EXHIBIT 9(a)(2) HYBRIDON, INC. EXCHANGE AGREEMENT AND LETTER OF TRANSMITTAL TO TENDER AND TO ENTER INTO CERTAIN AGREEMENTS IN RESPECT OF ITS 9% CONVERTIBLE SUBORDINATED NOTES DUE 2004 IN EXCHANGE FOR ITS SERIES A PREFERRED STOCK AND EXCHANGE WARRANTS...Exchange Agreement • February 6th, 1998 • Hybridon Inc • Biological products, (no disgnostic substances) • New York
