PharmAthene Inc., an Annapolis, Md.-based biotech company focused on biological warfare threats, has agreed to go public via a reverse merger with Healthcare Acquisition Corp. (AMEX: HAQ), a special purpose acquisition company. The deal will provide PharmAthene with up to $70 million in cash, before payment of expenses. PharmAthene has raised over $76 million in VC funding from firms like Teachers' Private Capital, Canadian Medical Discoveries Fund Inc., MDS Life Sciences Technology Fund