PMBL® competitive advantages: Mechanical - PowerPoint Presentation

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PMBL® competitive advantages: Mechanical lysis vs Chemical lysis, Sublingual mode of administration

Mario Cazzola, FERSHonorary Professor

University of Rome Tor VergataDepartment of Experimental Medicine and Surgery Chair of Respiratory Medicine

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Bacterial

immunostimulation

has been advocated as a management strategy in COPD for the purposes of preventing acute exacerbations.It is not surprising, therefore, that use of bacterial immunostimulants is an option included in the management recommendation of some guidelines. Inactivated microorganisms offer certain advantages as a potential vaccine for mucosal immunization. They are naturally occurring microparticles, which possess multiple antigens and are relatively inexpensive to produce. These immunomodulatory bacterial extracts are commonly administered by the oral or sublingual route.

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Polyvalent bacterial lysates are prepared from different species of bacteria – typically the most commonly occurring pathogens of the upper and lower respiratory tract.

Each bacterial strain is grown independently, harvested, inactivated and lysed.

Effective lysis of bacterial cells is a key step.

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A number of methods have been described for lysing bacterial cells:

boiling

lysis, lysis with detergents, enzymatic digestion, alkaline lysis, mechanical lysis. Bacterial antigens are mainly obtained after a mass culture of reference bacterial strains using a chemical (PCBL) or mechanical (PMBL) cellular lysis of the organisms and lyophilization, then mixed in the same proportions.

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PMBL are produced through a process that preserves the structure of the bacterial antigens and consists in

lysis

in vitro, fractionation of bacterial bodies and/or supernatant and finally attainment of the particulate antigens.PCBL are obtained through chemical alkaline substances and processes that may determine proteins denaturation, with a consequent lower immunogenicity of the antigens themselves.Differences between PMBL and PCBL

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Bacterial lysate obtained by mechanical

lysis

(PMBL) PMBL is a a polyvalent mechanical bacterial lysate prepared by 48 billion bacteria belonging to the following species Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus, Streptococcus pyogenes, Streptococcus viridans, Klebsiella

pneumoniae, Klebsiella ozaenae, obtained by mechanical lysis

(by

high pressure)

.

Mechanical

lysis does not alter the structure of the antigens: this ensures a preparation having excellent antigenic properties.

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The addition of the mixture of the particulate fractions of the different bacterial strains was able to mediate an optimal maturation, as evaluated by the expression of an activating phenotype on DCs and the amount of cytokine

secretion, more than their soluble counterparts.

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The capacity of PMBL to recruit selected subsets of T and B cells, and, in addition, to significantly increase the number of circulating NK cells has been demonstrated even in a population of elderly patients.

Phenotypic analysis of T, B and NK cell populations and subsets in COPD patients treated with PMBL and matched controls: percent values

Evolution of transitional B cells during the treatment. T3 represented the main population.

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OM-85 administered in early life, in human-equivalent doses, did not inhibit the development of allergic pulmonary response in mice, when total cells count, eosinophil numbers, IL-4 and OVA-specific IgE levels were analysed.

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There are many different mucosal routes of immunization.

The selection of the route of immunization is based on different parameters, such as the targeted pathogen, the type and quality of immune response elicited and most importantly, the safety issues related to the route of immunization that often preclude the possibility of choice.

The sublingual route of administration of bacterial preparations has been proposed as a safer and effective route to stimulate strong and long-lasting systemic and mucosal antigen-specific humoral and cell-mediated immunity. Mucosal routes of immunization

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Submucosal

immunization induced a significant increase in salivary response, whereas subcutaneous immunization did not.

Oral immunization appeared to lead to a salivary antibody response of short duration and is therefore unlikely to be useful.1979

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Long‐term administration of a sublingual polyvalent bacterial preparation in patients with recurrent respiratory tract infections

exerts an immune stimulating effect on CD4+ T helper cell responses to bacterial antigens.This effect could upregulate Th1 immune responses enhancing more efficient anti-microbial defences and, consequently, could be associated with clinical benefit.

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Dendritic

cells are able to capture, process and cross-present the antigen to CD4+ and CD8+ T cells.The high CD8+ T cell response observed after vaccination with a soluble protein is likely due to the presence of high number of dendritic cells in

the sublingual mucosa especially upon administration of mucosal adjuvants

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When a group of healthy donors was treated with a sublingual bacterial lysate, the large majority developed a specific immune-response in the salivary fluid.

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The induction of immunological memory to the specific pathogen is critical to maintain long-lasting immune surveillance upon vaccination using the sublingual immunization strategy

Longitudinal analysis of systemic antibody response after sublingual immunization.

Longitudinal analysis of mucosal antibody response after sublingual immunization

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It is important to highlight that sublingual administration guarantees effective protection of the respiratory mucosae, which represent the first barrier to infection, making it possible to bypass the gastroenteric tract. This avoids denaturing the antigens and puts them directly in contact with the

Langherans cells that best carry out the task of antigen-presenting cells.

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Potential

utility

of the sublingual route It is able to stimulate the distant mucosa (respiratory, genitourinary and gastrointestinal tract) and also confers a systemic immunostimulation.It is safe and highly effective and induces a robust immune response similar to that induced by nasal stimulation and superior to that achieved with the oral pathway. Sublingual immunization induces protective immunity mediated by systemic and mucosal humoral and cellular responses.

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Potential

utility

of the sublingual route The strength of sIgA induction by the sublingual route is similar to that achieved via the nasal and oral routes. Vaccination via this route also induces the production of specific sIgA in the intestine, which is not observed following nasal administration. Sublingual immunization has several advantages over other routes of immunization: no medical personnel is required for its administration, sublingual vaccines are easier to administer than nasal vaccines, this route has an advantage over the oral route that the antigen is not subject to significant proteolytic degradation by digestive enzymes.

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Utilizing quantitative pooled analysis in studies with one or more acute exacerbations as the endpoint, the Authors found a non-statistically significant trend in favour of OM-85 BV.

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Comparison of PMBL vs. placebo, another conventional bacterial lysate or no treatment in patients with COPD or bronchitis

Three RCTs (305 treated and 335 placebo participants) reported on the prevention of exacerbations in patients with COPD or bronchitis. (RR -0.404; 95% CI -0.864−0.057), but the difference between the use of PMBL and placebo was not statistically significant (p = 0.086).

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Pooled

analysis: one or more exacerbations during the study period in the 7 trials incorporating entry criteria of COPD or chronic bronchitis

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Patients of the first group

(

PMBL, Ismigen) were treated by sublingual route with one tablet of the assigned compound every morning for 10 days of each month of the 3 months period.To the patients of the second group (CLBL) one capsule of the assigned compound was administered by oral route every morning with the same therapeutic schedule as above. The patients of the third group (no immunostimulating treatment, NT) did not get any immunostimulating treatment.

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The mean number of URTIs per patient (primary end point) during the treatment period in the PMBL group was 0.34 ± 0.48, being significantly lower than those in the CLBL (1 ± 0.83) and NT (1.23 ± ± 0.77) groups (p < 0.05).

Conversely, the difference in the means of the last two groups failed to reach the level of significance

.

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During

both the treatment and follow-up period a higher proportion of patients treated with PMBL remained free from URTIs (65.9 and 60.5%, respectively) and the difference versus the other two groups was statistically significant.

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The duration of infectious episodes (a secondary end point) in the PMBL group was the shortest among the three groups (p < 0.05) both in the treatment and follow-up period; also in line with these data are those concerning the loss of working days due to infections.

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No patient treated with PMBL needed any antibacterial agent; conversely, 9 patients from the CLBL group received an antibiotic treatment (p < 0.002).

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Patients of the first group (bacteria obtained by mechanical

lysis

, MLBL) were treated by sublingual route with one tablet of the assigned compound every morning for 10 days of each month of the 3 months period.To the patients of the second group (bacteria obtained by chemical lysis, CLBL) one capsule of the assigned compound was administered by oral route every morning with the same therapeutic schedule as above. The patients of the third group (no immunostimulating treatment, NT) did not get any immunostimulating treatment.

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In the NT group 96% patients had at least one acute episode; the percentage was 22% in the MLBL and in 70 % in CLBL group. The difference among groups was statistically significant and in favour of MLBL.

No LRTI was observed in this last group in the first month of treatment.

The mean number of acute episodes (primary variable) was significantly lower (p< 0.05) in the MLBL group than in the CLBL and in the NT group (0.3 ± 0.63 vs. 0.9 ± 0.7 vs. 1.7 ± 0.9). No significant difference was observed in the mean duration of acute respiratory infective episodes reported during the 3-month treatment.

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Significant differences were observed in the antibiotic need. Only 4 patients (17.4 %) received an antibiotic treatment in the MLBL group, versus 14 patients (60.9 %) in the CLBL group and 21 patients (91.3 %) in the NT group.

There were no differences in the duration of antibiotic treatment between the three groups.

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In the three-month follow-up period, infectious episodes were reported in 5 patients (21.7 %) of the MLBL group, in 6 (26.1 %) of the CLBL and in 7 (30.4 %) of the NT group.

No significant difference was found among groups in the duration of these episodes and in the length of the antibiotic treatment.

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At the end of the first 3 months dyspnoea improved or disappeared in 86.7% of the patients of MLBL group while improved or disappeared in 40% and 11.8% of CLBL and NT patients, respectively.

At follow-up, 39.1% of patients in the MLBL group and in the CLBL group showed dyspnoea versus 73.9% in the NT group.

Cough, sputum and thoracic pain disappeared in almost all patients while auscultatory thoracic pathological findings disappeared in 67 %, 56 %, and 32 % in MLBL, CLBL and NT patients, respectively, without any significant difference among groups.No adverse events were reported during the study.

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The primary objective of the trial was to demonstrate the clinical efficacy of Ismigen®, defined as reducing the number of exacerbations by 25% in patients with moderate, severe and very severe COPD and determined by the GOLD 2006 classification guidelines over a 12-month observation period.The treatment schedule was based on two three-month cycles. One cycle consisted of sublingual consumption of one tablet per day for 10 consecutive days, followed by 20 days of standard treatment for three consecutive months.

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Lung

2015;193:513-9

The primary efficacy endpoint of the study was the proportion of patients with recurrent acute exacerbations during the 12-week treatment period.Patients were randomly assigned, in a 1:1 ratio, to receive one OM-85 or placebo capsule daily ‘per os’ for 10 consecutive days per month, for 3 consecutive months (12 weeks), followed by a 10-week observational period.

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Lung

2015;193:513-9

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Lung

2015;193:513-9

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71.13% of placebo patients and 70.55% of treated patients did not experience exacerbation during the study period.

These results corresponded to 0.52 exacerbations/patient/year in the placebo group, compared to 0.51 in the PMBL group (p = 0.93).

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Although no differences were observed in the first period, the time to the second exacerbation was significantly longer in the PMBL treated group

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During the 12-week treatment period the percentage of patients with recurrent acute exacerbations was significantly lower in the OM-85 group compared to the placebo group (23.4 % vs. 33.3 %, p = 0.03), but this effect was lost during the observational period (12.5% vs. 14.06%)

Lung

2015;193:513-9

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The mean numbers of days with fever were 0.06 for the treatment group (corresponding to 21.9 days per year) and 0.11 for the placebo group (corresponding to 40.15 days per year) (p < 0.001).

Similarly, the numbers of days in poor health were 0.3 ± 0.026 (109 days/year) for the PMBL group and 0.47 ± 0.021 (171 days/year) for the placebo group (p < 0.001).

Concerning hospitalisations, although the overall number of days of hospitalisations, independent of cause, was not statistically significantly different (p value = 0.21) between the study arms, the number of days of hospitalisation due to COPD exacerbation was significantly smaller in the PMBL group (65 days vs 162 days; p < 0.001).

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During the Week 12 and Week 22 visits, the mean scores of the four symptoms (amount of sputum, severity of dyspnea, frequency of cough, and fever) were similar in both groups with no statistically significant differences.When compared against their baseline values, the scores of the four symptoms in both groups decreased significantly not only at the Week 12 visit but also at the Week 22 visit.

There were no statistically significant differences in the proportions of patients concomitantly treated with antibiotics and/or inhaled β2-agonists between the two groups.

Lung 2015;193:513-9

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The rate of adverse events potentially related to the drug was low (2.99% with placebo and 0% with PMBL), with no significant difference between the groups

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Adverse events were similarly reported in both groups (27.9 % in the OM-85 group and 27.7 % in the placebo group). Serious adverse events of hospitalization occurred in 1.9 % in the OM-85 group and 1.4 %in the placebo group.

Lung

2015;193:513-9

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Upper Respiratory Tract Infections

The mean number (±SD) of URTIs per patient was 0.34 (0.48) in the PMBL group, 1.0 (0.83) and 1.23 (0.77) in the PCBL and “no immunostimulant treatment” (NT) groups, respectively. Results of PMBL treatment were significantly better (p < 0.05) than the results in the other two groups; PCBL was not significantly different from the control group.

In the three months of follow-up, the mean number (±SD) of URTIs per patient was: 0.42 (0.55) in the PMBL group, 0.92 (0.67) in the PCBL group, and 1.55 (0.88) in the NT group. The PMBL group was significantly better than the other two (p < 0.05). During the 6-month study, significantly more patients of the PMBL group remained free from respiratory infections in comparison to the other two groups.As regards other secondary end points (duration of infectious episodes and number of working days lost), the mean values of the PMBL group were statistically significantly lower than those of the other two groups, in both the treatment and follow-up periods. No PMBL treated patient needed concomitant administration of an antibiotic, while 9 patients of the PCBL group received such treatment (p < 0.05). No patient reported adverse events.

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Upper Respiratory Tract Infections

Mean number of URTIs (±SD)/patient 0.34 (0.48) with PMBL, 1.0 (0.83) with PCBL, and 1.23 (0.77) with NT.

statistical significance: PMBL better than PCBL = NT.Mean number of URTIs (±SD)/patient in the three months of follow-up, 0.42 (0.55) with PMBL, 0.92 (0.67) with PCBL, and 1.55 (0.88) with NT. statistical significance: PMBL better than PCBL = NT. during the 6-month study, significantly more patients of the PMBL group remained free from respiratory infections in comparison to the other two groups.Other secondary end points the mean values of duration of infectious episodes and number of working days lost in the PMBL group were statistically significantly lower than those of the other two groups, in both the treatment and follow-up periods. concomitant administration of an antibiotic: in 0 patients in PMBL group; in 9 in PCBL group (p < 0.05). no patient reported adverse events.

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Acute Lower Respiratory Tract Infections

In the “no immunostimulant treatment” (NT) group, 96% of patients had, at least, one acute episode; this percentage was 22% in the PMBL group and 70% in the PCBL group, respectively. The difference among the three groups was statistically significant and in favour of PMBL. No LRTIs in this last group were observed in the first month of treatment.

The mean number of acute episodes was significantly lower (p<0.05) in the PMBL group than in the PCBL and in the NT groups (0.3 ± 0.63 vs 0.9 ± 0.7 vs 1.7 ± 0.9). During the three months of treatment a significantly lower number of patients in the PMBL group needed an antibiotic therapy and complained of dyspnoea in comparison to the other two groups.

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Indirect comparison between PMBL and PCBL in COPD

ExacerbationsPMBL0.52 exacerbations/patient/year in the placebo group, compared to 0.51 in the PMBL group, however the time to the second exacerbation was significantly longer in the PMBL treated group.

PCBLDuring the 12-week treatment period the percentage of patients with recurrent acute exacerbations was significantly lower in the OM-85 group compared to the placebo group (23.4 % vs. 33.3 %, p = 0.03), but this effect was lost during the observational period (12.5% vs. 14.06%).

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Indirect comparison between PMBL and PCBL in COPD

Other end pointsPMBLThe mean numbers of days with fever were 0.06 for the treatment group (corresponding to 21.9 days per year) and 0.11 for the placebo group (corresponding to 40.15 days per year), The numbers of days in poor health were 0.3 ± 0.026 (109 days/year) for the PMBL group and 0.47 ± 0.021 (171 days/year) for the placebo group (p < 0.001), the number of days of hospitalisation due to COPD exacerbation was significantly smaller in the PMBL group (65 days

vs 162 days; p < 0.001).PCBLDuring the Week 12 and Week 22 visits, the mean scores of the four symptoms (amount of sputum, severity of dyspnea, frequency of cough, and fever) and the proportions of patients concomitantly treated with antibiotics and/or inhaled β2-agonists were similar in both groups with no statistically significant differences.

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Indirect comparison between PMBL and PCBL in COPD

Adverse eventsPMBLThe rate of adverse events potentially related to the drug was low (2.99% with placebo and 0% with PMBL), with no significant difference between the

groups.PCBLAdverse events were similarly reported in both groups (27.9 % in the OM-85 group and 27.7 % in the placebo group). Serious adverse events of hospitalization occurred in 1.9 % in the OM-85 group and 1.4 % in the placebo group.