Analysis of the Authorized Target Populations for Fixed Dose Combination Products Between 2000 and 2017 Reveals Discrepancies Between EMA's and FDA's Views on Initial Dual-Therapy.

BACKGROUND: A fixed dose combination (FDC) product containing two components can be authorized for the use in 3 conceptual scenarios (1) as substitution for a treatment regimen containing both components given separately (substitution therapy) or (2) as replacement for a treatment regimen where the patient currently receives one of the components (add-on therapy) or (3) initial treatment of patients naïve to both components (initial combination therapy). METHOD: Trends in European Medicine Agency (EMA) and Food and Drug Administration (FDA) approvals of FDC products for the 3 scenarios were explored by comparing the therapeutic indications retrieved from the EMA and FDA websites for FDCs approved between January 2000 and April 2017 within 5 selected therapeutic areas: type 2 diabetes mellitus (T2DM), asthma, chronic obstructive pulmonary disease, hypertension, and human immunodeficiency virus (HIV) infection. RESULT: Approval decisions between EMA and FDA were largely aligned for the substitution therapy and add-on therapy scenarios. Discrepancies were found for the initial combination therapy scenario. CONCLUSION: Since EMA and FDA rely on similar conceptional models when approving FDCs, the reasons behind this general disparity are not clear, but may be found in the lack of evidence from the registration studies. Sponsors and health authorities should work collaboratively on closing that gap.

Biodistribution and PET imaging of a novel [68Ga]-anti-CD163-antibody conjugate in rats with collagen-induced arthritis and in controls.

PURPOSE: The hemoglobin scavenger receptor CD163 is exclusively expressed on monocytes and tissue macrophages, also at sites of inflammation. We examined whether gallium-68 (Ga-68)-labeled anti-CD163-antibody can detect the receptor in vivo. PROCEDURES: We radiolabeled anti-CD163 antibody with Ga-68 and evaluated stability and binding specificity of the conjugate ([(68)Ga]ED2) in vitro. Furthermore, tracer biodistribution was assessed in vivo in healthy rats and rats with acute collagen-induced arthritis (CIA) by MicroPET and tissue analysis. RESULTS: Radiosynthesis of [(68)Ga]ED2 antibody yielded a tracer with high-specific activity and radiochemical purity. [(68)Ga]ED2 bound specifically to CD163 in vitro. In rats, [(68)Ga]ED2 rapidly accumulated in macrophage-rich tissues. The arthritic paws exhibited a low but significant [(68)Ga]ED2 uptake. Interestingly, the systemic distribution was also changed in the sense that a significantly higher liver uptake and lower spleen uptake of [(68)Ga]ED2 was measured in CIA rats that accordingly showed a corresponding change in level of CD163 expression. CONCLUSIONS: [(68)Ga]ED2 specifically binds CD163 in vitro and in vivo. Biodistribution studies in CIA rats suggest that this novel tool may have applications in studies of inflammatory diseases.