1 ARONEX PHARMACEUTICALS, INC. AND SUBSIDIARIES STATEMENT REGARDING COMPUTATION OF PER SHARE EARNINGS The following reflects the information used in calculating the number of shares in the computation of net loss per share for each of the periods set forth in the Statements of Operations. INCOME AVERAGE (LOSS) DAYS SHARES INCOME PER SHARES OUTSTANDING SHARES X DAYS OUTSTANDING (LOSS) SHARE SIX MONTHS ENDED JUNE 30, 1999: 16,379,309 3 49,137,927 16,415,664 50 820,783,200 22,415,664 14 313,819,296 22,463,211 21 471,727,431 22,474,987 1 22,474,987 22,494,671 1 22,494,671 22,495,050 64 1.439,683,200 22,496,505 26 584,909,130 22,555,435 1 22,555,435 181 3,747,585,277 /181 20,704,891 (1,906,000) (0.09) SIX MONTHS ENDED JUNE 30, 2000: 22,853,782 21 479,929,422 22,873,782 3 68,621,346 22,876,765 4 91,507,060 22,877,930 12 274,535,160 22,879,230 23 526,222,290 22,888,646 6 137,331,876 22,905,144 14 320,672,016 22,922,078 54 1,237,792,212 25,854,652 44 1,137,604,688 25,890,127 1 25,890,127 182 4,300,106,197 /182 23,626,957 (7,918,000) (0.34) QUARTER ENDED JUNE 30, 1999: (BASIC) 22,495,050 64 1,439,683,200 22,496,505 26 584,909,130 22,555,435 1 22,555,435 92 2,047,147,765 /91 22,496,129 1,269,000 0.06 QUARTER ENDED JUNE 30, 1999: 22,652,230 19 430,392,370 (DILUTED) 22,652,380 14 317,133,320 22,652,592 8 181,220,736 22,661,974 10 226,619,740 23,236,687 14 325,313,618 23,237,687 25 580,942,175 23,297,072 1 23,297,072 91 2,084,919,031 /91 22,911,198 1,269,000 0.06 QUARTER ENDED JUNE 30, 2000: 22,922,078 47 1,077,337,666 25,854,652 44 1,137,604,688 25,890,127 1 25,890,127 92 2,240,832,481 /92 24,356,875 (4,466,000) (0.18)