Ackman, Valeant lawyers say Allergan CEO oversaw campaign to discredit Valeant

BOSTON, Oct 20 (Reuters) - Billionaire investor William Ackman, whose fund is the largest shareholder in Allergan Inc. , and Valeant Pharmaceuticals said the botox maker's Chief Executive Officer David Pyott tried to discredit Valeant as it was making a hostile takeover bid, court documents showed.