Phase 1 pharmacokinetics and phase 3 efficacy of testosterone nasal gel in subjects with seasonal allergies
Introduction: NATESTO® testosterone nasal gel (TNG) is a liquid gel that is applied in the nose for the treatment of male hypogonadism. There is a reasonable concern that administration of TNG to patients with active rhinitis could modify absorption. Results from two clinical studies are reported wherein subjects with allergic rhinitis (AR) subjects are treated with TNG.
Methods: The 24-hour pharmacokinetics (PK) and relative bioavailability of serum total testosterone (sTT) from TNG (11 mg tid) were determined using a phase 1 Latin-square design with 18 eugonadal AR subjects crossed over between asymptomatic, symptomatic-untreated, and symptomatic-treated (oxymetazoline) conditions. Allergy symptoms, assessed using Total Nasal Symptom Score (TNSS), were induced using grass pollen in an allergy challenge chamber (ACC) prior to administration of TNG. The data are discussed in relation to results from a phase 3 study in 306 hypogonadal patients which compare clinical outcomes of AR and non-AR patients treated with TNG.
Results: PK analysis (Tmax, maximum observed concentration [Cmax], area under the curve [AUC]) of sTT showed no difference in the rate or extent of absorption of exogenous testosterone from TNG as a function of allergy symptoms. The relative bioavailability also showed all three conditions to be equivalent. However, pre-dose mean sTT in AR patients was 21‒25% lower when symptomatic vs. asymptomatic, which is attributed to the allergic reaction. A large phase 3 study, based predominantly on PK measures of sTT, showed that clinical outcomes for AR and non-AR patients treated with TNG were identical, including the percentage of patients in the eugonadal range, hormone profiles, and adverse events.
Conclusions: AR does not affect absorption of TNG. Patient outcomes for long-term treatment with TNG for up to one year are not dependent on AR history.
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