<PAGE>   1
                                                                    EXHIBIT 11.1

                  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.

<TABLE>
<CAPTION>
                                                                                                                            INCOME
                                                                                              AVERAGE                       (LOSS)
                                                             DAYS                              SHARES         INCOME         PER
                                            SHARES        OUTSTANDING  SHARES X  DAYS       OUTSTANDING       (LOSS)        SHARE
<S>                                         <C>           <C>          <C>                  <C>               <C>           <C>
NINE MONTHS ENDED SEPTEMBER 30, 1998:
                                            15,459,166        11          170,050,826
                                            15,460,684        71        1,097,708,564
                                            15,465,729         1           15,465,729
                                            15,467,281        98        1,515,793,538
                                            15,497,443        92        1,425,764,756
                                            15,503,745         1           15,503,745
                                                              274       4,240,287,158  /274  15,475,501      (16,546,000)    (1.07)


NINE MONTHS ENDED SEPTEMBER 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
                                            22,555,977         8          180,447,816
                                            22,560,179        27          609,124,833
                                            22,697,866        20          453,957,320
                                            22,719,999         6          136,319,994
                                            22,723,765         3           68,171,295
                                            22,723,927        13          294,411,051
                                            22,773,927         5          113,869,635
                                            22,775,753         9          204,981,777
                                            22,788,071         1           22,788,071
                                                              273       5,832,657,069  /273  21,365,044       (7,305,000)    (0.34)



QUARTER ENDED SEPTEMBER 30, 1998:
                                            15,497,443        91        1,410,267,313
                                            15,503,745         1           15,503,745
                                                              92        1,425,771,058   /92  15,497,512       (6,059,000)    (0.39)




QUARTER ENDED SEPTEMBER 30, 1999:           22,555,977         8          180,447,816
                                            22,560,179        27          609,124,833
                                            22,697,866        20          453,957,320
                                            22,719,999         6          136,319,994
                                            22,723,765         3           68,171,295
                                            22,723,927        13          295,411,051
                                            22,723,927         5          113,869,635
                                            22,775,753         9          204,981,777
                                            22,788,071         1           22,788,071
                                                              92        2,085,071,792   /92  22,663,824       (5,399,000)    (0.24)
</TABLE>