One-year follow-up of the immunogenicity and safety of a primary series of the NVX-CoV2373 (TAK-019) vaccine in healthy Japanese adults: Final report of a phase I/II randomized controlled trial

BACKGROUND

In the interim report of this phase I/II randomized, placebo-controlled trial in Japanese adults, a two-dose primary series of NVX-CoV2373 (5 µg SARS-CoV-2 recombinant nanoparticle spike protein [rS]; 50 µg Matrix-M) administered 21 days apart induced robust anti-SARS-CoV-2 immune responses up to day 50 and had an acceptable safety profile.

METHODS

Following the double-blind phase of this study (day 1-50), participants were informed about their assignment to NVX-CoV2373 or placebo, and their reconsent was required for continuation in the open-label phase (day 51-387). This final report evaluated immunogenicity on days 202 and 387, and safety findings from the 1-year follow-up.

RESULTS

In total, 131/150 participants in the NVX-CoV2373 arm and 4/50 in the placebo arm completed the study. The most common reason for discontinuation was because the participant requested a publicly available COVID-19 vaccine. At 6 months and 1 year after the second vaccine dose, both the geometric mean titres of anti-SARS-CoV-2 rS serum immunoglobulin G and serum neutralizing antibodies against the SARS-CoV-2 ancestral strain were numerically higher than before the second dose. There were no deaths, adverse events (AEs) leading to participant withdrawal, or AEs of special interest throughout the trial. During follow-up, 2.0 % (1/50) of participants in the placebo arm reported COVID-19 approximately 1 month after the second vaccine dose (serious AE requiring hospitalisation, already presented in the interim report) and 2.7 % (4/150) in the NVX-CoV2373 arm after approximately 10 months (mild [2/4] or moderate [2/4] in severity).

DISCUSSION

A primary series of NVX-CoV2373 induced persistent immune responses up to 1 year after the second dose. The vaccine was well tolerated and had an acceptable safety profile. We believe our findings offer important insights for determining dosing intervals between primary and booster vaccinations.

Immunogenicity and safety of a second heterologous booster dose of NVX-CoV2373 (TAK-019) in healthy Japanese adults who had previously received a primary series of COVID-19 mRNA vaccine: Interim analysis report of a phase 3 open-label trial

BACKGROUND

The phase 3, single-arm, open-label TAK-019-3001 study assessed two heterologous booster doses of NVX-CoV2373 administered 5 months apart in healthy Japanese adults who had completed a primary series of a COVID-19 mRNA vaccine 6-12 months previously. In the main part of this study, a first booster induced rapid and robust anti-SARS-CoV-2 immune responses, addressing waning immunity in participants.

METHODS

This interim analysis evaluated the immunogenicity and safety of a second booster in the extension part of this study including comparisons with the first booster. Immunogenicity was assessed on extension day (ED) 1 (before vaccination) and ED15. Solicited and unsolicited adverse events occurring in the 7 and 28 days, respectively, after vaccination were assessed.

RESULTS

Of the 150 participants who received a first NVX-CoV2373 booster, 129 were administered a second booster on ED1. Participant characteristics were consistent between the main and extension parts of the study. Titres of anti-SARS-CoV-2 rS serum immunoglobulin G and serum neutralizing antibodies against the SARS-CoV-2 ancestral strain at ED15 were 4.0- and 3.0-fold higher, respectively, than those observed 5 months after the first booster on ED1, and 3.0- and 1.4-fold higher, respectively, than those observed 14 days after the first booster on day 15. The proportions of participants who experienced solicited local and systemic adverse events (AEs) in the 7 days after the second booster were 73.6 % and 51.2 %, respectively: most were of grade 2 severity or lower. Seven percent of participants experienced unsolicited AEs in the 28 days after the second booster: all were unrelated to the treatment. There were no deaths or AEs leading to study discontinuation.

DISCUSSION

A second heterologous NVX-CoV2373 booster in healthy Japanese adults induced more robust anti-SARS-CoV-2 immune responses than the first booster. The second booster was well tolerated. No new safety concerns were identified.

Immunogenicity and safety of a single booster dose of NVX-CoV2373 (TAK-019) in healthy Japanese adults who had previously received a primary series of COVID-19 mRNA vaccine: Primary analysis report of a phase 3 open-label trial

BACKGROUND

We evaluated the immunogenicity and safety of a booster dose of NVX-CoV2373 in Japanese adults who had completed a primary series of COVID-19 mRNA vaccine 6-12 months previously.

METHODS

This single-arm, open-label, phase 3 study, conducted at two Japanese centres, enrolled healthy adults ≥ 20 years old. Participants received a booster dose of NVX-CoV2373. The primary immunogenicity endpoint was non-inferiority (lower limit of the 95 % confidence interval [CI] ≥ 0.67) of the geometric mean titre (GMT) ratio of titres of serum neutralizing antibodies (nAbs) against the SARS-CoV-2 ancestral strain 14 days after booster vaccination (day 15) in this study, compared with those 14 days after the second primary NVX-CoV2373 vaccination (day 36) in the TAK-019-1501 study (NCT04712110). Primary safety endpoints included local and systemic solicited adverse events (AEs) up to day 7 and unsolicited AEs up to day 28.

RESULTS

Between 15 April 2022 and 10 May 2022, 155 participants were screened and 150, stratified by age (20-64 years old [n = 135] or ≥ 65 years old [n = 15]), received an NVX-CoV2373 booster dose. The GMT ratio between titres of serum nAbs against the SARS-CoV-2 ancestral strain on day 15 in this study and those on day 36 in the TAK-019-1501 study was 1.18 (95 % CI, 0.95-1.47), meeting the non-inferiority criterion. Following vaccination, the proportion of participants who reported local and systemic solicited AEs up to day 7 was 74.0 % and 48.0 %, respectively. The most common local and systemic solicited AEs were tenderness (102 participants [68.0 %]) and malaise (39 participants [26.0 %]), respectively. Seven participants (4.7 %) reported unsolicited AEs between vaccination and day 28; all were severity grade ≤ 2.

DISCUSSION

A single heterologous NVX-CoV2373 booster induced rapid and robust anti-SARS-CoV-2 immune responses, addressing waning immunity in healthy Japanese adults, and had an acceptable safety profile.

CLINICALTRIALS

gov identifier: NCT05299359.

Safety and immunogenicity of NVX-CoV2373 (TAK-019) vaccine in healthy Japanese adults: Interim report of a phase I/II randomized controlled trial

Background

We evaluated the safety and immunogenicity of NVX-CoV2373, a recombinant SARS-CoV-2 nanoparticle vaccine, in healthy Japanese participants.

Methods

This phase 1/2, randomized, observer-blind, placebo-controlled trial conducted in Japan (two sites), enrolled healthy Japanese adults aged ≥ 20 years with no history/risk of SARS-CoV-2 infection and no prior exposure to other approved/investigational SARS-CoV-2 vaccines or treatments. Participants were stratified by age (< 65 or ≥ 65 years) and randomized to receive two doses of either NVX-CoV2373 (5 μg SARS-CoV-2 rS; 50 μg Matrix-M1) or placebo, 21 days apart. Primary outcomes were safety and immunogenicity assessed by serum IgG antibody levels against SARS-CoV-2 rS protein on day 36. Herein, we report the primary data analysis at 4 weeks after the second dose, ahead of 12-month follow-up completion (data cut-off: 8 May 2021).

Results

Between 12 February 2021 and 17 March 2021, 326 subjects were screened, and 200 participants enrolled and randomized: NVX-CoV2373, n = 150; placebo, n = 50. Solicited adverse events (AEs) through 7 days after each injection occurred in 121/150 (80.7%) and 11/50 (22.0%) participants in the NVX-CoV2373 and placebo arms, respectively. In the NVX-CoV2373 arm, tenderness and injection site pain were the most frequently reported solicited AEs after each vaccination, irrespective of age. Robust immune responses occurred with NVX-CoV2373 (n = 150) by day 36: IgG geometric mean fold rise (95% confidence interval) 259 (219, 306); seroconversion rate 100% (97.6, 100). No such response occurred with placebo (n = 49).

Conclusion

Two doses of NVX-CoV2373 given with a 21-day interval demonstrated acceptable safety and induced robust anti-SARS-CoV-2 immune responses in healthy Japanese adults. Funding: Takeda Pharmaceutical Company Limited and Japan Agency for Medical Research and Development (AMED). ClinicalTrials.gov identifier: NCT04712110.

Protective effect of the combination BCG vaccination and rifampicin prophylaxis in leprosy prevention

BCG vaccination and rifampicin chemoprophylaxis are both strategies for leprosy prevention. While the combined effect is unknown, the combination may give the desired push to halt leprosy transmission. Secondary analysis was done on results from a single centre, double blind, cluster randomized, and placebo-controlled trial. Individually, BCG (given at infancy) and rifampicin showed to protect against leprosy (57% [95% CI: 24-75%] and 58% [95% CI: 30-74%], respectively). The combined strategies showed a protective effect of 80% (95% CI: 50-92%). This is the first time that the additive effect of BCG and rifampicin are shown; the combined strategies can possibly lower leprosy incidence.

Polymorphism N248S in the human Toll-like receptor 1 gene is related to leprosy and leprosy reactions

We investigated the association between a polymorphism of a key innate immunity receptor, Toll-like receptor 1 (TLR1) N248S, and susceptibility to leprosy and its clinical presentation. TLR1 N248S has been shown elsewhere to diminish TLR1 signaling and subsequent leprosy disease. The homozygous genotype SS was more frequent (P=.012) and the heterozygous SN genotype was less frequent (P=.015) in patients with leprosy than in control subjects. Additional observed differences in allelic frequency in patients who experienced reversal reactions and/or erythema nodosum leprosum reactions indicates that altered TLR1 function, or at least a TLR1 N248S-linked trait, may affect the progression from infection to disease as well as the disease course and the risk of debilitating reactional episodes in this population.

Low frequency of the TIRAP S180L polymorphism in Africa, and its potential role in malaria, sepsis, and leprosy

Background

The Toll-like receptors (TLRs) mediate innate immunity to various pathogens. A mutation (S180L) in the TLR downstream signal transducer TIRAP has recently been reported to be common in Europeans and Africans and to roughly half the risks of heterogeneous infectious diseases including malaria, tuberculosis, bacteremia, and invasive pneumococal disease in heterozygous mutation carriers.

Methods

We assessed the TIRAP S180L variant by melting curve and RFLP analysis in 1095 delivering women from malaria-endemic Ghana, as well as in a further 1114 individuals participating in case control studies on sepsis and leprosy in Germany, Turkey and Bangladesh.

Results

In Ghana, the TIRAP S180L polymorphism was virtually absent. In contrast, the mutation was observed among 26.6%, 32.9% and 12% of German, Bangladesh and Turkish controls, respectively. No significant association of the heterozygous genotype with sepsis or leprosy was observed. Remarkably, homozygous TIRAP 180L tend to increase the risk of sepsis in the German study (P = 0.04).

Conclusion

A broad protective effect of TIRAP S180L against infectious diseases per se is not discernible.

Preventing nerve function impairment in leprosy: validation and updating of a prediction rule

Background

To validate and update a prediction rule for estimating the risk of leprosy-related nerve function impairment (NFI).

Methodology/Principal Findings

Prospective cohort using routinely collected data, in which we determined the discriminative ability of a previously published rule and an updated rule with a concordance statistic (c). Additional risk factors were analyzed with a Cox proportional hazards regression model. The population consisted of 1,037 leprosy patients newly diagnosed between 2002 and 2003 in the health care facilities of the Rural Health Program in Nilphamari and Rangpur districts in northwest Bangladesh. The primary outcome was the time until the start of treatment. An NFI event was defined as the decision to treat NFI with corticosteroids after diagnosis. NFI occurred in 115 patients (13%; 95% confidence interval 11%–16%). The original prediction rule had adequate discriminative ability (c = 0.79), but could be improved by substituting one predicting variable: ‘long-standing nerve function impairment at diagnosis’ by ‘anti-PGL-I antibodies’. The adjusted prediction rule was slightly better (c = 0.81) and identified more patients with NFI (80%) than the original prediction rule (72%).

Conclusions/Significance

NFI can well be predicted by using the risk variables ‘leprosy classification’ and ‘anti-PGL-I antibodies’. The use of these two variables that do not include NFI offer the possibility of predicting NFI, even before it occurs for the first time. Surveillance beyond the treatment period can be targeted to those most likely to benefit from preventing permanent disabilities.

Leprosy is caused by a bacterium that attacks the peripheral nerves. This may cause nerve function impairment (NFI), resulting in handicaps and disabilities. Therefore, prediction and prevention of NFI is extremely important in the management of leprosy. In 2000, a prediction rule for NFI was published, but circumstances have changed since the study was performed in the 1990s: the leprosy detection delay has shortened and the definition of NFI has changed. The original rule used ‘leprosy classification’ and ‘NFI present at diagnosis’ to predict future NFI. In the current patient population we studied an adjusted rule based on ‘leprosy classification’ and ‘presence of antibodies’. This adjusted rule predicted NFI more often than the original rule. With the adjusted rule it is now also possible to assess NFI risk before the first nerve damage event takes place. This may help doctors and health workers to improve surveillance for people at high risk. Early detection and treatment can then prevent permanent disabilities.

The prevalence of previously undiagnosed leprosy in the general population of northwest bangladesh

BACKGROUND

The prevalence of previously undiagnosed leprosy (PPUL) in the general population was determined to estimate the background level of leprosy in the population and to compare this with registered prevalence and the known PPUL in different levels of contacts of leprosy patients.

METHODOLOGY AND PRINCIPAL FINDINGS

Multistage cluster sampling including 20 clusters of 1,000 persons each in two districts with over 4 million population. Physical examination was performed on all individuals. The number of newly found leprosy cases among 17,862 people above 5 years of age from the cluster sample was 27 (19 SLPB, 8 PB2-5), giving a PPUL rate of 15.1 per 10,000.

CONCLUSIONS AND SIGNIFICANCE

PPUL in the general population is six times higher than the registered prevalence, but three times lower than that in the most distant subgroup of contacts (neighbour of neighbour and social contacts) of leprosy patients in the same area. Full village or neighbourhood surveys may be preferable to contact surveys where leprosy is highly endemic.

Association between anti-pGL-I IgM and clinical and demographic parameters in leprosy

OBJECTIVE

To determine the risk factors and clinical significance of anti-PGL-I seropositivity.

DESIGN

A large-scale sero-epidemiological study (COLEP) was carried out in northwest Bangladesh. Blood on filter paper from 1025 newly diagnosed patients was collected before treatment was started and tested with an anti-PGL-I ELISA; the relation between patient determinants and seropositivity was calculated using logistic regression.

RESULTS

The median age was 30 years and the male:female ratio 1.9. Overall, 342 patients (33.4%) were seropositive. The following determinants showed a significant correlation with seropositivity (P < 0-05) in multivariate analysis: sex, age, disability grade, bacterial index and classification according to the World Health Organization (WHO) system. The number and extent of clinical signs correlated with seropositivity, except for the presence of satellite lesions. People with or without a BCG vaccination scar had a similar risk to be seropositive.

CONCLUSION

Serology is a marker for a higher systemic bacterial load and may identify potential infectious sources among patients with few clinical signs. The size of skin lesions was positively correlated with seropositivity. We did not find different levels of seropositivity among patients with one or two skin lesions, neither did we find different levels among patients with or without satellite

Physical Distance, Genetic Relationship, Age, and Leprosy Classification Are Independent Risk Factors for Leprosy in Contacts of Patients with Leprosy

BACKGROUND

Close contacts of patients with leprosy have a higher risk of developing leprosy. Several risk factors have been identified, including genetic relationship and physical distance. Their independent contributions to the risk of developing leprosy, however, have never been sufficiently quantified.

METHODS

Logistic-regression analysis was performed on intake data from a prospective cohort study of 1037 patients newly diagnosed as having leprosy and their 21,870 contacts.

RESULTS

Higher age showed an increased risk, with a bimodal distribution. Contacts of patients with paucibacillary (PB) leprosy with 2-5 lesions (PB2-5) and those with multibacillary (MB) leprosy had a higher risk than did contacts of patients with single-lesion PB leprosy. The core household group had a higher risk than other contacts living under the same roof and next-door neighbors, who again had a higher risk than neighbors of neighbors. A close genetic relationship indicated an increased risk when blood-related children, parents, and siblings were pooled together.

CONCLUSIONS

Age of the contact, the disease classification of the index patient, and physical and genetic distance were independently associated with the risk of a contact acquiring leprosy. Contact surveys in leprosy should be not only focused on household contacts but also extended to neighbors and consanguineous relatives, especially when the patient has PB2-5 or MB leprosy.