TB VACCINES: What’s New?? Dr S G KASI Consultant Pediatrician Bengaluru

Existing TB Vaccine Ineffective BCG introduced in 1921 BCG unreliable against pulmonary TB, which accounts for most TB disease worldwide BCG is not known to protect against latent TB BCG is not recommended for use in infants infected with HIV - increased risk for severe BCG-related complications Despite wide use, BCG has had no apparent impact on the growing global TB epidemic BCG does reduce risk of severe pediatric TB disease, so it should continue to be used until a better TB vaccine is available Global health authorities, including the WHO and the Stop TB Partnership, agree that TB will not be eliminated without new technologies, including a new, more effective vaccine.

TB Vaccine Pipeline Preclinical Phase I Phase II Phase IIb Phase III As of November 2009 Preclinical Phase I Phase II Phase IIb Phase III AERAS-422 Aeras Mtb [∆lysA ∆panCD ∆secA2] Albert Einstein College of Medicine MTBVAC01 [∆phoP, ∆fad D26] University of Zaragoza, Institute Pasteur, TuBerculosis Vaccine Initiative (TBVI) HBHA Institute Pasteur of Lille, INSERM, TBVI Hybrid 56 Statens Serum Institute (SSI), Aeras, Intercell, TBVI HG85 A/B Shanghai H&G Biotech VPM 1002 Max Planck, Vakzine Projekt Mgmt, TBVI rBCG30* UCLA, NIH, NIAID, Aeras AdAg85A McMaster University Hybrid-I+CAF01 SSI Hyvac 4/ AERAS-404 SSI, Sanofi-Pasteur, Aeras, Intercell RUTI Archivel Farma M smegmatis* Hybrid-I+IC31 SSI, TBVI, Intercell M72 GSK, Aeras MVA85A/ AERAS-485 Oxford-Emergent Tuberculosis Consortium (OETC), Aeras AERAS-402/ Crucell Ad35 Crucell, Aeras M vaccae* Immodulon, NIH Prime Boost Post-infection Immunotherapy Preclinical vaccine candidates are not yet in clinical trials, but have been manufactured under Good Manufacturing Practice (GMP) for clinical use and have undergone some preclinical testing that meets regulatory standards. *indicates candidates that have been in clinical trials in the past, but are not currently being tested in clinical trials Source: Tuberculosis Vaccine Candidates – 2009; Stop TB Partnership Working Group on New TB Vaccines

New TB vaccines in Clinical Development

R-bcg prime vaccines:

VPM1002 rBCGDureC:Hly Expresses listeriolysin (Hly) derived from Listeria monocytogenes and enables BCG to escape from the endosome. Made urease-C-deficient to provide the optimal pH for Hly activity . A Phase I clinical trial evaluating the safety and immunogenicity of this vaccine in healthy male subjects has been completed A dose-escalation RCT (Phase 2a)comparing the safety and immunogenicity of VPM1002 and BCG in healthy adults in South Africa is ongoing

AERAS-422 (rBCG) Genetically modify BCG such that it overexpresses one or more major secretory proteins, early targets for the host immune response against M Tb (antigen 85B) . In a Phase I RCT, rBCG30 was well tolerated and had a comparable safety profile to nonrecombinant Tice BCG. Antigen 85B-specific T-cell proliferation and IFN-g ELISpot responses were enhanced and antigen specific CD4+ and CD8+ effector T-cell expansion was demonstrated The antigen 85B-specific T cells induced were also capable of inhibiting the growth of intracellular mycobacteria

AERAS-422 (research strain AFRO-1) Recombinant BCG Danish 1331 strain Expresses perfringolysin O as an endosome escape mechanism Overexpresses immunodominant and protective M. tuberculosis antigens, 85A, 85B and Rv3407 A Phase I clinical trial in healthy human subjects will soon be starting in the USA

Subunit vaccines designed to enhance BCG Enhance the effectiveness of BCG. Regimens would retain BCG vaccination of neonates Involve the delivery of immunodominant mycobacterial antigens to the immune system, using: Viral vectored vaccines Protein – adjuvant vaccines

MVA85A MVA as a delivery system for the mycobacterial antigen 85A Evaluated in a series of Phase I clinical trials in healthy adults in the UK since 2002, including BCG-vaccinated subjects and subjects with LTBI Phase I and IIa clinical trials in target populations in South Africa, The Gambia and Senegal Has been safely administered to high-risk target populations, namely HIV-infected adults, subjects coinfected with HIV and M. tuberculosis and infants

Results of MVA85 so far… High frequencies of antigen-specific IFN-g-producing polyfunctional CD4+ T cells are induced Expansion of a memory population Frequency of antigen-specific cells remains significantly higher than baseline for at least 1 year after vaccination Antigen-specific, IFN-g-producing CD8+ T cells have also been detected A Phase IIb efficacy trial in BCG-vaccinated South African infants is now underway

MVA85A in HIV+ adults A Phase I study evaluating the safety and immunogenicity of MVA85A, a candidate TB vaccine, in HIV-infected adults. BMJ Open 2011;1:e000223. doi:10.1136/ bmjopen-2011-000223 MVA85A was safe in subjects with HIV infection, No clinically significant vaccine-related changes in CD4 count or HIV RNA load in any subjects, Both doses of MVA85A induced an antigen-specific IFN- response that was durable for 24 weeks, The functional quality of the vaccine-induced T cell response in HIV-infected subjects was remarkably comparable with that observed in healthy HIV-uninfected controls

MVA 85A in Infants Dose-Finding Study of the Novel Tuberculosis Vaccine, MVA85A, in Healthy BCG-Vaccinated Infants. JID 2011;203:1832–43 Infants aged 5–12 months were vaccinated intradermally with either of 3 escalating dose schedule of MVA85A, or placebo. MVA85A induced potent, durable T-cell responses, which exceeded prevaccination responses up to 168 days after vaccination. Conclusions. MVA85A was safe and induced robust, polyfunctional, durable CD4 and CD8 T-cell responses in infants. These data support efficacy evaluation of MVA85A to prevent tuberculosis in infancy.

MVA85 & EPI Vaccines Immunogenicity of the Tuberculosis Vaccine MVA85A Is Reduced by Coadministration with EPI Vaccines in a Randomized Controlled Trial in Gambian Infants Sci Transl Med 22 June 2011: Vol. 3, Issue 88, p. 88ra56 Coadministration of MVA85A with EPI vaccines was associated with a significant reduction in MVA85A immunogenicity, but did not affect humoral responses to the EPI vaccines Suggest that modifications to the standard EPI schedule may be required to incorporate a new generation of T cell–inducing vaccines.

AERAS-402/Crucell Ad35 Nonreplicating adenovirus (Ad) type 35 as vector Expressing a fusion protein of mycobacterial antigens 85A, 85B and TB10.4 IM administration of AERAS-402 was well tolerated and induced polyfunctional CD4+ T cells and IFN-g-producing CD8+ T cells in response to antigen stimulation with antigens 85A, 85B and TB10.4

AERAS-402/Crucell Ad35 2 A Phase II trial in South Africa is recruiting HIV-infected, BCG-vaccinated adults and assessing the safety (including effect on CD4 count) and immunogenicity In Kenya, a Phase I and II safety, immunogenicity and efficacy trial in BCG-vaccinated, HIV-uninfected infants is ongoing

Ad5Ag85A Intranasal but not IM administration afforded better protection against M. tuberculosis aerosol challenge than cutaneous BCG and enhanced protection when given as a boost to BCG in both BALB/c mice and guinea pigs A safety and immunogenicity Phase 1 trial in Humans is ongoing in Canada in healthy BCG-vaccinated and unvaccinated subjects

Protein–adjuvant vaccines Adjuvants used may be – aluminium based compounds or immunopotentiating agents eg, TLR ligands, saponins, cytokines and bacterial toxins

M72 Fusion of two proteins, Mtb32 and Mtb39, Formulated in the adjuvant AS02A- oil-in-water emulsion and the immunostimulants 3-deacylated monophosphoryl lipid A (MPL) and QS-21, a detergent purified from the bark of Quillaja saponaria Well tolerated in a Phase I trial of PPD-healthy adult subjects in the USA and induced antigen-specif ic IFN-g and IL-2 production and CD4+ T cells Phase IIa trials in TST-positive healthy adults in a TB-endemic area (South Africa) and of different formulations in the Philippines have also been completed.

Hybrid 1 Fusion protein of antigens 85B and ESAT-6 Hybrid 1, adjuvanted with IC31, in a Phase I trial in PPD-negative healthy adults, was associated with antigen-specific T-cell responses. The T-cell responses were maintained for 2 years Hybrid 1 formulated with a novel liposomal adjuvant, cationic adjuvant formulation (CAF01), is now in an open-label Phase I clinical trial in The Netherlands

HyVac4 Fusion protein of antigen 85B and TB 10.4 HyVac4 formulated in IC31 and given in a prime–boost regimen with BCG was immunogenic and offered enhanced protection to M. tuberculosis aerosol challenge over BCG in guinea pigs HyVac4 with IC31 (AERAS-404) is currently in ongoing Phase I clinical trials

Therapeutic vaccines in clinical trials Mycobacterium vaccae : 1 dose not very effective. 5 doses in BCG-vaccinated, HIV-infected patients in Tanzania demonstrated significant protection against the secondary end point of definite (culture positive) TB, although not against the primary end point of disseminated (bacteremic) disease or against the other secondary end point, probable TB RUTI® (Archivel Farma): detoxified liposomal cellular fragments of M. tuberculosis bacilli. In a double-blind Phase I RCT in BCG-naive healthy men in Spain, RUTI was well tolerated and associated with modestly enhanced responses to PPD and mycobacterial antigens, including ESAT-6 and 85B .

The indian contribution…..

Therapeutic Candidate Vaccine An adjunctive therapeutic vaccine against reactivation and post-treatment relapse tuberculosis. Vaccine 2011 Nov 8. [Epub ahead of print] A recombinant M. tuberculosis cell wall protein (Mce1A), encoded by a gene in the mce1 operon, was tested for its ability to prevent post-treatment TB. At 32 weeks of follow-up, a complete sterilizing protection was observed in lungs of the vaccinated mice The combination of anti-TB drugs and a vaccine may serve as a powerful treatment modality against TB reactivation and relapse.

Delivery of a multivalent scrambled antigen vaccine induces broad spectrum immunity and protection against tuberculosis. Vaccine. 2011 Oct 13;29(44):7759-65. Epub 2011 Aug 16 Synthetic scrambled antigen vaccine (TB-SAVINE), comprised of overlapping, recombined peptides from four M. tuberculosis proteins, Ag85B, ESAT-6, PstS3 and Mpt83, each of which is immunogenic and protective against experimental TB. Construct stimulated CD4 and CD8T cell responses against the individual proteins and M. tuberculosis in C57BL/6 and Balb/c mice, when delivered as DNA, Fowl Pox Virus or Vaccinia Virus vaccines.

Ag85B-ESAT-6 adjuvanted with IC31 Ag85B-ESAT-6 adjuvanted with IC31® promotes strong and long-lived Mycobacterium tuberculosis specific T cell responses in volunteers with previous BCG vaccination or tuberculosis infection. Vaccine. 2011 Mar 3;29(11):2100-9. Epub 2011 Jan 20. Fusion protein Ag85B-ESAT-6 combined with the adjuvant IC31(®), administered at 0 and 2 months Elicited strong antigen-specific T cell responses against Ag85B-ESAT-6 and both the Ag85B and ESAT-6 components, that could be augmented by second vaccination. The strong responses persisted through 32 weeks of follow-up, indicating the induction of a persistent memory response in the vaccine recipients

Novel Prophylactic Vaccine Using a Prime-Boost Method andHemagglutinating Virus of Japan-Envelope against Tuberculosis. Clinical and Developmental Immunology Volume 2011, Article ID 549281, BCG prime followed by IgHSP65+murine IL-12/HVJ-envelope boost Significant protective efficacy (>10, 000-fold versus BCG alone) against TB infection in the lungs of mice. The vaccine increased the number of T cells secreting IFN-γ.

A multistage tuberculosis vaccine that confers efficient protection before and after exposure Nat. Med. DOI: 10.1038/nm.2285 (2011) H56 Vaccine- Ag85B & ESAT6 (early antigens) + Rv2660c, (a latency-associated protein that is stably expressed in the late stages of M. tuberculosis infection) Administered to uninfected CB6F1 mice prior to, and after, BCG vaccination; 6 weeks later the vaccinated mice were exposed to M. tuberculosis. The H56 vaccine was able to promote a T lymphocyte-mediated response against the three protein components of the vaccine, as characterized by a high proportion of polyfunctional CD4+ T cells. Protected against initial illness, but it also controlled reactivation of latent infection and reduced pulmonary levels of the mycobacterium more effectively than vaccination with BCG alone.  

Cellular Immune Responses to Nine Mtb Vaccine Candidates following Intranasal Vaccination. PLoS ONE 6(7): e22718. doi:10.1371/journal.pone.0022718, Published July 25, 2011 Suraj B. Sable, Mani Cheruvu, Subhadra Nandakumar, Sunita Sharma,et al In this study, a comparison of intranasal (i.n.) and subcutaneous (s.c.) vaccination with the BCG vaccine demonstrated that a single moderate dose delivered intranasally induced a stronger and sustained M. tuberculosis-specific T-cell response in lung parenchyma and cervical lymph nodes of BALB/c mice than vaccine delivered subcutaneously.

A Booster Vaccine Expressing a Latency-Associated Antigen Augments BCG Induced Immunity and Confers Enhanced Protection against Tuberculosis Bappaditya Dey., Ruchi Jain., Umesh D. Gupta, V. M. Katoch, V. D. Ramanathan, Anil K. Tyagi Department of Biochemistry, University of Delhi South Campus, New Delhi, India, 2 National JALMA Institute for Leprosy and Other Mycobacterial Diseases, Agra, Uttar Pradesh, India, 3Department of Clinical Pathology, Tuberculosis Research Center, Chennai, Tamil Nadu, India Evaluated the ability of a DNA vaccine expressing a-crystallin- a key latency antigen of Mtb to boost the BCG induced immunity ‘BCG prime – DNA boost’ regimen (B/D) confers robust protection in guinea pigs along with a reduced pathology in comparison to BCG vaccination B/D immunization in mice results in a heightened frequency of PPD and antigen specific multi-functional CD4 T cells (3+) simultaneously producing interferon (IFN)c, tumor necrosis factor (TNF)a and interleukin (IL)2.

Novel TB Vaccines: Cost effective? Cost-effectiveness of novel vaccines for tuberculosis control: a decision analysis study. BMC Public Health 2011, 11:55 http://www.biomedcentral.com/1471-2458/11/55 Chia-Lin Tseng, Olivia Oxlade, Dick Menzies, Anne Aspler, Kevin Schwartzman Conclusions: Investment in an improved TB vaccine is predicted to result in considerable cost savings, as well as a reduction in TB morbidity and TB-related mortality, when added to existing control strategies. For a vaccine with waning efficacy, a prime-boost strategy is more cost-effective in the long term.

Future Vaccination Strategies 1 Pre-exposure vaccination with superior BCG replacement to prevent tuberculosis in early childhood and to delay tuberculosis disease outbreak in adults Pre-exposure boost with subunit vaccine in children primed with BCG to prevent tuberculosis in early childhood and to delay tuberculosis disease outbreak in adults Post-exposure boost with subunit vaccine in adults who had been primed with BCG during early childhood to delay tuberculosis disease outbreak in adults

Future Vaccination Strategies 2 4. Heterologous prime-boost vaccination with superior BCG replacement and subunit vaccine, to achieve sterile eradication 5. Heterologous prime-boost vaccination in individuals with latent infection by prime with superior BCG replacement and subunit vaccine boost to prevent tuberculosis disease outbreak 6. Therapeutic vaccination in adjunct to chemotherapy in patients with active tuberculosis

Tuberculosis Pandemic (2008 data) >2 billion people infected with Mtb 5-10% will reactivate 9.4 million people newly infected (1.4 million were HIV-coinfected) HIV-infected individuals are 20-40 times more likely to reactivate 1.8 million deaths Emergence of MDR-TB and XDR-TB and the interaction of HIV and TB pose a serious risk to TB control www.who.int/features/factfiles/tuberculosis

Goals for Better TB Vaccines Eliminate TB as a public health threat, in line with global targets (<1 case/million), in conjunction with new drugs and diagnostics Safe and effective in preventing TB in children, adolescents and adults, including people with HIV (for whom BCG is unsafe) Protect against all forms of TB – including MDR and XDR In conjunction with new drugs and diagnostics TB will not be eliminated without a new TB vaccine Vaccines can prevent onset and reduce transmission of disease

Attributes of an ideal TB vaccine Safety and efficacy in at-risk infants, children and adults (including HIV infection); Effectiveness against all forms of TB including pulmonary, MDR-TB, XMDR, LTBI Logistically practical (timing of vaccination and noninterference with other childhood immunizations), Formulation that can be feasibly manufactured on a mass scale Can be stored and administered under low- technology conditions.

Future Vaccination Strategies ‘heterologous prime-boost strategy’ ‘PRIMED’ with BCG or recombinant/genetically modified BCG (rBCG) ‘BOOSTED’, using some of the antigens derived from MTb, but delivered in a different way, hence ‘heterologous’

New TB vaccines in Clinical Development