Adjunct immune therapy of first-diagnosed TB, relapsed TB, treatment-failed TB, multidrug-resistant TB and TB/HIV

Dzherelo (Immunoxel) as adjunctive therapy to standard antituberculosis treatment in patients with pulmonary tuberculosis: a systematic review and meta-analysis of clinical trials

BACKGROUND

Dzherelo (Immunoxel) is one of the few approved immunomodulators that has been shown to produce positive treatment outcomes in patients with tuberculosis (TB). The aim of this review was to assess the effectiveness of Immunoxel used as adjunct therapy with conventional anti-TB therapy for the treatment of pulmonary TB.

METHODS

Comprehensive search was conducted in different major databases: PubMed (MEDLINE), EMBASE (OVID), Cochrane Central Register of Controlled Trials (CENTRAL), Scopus (Elsevier). We also searched Google Scholar along with trial registries and hand-searched the reference list of identified original research as well as review articles. Conference proceedings of relevant TB and lung disease annual conferences were also screened. Two independent authors extracted outcome data using a standardised extraction form. Relative risk (RR), mean difference (MD) and standardised mean difference (SMD) with a 95% confidence interval (CI) were used as measures of effect. We assessed certainty of evidence using GRADE.

RESULTS

Six clinical trials, which met the criteria for the review, were identified, and these provided data for the review. Overall results from the six trials that compared antituberculosis treatment (ATT) alone versus ATT and Immunoxel, and ATT and placebo versus ATT and Immunoxel showed an increased number of patients becoming sputum-negative in the Immunoxel group (RR 3.19; 95% CI 2.44 to 4.17; 488 participants). There was also reduction in body temperature among patients receiving Immunoxel compared to ATT alone (MD -0.20, 95% CI -0.22 to -0.18, 345 participants). However, there were no differences in body weight changes across all the studies (MD 5.65; 95% CI -0.80 to 12.11; 382 participants).

CONCLUSION

Current evidence indicates that the use of Immunoxel as an adjunctive treatment in patients with pulmonary tuberculosis has the potential to enhance the efficacy of antituberculosis treatment. However, well-designed, conducted and adequately powered clinical trials are needed to establish the effectiveness of this adjunctive treatment.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number: CRD42019127823.

Modulation of immune responses using adjuvants to facilitate therapeutic vaccination

Therapeutic vaccination offers great promise as an intervention for a diversity of infectious and non-infectious conditions. Given that most chronic health conditions are thought to have an immune component, vaccination can at least in principle be proposed as a therapeutic strategy. Understanding the nature of protective immunity is of vital importance, and the progress made in recent years in defining the nature of pathological and protective immunity for a range of diseases has provided an impetus to devise strategies to promote such responses in a targeted manner. However, in many cases, limited progress has been made in clinical adoption of such approaches. This in part results from a lack of safe and effective vaccine adjuvants that can be used to promote protective immunity and/or reduce deleterious immune responses. Although somewhat simplistic, it is possible to divide therapeutic vaccine approaches into those targeting conditions where antibody responses can mediate protection and those where the principal focus is the promotion of effector and memory cellular immunity or the reduction of damaging cellular immune responses as in the case of autoimmune diseases. Clearly, in all cases of antigen-specific immunotherapy, the identification of protective antigens is a vital first step. There are many challenges to developing therapeutic vaccines beyond those associated with prophylactic diseases including the ongoing immune responses in patients, patient heterogeneity, and diversity in the type and stage of disease. If reproducible biomarkers can be defined, these could allow earlier diagnosis and intervention and likely increase therapeutic vaccine efficacy. Current immunomodulatory approaches related to adoptive cell transfers or passive antibody therapy are showing great promise, but these are outside the scope of this review which will focus on the potential for adjuvanted therapeutic active vaccination strategies.

Phase III, placebo-controlled, randomized, double-blind trial of tableted, therapeutic TB vaccine (V7) containing heat-killed M. vaccae administered daily for one month

Objective

Immunotherapy of tuberculosis (TB) to shorten treatment duration represents an unmet medical need. Orally delivered, tableted TB vaccine (V7) containing heat-killed Mycobacterium vaccae (NCTC 11659) has been demonstrated in prior clinical studies to be safe and fast-acting immune adjunct.

Methods

The outcome of Phase III trial of V7 containing 10 µg of hydrolyzed M. vaccae was evaluated in 152 patients randomized at 2:1 ratio: V7 (N = 100), placebo (N = 52). Both arms received conventional 1st or 2nd line TB drugs co-administered with daily pill of V7 or placebo.

Results

After one month mycobacterial clearance was observed in 68% (P < 0.0001) and 23.1% (P = 0.04) of patients on V7 and placebo. Stratified conversion rates in V7 recipients with drug-sensitive and multidrug-resistant TB were 86.7% and 55.6% vs 27.2% and 15% in placebo. Patients on V7 gained on average 2.4 kg (P < 0.0001) vs 0.3 kg (P = 0.18) in placebo. Improvements in hemoglobin levels, erythrocyte sedimentation rate and leukocyte counts were significantly better than in controls. Liver function tests revealed that V7 can prevent chemotherapy-induced hepatic damage.

Conclusion

Oral M. vaccae is safe, can overcome TB-associated weight loss and inflammation, reduce hepatotoxicity of TB drugs, improve sputum conversion three-fold OR 3.15; 95%CI (2.3,4.6), and cut treatment length by at least six-fold. Longer follow-up studies might be needed to further substantiate our findings (Clinicaltrials.gov: NCT01977768).

Meeting report: 5th Global Forum on TB Vaccines, 20-23 February 2018, New Delhi India

The 5th Global Forum on TB Vaccines was held in New Delhi, India from 20 to 23 February 2018. This was the largest Global Forum on TB Vaccines to date with nearly 350 participants from more than 30 countries. The program included over 60 speakers in 12 special, plenary and breakout sessions and 72 posters. This Global Forum brought a great sense of momentum and excitement to the field. New vaccines are in clinical trials, new routes of delivery are being tested, novel assays and biomarker signatures are being developed, and the results from the first prevention of infection clinical trial with the H4:IC31 vaccine candidate and BCG revaccination were presented. Speakers and participants acknowledged the significant challenges that the TB vaccine R&D field continues to face - including limited funding, and the need for novel effective vaccine candidates and tools such as improved diagnostics and biomarkers to accurately predict protective efficacy. New solutions and approaches to address these challenges were discussed. The following report presents highlights from talks presented at this Global Forum. A full program, abstract book and presentations (where publicly available) from the Forum may be found at tbvaccinesforum.org.

Immunotherapy for tuberculosis: future prospects

Tuberculosis (TB) is still a major global health problem. A third of the world’s population is infected with Mycobacterium tuberculosis. Only ~10% of infected individuals develop TB but there are 9 million TB cases with 1.5 million deaths annually. The standard prophylactic treatment regimens for latent TB infection take 3–9 months, and new cases of TB require at least 6 months of treatment with multiple drugs. The management of latent TB infection and TB has become more challenging because of the spread of multidrug-resistant and extremely drug-resistant TB. Intensified efforts to find new TB drugs and immunotherapies are needed. Immunotherapies could modulate the immune system in patients with latent TB infection or active disease, enabling better control of M. tuberculosis replication. This review describes several types of potential immunotherapies with a focus on those which have been tested in humans.

Morphological changes in experimental tuberculosis resulting from treatment with quercetin and polyvinylpyrrolidone

RESEARCH OBJECTIVE

Morphological study of tissue necrosis stages in experimental organ-preserving tuberculosis pharmacotherapy using Quercetin and Polyvinylpyrrolidone (QP).

BACKGROUND AND METHODS

32 laboratory mice of C57BL/6JLacSto strain were used in the experiment. The animals were divided into five groups, six to seven mice in each: group 1- Mycobacterium tuberculosis (MBT) uninfected mice; group 2- MBT infected mice; group 3- MBT infected and treated with antituberculosis preparation (ATP); group 4- MBT infected and QP treated; group 5- MBT infected and treated with ATP and QP. The mice were infected through caudal vein injection with MTB H37Rv strain. The preparation QP, which belongs to the capillary-stabilizing-remedy group, was used for the research. The ATP were izoniazid and streptomycin.

RESULTS

QP produced a strict delineation of caseous necrosis from the unaffected parts of the connective tissue with fibrosis in the center and a large number of Langerhans cells, which was not observed in the control groups without QP. The combination of QP and ATP had more pronounced effects. In MBT-infected mice, where QP was not used, unlike the group where QP was used, adipose dystrophy of hepatocytes was observed. Thus, the hepatoprotective effect of QP against TB can be suggested.

CONCLUSION

QP produces a clear delineation of caseous necrosis from an uninfected tissue by connective-tissue formation, and by forming fibrotic tissue in the center of epithelioid cells that prevents further TB dissemination by enhancing TB pharmacotherapy.

Tuberculosis vaccine development at a divide

PURPOSE OF REVIEW

Tuberculosis (TB) remains a major health threat that will only be defeated by a combination of better drugs, diagnostics and vaccines. The only licensed TB vaccine, bacille Calmette-Guérin (BCG), protects against extrapulmonary TB in infants.

RECENT FINDINGS

Novel vaccine candidates that could protect against pulmonary TB either in TB naïve or in latent TB-infected healthy individuals have been developed and are currently being assessed in clinical trials. Subunit booster vaccines are either based on viral vectors expressing TB-specific antigens or on TB-protein antigens in adjuvants. Subunit vaccines are administered on top of BCG. Replacement vaccines for BCG are recombinant viable BCG or Mycobacterium tuberculosis. Several candidates are undergoing, or will soon start, phase IIb assessment for efficacy. The first vaccine candidate, MVA85A, to complete a phase IIb trial, unfortunately failed to show protection against TB in infants. Therapeutic vaccines composed of killed mycobacterial preparations target patients with complicated TB in adjunct to drug treatment.

SUMMARY

With increasing numbers of TB vaccine candidates in clinical trials, financial, regulatory and infrastructural issues arise, which would be best tackled by a global strategy. In addition, selection of the most promising vaccine candidates for further clinical development gains increasing importance.

Novel drugs against tuberculosis: a clinician's perspective

The United Nations Millennium Development Goal of reversing the global spread of tuberculosis by 2015 has been offset by the rampant re-emergence of drug-resistant tuberculosis, in particular fluoroquinolone-resistant multidrug-resistant and extensively drug-resistant tuberculosis. After decades of quiescence in the development of antituberculosis medications, bedaquiline and delamanid have been conditionally approved for the treatment of drug-resistant tuberculosis, while several other novel compounds (AZD5847, PA-824, SQ109 and sutezolid) have been evaluated in phase II clinical trials. Before novel drugs can find their place in the battle against drug-resistant tuberculosis, linezolid has been compassionately used with success in the treatment of fluoroquinolone-resistant multidrug-resistant tuberculosis. This review largely discusses six novel drugs that have been evaluated in phase II and III clinical trials, with focus on the clinical evidence for efficacy and safety, potential drug interactions, and prospect for using multiple novel drugs in new regimens.

Randomized, placebo-controlled Phase II trial of heat-killed Mycobacterium vaccae (Immodulon batch) formulated as an oral pill (V7)

AIM

A 1-month Phase II trial was conducted in 41 patients with pulmonary TB who were randomized into treatment (n = 20) and placebo (n = 21) arms to investigate the safety and efficacy of an orally-administered therapeutic TB vaccine (V7) containing 10 µg heat-killed Mycobacterium vaccae provided by Immodulon Therapeutics Ltd (London, UK).

MATERIALS & METHODS

Both arms received conventional anti-TB therapy administered along with a daily pill of V7 or placebo. The subject population had four categories of TB: drug-sensitive TB; retreated TB; drug-resistant TB; and TB with HIV distributed in V7 and placebo arms at 9:4:7:6 and 14:1:6:8 ratios, respectively.

RESULTS

The mycobacterial clearance in sputum smears was observed in 72.2% (p < 0.0001) and 19% (p = 0.03) of patients on V7 and placebo, respectively. The average weight accrual among V7 recipients was 2.6 kg (p = 0.002) versus -0.2 kg (p = 0.69) in the control group. Except reduction in fever and increased lymphocyte counts, the changes in other secondary end points, such as hemoglobin, erythrocyte sedimentation rate and leukocyte counts, were not statistically different, although the proportion of patients responding favorably to V7 was invariably higher compared with placebo (p = 0.002). In control patients, no difference from baseline levels was noted except decreased hemoglobin content (p = 0.02).

CONCLUSION

Oral M. vaccae was safe and has potential as an adjunct immunotherapy, targeting mucosal immunity, to improve efficacy and shorten treatment duration of TB chemotherapy.

Randomized, placebo-controlled phase II trial of heat-killed Mycobacterium vaccae (Longcom batch) formulated as an oral pill (V7)

One-month Phase II trial was conducted in 43 sputum smear-positive patients with pulmonary tuberculosis randomized into treatment (n = 22) and placebo (n = 21) arms to investigate the safety and efficacy of an orally-administered therapeutic TB vaccine (V7) containing 10 μg of heat-killed Mycobacterium vaccae provided by Longcom company. Immunotherapy and control groups comprised 8 newly diagnosed (1stDx TB; 18.6%), 6 re-treated (RTB; 14%), and 29 multidrug-resistant (MDR-TB; 67.4%) cases distributed at 5:4:13 and 3:2:16 ratios, respectively. Both arms received conventional TB drugs administered under directly observed therapy. The average weight gain in V7 arm was modest, but statistically significant (0.6 kg; p = 0.004), while placebo patients lost 0.1 kg (p = 0.77). Except defervescence and increased lymphocyte percentage, other secondary endpoints such as erythrocyte sedimentation rate (ESR), leukocyte counts and hemoglobin content were not significantly affected. In control patients only one secondary endpoint, ESR, has improved. After one month mycobacterial clearance in sputum smears was observed in 31.8% (p = 0.03) and 9.5% (p = 0.83) of patients on V7 and placebo. However, the difference between outcomes in two arms was below significance threshold (p = 0.07). Thus, larger population of patients with prolonged follow-up is required to support these preliminary findings.