Pre-activated antiviral innate immunity in the upper airways controls early SARS-CoV-2 infection in children.

Children have reduced severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection rates and a substantially lower risk for developing severe coronavirus disease 2019 compared with adults. However, the molecular mechanisms underlying protection in younger age groups remain unknown. Here we characterize the single-cell transcriptional landscape in the upper airways of SARS-CoV-2-negative (n = 18) and age-matched SARS-CoV-2-positive (n = 24) children and corresponding samples from adults (n = 44), covering an age range of 4 weeks to 77 years. Children displayed higher basal expression of relevant pattern recognition receptors such as MDA5 (IFIH1) and RIG-I (DDX58) in upper airway epithelial cells, macrophages and dendritic cells, resulting in stronger innate antiviral responses upon SARS-CoV-2 infection than in adults. We further detected distinct immune cell subpopulations including KLRC1 (NKG2A)+ cytotoxic T cells and a CD8+ T cell population with a memory phenotype occurring predominantly in children. Our study provides evidence that the airway immune cells of children are primed for virus sensing, resulting in a stronger early innate antiviral response to SARS-CoV-2 infection than in adults.

[Management of Primary Ciliary Dyskinesia]. / Management der Primären Ciliären Dyskinesie.

Primary Ciliary Dyskinesia (PCD, MIM 242650) is a rare, hereditary multiorgan disease characterized by malfunction of motile cilia. Hallmark symptom is a chronic airway infection due to mucostasis leading to irreversible lung damage that may progress to respiratory failure. There is no cure for this genetic disease and evidence-based treatment is limited. Until recently, there were no randomized controlled trials performed in PCD, but this year, data of the first placebo-controlled trial on pharmacotherapy in PCD were published. This cornerstone in the management of PCD was decisive for reviewing currently used treatment strategies. This article is a consensus of patient representatives and clinicians, which are highly experienced in care of PCD-patients and provides an overview of the management of PCD. Treatments are mainly based on expert opinions, personal experiences, or are deduced from other lung diseases, notably cystic fibrosis (CF), COPD or bronchiectasis. Most strategies focus on routine airway clearance and treatment of recurrent respiratory tract infections. Non-respiratory symptoms are treated organ specific. To generate further evidence-based knowledge, other projects are under way, e. g. the International PCD-Registry. Participating in patient registries facilitates access to clinical and research studies and strengthens networks between centers. In addition, knowledge of genotype-specific course of the disease will offer the opportunity to further improve and individualize patient care.

[Biometrical methods for the proof of efficacy in regulatory submissions. Non-inferiority in clinical studies]. / Biometrische Verfahren zum Wirksamkeitsnachweis im Zulassungsverfahren Nicht-Unterlegenheit in klinischen Studien.

The increasing number of approved efficacious therapies for various indications raises the question of whether the inclusion of a placebo group is still justified. In addition, pharmaceutical companies and regulatory agencies acknowledge that it may be sufficient to prove that a new therapy is comparable to an approved reference therapy regarding efficacy and safety in some situations. This becomes especially striking for the approval to market a generic drug. Another, perhaps even more important example is the increasing resistance of bacteria which calls for new antibiotics based on new therapeutic principles without having the claim for better efficacy. In these situations, a comparable efficacy would constitute progress. In the present paper, we discuss the numerous methodological challenges and approaches to overcome these problems that occur when it is not possible or even not wanted to use the classic approach of a randomized placebo-controlled superiority trial. Here, the field of medical biometry, which has proved in the last 25 years to be an integral part of the development of new drugs, demonstrates its suitability as a flexible and scientifically based means to fulfil the requirements resulting from clinical practice. Starting from the fact that statistical methods are not able to prove "equality" of two treatments, "shifted" hypotheses are considered and their importance for the different study designs is discussed. We show how the classic hypotheses known from placebo-controlled clinical trials can be embedded in this concept. The implications of this approach for the analysis and interpretation of study results is further discussed. The relevant guidelines of the European and US regulatory agencies are taken into account.

[Statistical principles of "good clinical practice" in veterinary medicine--a position paper for planning, implementation and evaluation of empirical studies]. / Statistische Grundlagen von "Good Clinical Practice" in der Veterinärmedizin--ein Positionspapier zur Planung, Durchführung und Auswertung empirischer Untersuchungen.

The complexity of the design, conduct, analysis and evaluation of empirical studies necessitates a high degree of interdisciplinary collaboration in all areas of research. In order to make sure that no essential harmonisation is missed among the plenitude of processes, it has become common to provide direction on the essential operating procedures in so called "Good ... Practice" guidelines in recent years. In pharmaceutical research on human medicinal products guidelines on Good Clinical Practice have been an integral part of research and development in industry, academia, and the regulatory authorities for a long time. On the other hand, in the development and registration of pharmaceuticals for veterinary use such procedures are not yet established to this extent in Germany. Notwithstanding there being a lot of regulations on specialised subjects. This paper tries to summarise the current state of the discussion and to give an overview on the important points in the design, conduct, analysis and reporting of veterinary clinical studies mainly from an biometrical point of view.

Statistical considerations of FDA and CPMP rules for the investigation of new anti-bacterial products.

In this paper I investigate statistical properties of some guidance given by the FDA and by the CPMP on the planning, conduct and analysis of clinical trials with new anti-bacterial substances using an active control design. It is demonstrated that the non-inferiority margin proposed by the FDA has some undesirable features, and that the CPMP guidance may need further interpretation with respect to a statement that the non-inferiority margin may be smaller than 10 per cent for response rates >90 per cent. A new margin is proposed that combines the desirable properties from both the FDA and the CPMP guidance. It is also shown that the approximate unconditional tests that are in use in such trials are quite unreliable with respect to preserving the nominal type I error. Unconditional exact tests are presented as a remedy for this issue.

Controversies about sponsor initiated re-analyses of clinical trial data in the licensing process.

I present my experience with sponsor initiated re-analyses as a response to the regulatory agency's 'Mängelbericht', and the difficulties which arose from the fact that the regulatory agency was not involved in the plans for correcting mistakes or irregularities in the data and for the (re-)analysis of them. I also discuss the related problem when there are major discrepancies between the planned procedures laid down in the protocol and the actually applied procedures in the study report. I give examples for poor planning of a clinical study (sample size, statistical analysis, target variable(s)) and how this reduces the strength and value of a study. I introduce the phrase 'neutral party' as a means to resolve regulatory concerns about partiality in the sponsor's decisions, for example, introduction of new statistical models, different from the one planned, change in the order of the target variables, or dropping variables from the list of target variables.

Testing strategies in multi-dose experiments including active control.

Inferential test strategies for multi-arm trials are adapted or proposed for the special situation when more than one dose of a test treatment, placebo and active control(s) are compared. This includes between doses, dose-placebo and dose-active-control comparisons. The procedures refer to situations when detailed comparisons make sense only if the sensitivity of the trial has been shown, for example, if a dose-response relationship or a difference between active control and placebo has been established. Split strategies, hierarchical (assuming an order restriction among doses) or linked procedures are introduced. In linked procedures, equivalence to the active control will be established only if the dose is also shown to be effective as compared to placebo. All the inferential procedures control the experimentwise error rate in the strong sense for the respective sets of null hypotheses considered.

Therapeutic equivalence investigations: statistical considerations.

Therapeutic equivalence studies still present problems to regulatory reviewers from many perspectives. This paper is intended to discuss some of these concerns from the statistical viewpoint. There are, however, also some newer approaches which may be particularly useful for the investigation of therapeutic equivalence.

An adaptive method for establishing a dose-response relationship.

A multistage sampling method is proposed in dose-response trials, where dose adaptions can be performed in the preplanned adaptive interim analyses. The overall test for proving a dose-response relationship is performed by Fisher's product criterion for the p-values from the separate tests of a dose effect in the disjoint samples at the different stages. Based on these p-values decision boundaries for early stopping with the rejection of the global null hypothesis of no existing dose-response relationship are introduced. The power of the adaptive two-stage procedure using a particular adaptation rule is compared with the power of the test for a linear trend under analysis of variance assumptions in extensive simulations. The bias in estimation is also quantified. This procedure could be used for establishing a dose-response relationship without including a placebo treatment.

Clinical and statistical issues in therapeutic equivalence trials.

Absolute proof of efficacy can only be given by placebo controlled trials. It is, however, important to classify a drug within the spectrum of existing therapeutic alternatives and, where effective treatment is available, it may be imperative due to ethical considerations to demonstrate that one drug is as effective as another. The issue of therapeutic equivalence trials is discussed along the lines of the important items which should be defined in the protocol: a) the target parameter, which is the primary endpoint of the trial, b) the reference drug, which should be selected with respect to efficacy (superior to others), and safety (largest amount of data), c) the acceptance range, which depends on the primary endpoint, and its implication for the clinical endpoints of morbidity and mortality (the conventional acceptance range for bioequivalence trials does not apply), and d) the statistical procedures, which must take into consideration the unsuitability of the conventional power approach for confirming equivalence. In an equivalence trial, compared to those that are placebo-controlled, the proof that one drug is as effective as another relies much more upon the quality of conduct of the study according to Good Clinical Practice.

Cigarette smoking, gastric acidity and peptic ulceration. What are the relationships?

The influence of cigarette smoking on intragastric acidity was assessed in duodenal ulcer patients in symptomatic remission and in healthy volunteers in a retrospective study. Continuous 24-hr pH recordings in 150 nonsmokers and 174 smokers receiving placebo treatment were compared. Daytime intragastric acidity was higher in smokers with a median pH (interquartile range) of 1.56 (1.34-1.80) than in nonsmokers, who had a median pH of 1.70 (1.45-1.97) (P less than 0.001). There was no difference in 24-hr and nighttime median pH between the two groups. The small difference in daytime intragastric acidity in smokers and nonsmokers is unlikely to account for the increased prevalence of peptic ulcer disease in smokers. The analysis of smoking status in duodenal ulcer patients and healthy controls and males and females supports the general trend towards higher daytime acidity in smokers. Again, no differences in pH during the 24-hr or night period were found between the groups. The epidemiological and clinical correlation between smoking and duodenal ulcer disease is not adequately explained by increased intragastric acidity.

[Antisecretory effect of the H2-histamine receptor antagonist ranitidine in water-soluble tablets and film-coated tablets. Results of a randomized, placebo-controlled crossover study in humans]. / Antisekretorische Wirksamkeit des H2-Histaminrezeptor-Antagonisten Ranitidin in Form von wasserlöslichen Tabletten und Filmtabletten. Ergebnisse einer randomisierten, Plazebo-kontrollierten Cross-over-Prüfung an Probanden.

This clinico-pharmacological trial aimed to prove equivalence between the known film-coated tablets of ranitidine (Sostril Filmtabletten) and the novel dispersible tablets for the preparation of a drinkable solution (Sostril Aquatabs) on a pharmacodynamic level. Therefore, the influence of single oral doses of the two ranitidine preparations (2 X 150 mg p.e.m. each) and placebo on the gastric hydrogen ion concentration was studied in 12 healthy volunteers using a randomized cross-over design. pH-values of the gastric juice were measured and recorded continuously for 24 h. Median pH-values for the entire study period were 2.20, 2.15 and 1.40 for dispersible tablets, filmcoated tablets and placebo, respectively. During the night-time median pH-values of 3.45 for both ranitidine preparations and 1.40 for placebo were calculated. From these results it can be concluded that the novel dispersible tablets are equivalent to the ranitidine filmcoated tablets with regard to their pharmacodynamic potency.

[Double blind biometric study on postoperative effects of analgesics]. / Doppelblindstudie über postoperative Analgetikawirkungen.

A double blind trial to study the effects of analgetics was carried out in patients suffering from pain after third molar osteotomy. 204 patients were evaluated after random allocation to treatment with paracetamol 500 mg and paracetamol 500 mg plus codeine 30 mg. Statistical evaluation revealed a tendency for better analgesia using the combination of paracetamol and codeine. For further studies an exact stratification for sex and age is necessary. Sample sizes of 150 patients are necessary for each parameter.

Pattern of 24 hour intragastric acidity in active duodenal ulcer disease and in healthy controls.

Twenty four hour intragastric acidity was measured by continuous recording using intragastric combined glass electrodes in 46 duodenal ulcer patients within 48 hours of endoscopic confirmation of active ulceration. Acidity during predefined time periods was compared with that measured in 40 healthy controls without gastrointestinal disease: it was significantly higher in duodenal ulcer patients at all times, but 25% of ulcer patients had median 24 hour acidity within the interquartile range of the normal group. During the evening (18,00 to 22,00 h) ulcer patients had considerable acidity with a median of 39.8 (63.1-31.6) mmol/l (interquartile range) compared with 5.6 (22.3-0.4) mmol/l of controls. It is suggested that antisecretory treatment be directed to decrease this period of unbuffered acidity, as well as during the night, which is presently considered of prime importance.

Early evening ranitidine administration promotes faster duodenal ulcer healing.

In a prospective double-blind clinical trial, 141 patients with endoscopically diagnosed duodenal ulcer were randomly assigned to treatment with ranitidine 300 mg, taken either at 6 PM or at 10 PM. After 2 wk of treatment, 52 of 70 patients (74%) in the 6 PM treatment group had healed, compared with 32 of 64 patients (50%) taking ranitidine at 10 PM (p less than 0.01). After 4 wk, the cumulative healing rates were 100% and 94%, respectively, for the 6 PM and 10 PM treatment regimens. These results suggest that ranitidine, taken as a single daily 300-mg dose at 6 PM after dinner, provides more rapid duodenal ulcer healing than the same dose of the drug taken at 10 PM.

Day-to-day variation of 24-hour intragastric acidity.

Twenty-four-hour intragastric acidity was measured continuously using an intragastric electrode in 13 normal volunteers studied four times. Subjects were studied twice in the hospital and twice as outpatients. The dietary conditions were strictly controlled and the replicate studies were compared to assess the variability of such recordings of acidity. The accuracy of the technique was assessed, and a detection limit for differences was calculated for commonly used time periods. Over 24 h, during the night, during the day, and during the evening the technique is able to detect consistent changes of pH of greater than 0.1 units. During separate 5-min periods the limits of detection were considerably greater. This study demonstrates the variability of 24-h intragastric acidity and confirms that continuous monitoring is able to detect important changes of acidity under both hospitalized and ambulant conditions.