<ARTICLE> 5 <LEGEND> THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM (A) THE BALANCE SHEETS, STATEMENTS OF OPERATIONS, CASH FLOW STATEMENTS AND THE STATEMENT OF STOCKHOLDERS' EQUITY FILED AS PART OF ALTEON INC'S ANNUAL REPORT ON FORM 10-K FOR THE YEAR ENDED DECEMBER 31, 1998, AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH (B) ANNUAL REPORT ON FORM 10-K. </LEGEND> <MULTIPLIER> 1 <CURRENCY> U.S. DOLLARS <PERIOD-TYPE> YEAR <FISCAL-YEAR-END> DEC-31-1998 <PERIOD-START> JAN-01-1998 <PERIOD-END> DEC-31-1998 <EXCHANGE-RATE> 1 <CASH> 10,839,586 <SECURITIES> 13,292,666 <RECEIVABLES> 0 <ALLOWANCES> 0 <INVENTORY> 0 <CURRENT-ASSETS> 24,406,397 <PP&E> 2,985,156 <DEPRECIATION> 0 <TOTAL-ASSETS> 27,651,633 <CURRENT-LIABILITIES> 4,313,275 <BONDS> 0 <PREFERRED-MANDATORY> 0 <PREFERRED> 31 <COMMON> 188,147 <OTHER-SE> 23,150,180 <TOTAL-LIABILITY-AND-EQUITY> 27,651,633 <SALES> 0 <TOTAL-REVENUES> 1,320,538 <CGS> 0 <TOTAL-COSTS> 0 <OTHER-EXPENSES> 27,662,970 <LOSS-PROVISION> 0 <INTEREST-EXPENSE> 3,610 <INCOME-PRETAX> (26,346,042) <INCOME-TAX> 0 <INCOME-CONTINUING> (26,346,042) <DISCONTINUED> 0 <EXTRAORDINARY> 2,207,205 <CHANGES> 0 <NET-INCOME> (28,553,247) <EPS-PRIMARY> (1.57) <EPS-DILUTED> (1.57)