Though doubtless pleased with Nuedexta, Avanir Pharmaceuticals Inc.'s approved therapy for pseudobulbar affect (PBA), Otsuka Pharmaceutical Co. Ltd. may have been playing it safe with regard to chances in the lucrative Alzheimer's disease (AD) agitation market, offering $17 per share in cash, or $3.5 billion, in the buyout expected to close during the first quarter of next year.