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[00:00:06] Prof. Susanna Esposito: Good day to everybody and thank you for coming to this webinar on understanding immune system dysfunction and the recurring infections in alpha-mannosidosis. It is a pleasure for me to be here with Giacomo Biasucci and I would like just to remind you some notes so do not make any screenshot. We will do the panel discussion at the end of our presentation. The format is 45 minute presentation followed by question and answer via text and you can submit your questions at any point via the question panel. Questions can only be submitted via text and not verbally. We will answer as many questions as possible at the end of the session. This is a recorded webinar and you can find it available online in the online library of excellence in pediatrics. So I will start my presentation trying to focus on the immune system dysfunction and recurring infections in alpha-mannosidosis but just starting with a brief introduction on the disease.
Thereafter Giacomo will come back again on the disease with more details on clinical findings but just to introduce the topics I would like to remember all of you that alpha-mannosidosis is a rare lysosomal storage disease with an incidence of one out of five hundred thousand one million people. It is caused by a mutation in the MAN2B1 gene which encodes for lysosomal alpha-mannosidosis. This causes the accumulation of mannose-rich oligosaccharides that causes lysosomal engorgement, disruption of normal cell function and apoptosis. Here you can see the clinical consequences of this metabolic problem. The disease presents with a broader heterogeneity of symptoms and also the phenotypic variability is high even between siblings with identical genotypes. We should remember the neurologic involvement with ataxia and intellectual disability as well as hearing loss. Then it is important to remember muscular weakness and also skeletal abnormalities with joint abnormalities and thereafter the problem of recurrent infections and immunodeficiency. When we try to understand from the clinical point of view the classification of this disease, in the past the disease was classified according to the age of onset in mild, moderate or severe. The mild disease usually was recognized at the age of at least 10 years whereas the moderate one in children below the age of 10 and the severe was recognized at birth. Nowadays, however, there is a new classification and the classification considers a continuum in symptoms and severity with mild forms, moderate forms and severe forms that are part of the same disease course. When we should consider the red flags that may be suggestive of AM, we should remember the facial features. First of all, Giacomo will enter in details of this also with some pictures of patients, developmental delay as I told before, hearing loss, ataxia and intellectual disability.
Moreover, infections are very frequent. We will see later that they frequently occur in the course of the disease, even at disease presentation and skeletal abnormalities. Moreover, psychiatric symptoms are quite common. They affect roughly 25% of patients with depressive symptoms that are common and may be supplemented by organic and or psychotic symptoms. Regarding the diagnosis, the diagnosis can be done looking at oligosaccharides in urine. This test is suggestive of AM but not diagnostic. For the diagnosis, it is important to perform the enzyme activity assays that evaluate the functions of leukocyte. Usually, the leukocyte activity is 5 to 10% of normal activity in patients with disease and in carriers, the enzyme activity is usually between 40 to 60%. Thereafter, genetic counselling and also prenatal screening in case of at- risk pregnancies are very important for the diagnosis of the disorder. So, when we look at the age and cause of death in patients with AM, I think that it is important to mention the studies that collected data from more than 20 countries and from several patient organizations. Looking at results of patients with the details on year of birth, year of death, and also age of death. And in these multi- central studies, at the end, 15 patients were detected, 7 of these died of pneumonia, whereas 3 patients died of cancer. This highlights very well the importance of immunologic disorders in these patients. Regarding the age of the patient at death, you can see that the majority of the patients reached the third decade of life, so the mean age was 40. 3 years at death. And considering this, we should remember that nowadays we have some therapeutic options. First of all, there is the possibility to administer long- term enzyme replacement therapy that is very effective and can permit to contain the clinical manifestations, also improving immunological biomarkers.
Giacomo will enter in detail in the administration of the enzyme. You can see that the replacement therapy should be done intravenously once a week. The other possibility is the hematopoietic stem cell transplantation. Also, this approach is quite invasive and can be associated with other negative consequences. Starting from this point, I would like to introduce the problem of the immune dysfunction. Because when we speak about the immune system, we should remember that children present an increase in humoral and adaptive immunity in times, and the first five years of life are critical for seeing an increase in the IgA, IgG, and IgM levels, and also in the normal function of humoral immunity. The same is true also for cell- mediated immunity. And you can see how cell- mediated immunity is very important in the defense against intracellular pathogens, extracellular pathogens, and also in mutant infections, or in any case, immune suppression. This explains why in children in the first five years of life, recurrent infections are very frequent, even in absence of any kind of underlying disease. And between humoral and cell-mediated immunity, there is a complex system where the genetic cells are a sort of bridge that permits to connect humoral and cell-mediated cells. So considering overall the normal immune system function, we should remember that innate immunity provides first-line defense. Adaptive immunity is characterized by T cells, B cells, and NK cells that are naive in the first years of life. And in this network of activities, IL-2 that is produced by CD4 cells is crucial for lymphocyte activation. What happens in alpha-mannnosidosis is that in this heterogeneous spectrum of disorder, as in other metabolic diseases, you have a dysfunction that is due in part or in certain cases to problems in T cells, in other cases to problems in B cells, in other cases in problems in the overall activities of the immune system. And when we look at what happens regarding clinical findings, you can see that one third of the patients present at their first visit for recurrent infections, whereas the large majority present a history of recurrent infections at their last clinical examinations. So this means that recurrent infections are common quite earlier diagnosis but during the course of the disease, the risk of infections increases. And when we take into account the biochemical basis for this immune dysfunction, we should consider the accumulation of one of the rich oligosaccharides in plasma tissues and also the fact that these oligosaccharides can bind to the IL- 2 receptor on immune cells. IL- 2 is critical for the activation and proliferation of T cells, B cells, and NK cells. And binding also of oligosaccharides interferes with IL- 2 signaling, dampening immune response. So when we consider the functional consequences of this effect, you can see that there is a lower antibody responses after infections or vaccinations, a reduced lymphocyte activation with an impaired adaptive immunity, a defective NK cell activity with a compromised antiviral defense, and the differential findings include impaired leukocyte chemotaxis and reduced phagocytosis in some patients. So this explains why the spectrum of these disorders, from a neurological point of view, is very complex.
Among clinical manifestations, recurrent infections include respiratory recurrences, increased susceptibility to bacterial and viral infections, and an overlap with primary immunodeficiency syndromes, making diagnosing challenging. When we consider the immune response to vaccine, you can see that the population is very heterogeneous. So these are results related to six patients. You can see that patient one, for example, has significantly reduced antibody response against poliovirus 1, 2, 3, against diphtheria toxin and tetanus. But if you look, as an example, to patient two, you can see that the antibody levels are very similar, whereas looking to the other patients, the antibody levels are lower, but not so low as the one observed in patient one. So for this reason, I said to you before, that it is very complicated to classify as a homogenous group, these patients, from a neurological point of view. In addition, when you look at the phagocytosis of these patients, you can see that in comparison with healthy controls, their activity against an opsonized bacteria, and also against bacteria opsonized with a pooled human serum, and also with autologous serum, is reduced. But again, in this case, with a large difference between what is observed between patients. And again, when we consider the activity of CD11 and CD16 receptor density on monocytes and PMN in patients and measured controls, you can see that in patients, there is a sort of great amount of these receptors density. So, they do not function as it happens in normal controls. So, when we look at the monocytes of these patients, and we compare them with the monocytes of controls, you can see that there are large differences that can clearly be observed at the microscope. So, here you can see a lymphocyte of a patient. Here, a lymphocyte of controls. You can see that in the patient, there is cytoplasm that is filled with a variable size of membrane-bound vacuoles.And this explains why the cells do not work as in normal controls. So, when we consider this data and when we look at the experiments in vitro, again, we can see that when we try to test the lymphocytes of these patients against, for example, mycobacterial strains, they have difficulties in the production of defense cytokines as, for example, interferon gamma. And this explains why the susceptibility to infection is higher in clinical practice. In addition, even when you look at the animal models, you can see that the risk of infection is increased in absence of the enzyme activities. So, looking at the study in mice, it is observed that alpha-mannnosidase is essential for the glycosylation and is required for the regulatory T-cell migration and allograft tolerance. This explains why there is an increased risk of infections in absence of these activities. These results are confirmed in four separate experiments and they can be observed even looking at the different types of cells with fluorocytomatic analysis. So, on the basis of these findings You can understand why, in clinical practice, the problem of infection is so relevant.
And when should we compare the clinical findings with the immunodeficiency? At the end it is quite interesting to see that the heterogeneous spectrum of this disorder demonstrates how alpha- mannosidosis can overlap the common antibody- mediated immunodeficiency, including selective IgA deficiency because of frequent respiratory and gastrointestinal infections but also X- linked Agammaglobulinemia for the absence of mature B cells in certain patients and recurrent bacterial infections. And also common variable immunodeficiency for hypogammaglobulinemia, poor vaccine response, recurrent respiratory infections. Some patients that present conditions that are quite similar to the combined immunodeficiencies that involve T and B cells, so as a SCID, for example, or hyper- IgM syndrome. And similarly, there are a lot of similarities in certain patients with complement deficiencies because of recurrent bacterial infections, particularly Neisseria, and phagocytic function disorders as CGD and also LAD, and other syndromic immunodeficiencies. So the spectrum is very heterogeneous. What does it mean? This means that in clinical practice, it is important the multidisciplinary approach, because when you look at the management, I mentioned before the enzyme replacement therapy. This therapy works, and it works also in the immune system. So it is important to have an expert of metabolic disorders. It is important to have a genetician in the team, but it is also important to have an immunologist. And in fact, the team, you can see, includes several types of specialists, including psychologists, immunologists, physiotherapists, orthopedic consultants, speech- language consultants, and other kinds of specialists, also nutricionists, occupational therapists, consultant neurologists, but when you take into account the results using enzyme replacement therapy, you can see that in addition to improvement in quality of life in the mobility, in self- care, in usual activities, in pain discomfort, and anxiety depression, we have a significant improvement in serum IgG. This is observed in the pediatric population, but it is observed also in adult population. And this is extremely important, because this explains that with enzyme therapy, it is possible to survive longer and also to survive with a better quality of life, reducing the risk of infections. So considering the findins of these studies using the enzyme therapy, you can understand why it is so important to put and to include the immunologists in the clinical group. When we consider these recurrent infections in patients, we should first of all remember the problem of upper respiratory tract infections and respiratory infections in general. I mentioned before the pneumonia risk in children between 30 and 50 years of age. Moreover, there is a problem of viral and bacterial susceptibility, and the impact on quality of life and prognosis of these patients. When you consider this, of course, you should remember the diagnosis of AM in patients with a suspicion of immunodeficiency. Of course, you should start with initial immunological screening tests and then, in case of doubt because of other red flags, you should move towards the genetic confirmation of AM. When you take into account this disorder and the type of tests that should be performed, you should remember the overlaps with other immunodeficiency, the risk of misdiagnosis due to similar clinical signs, and the need for precise immunological workup. And in this workup, you should test, first of all, the Ig levels, because I demonstrated before that in absence of enzyme replacement therapy, the Ig are lower than usual. Then the response to vaccination, so looking at specific IgG against diphtheria, tetanus, toxoids, for example, or what you can test in your lab, and the lymphocytes of populations because of the heterogeneous spectrum of the disorder.
And thereafter, you should remember the pitfalls in differential diagnosis. The fact that in some cases you can have late recognition of disease, the fact that you can have overlapping symptoms with other primary immunodeficiency or metabolic disorders, Giacomo will enter in details of this, and the importance of multidisciplinary collaboration in order to reach an appropriate diagnosis of a disease that is very rare. Thank you very much for your attention. Just a comment on vaccination, if I can add. My comment on vaccination is related to what usually happens in primary immunodeficiency, because usually in primary immunodeficiency, the approach is different according to the disease and according also to the risk of autoimmune disorders. So, vaccines could play a role in preventing infections with vaccine-preventable problems, and it is important also to remember the role of vaccination in parents of these children. The point is related to live attenuated vaccines, because if we have T cells disorders, at the end, these vaccinations are not recommended. So, it is very important to look at the immunoglobulin levels. If the T cells are normal, live attenuated vaccine can be administered. Otherwise, it is important to check which kind of defects we have and looking at vaccination and recommendations that are available for primary immunodeficiency. What does it mean? It means that usually in these patients, the normal vaccination plan can be followed. But if these defects are documented, live attenuated vaccine as measles, mumps, rubella and varicella cannot be administered because of the risk of reactivation. Otherwise, if the enzyme replacement therapy is ongoing and the Ig levels as well as the function of the lymphocytes is normal, even live attenuated vaccine can be administered. In addition, annual influenza vaccination is recommended and also a complete coverage against pneumococci. That means not only premococcal vaccination in the first year of life, but also vaccination later, starting from the age of five years with boosters every five to 10 years is recommended, as well as boosters against necessary meningitis. This means that these patients are at risk of infections. We should try to protect them at best. The only limitation is related to, you know, now in the majority of the countries, IPV is used instead of OPV. For sure, these patients require IPV vaccination and not OPV. And regarding BCG, BCG that usually is administered. very early is not administered if an early diagnosis is done in these patients before they complete the diagnostic approach and before arriving to a final diagnosis. So in conclusion I think that it is very important to highlight the role of multidisciplinary teams, the importance of collaboration for a comprehensive care. Thank you very much.
[00:25:45] Prof. Giacomo Biasucci: So once again hi everyone and many thanks to Susanna for your very comprehensive and excellent presentation. I have just one question if I may. Do you think there is room for any further therapeutic option to enhance the functions of leukocytes in these patients besides the ERT? I mean we notice that ERT leads to an increase in IgG concentrations. Is this enough to control the recurrent infections or do you think there may be some other therapeutic options to put in there? You know usually in patients with immunodeficiency it is very important to balance the stimulation of the direct stimulation of the immune system because sometimes the immune system can be associated also with autoimmunity. So in my opinion enzyme therapy is very useful because it permits to increase the IgG levels. In addition what we can consider is for example the use of some immunostimulants for reducing recurrent infections such as OM-85 or pidotimod that are administered before the winter months can permit to reduce the immune reactivity and to increase the immune tolerance. In addition vitamin D can be useful in these patients in order to try to stimulate the immune system. But I will try to work only on these products not on something stronger. For example in glycogen storage disease type 1b in which we have some problems in phagocytosis for example and neutrophil functions we use granulocyte colony stimulating factor in order to prevent bacteria or fungi infection. Do you think there could be a chance for this therapy also in alpha man or it's not the case? I don't suggest to use. I think that at the end an inappropriate stimulation can also create autoimmunity. So I think that the available results are not in favour of this kind of approach. Okay thanks.
[00:28:41] Prof. Susanna Esposito: Now the floor is yours Giacomo. Thank you.
[00:28:44] Prof. Giacomo Biasucci: Thanks a lot. I will try to get my remote control. Okay. I can go. I can go further on with my slides. Just a minute. Okay. Okay. I will skip this slide because you already heard about the genetic basis of alpha-mannosidosis in the presentation by Professor Esposito. I just want to underline that this is an autosomal recessive inherited disease. That means that both parents must be heterozygous for this defect and this means that they have 25% possibility of having an unaffected child and 25% of having a heterozygous child. In this, a recurrence rate accounts for each pregnancy, of course. I skip also this one because Professor Esposito Already mentioned about the pathogenesis of this accumulation of mannose-rich oligosaccharides in the lysosome quite ubiquitously in all tissues and this leads cytotoxicity and so apoptosis phenomena. And these are the red flags which each general pediatrician and each physician should bear in mind in order to think about the possibility of facing with this progressive and debilitating disease because the early is better, of course. Once we have stated that there is a continuum spectrum of severity and of clinical features, we also understand why the classification has changed in the recent years, focusing on the severity and on the continuum spectrum and changes in the clinical features that may occur starting from early childhood to later years, and this is correlated to a higher life expectancy once the clinical symptoms occur firstly in adulthood. So, we should think about and remind that there are some main areas that could be suggested for alpha-mann diagnosis, hearing loss, for example, cognitive impairment, and if these symptoms are combined with the current infections in immunodeficiency consequences or skeletal involvement, then the diagnosis of alpha-mann must be considered. Once we have a clinical suspicion, we can go to a laboratory workup already mentioned by Susanna earlier on, and then we have two possibilities. Once we have found elevated oligosaccharide in urine, we can go to the enzyme activity assays on peripheral leukocytes, for example, or straight to the gene analysis. The genetic confirmation, of course, enables us to provide genetic prenatal counseling and also prenatal diagnosis based on the enzymatic testing or genetic testing on fetal cells coming from chronic delay or amniotic cells. We know that there are several clinical features that both childhood and adulthood may present, but there are some of these clinical features that are more common in the childhood, for example, facial dysmorphisms, as represented in this slide, namely macrocephaly, prominent frontal bossing, saddle nose deformity, highly arched eyebrows, periorbital edema, evident in this child, bulbous nasal tip, which is quite common in all these children and also in adults, as well as smooth philtrum or thin upper lip, and prognathism, which is quite evident in this slide, this picture. And the same occurs for the ligamentous laxity or skeletal abnormalities, namely kyphoscoliosis, for example, or lordosis or scoliosis, which are very common in our patients, or gibbous deformity, such as in this picture, in this child. Also, we can also have mild to moderate hepatomegaly or splenomegaly and another quite common feature is inguinal hernia, for example, as described in this picture here. I will not go into details about immunodeficiency and, of course, all the consequences of immunodeficiency because Susanna has already mentioned all of them very thoroughly.
I come to other clinical features that are present either in childhood or in adulthood and these are especially delayed language acquisition or psychomotor and speech delay or movement disorders, which are more common in childhood, to go to ataxia or psychiatric symptoms or intellectual disability, which is more evident and more present in adult patients. This includes also depression, anxiety, hallucinations, and as for motor problems and movement disorders, many of our patients appear to be clumsy, for example, hypotonic or ataxic. Again, I will not focus on recurrent respiratory infections because it's already been focused by Professor Esposito. Sorry, I'm going back and not forward. Okay. This is a prominent feature, a major feature, very, very common in childhood. Mixed hearing loss, especially sensorineural or mixed hearing loss, is a prominent and preeminent feature we can find in our children and, I'm sorry, I cannot, okay, and based on these findings, many diagnostic flowcharts have been proposed. One of these is represented in this slide by some of our Italian colleagues and it's important to notice how, starting from hearing impairment or speech delay, if this finding is combined with two or more than two clinical manifestations, such as cognitive delay, motor disturbances, or facial features, we should, in this case, we should really think about the possibility of diagnosis of alpha-mannosidosis and refer the patients to an expert metabolic center, as well as starting from mental retardation, this is more common in adult patients, as we already mentioned before, combined with psychiatric manifestations. If, in the presence of other clinical features, for example, hearing impairment, intellectual disability, and so on, also in this case, alpha-mannosidosis diagnosis must be considered. Okay, based on this consideration, also in our center, we collected some urine samples for 48 children, sharing as main clinical feature the hearing impairment or hearing loss, even from birth, and we collected 48 urinary samples from December 22 to August 25.
Of these urinary samples, we found two elevated oligosaccharide concentrations in two of these. In one patient, the enzymatic activity was subsequently measured and found to be normal, while the second one is still under investigation. We have adopted this model as a screening test for selected children with hearing loss in order to find out a possible diagnosis of alpha-mannosidosis, once we have, of course, an effective therapy, as we are going to focus on. Thank you. Of course, and also Susanna already mentioned this, There are many possible diagnostic overlapping with the alpha- mannosidosis. For example, some syndromes, such as Cantú syndromes, or some other metabolic disorders are already also involving lysosomal storage disease, such as mucopolysaccharidosis, for example, that share some clinical features as for example coarse facial features, or multiple dysostosis with the alpha-mannnosidosis. If we think about Cantú syndrome, for example, I can show some pictures of girls affected by Cantú syndrome, and you can see, of course, the coarse facial dysmorphisms, and also some characteristic problems involving ribs, for example, but in this case, we can also have hypertrichosis, which is not that common in alpha-mannnosidosis, or heart defects.
To move forward to other possible differential diagnoses, here you have the example of mucopolysaccharidosis type I, which is a continuum and has got various degrees of severity, ranging from Hurler, which is the most severe form, with mandatory contractures and short statures, moving to the Scheie form, which is the milder form of the disease, and it makes the diagnosis hard to find, of course. But also, mucopolysaccharidosis should be ruled out in order to assess our final diagnosis of alpha-mannnosidosis, because you see many of these clinical features are very overlapping. And what about growth impairment? In mucopolysaccharidosis, for example, it's mandatory, but we also know that in some patients affected by alpha-mannosidosis, we can also have difficulties to reach the third centile of the general population, as shown in this study, in this multicenter study, and these data are confirmed, for example, in this single-center study from our Polish colleagues, which demonstrate that AM patients grow slowly, with no growth acceleration observed during the adolescence, and finally reaching the third percentile in not all the case. There are some patients who are not able to reach the third percentile at their final height. Again, some other metabolic disorders need to be ruled out in our diagnostic flowchart, such as sialuria, mucolipidosis type 2 or 3, or sialidosis, which, of course, are also ultra-rare diseases, but share some clinical features with alpha-mannosidosis. So the diagnostic flowchart is very complex.
We should know this disease in order to make the final diagnosis, because we recognize, of course, what we already know. So, moving to the therapeutic options, you already saw these slides in the presentation of Susanna, just to summarize that we, in the past, had just one chance linked to the hematopoietic stem cell transplantation with related mortality and high rate of complications, and in the recent years, starting from January 2018 in Europe and 2023 in the U. S., the enzymatic replacement therapy was approved. With velmanase alfa availability, this is a drug which should be delivered intravenously once a week in our patients. As I mentioned before, before having the possibility to use ERT, we only had to rely on the hematopoietic stem cell transplantation and I show you this very recent data of a study who collected 21 patients with alpha-mannnosidosis who underwent the HSCT and the results were that among children with clinical symptoms, improvement was documented in hepatomegaly. The percentage of hepatomegaly dropped from 40% to 10% after transplant. The recurrent infection dropped from 62% to 30% and hearing disorders from 85% to 65%. There were no concerns about safety of this transplantation, but you see in 13 patients out of 25, mild delays persisted in intellectual development, mild delays persisted post- transplant in the vast majority of the patients. So also this therapeutic option does not solve all the problems linked to a late diagnosis of alpha-mannnosidosis. And coming to the velmanase alfa therapy, this study aimed at defining the responders to velmanase alfa by defining some clinical domains. They identified some clinical domains and the related endpoints, for example serum oligosaccharides for pharmacodynamic domain, three- minute stair- climb test or six- minute walking test and forced vital capacity percentage predicted for functional domain, some specific charts for quality of life. And they also identified, if I can go forward, okay, they also defined a minimal clinical important difference for each of these endpoints, defining as responders in a domain a patient achieving established MCID in at least one endpoint of a domain, and as a global responder to a treatment, a patient responding in at least two domains. And the results were very promising. You can see the efficacy of the therapy increases with the treatment duration, with 79% of global responders after one year and 88% of global responders after 29 months of therapy. Again, this improvement was not only confined to the biomarker reduction effect, that means oligosaccharide reduction, but also included the quality of life and functional parameters considered in the population, and were also evidence for improvement linked to the length of the treatment. And there were also meaningful improvements in both adults and children with the duration of the therapy. 100% of responders in the pediatric population, of course, they responded better because the earlier the diagnosis, the better is the response to the ERT, and this is already known for any kind of enzymatic replacement therapy in any diseases. And also, with respect to pain and discomfort, we found a relevant reduction and amelioration of these symptoms, especially in the adult population. Thank you. These data were confirmed by more recent publications linked to two different Phase IIIb studies aimed to evaluate the long-term efficacy and safety of the enzyme replacement therapy up to 12 years in patients with a confirmed diagnosis of alpha-mannosidosis. And these studies, both studies, identified efficacy endpoints, six-minute walk tests, three-minute stair climb, pulmonary function using forced vital capacity, serum oligosaccharide, serum immunoglobulin G, and other, such as patient demographic or safety outcomes.
And the results are very promising. The six- minute walk test showed an increase in percentage or even also an absolute change in children, especially in children, but also in adults, already after eight years of follow- up, as well as the three- minute stair climb test. These results, as you can see here, are more evident in children, but also stabilized in the adult population. Also the respiratory function test showed an improvement in absolute change and percent change, especially in childhood, but also adult patient stabilized their function and in the first years also improved very significantly their functions. So, to summarize the efficacy and the effect of enzyme on the forced vital capacity, we can sum the results up by saying that the function was stabilized or improved within six years of therapy, improved clearly at eight years, and improved also after ten years of follow- up. These results were reached to a lesser extent also in adult population. And moving to the oligosaccharide concentration, these levels decreased in all patients treated with the enzyme replacement therapy, even after ten years of follow- up. And serum IgG concentration increased in all our patients, both in children and in adult patients, as you can see here. Okay. So, in conclusion, this study showed that there is no concern about the safety of enzyme replacement therapy in all the patients treated and followed up to 12 years after initiation of treatment, that treatment with velmanase alfa may successfully delay non- sensory nervous system disease, which is the limitation of this indication. I mean the ERT should be limited to a patient not having a central nervous system implication. And so there is a delay in non- central nervous system disease progression in all age groups. As many pediatric patients achieved improvement in motor and pulmonary fractions, and these functional outcomes in the adult cohort appear to stabilize during long- term treatment. Again, we should focus our attention on an early diagnosis of this disease in order to achieve the best treatment. results in our treatment option. Substantial decreases in serum oligosucuride concentrations and increases in IgG levels persisted throughout the observation regardless of age. So ERT was generally well- tolerated with mostly mild to moderate side effects and no safety concerns were identified with this extended treatment. So with this I thank you for your attention.
[00:55:49] Prof. Susanna Esposito: Thank you Giacomo and thank you very much. I have just a question for you. You know we are speaking about ultra-rare disease and I wonder in your opinion which is the most important challenge from a clinical point of view for this disorder?
[00:56:14] Prof. Giacomo Biasucci: I mean we have many clinical challenges because we can, I mean there is as you said a continuum in the occurrence and the onset of different clinical symptoms and so our challenge as physicians and above all pediatricians should be to intercept as early as possible these clinical symptoms and with regard to this I know that there are some discussions about the possibility to include alpha-mannosidosis in the neonatal screening test, universal neonatal screening test, just in order to prevent any kind of clinical features that may occur in the early childhood for example. Without any doubt hearing impairment is one of the most common clinical features we have to face with and we know that each newborn is screened for hearing impairment nowadays. So I mean this can help us finding these clinical features and then to move on a more definite and finalized diagnostic flowchart for example in order to rule out alpha-malnosidosis. So it's a big challenge of course. But first of all we have to, I mean to broaden the knowledge of this disease among physicians and pediatricians and also neonatologists I should say.
[00:58:07] Prof. Susanna Esposito: Thank you. Now there's a question for me but you know you can also add comments. How can I distinguish AM from other primary immunodeficiency syndromes that present with similar recurrent respiratory infections? It is not easy. For sure we should start as I said before by immunological tests, so Ig levels, lymphocyte subpopulations, response to vaccinations and then I think that it is important to remember the red flags that myself and Giacomo presented to you because only putting together laboratory tests and red flags we can move forward with the genetic diagnosis or anyway with testing the urine and moving towards enzyme activity and genetic diagnosis. I don't know if Giacomo do you want to add something. There is another question. You mentioned that intracellular accumulation of mannose-rich oligosaccharides may interfere with antibody response, chemotaxis and phagocytosis. What are the practical implications of this for managing infections? You know the practical implications are very important because this means that it is extremely relevant to vaccinate appropriately these patients. That means following the regular vaccination plan, adding influenza vaccination, premucoccal vaccination and meningococcal vaccination with annual vaccination against influenza and then with boosters for pneumo and meningo and then with an aggressive approach in presence of infections. So if the infection is probably bacterial, starting antibiotic therapy soon.
[00:59:55] Prof. Susanna Esposito: So there is no more time for questions.
[01:00:02] Prof. Susanna Esposito: I would like to thank all those that participated in the webinar and it has been a pleasure for us to do this presentation and we look forward to meet you again in Excellence in Pediatrics. Thank you very much.
[01:00:17] Speaker 3: Thank you. Bye bye. Thanks.