Radial-flow membrane chromatography is widely used for biopharmaceutical purification, particularly for separations carried out in the flow-through mode. In this article, we propose laterally fed membrane chromatography (LFMC) as an alternative to radial-flow membrane chromatography. LFMC has already been shown to be suitable for carrying out fast, high-resolution separations. In this study, we compare the performance of a radial-flow cation exchange membrane device with its equivalent LFMC device for flow-through separation of SP1, a recombinant protein that is currently under development by Sanofi Pasteur as a vaccine candidate. The flow-through of SP1 was monitored by UV absorbance while the breakthrough of the impurities such as host cell proteins was measured by analysing collected samples by Western blotting followed by densitometric scanning. The results obtained clearly demonstrated multiple-attribute superiority of the LFMC device in the above separation.