Safety and immunogenicity of the adjunct therapeutic vaccine ID93 + GLA-SE in adults who have completed treatment for tuberculosis: a randomised, double-blind, placebo-controlled, phase 2a trial.

BACKGROUND: A therapeutic vaccine that prevents recurrent tuberculosis would be a major advance in the development of shorter treatment regimens. We aimed to assess the safety and immunogenicity of the ID93 + GLA-SE vaccine at various doses and injection schedules in patients with previously treated tuberculosis. METHODS: This randomised, double-blind, placebo-controlled, phase 2a trial was conducted at three clinical sites near Cape Town, South Africa. Patients were recruited at local clinics after receiving 4 months of tuberculosis treatment, and screened for eligibility after providing written informed consent. Participants were aged 18-60 years, BCG-vaccinated, HIV-uninfected, and diagnosed with drug-sensitive pulmonary tuberculosis. Eligible patients had completed standard treatment for pulmonary tuberculosis in the past 28 days. Participants were enrolled after completing standard treatment and randomly assigned sequentially to receive vaccine or placebo in three cohorts: 2 µg intramuscular ID93 + 2 µg GLA-SE on days 0 and 56 (cohort 1); 10 µg ID93 + 2 µg GLA-SE on days 0 and 56 (cohort 2); 2 µg ID93 + 5 µg GLA-SE on days 0 and 56 and placebo on day 28 (cohort 3); 2 µg ID93 + 5 µg GLA-SE on days 0, 28, and 56 (cohort 3); or placebo on days 0 and 56 (cohorts 1 and 2), with the placebo group for cohort 3 receiving an additional injection on day 28. Randomisation was in a ratio of 3:1 for ID93 + GLA-SE and saline placebo in cohorts 1 and 2, and in a ratio of 3:3:1 for (2 ×) ID93 + GLA-SE, (3 ×) ID93 + GLA-SE, and placebo in cohort 3. The primary outcomes were safety and immunogenicity (vaccine-specific antibody response and T-cell response). For the safety outcome, participants were observed for 30 min after each injection, injection site reactions and systemic adverse events were monitored until day 84, and serious adverse events and adverse events of special interest were monitored for 6 months after the last injection. Vaccine-specific antibody responses were measured by serum ELISA, and T-cell responses after stimulation with vaccine antigens were measured in cryopreserved peripheral blood mononuclear cells specimens using intracellular cytokine staining followed by flow cytometry. This study is registered with ClinicalTrials.gov, number NCT02465216. FINDINGS: Between June 17, 2015, and May 30, 2016, we assessed 177 patients for inclusion. 61 eligible patients were randomly assigned to receive: saline placebo (n=5) or (2 ×) 2 µg ID93 + 2 µg GLA-SE (n=15) on days 0 and 56 (cohort 1); saline placebo (n=2) or (2 ×) 10 µg ID93 + 2 µg GLA-SE (n=5) on days 0 and 56 (cohort 2); saline placebo (n=5) on days 0, 28 and 56, or 2 µg ID93 + 5 µg GLA-SE (n=15) on days 0 and 56 and placebo injection on day 28, or (3 ×) 2 µg ID93 + 5 µg GLA-SE (n=14) on days 0, 28, and 56 (cohort 3). ID93 + GLA-SE induced robust and durable antibody responses and specific, polyfunctional CD4 T-cell responses to vaccine antigens. Two injections of the 2 µg ID93 + 5 µg GLA-SE dose induced antigen-specific IgG and CD4 T-cell responses that were significantly higher than those with placebo and persisted for the 6-month study duration. Mild to moderate injection site pain was reported after vaccination across all dose combinations, and induration and erythema in patients given 2 µg ID93 + 5 µg GLA-SE in two or three doses. One participant had grade 3 erythema and induration at the injection site. No vaccine-related serious adverse events were observed. INTERPRETATION: Vaccination with ID93 + GLA-SE was safe and immunogenic for all tested regimens. These data support further evaluation of ID93 + GLA-SE in therapeutic vaccination strategies to improve tuberculosis treatment outcomes. FUNDING: Wellcome Trust (102028/Z/13/Z).

Live-attenuated Mycobacterium tuberculosis vaccine MTBVAC versus BCG in adults and neonates: a randomised controlled, double-blind dose-escalation trial.

BACKGROUND: Infants are a key target population for new tuberculosis vaccines. We assessed the safety and immunogenicity of the live-attenuated Mycobacterium tuberculosis vaccine candidate MTBVAC in adults and infants in a region where transmission of tuberculosis is very high. METHODS: We did a randomised, double-blind, BCG-controlled, dose-escalation trial at the South African Tuberculosis Vaccine Initiative site near Cape Town, South Africa. Healthy adult community volunteers who were aged 18-50 years, had received BCG vaccination as infants, were HIV negative, had negative interferon-γ release assay (IGRA) results, and had no personal history of tuberculosis or current household contact with someone with tuberculosis were enrolled in a safety cohort. Infants born to HIV-negative women with no personal history of tuberculosis or current household contact with a person with tuberculosis and who were 96 h old or younger, generally healthy, and had not yet received routine BCG vaccination were enrolled in a separate infant cohort. Eligible adults were randomly assigned (1:1) to receive either BCG Vaccine SSI (5 × 105 colony forming units [CFU] of Danish strain 1331 in 0·1 mL diluent) or MTBVAC (5 × 105 CFU in 0·1 mL) intradermally in the deltoid region of the arm. After favourable review of 28-day reactogenicity and safety data in the adult cohort, infants were randomly assigned (1:3) to receive either BCG Vaccine SSI (2·5 × 105 CFU in 0·05 mL diluent) or MTBVAC in three sequential cohorts of increasing MTBVAC dose (2·5 × 103 CFU, 2·5 × 104 CFU, and 2·5 × 105 CFU in 0·05 mL) intradermally in the deltoid region of the arm. QuantiFERON-TB Gold In-Tube IGRA was done on days 180 and 360. For both randomisations, a pre-prepared block randomisation schedule was used. Participants (and their parents or guardians in the case of infant participants), investigators, and other clinical and laboratory staff were masked to intervention allocation. The primary outcomes, which were all measured in the infant cohort, were solicited and unsolicited local adverse events and serious adverse events until day 360; non-serious systemic adverse events until day 28 and vaccine-specific CD4 and CD8 T-cell responses on days 7, 28, 70, 180, and 360. Secondary outcomes measured in adults were local injection-site and systemic reactions and haematology and biochemistry at study day 7 and 28. Safety analyses and immunogenicity analyses were done in all participants who received a dose of vaccine. This trial is registered with ClinicalTrials.gov, number NCT02729571. FINDINGS: Between Sept 29, 2015, and Nov 16, 2015, 62 adults were screened and 18 were enrolled and randomly assigned, nine each to the BCG and MTBVAC groups. Between Feb 12, 2016, and Sept 21, 2016, 36 infants were randomly assigned-eight to the BCG group, nine to the 2·5 × 103 CFU MTBVAC group, nine to the 2·5 × 104 CFU group, and ten to the 2·5 × 105 CFU group. Mild injection-site reactions occurred only in infants in the BCG and the 2·5 × 105 CFU MTBVAC group, with no evidence of local or regional injection-site complications. Systemic adverse events were evenly distributed across BCG and MTBVAC dose groups, and were mostly mild in severity. Eight serious adverse events were reported in seven vaccine recipients (one adult MTBVAC recipient, one infant BCG recipient, one infant in the 2·5 × 103 CFU MTBVAC group, two in the 2·5 × 104 CFU MTBVAC group, and two in the 2·5 × 105 CFU MTBVAC group), including one infant in the 2·5 × 103 CFU MTBVAC group treated for unconfirmed tuberculosis and one in the 2·5 × 105 CFU MTBVAC group treated for unlikely tuberculosis. One infant died as a result of possible viral pneumonia. Vaccination with all MTBVAC doses induced durable antigen-specific T-helper-1 cytokine-expressing CD4 cell responses in infants that peaked 70 days after vaccination and were detectable 360 days after vaccination. For the highest MTBVAC dose (ie, 2·5 × 105 CFU), these responses exceeded responses induced by an equivalent dose of the BCG vaccine up to 360 days after vaccination. Dose-related IGRA conversion was noted in three (38%) of eight infants in the 2·5 × 103 CFU MTBVAC group, six (75%) of eight in the 2·5 × 104 CFU MTBVAC group, and seven (78%) of nine in the 2·5 × 105 CFU MTBVAC group at day 180, compared with none of seven infants in the BCG group. By day 360, IGRA reversion had occurred in all three infants (100%) in the 2·5 × 103 CFU MTBVAC group, four (67%) of the six in the 2·5 × 104 CFU MTBVAC group, and three (43%) of the seven in the 2·5 × 105 CFU MTBVAC group. INTERPRETATION: MTBVAC had acceptable reactogenicity, and induced a durable CD4 cell response in infants. The evidence of immunogenicity supports progression of MTBVAC into larger safety and efficacy trials, but also confounds interpretation of tests for M tuberculosis infection, highlighting the need for stringent endpoint definition. FUNDING: Norwegian Agency for Development Cooperation, TuBerculosis Vaccine Initiative, UK Department for International Development, and Biofabri.

Dose Optimization of H56:IC31 Vaccine for Tuberculosis-Endemic Populations. A Double-Blind, Placebo-controlled, Dose-Selection Trial.

RATIONALE: Global tuberculosis (TB) control requires effective vaccines in TB-endemic countries, where most adults are infected with Mycobacterium tuberculosis (M.tb). OBJECTIVES: We sought to define optimal dose and schedule of H56:IC31, an experimental TB vaccine comprising Ag85B, ESAT-6, and Rv2660c, for M.tb-infected and M.tb-uninfected adults. METHODS: We enrolled 98 healthy, HIV-uninfected, bacillus Calmette-Guérin-vaccinated, South African adults. M.tb infection was defined by QuantiFERON-TB (QFT) assay. QFT-negative participants received two vaccinations of different concentrations of H56 in 500 nmol of IC31 to enable dose selection for further vaccine development. Subsequently, QFT-positive and QFT-negative participants were randomized to receive two or three vaccinations to compare potential schedules. Participants were followed for safety and immunogenicity for 292 days. MEASUREMENTS AND MAIN RESULTS: H56:IC31 showed acceptable reactogenicity profiles irrespective of dose, number of vaccinations, or M.tb infection. No vaccine-related severe or serious adverse events were observed. The three H56 concentrations tested induced equivalent frequencies and functional profiles of antigen-specific CD4 T cells. ESAT-6 was only immunogenic in QFT-negative participants who received three vaccinations. CONCLUSIONS: Two or three H56:IC31 vaccinations at the lowest dose induced durable antigen-specific CD4 T-cell responses with acceptable safety and tolerability profiles in M.tb-infected and M.tb-uninfected adults. Additional studies should validate applicability of vaccine doses and regimens to both QFT-positive and QFT-negative individuals. Clinical trial registered with www.clinicaltrials.gov (NCT01865487).

Elevated IgG Responses in Infants Are Associated With Reduced Prevalence of Mycobacterium tuberculosis Infection.

BACKGROUND: It is unclear whether antibodies can prevent Mycobacterium tuberculosis (Mtb) infection. In this study, we examined the relationship between total plasma IgG levels, IgG elicited by childhood vaccines and soil-transmitted helminths, and Mtb infection prevalence, defined by positive QuantiFERON (QFT) test. METHODS: We studied 100 Mtb uninfected infants, aged 4-6 months. Ten infants (10%) converted to positive QFT test (QFT+) within 2 years of follow-up for Mtb infection. Antibody responses in plasma samples acquired at baseline and tuberculosis investigation were analyzed by enzyme-linked immunosorbent assay and ImmunoCAP® assay. RESULTS: QFT- infants displayed a significant increase in total IgG titers when re-tested, compared to IgG titers at baseline, which was not observed in QFT+ infants. Bacille Calmette-Guérin (BCG) vaccine-specific IgG2 and live-attenuated measles vaccine-specific IgG were raised in QFT- infants, and infants who acquired an Mtb infection did not appear to launch a BCG-specific IgG2 response. IgG titers against the endemic helminth Ascaris lumbricoides increased from baseline to QFT re-testing in all infants. CONCLUSION: These data show raised IgG associates with a QFT-status. Importantly, this effect was also associated with a trend showing raised IgG titers to BCG and measles vaccine. Our data suggest a possible protective association between raised antibody titers and acquisition of Mtb infection, potentially mediated by exposure to antigens both related and unrelated to Mtb.

Safety and immunogenicity of the novel tuberculosis vaccine ID93 + GLA-SE in BCG-vaccinated healthy adults in South Africa: a randomised, double-blind, placebo-controlled phase 1 trial.

BACKGROUND: A vaccine that prevents pulmonary tuberculosis in adults is needed to halt transmission in endemic regions. This trial aimed to assess the safety and immunogenicity of three administrations at varying doses of antigen and adjuvant of an investigational vaccine (ID93 + GLA-SE) compared with placebo in previously BCG-vaccinated healthy adults in a tuberculosis endemic country. METHODS: In this randomised, double-blind, placebo-controlled phase 1 trial, we enrolled HIV-negative, previously BCG-vaccinated adults (aged 18-50 years), with no evidence of previous or current tuberculosis disease, from among community volunteers in the Worcester region of Western Cape, South Africa. Participants were randomly assigned to receive varying doses of ID93 + GLA-SE or saline placebo at day 0, day 28, and day 112. Enrolment into each cohort was sequential. Cohort 1 participants were Mycobacterium tuberculosis uninfected (as defined by negative QuantiFERON [QFT] status), and received 10 µg ID93 plus 2 µg GLA-SE, or placebo; in cohorts 2-4, QFT-negative or positive participants received escalating doses of vaccine or placebo. Cohort 2 received 2 µg ID93 plus 2 µg GLA-SE; cohort 3 received 10 µg ID93 plus 2 µg GLA-SE; and cohort 4 received 10 µg ID93 plus 5 µg GLA-SE. Dose cohort allocation was sequential; randomisation within a cohort was according to a randomly-generated sequence (3 to 1 in cohort 1, 5 to 1 in cohorts 2-4). The primary endpoint was safety of ID93 + GLA-SE as defined by solicited and unsolicited adverse events up to 28 days after each study injection and serious adverse events for the duration of the study. Specific immune responses were measured by intracellular cytokine staining, flow cytometry, and ELISA. All analyses were done according to intention to treat, with additional per-protocol analyses for immunogenicity outcomes. This trial is registered with ClinicalTrials.gov, number NCT01927159. FINDINGS: Between Aug 30, 2013, and Sept 4, 2014, 227 individuals consented to participate; 213 were screened (three participants were not included as study number was already met and 11 withdrew consent before screening occurred, mostly due to relocation or demands of employment). 66 healthy, HIV-negative adults were randomly allocated to receive the vaccine (n=54) or placebo (n=12). All study participants received day 0 and day 28 study injections; five participants did not receive an injection on day 112. ID93 + GLA-SE was well tolerated; no severe or serious vaccine-related adverse events were recorded. Vaccine dose did not affect frequency or severity of adverse events, but mild injection site adverse events and flu-like symptoms were common in M tuberculosis-infected participants compared with uninfected participants. Vaccination induced durable antigen-specific IgG and Th1 cellular responses, which peaked after two administrations. Vaccine dose did not affect magnitude, kinetics, or profile of antibody and cellular responses. Earlier boosting and greater T-cell differentiation and effector-like profiles were seen in M tuberculosis-infected than in uninfected vaccinees. INTERPRETATION: Escalating doses of ID93 + GLA-SE induced similar antigen-specific CD4-positive T cell and humoral responses, with an acceptable safety profile in BCG-immunised, M tuberculosis-infected individuals. The T-cell differentiation profiles in M tuberculosis-infected vaccinees suggest priming through natural infection. While cohort sample sizes in this phase 1 trial were small and results should be interpreted in context, these data support efficacy testing of two administrations of the lowest (2 µg) ID93 vaccine dose in tuberculosis endemic populations. FUNDING: Aeras and the Paul G Allen Family Foundation.

Evaluation of Xpert® MTB/RIF Assay in Induced Sputum and Gastric Lavage Samples from Young Children with Suspected Tuberculosis from the MVA85A TB Vaccine Trial.

OBJECTIVE: Diagnosis of childhood tuberculosis is limited by the paucibacillary respiratory samples obtained from young children with pulmonary disease. We aimed to compare accuracy of the Xpert® MTB/RIF assay, an automated nucleic acid amplification test, between induced sputum and gastric lavage samples from young children in a tuberculosis endemic setting. METHODS: We analyzed standardized diagnostic data from HIV negative children younger than four years of age who were investigated for tuberculosis disease near Cape Town, South Africa [2009-2012]. Two paired, consecutive induced sputa and early morning gastric lavage samples were obtained from children with suspected tuberculosis. Samples underwent Mycobacterial Growth Indicator Tube [MGIT] culture and Xpert MTB/RIF assay. We compared diagnostic yield across samples using the two-sample test of proportions and McNemar's χ2 test; and Wilson's score method to calculate sensitivity and specificity. RESULTS: 1,020 children were evaluated for tuberculosis during 1,214 admission episodes. Not all children had 4 samples collected. 57 of 4,463[1.3%] and 26 of 4,606[0.6%] samples tested positive for Mycobacterium tuberculosis on MGIT culture and Xpert MTB/RIF assay respectively. 27 of 2,198[1.2%] and 40 of 2,183[1.8%] samples tested positive [on either Xpert MTB/RIF assay or MGIT culture] on induced sputum and gastric lavage samples, respectively. 19/1,028[1.8%] and 33/1,017[3.2%] admission episodes yielded a positive MGIT culture or Xpert MTB/RIF assay from induced sputum and gastric lavage, respectively. Sensitivity of Xpert MTB/RIF assay was 8/30[26.7%; 95% CI: 14.2-44.4] for two induced sputum samples and 7/31[22.6%; 11.4-39.8] [p = 0.711] for two gastric lavage samples. Corresponding specificity was 893/893[100%;99.6-100] and 885/890[99.4%;98.7-99.8] respectively [p = 0.025]. CONCLUSION: Sensitivity of Xpert MTB/RIF assay was low, compared to MGIT culture, but diagnostic performance of Xpert MTB/RIF did not differ sufficiently between induced sputum and gastric lavage to justify selection of one sampling method over the other, in young children with suspected pulmonary TB. TRIAL REGISTRATION: ClinicalTrials.gov NCT00953927.

First-in-human trial of the post-exposure tuberculosis vaccine H56:IC31 in Mycobacterium tuberculosis infected and non-infected healthy adults.

BACKGROUND: H56:IC31 is a candidate tuberculosis vaccine comprising a fusion protein of Ag85B, ESAT-6 and Rv2660c, formulated in IC31 adjuvant. This first-in-human, open label phase I trial assessed the safety and immunogenicity of H56:IC31 in healthy adults without or with Mycobacterium tuberculosis (M.tb) infection. METHODS: Low dose (15 µg H56 protein in 500 nmol IC31) or high dose (50 µg H56, 500 nmol IC31) vaccine was administered intramuscularly thrice, at 56-day intervals. Antigen-specific T cell responses were measured by intracellular cytokine staining and antibody responses by ELISA. RESULTS: One hundred and twenty-six subjects were screened and 25 enrolled and vaccinated. No serious adverse events were reported. Nine subjects (36%) presented with transient cardiovascular adverse events. The H56:IC31 vaccine induced antigen-specific IgG responses and Th1 cytokine-expressing CD4(+) T cells. M.tb-infected vaccinees had higher frequencies of H56-induced CD4(+) T cells than uninfected vaccinees. Low dose vaccination induced more polyfunctional (IFN-γ(+)TNF-α(+)IL-2(+)) and higher frequencies of H56-specific CD4(+) T cells compared with high dose vaccination. A striking increase in IFN-γ-only-expressing CD4(+) T cells, displaying a CD45RA(-)CCR7(-) effector memory phenotype, emerged after the second high-dose vaccination in M.tb-infected vaccinees. TNF-α(+)IL-2(+) H56-specific memory CD4(+) T cells were detected mostly after low-dose H56 vaccination in M.tb-infected vaccinees, and predominantly expressed a CD45RA(-)CCR7(+) central memory phenotype. Our results support further clinical testing of H56:IC31.