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Clinical Study Options for locally acting nasal suspension products. Robert J. Meyer, MD Director, Div. Of Pulmonary and Allergy Drug Products CDER / FDA. Introduction. What are the options for a ‘clinical’ study? What is the question to be answered?
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Clinical Study Optionsfor locally acting nasal suspension products Robert J. Meyer, MD Director, Div. Of Pulmonary and Allergy Drug Products CDER / FDA CDER / FDA
Introduction • What are the options for a ‘clinical’ study? • What is the question to be answered? • Given the question, what is the best answer? • Observations and recommendations CDER / FDA
What are the options? • The disease in question is Allergic Rhinitis, primarily experienced and assessed subjectively • The basis of approval has been clinical studies with subjective symptom scoring • TNSS (rhinorrhea, congestion, sneezing, itch) • PD questions (onset of action, appropriate dose/interval) frequently addressed with differing designs CDER / FDA
Types of Studies: • “Natural” Clinical Study • Generally 2 - 6 week Parallel group study looking at comparative changes in TNSS over the treatment period • Patients are enrolled prior to or at start of season, randomized when symptomatic • Also allows for assessment of safety and tolerability over a reasonable period of use CDER / FDA
Types of Studies: • EEU study • Takes patient out of season and exposes them to high levels of a specific pollen to which they are all allergic • Symptoms are assessed in the short-term (over a period of hours) • Often used for assessing onset of effect, dose-finding CDER / FDA
Types of Studies: • Day in the Park Study • Cohort of patients with known allergen sensitivity, but low level of symptoms • Taken to an outdoor setting (“Park”) in cohort for natural exposure to allergen • Short-term efficacy and safety assessed • Also used for assessing onset, assessing dose-effects, duration of effects,… CDER / FDA
Types of Studies: • DPADP regards the natural clinical study to be the most informative for approval purposes • DPADP regards EEU and Day in the Park studies as more pharmacodynamic • Other “objective” endpoints in any of the study designs (nasal patency, markers of inflammation) are regarded as interesting, but not clinically validated CDER / FDA
Dose ln Dose Model of Nasal Spray Dosage Form Performance Clinical/PD Measurements Dosage Form Performance (Device and Formulation) Membrane (Nasal) Site of Activity Therapeutic Effect Drug in Solution Dosage Form GI Tract, Lung Blood Toxic/Ther. Effect Pharmacokinetic Measurement CDER / FDA
What is the Question for the Clinical study in the BE setting? • Is clinical study confirmatory or pivotal? • Depends on findings and interpretation of In Vitro and BE comparisons • “Confirmatory” • Study necessary to confirm a lack of important clinical differences as a part of larger BE package • “Pivotal” • Clinical study to primarily establish BE CDER / FDA
If Intent is to Confirm Other Data: • Design to broadly assure no important clinical differences • Rigorous showing of dose-response and strict equivalence between T and R not required • Comparison may be on one dose level of each to show comparable efficacy, safety and tolerability CDER / FDA
If Intent is to Establish BE: • Design must show sensitivity of the ‘assay’ (i.e., can detect dose-response); AND • Results must show that the dose-response curve of the T + R are “equivalent” • Clinical study would also compare relative safety and tolerability CDER / FDA
FDA experience: • Standard clinical studies of locally acting nasal products can easily fulfill confirmatory role • BE role would be VERY difficult with standard design / endpoints • PD studies (EEU, Day-in-the-Park studies) • MAY be better approach to BE, but unknown • May have a role in confirmatory setting CDER / FDA
FDA experience (continued): • Objective local PD endpoints (e.g., using markers of inflammation or measures of nasal patency) • unproven in sensitivity to dose-response • and/or not clinically validated • Other endpoints in standard trials (e.g., HRQOL instruments) • unproven as superior in sensitivity to dose-response CDER / FDA
If “Equivalence” In Vitro and Systemic Exposure are shown: • Main uncertainty will be drug particle size in the suspension formulation • More problematic in aqueous spray than aerosol • FDA now contemplating shifting the question asked of the clinical study in the BE package • Clinical Study would NOT “trump” lack of equivalence from In Vitro or systemic BA CDER / FDA
If “Equivalence” In Vitro and Systemic Exposure are shown: • Confirmatory Study: • Examine lowest dose of T+R • Statistical comparison between the lowest dose of T and R (vs. Placebo) • Assure that T is not meaningfully different from R • Under this paradigm • ? Best Study - 2 wk. Clinical, EEU, Park??? CDER / FDA