Immunotherapy maintenance in acute non-lymphocytic leukaemia

Between January 1975 and December 1977, 264 adult patients with acute non-lymphocytic leukaemia entered the Australian National Leukaemia Trial. Of 251 evaluable patients, three induction regimens achieved similar complete response (CR) rates. CROP (cytosine arabinoside, daunorubicin, vincristine, prednisolone) produced CR in 41% of patients, 7 and 3 (cytosine arabinoside, daunorubicin) in 42% and 7 and 3 plus hydroxyurea in 52%. Remission duration and survival were similar when induction regimens were compared. Forty-five patients reaching maintenance therapy were randomised to either chemo-immunotherapy (BCG plus intradermal leukaemic blast cells) or chemotherapy alone. The duration of CR in these two groups was almost identical, though patients receiving chemotherapy alone had prolonged survival (median 161 weeks) when compared to the chemo-immunotherapy group (84 weeks, p = 0 . 07). Institutions with less developed supportive facilities reported lower CR rates (p = 0 . 04). Leucocytosis (greater than 100 X 10(9)/1) and older age (greater than 50 years) were associated with shortened survival. The Trial has failed to show any advantage for this form of immunotherapy.