This paper explores the idea that spatial planning-triggered satellite industrial platform-type concentrations may, over time, automatically gain the capacity to generate substantial agglomeration economies and ultimately transform into entities capable of stimulating self-perpetuating growth. Applying the lexicon of agglomeration theory, the idea is explored in the context of the spatial dynamics of the pharmaceutical industry in Ireland. Spatial concentration indices indicate a particularly high level of spatial concentration in one of the industry’s sub-sectors, namely, drug substance production. Based on interview data and secondary sources, a detailed investigation of the spatial dynamics of the Irish concentrations suggests that, while some agglomeration advantages have emerged, they remain relatively limited and have played only a minor role in shaping local industrial concentration. They are mainly of the urbanisation type, relating particularly to the pooled market for workers. The evidence serves to show that the kind of spatial planning-triggered satellite industrial platforms in late-developing economies do not automatically start generating substantial agglomeration economies and crucial technological spillovers, not even after, as in the case of the Cork pharmaceuticals concentration, nearly 40 years of existence.