Respiratory syncytial virus market

Respiratory Syncytial Virus Infection: Treatments and Clinical Management

Respiratory syncytial virus (RSV) is a major healthcare concern, especially for immune-compromised individuals and infants below 5 years of age. Worldwide, it is known to be associated with incidences of morbidity and mortality in infants. Despite the seriousness of the issue and continuous rigorous scientific efforts, no approved vaccine or available drug is fully effective against RSV. The purpose of this review article is to provide insights into the past and ongoing efforts for securing effective vaccines and therapeutics against RSV. The readers will be able to confer the mechanism of existing therapies and the loopholes that need to be overcome for future therapeutic development against RSV. A methodological approach was applied to collect the latest data and updated results regarding therapeutics and vaccine development against RSV. We outline the latest throughput vaccination technologies and prophylactic development efforts linked with RSV. A range of vaccination approaches with the already available vaccine (with limited use) and those undergoing trials are included. Moreover, important drug regimens used alone or in conjugation with adjuvants or vaccines are also briefly discussed. After reading this article, the audience will be able to understand the current standing of clinical management in the form of the vaccine, prophylactic, and therapeutic candidates against RSV. An understanding of the biological behavior acting as a reason behind the lack of effective therapeutics against RSV will also be developed. The literature indicates a need to overcome the limitations attached to RSV clinical management, drugs, and vaccine development that could be explained by dealing with the challenges of current study designs with continuous improvement and further work and approval on novel therapeutic applications.

Evolutionary dynamics of group A and B respiratory syncytial virus in China, 2009-2018

Respiratory syncytial virus (RSV) is a major cause of acute respiratory tract infections in children and is a public health threat globally. To investigate the spatiotemporal dynamics of RSV evolution, we performed systematic phylogenetic analysis using all available sequences from the GenBank database, together with sequences from Shanghai, China. Both RSV-A and RSV-B appear to have originated in North America, with an inferred origin time of 1954.0 (1938.7-1967.6) and 1969.7 (1962.6-1975.5), respectively. BA-like strains of RSV-B, with a 60-nt insertion, and the ON1 strain of RSV-A, with a 72-nt insertion, emerged in 1997.6 (1996.2-1998.6) and 2010.1 (2009.1-2010.3), respectively. Since their origin, both genotypes have gradually replaced the former circulating genotypes to become the dominant strain. The population dynamic of RSV-A showed a seasonal epidemic pattern with obvious expansion in the periods of 2006-2007, 2010-2011, 2011-2012, and 2013-2014. Thirty fixed amino acid substitutions were identified during the divergence of NA4 from GA1 genotypes of RSV-A, and 13 were found during the divergence of SAB4 from GB1 of RSV-B. Importantly, ongoing evolution has occurred since the emergence of ON1, including four amino acid substitutions (I208L, E232G, T253K, and P314L). RSV-A genotypes GA5, NA4, NA1, and ON1 and RSV-B genotypes CB1, SAB4, BA-C, BA10, BA7, and BA9 were co-circulating in China from 2005 to 2015. In particular, RSV-A genotype ON1 was first detected in China in 2011, and it completely replaced GA2 to become the predominant strain after 2016. These data provide important insights into the evolution and epidemiology of RSV.

Preferential Presentation of High-Affinity Immune Complexes in Germinal Centers Can Explain How Passive Immunization Improves the Humoral Response

Passive immunization (PI) with external antibodies has been used classically for rapid but temporary alleviation of disease. Transcending this role, recent studies have shown PI to induce lasting improvements in natural antibody production, suggesting that PI could become a powerful tool to engineer humoral responses. We propose a mechanism with which PI can alter the humoral response. Antigen-specific B cells evolve and get selected in germinal centers (GCs) on the basis of their ability to acquire antigen from antibody-antigen complexes presented in GCs. When external antibodies of high affinity for antigen are used, they form the majority of the complexes in GCs, letting only B cells with even higher affinities be selected. Using an in silico GC reaction model, we show that this mechanism explains the improved humoral responses following PI. The model also synthesizes several independent experimental observations, indicating the robustness of the mechanism, and proposes tunable handles to optimize PI.

Antiviral activity of ethanol extract of Lophatherum gracile against respiratory syncytial virus infection

ETHNOPHARMACOLOGICAL RELEVANCE

Lophatherum gracile, an important medicinal plant, is used traditionally in the treatment of cough associated with lung heat and inflammation. In this study, an ethanol extract of L. gracile (DZY) was shown to inhibit respiratory syncytial virus (RSV) infection and RSV-induced inflammation in vitro and in vivo. These findings provide a strong and powerful support for the traditional use of L. gracile in the treatment of RSV-related diseases.

AIM OF THE STUDY

To determine the anti-RSV activities of DZY and its ingredients, and explore the relationship between RSV infection and inflammation.

MATERIALS AND METHODS

DZY was extracted from L. gracile and its major ingredients were determined by high-performance liquid chromatography (HPLC). RSV-infected HEp-2 and RAW264.7 cell models were established to assess the inhibitory effect of DZY on RSV replication and nitric oxide (NO) production in vitro. Three-week-old BALB/c mice challenged intranasally with RSV were used to establish RSV-infected animal mode. The mice were respectively administered DZY at high-, middle-, and low-dose in different groups. The anti-RSV activity of DZY was evaluated by detecting viral load, lung lesion, CD4⁺ and CD8⁺ T cell population, and interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ expression in the lung tissue.

RESULTS

In HEp-2 cell line, DZY effectively inhibited RSV infection in a dose-dependent manner with IC₅₀ values of 20 μg/mL against RSV (Long strain) and IC₅₀ values of 25 μg/mL against RSV (A2 strain). The anti-RSV activity of DZY was mainly determined by isoorientin, swertiajaponin, 3, 5-di-caffeoylquinic acid, and 3, 4-di-caffeoylquinic acid. Moreover, DZY suppressed NO production induced by RSV in vitro. In vivo, oral administration of DZY significantly reduced the viral load and ameliorated lesions in the lung tissue. A probable antiviral mechanism was mediated by slightly improving the ratio of CD4⁺/CD8⁺ T cells and inhibiting the mRNA and protein expression of IL-1β, TNF-α, and IFN-γ.

CONCLUSIONS

(1) DZY exhibits anti-RSV activities both in vitro and in vivo. (2) RSV infection can trigger a series of inflammatory reactions; thus, ameliorating inflammation is helpful to control the course of disease caused by RSV. These findings provide the rationale and scientific evidence behind the extensive use of L. gracile in traditional medicine for the treatment of diseases potentially caused by RSV.

Targeting Intracellular Ion Homeostasis for the Control of Respiratory Syncytial Virus

Respiratory syncytial virus (RSV) is a leading cause of mortality in infants and young children. Despite the RSV disease burden, no vaccine is available, and treatment remains nonspecific. New drug candidates are needed to combat RSV. Toward this goal, we screened over 2,000 compounds to identify approved drugs with novel anti-RSV activity. Cardiac glycosides, inhibitors of the membrane-bound Na⁺/K⁺-ATPase, were identified to have anti-RSV activity. Cardiac glycosides diminished RSV infection in human epithelial type 2 cells and in primary human airway epithelial cells grown at an air-liquid interface. Digoxin, a U.S. Food and Drug Administration-approved cardiac glycoside, was also able to inhibit infection of primary nasal epithelial cells with community isolates of RSV. Our results suggest that the antiviral effects of cardiac glycosides may be dependent on changes in the intracellular Na⁺ and K⁺ composition. Consistent with this mechanism, we demonstrated that the ionophoric antibiotics salinomycin, valinomycin, and monensin inhibited RSV in human epithelial type 2 cells and primary nasal epithelial cells. Our data indicate that the K⁺/Na⁺-sensitive steps in the RSV life cycle occur within the initial 4 hours of viral infection but do not include virus binding/entry. Rather, our findings demonstrated a negative effect on the RSV transcription and/or replication process. Overall, this work suggests that targeting intracellular ion concentrations offers a novel antiviral strategy.

Discovery of 3,3'-Spiro[Azetidine]-2-oxo-indoline Derivatives as Fusion Inhibitors for Treatment of RSV Infection

A new series of 3,3'-spirocyclic-2-oxo-indoline derivatives was synthesized and evaluated against respiratory syncytial virus (RSV) in a cell-based assay and animal model. Extensive structure-activity relationship study led to a lead compound 14h, which exhibited excellent in vitro potency with an EC₅₀ value of 0.8 nM and demonstrated 71% oral bioavailability in mice. In a mouse challenge model of RVS infection, 14h demonstrated superior efficacy with a 3.9log RSV virus load reduction in the lung following an oral dose of 50 mg/kg.

Functional Impairment of Mononuclear Phagocyte System by the Human Respiratory Syncytial Virus

The mononuclear phagocyte system (MPS) comprises of monocytes, macrophages (MΦ), and dendritic cells (DCs). MPS is part of the first line of immune defense against a wide range of pathogens, including viruses, such as the human respiratory syncytial virus (hRSV). The hRSV is an enveloped virus that belongs to the Pneumoviridae family, Orthopneumovirus genus. This virus is the main etiological agent causing severe acute lower respiratory tract infection, especially in infants, children and the elderly. Human RSV can cause bronchiolitis and pneumonia and it has also been implicated in the development of recurrent wheezing and asthma. Monocytes, MΦ, and DCs significantly contribute to acute inflammation during hRSV-induced bronchiolitis and asthma exacerbation. Furthermore, these cells seem to be an important component for the association between hRSV and reactive airway disease. After hRSV infection, the first cells encountered by the virus are respiratory epithelial cells, alveolar macrophages (AMs), DCs, and monocytes in the airways. Because AMs constitute the predominant cell population at the alveolar space in healthy subjects, these cells work as major innate sentinels for the recognition of pathogens. Although adaptive immunity is crucial for viral clearance, AMs are required for the early immune response against hRSV, promoting viral clearance and controlling immunopathology. Furthermore, exposure to hRSV may affect the phagocytic and microbicidal capacity of monocytes and MΦs against other infectious agents. Finally, different studies have addressed the roles of different DC subsets during infection by hRSV. In this review article, we discuss the role of the lung MPS during hRSV infection and their involvement in the development of bronchiolitis.

Transient Depletion of CD169+ Cells Contributes to Impaired Early Protection and Effector CD8+ T Cell Recruitment against Mucosal Respiratory Syncytial Virus Infection

Respiratory syncytial virus (RSV) is a major cause of respiratory viral infections in infants and children. Alveolar macrophages (AMs) play a crucial role in combatting airborne pathogens, strongly express CD169, and are localized in the lung alveoli. Therefore, we used CD169-diphtheria toxin receptor (DTR) transgenic mice to explore the roles of CD169⁺ cells in immune responses to mucosal RSV infection. The administration of diphtheria toxin to CD169-DTR mice induced specific AM depletion and reduced the recruitment of Ly6C^hi monocytes. Notably, CD169⁺ cell depletion reduced levels of innate cytokines, such as interferon-β, IL-6, and TNF-α, in bronchoalveolar lavage fluid during RSV infection without affecting the production of proinflammatory chemokines. Moreover, the depletion of CD169⁺ cells increased the recruitment of inflammatory cells to the lung during the early stage of RSV infection, although not during the later stages of RSV infection. Furthermore, the depletion of CD169⁺ cells reduced the recruitment of effector CD8⁺ T cells to the lungs after RSV mucosal infection. Our findings suggest that modulating the number of CD169⁺ cells to enhance immune responses to RSV infection may be useful as a new therapeutic strategy.

Evolution and Transmission of Respiratory Syncytial Group A (RSV-A) Viruses in Guangdong, China 2008-2015

Respiratory syncytial viruses (RSVs) including subgroups A (RSV-A) and B (RSV-B) are an important cause of acute respiratory tract infections worldwide. RSV-A include major epidemic strains. Fundamental questions concerning the evolution, persistence and transmission of RSV-A are critical for disease control and prevention, yet remain unanswered. In this study, we generated 64 complete G gene sequences of RSV-A strains collected between 2008 and 2015 in Guangdong, China. Phylogenetic analysis was undertaken by incorporating 572 publicly available RSV-A sequences. Current data indicate that genotypes GA1, GA4, and GA5 are endemic with limited epidemic activity. In contrast, the GA2 genotype which likely originated in 1980 has spread rapidly and caused epidemics worldwide. By analyzing GA2 genotype sequences across epidemic seasons within Guangdong, we find that RSV-A epidemics in Guangdong are caused by a combination of virus importation and local persistence, although the magnitude of the latter is likely overestimated due to infrequent sampling in other regions. Our results provide new insights into RSV-A evolution and transmission at global and local scales and highlights the rapid and wide spread of genotype GA2 compared to other genotypes. In order to control RSV transmission and outbreak, both local persistence and external introduction should be taken into account when designing optimal strategies.

Human Respiratory Syncytial Virus: Infection and Pathology

The human respiratory syncytial virus (hRSV) is by far the major cause of acute lower respiratory tract infections (ALRTIs) worldwide in infants and children younger than 2 years. The overwhelming number of hospitalizations due to hRSV-induced ALRTI each year is due, at least in part, to the lack of licensed vaccines against this virus. Thus, hRSV infection is considered a major public health problem and economic burden in most countries. The lung pathology developed in hRSV-infected individuals is characterized by an exacerbated proinflammatory and unbalanced Th2-type immune response. In addition to the adverse effects in airway tissues, hRSV infection can also cause neurologic manifestations in the host, such as seizures and encephalopathy. Although the origins of these extrapulmonary symptoms remain unclear, studies with patients suffering from neurological alterations suggest an involvement of the inflammatory response against hRSV. Furthermore, hRSV has evolved numerous mechanisms to modulate and evade the immune response in the host. Several studies have focused on elucidating the interactions between hRSV virulence factors and the host immune system, to rationally design new vaccines and therapies against this virus. Here, we discuss about the infection, pathology, and immune response triggered by hRSV in the host.

Efficacy and optimization of palivizumab injection regimens against respiratory syncytial virus infection

IMPORTANCE

Infection with the respiratory syncytial virus (RSV) is the leading cause of hospitalizations in children, accounting for more than 90,000 hospitalizations every year in the United States. For children who are at risk for severe RSV infections, the American Academy of Pediatrics recommends immunoprophylaxis with a series of up to 5 injections of the antibody palivizumab administered monthly, beginning on November 1 of each year. However, many practitioners initiate injections at the onset of RSV season as indicated by local surveillance.

OBJECTIVES

To evaluate the effectiveness of current regimens for palivizumab injections across different cities and to design an optimized regimen.

DESIGN, SETTING, AND PARTICIPANTS

We performed a mathematical modeling study of the risk for hospitalization due to RSV infection. The model accounted for the pharmacokinetics of the antibody, the timing of the injections, and seasonal patterns of RSV, including geographic and year-to-year variability. We used the model to estimate the efficacy of current regimens, including the American Academy of Pediatrics recommendation, and to design a more effective injection regimen, the optimized fixed start (OFS), which uses city-specific initiation dates. Participants were the approximately 700,000 individuals who had specimens tested for RSV by National Respiratory and Enteric Virus Surveillance System laboratories in 18 US cities from July 1, 1994, through June 30, 2011 (a total of 725,741 tests).

INTERVENTIONS

Different palivizumab injection regimens.

MAIN OUTCOMES AND MEASURES

The primary outcome measure was reduction in hospitalizations due to RSV infections. The secondary measures were cost (number of palivizumab doses) and duration of protection (in days).

RESULTS

The American Academy of Pediatrics-recommended 5-injection regimen is expected to reduce hospitalization risk by a median of 2.7% (range, -2.2% to 6.1%) compared with the conventional regimen based on RSV surveillance. The 5-injection OFS regimen is expected to further reduce risk by a median of 6.8% (range, 4.9% to 14.8%), and the 4-injection OFS regimen is expected to achieve efficacy comparable to that of the conventional 5-injection regimen while reducing costs by 20%.

CONCLUSIONS AND RELEVANCE

Modified palivizumab regimens can improve protection for children at risk for severe outcomes of RSV infection and thereby lower rates of hospitalization due to RSV.

Induction of long-term immunity against respiratory syncytial virus glycoprotein by an osmotic polymeric nanocarrier

Respiratory syncytial virus (RSV) is one of the most common causes of viral deaths in infants worldwide, yet no effective vaccines are available. Here, we report an osmotically active polysaccharide-based polysorbitol transporter (PST) prepared from sorbitol diacrylate and low-molecular-weight polyethylenimine (PEI) showing a potent, yet safe, adjuvant activity and acting as an effective delivery tool for RSV glycoprotein (RGp) antigen. PST showed no toxicity in vitro or in vivo, unlike PEI and the well-known experimental mucosal adjuvant cholera toxin (CT). PST formed nano-sized complexes with RGp by simple mixing, without affecting antigenic stability. The complexes exhibited negative surface charges that made them highly efficient in the selective activation of phagocytic cells and enhancement of phagocytic uptake. This resulted in an improved cytokine production and in the significant augmentation of RGp-specific antibody production, which persisted for over 200 days. Interestingly, PST/RGp enhanced phagocytic uptake owing to the osmotic property of PST and its negative zeta potential, suggesting that PST could selectively stimulate phagocytic cells, thereby facilitating a long-lived antigen-specific immune response, which was presumably further enhanced by the polysaccharide properties of PST.

Central nervous system alterations caused by infection with the human respiratory syncytial virus

Worldwide, the human respiratory syncytial virus (hRSV) is the leading cause of infant hospitalization because of acute respiratory tract infections, including severe bronchiolitis and pneumonia. Despite intense research, to date there is neither vaccine nor treatment available to control hRSV disease burden globally. After infection, an incubation period of 3-5 days is usually followed by symptoms, such as cough and low-grade fever. However, hRSV infection can also produce a larger variety of symptoms, some of which relate to the individual's age at infection. Indeed, infants can display severe symptoms, such as dyspnea and chest wall retractions. Upon examination, crackles and wheezes are also common features that suggest infection by hRSV. Additionally, infection in infants younger than 1 year is associated with several non-specific symptoms, such as failure to thrive, periodic breathing or apnea, and feeding difficulties that usually require hospitalization. Recently, neurological symptoms have also been associated with hRSV respiratory infection and include seizures, central apnea, lethargy, feeding or swallowing difficulties, abnormalities in muscle tone, strabismus, abnormalities in the CSF, and encephalopathy. Here, we discuss recent findings linking the neurological, extrapulmonary effects of hRSV with infection and functional impairment of the CNS.

Prophylactic and therapeutic testing of Nicotiana-derived RSV-neutralizing human monoclonal antibodies in the cotton rat model

Severe lower respiratory tract infection in infants and small children is commonly caused by respiratory syncytial virus (RSV). Palivizumab (Synagis(®)), a humanized IgG1 monoclonal antibody (mAb) approved for RSV immunoprophylaxis in at-risk neonates, is highly effective, but pharmacoeconomic analyses suggest its use may not be cost-effective. Previously described potent RSV neutralizers (human Fab R19 and F2-5; human IgG RF-1 and RF-2) were produced in IgG format in a rapid and inexpensive Nicotiana-based manufacturing system for comparison with palivizumab. Both plant-derived (palivizumab-N) and commercial palivizumab, which is produced in a mouse myeloma cell line, showed protection in prophylactic (p < 0.001 for both mAbs) and therapeutic protocols (p < 0.001 and p < 0.05 respectively). The additional plant-derived human mAbs directed against alternative epitopes displayed neutralizing activity, but conferred less protection in vivo than palivizumab-N or palivizumab. Palivizumab remains one of the most efficacious RSV mAbs described to date. Production in plants may reduce manufacturing costs and improve the pharmacoeconomics of RSV immunoprophylaxis and therapy.

p38 and OGT sequestration into viral inclusion bodies in cells infected with human respiratory syncytial virus suppresses MK2 activities and stress granule assembly

Respiratory syncytial virus (RSV) forms cytoplasmic inclusion bodies (IBs) that are thought to be sites of nucleocapsid accumulation and viral RNA synthesis. The present study found that IBs also were the sites of major sequestration of two proteins involved in cellular signaling pathways. These are phosphorylated p38 mitogen-activated protein kinase (MAPK) (p38-P), a key regulator of cellular inflammatory and stress responses, and O-linked N-acetylglucosamine (OGN) transferase (OGT), an enzyme that catalyzes the posttranslational addition of OGN to protein targets to regulate cellular processes, including signal transduction, transcription, translation, and the stress response. The virus-induced sequestration of p38-P in IBs resulted in a substantial reduction in the accumulation of a downstream signaling substrate, MAPK-activated protein kinase 2 (MK2). Sequestration of OGT in IBs was associated with suppression of stress granule (SG) formation. Thus, while the RSV IBs are thought to play an essential role in viral replication, the present results show that they also play a role in suppressing the cellular response to viral infection. The sequestration of p38-P and OGT in IBs appeared to be reversible: oxidative stress resulting from arsenite treatment transformed large IBs into a scattering of smaller bodies, suggestive of partial disassembly, and this was associated with MK2 phosphorylation and OGN addition. Unexpectedly, the RSV M2-1 protein was found to localize in SGs that formed during oxidative stress. This protein was previously shown to be a viral transcription elongation factor, and the present findings provide the first evidence of possible involvement in SG activities during RSV infection.

Inhibition of human respiratory syncytial virus infectivity by a dendrimeric heparan sulfate-binding peptide

Respiratory syncytial virus (RSV) interacts with cell surface heparan sulfate proteoglycans (HSPGs) to initiate infection. The interaction of RSV with HSPGs thus presents an attractive target for the development of novel inhibitors of RSV infection. In the present study, a minilibrary of linear, dimeric, and dendrimeric peptides containing clusters of basic amino acids was screened with the aim of identifying peptides able to bind HSPGs and thus block RSV attachment and infectivity. Of the compounds identified, the dendrimer SB105-A10 was the most potent inhibitor of RSV infectivity, with 50% inhibitory concentrations (IC(50)s) of 0.35 μM and 0.25 μM measured in Hep-2 and A549 cells, respectively. SB105-A10 was found to bind to both cell types via HSPGs, suggesting that its antiviral activity is indeed exerted by competing with RSV for binding to cell surface HSPGs. SB105-A10 prevented RSV infection when added before the viral inoculum, in line with its proposed HSPG-binding mechanism of action; moreover, antiviral activity was also exhibited when SB105-A10 was added postinfection, as it was able to reduce the cell-to-cell spread of the virus. The antiviral potential of SB105-A10 was further assessed using human-derived tracheal/bronchial epithelial cells cultured to form a pseudostratified, highly differentiated model of the epithelial tissue of the human respiratory tract. SB105-A10 strongly reduced RSV infectivity in this model and exhibited no signs of cytotoxicity or proinflammatory effects. Together, these features render SB105-A10 an attractive candidate for further development as a RSV inhibitor to be administered by aerosol delivery.

Monoclonal antibodies and toxins--a perspective on function and isotype

Antibody therapy remains the only effective treatment for toxin-mediated diseases. The development of hybridoma technology has allowed the isolation of monoclonal antibodies (mAbs) with high specificity and defined properties, and numerous mAbs have been purified and characterized for their protective efficacy against different toxins. This review summarizes the mAb studies for 6 toxins—Shiga toxin, pertussis toxin, anthrax toxin, ricin toxin, botulinum toxin, and Staphylococcal enterotoxin B (SEB)—and analyzes the prevalence of mAb functions and their isotypes. Here we show that most toxin-binding mAbs resulted from immunization are non-protective and that mAbs with potential therapeutic use are preferably characterized. Various common practices and caveats of protection studies are discussed, with the goal of providing insights for the design of future research on antibody-toxin interactions.

The Prophylaxis and Treatment with Antiviral Agents of Respiratory Syncytial Virus Infections

In this review, we consider recent advances in the discovery and development of antiviral agents for respiratory syncytial virus (RSV) infections. A background to the various manifestations of human RSV infection and current treatments is provided. The technical, clinical and commercial issues surrounding the development of such antiviral agents are discussed.

An evaluation of the emerging interventions against Respiratory Syncytial Virus (RSV)-associated acute lower respiratory infections in children

Background

Respiratory Syncytial Virus (RSV) is the leading cause of acute lower respiratory infections (ALRI) in children. It is estimated to cause approximately 33.8 million new episodes of ALRI in children annually, 96% of these occurring in developing countries. It is also estimated to result in about 53,000 to 199,000 deaths annually in young children. Currently there are several vaccine and immunoprophylaxis candidates against RSV in the developmental phase targeting active and passive immunization.

Methods

We used a modified CHNRI methodology for setting priorities in health research investments. This was done in two stages. In Stage I, we systematically reviewed the literature related to emerging vaccines against RSV relevant to 12 criteria of interest. In Stage II, we conducted an expert opinion exercise by inviting 20 experts (leading basic scientists, international public health researchers, international policy makers and representatives of pharmaceutical companies). The policy makers and industry representatives accepted our invitation on the condition of anonymity, due to the sensitive nature of their involvement in such exercises. They answered questions from the CHNRI framework and their “collective optimism” towards each criterion was documented on a scale from 0 to 100%.

Results

In the case of candidate vaccines for active immunization of infants against RSV, the experts expressed very low levels of optimism for low product cost, affordability and low cost of development; moderate levels of optimism regarding the criteria of answerability, likelihood of efficacy, deliverability, sustainability and acceptance to end users for the interventions; and high levels of optimism regarding impact on equity and acceptance to health workers. While considering the candidate vaccines targeting pregnant women, the panel expressed low levels of optimism for low product cost, affordability, answerability and low development cost; moderate levels of optimism for likelihood of efficacy, deliverability, sustainability and impact on equity; high levels of optimism regarding acceptance to end users and health workers. The group also evaluated immunoprophylaxis against RSV using monoclonal antibodies and expressed no optimism towards low product cost; very low levels of optimism regarding deliverability, affordability, sustainability, low implementation cost and impact on equity; moderate levels of optimism against the criteria of answerability, likelihood of efficacy, acceptance to end-users and health workers; and high levels of optimism regarding low development cost. They felt that either of these vaccines would have a high impact on reducing burden of childhood ALRI due to RSV and reduce the overall childhood ALRI burden by a maximum of about 10%.

Conclusion

Although monoclonal antibodies have proven to be effective in providing protection to high-risk infants, their introduction in resource poor settings might be limited by high cost associated with them. Candidate vaccines for active immunization of infants against RSV hold greatest promise. Introduction of a low cost vaccine against RSV would reduce the inequitable distribution of burden due to childhood ALRI and will most likely have a high impact on morbidity and mortality due to severe ALRI.

Meta-analysis of passive immunoprophylaxis in paediatric patients at risk of severe RSV infection

AIM

To review respiratory syncytial virus (RSV), passive immunoprophylaxis (PI) trials and meta-analysis (MA).

METHODS

A literature review.

RESULTS

Two MA of PI were found. Overall 3927 patients were randomized. PI reduces RSV hospitalization in patients with bronchopulmonary dysplasia (RR 0.58; 95% CI 0.41, 0.82) and with acyanotic congenital heart disease (RR 0.29; 95% CI 0.14, 0.62). In patients with cyanotic heart disease or premature infants without bronchopulmonary dysplasia, results are inconclusive. Passive immunoprophylaxis has a null effect in mechanical ventilation and death.

CONCLUSION

Passive immunoprophylaxis reduces RSV hospitalization in a subset of patients. However, it has no effect in harder endpoints of RSV disease severity.

Strategies and challenges for the next generation of therapeutic antibodies

Antibodies and related products are the fastest growing class of therapeutic agents. By analysing the regulatory approvals of IgG-based biotherapeutic agents in the past 10 years, we can gain insights into the successful strategies used by pharmaceutical companies so far to bring innovative drugs to the market. Many challenges will have to be faced in the next decade to bring more efficient and affordable antibody-based drugs to the clinic. Here, we discuss strategies to select the best therapeutic antigen targets, to optimize the structure of IgG antibodies and to design related or new structures with additional functions.