and butanoate were found reduced. Flavodoxin (fldX) formation and riboflavin biosynthesis (rib) were found enhanced, most likely to replace the missing ferredoxins. Proline reductase (prd), the corresponding ion pumping RNF complex (rnf) and the reaction product 5-aminovalerate were significantly enhanced. An ATP forming ATPase (atpCDGAHFEB,) of the F0F1-type was found induced while the formation of a V-type, mostly proton-pumping, ATP-consuming ATPase (atpDBAFCEKI, was decreased. The [Fe-S] enzyme-dependent pyruvate formate lyase (pfl), formate dehydrogenase (fdh) and hydrogenase (hyd) branch of glucose utilization and glycogen biosynthesis (glg) were significantly reduced, leading to an accumulation of glucose and pyruvate. The formation of [Fe-S] enzyme carbon monoxide dehydrogenase (coo) was inhibited. An intensive remodeling of the cell wall was observed most likely to increase antibiotic resistance. Polyamine biosynthesis (spe) was found induced leading to an accumulation of spermine, spermidine and putrescine. The fur mutant lost most of its flagella. Finally, the CRISPR/Cas and a prophage encoding operon were downregulated. Fur binding sites were found upstream of 20 of the regulated genes. Overall, adaptation to low iron conditions in C. difficile focused on an increase of iron import, significant decrease in metabolic iron utilization and protection during the complex transition.

Dataset Information

A Phase 2 Extension Study Evaluating the Immunogenicity, Safety, and Tolerability of 3 or 4 Doses of a Clostridioides difficile Vaccine in Healthy US Adults Aged 65 to 85 Years.

Background

Methods

Results

Conclusions

Publications

A Phase 2 Extension Study Evaluating the Immunogenicity, Safety, and Tolerability of 3 or 4 Doses of a Clostridioides difficile Vaccine in Healthy US Adults Aged 65 to 85 Years.

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