Reversal of doxorubicin and cisplatin resistance in vivo in murine leukemias by the calcium antagonist RO 11-2933.

The ability of RO 11-2933 to modulate in vivo Doxorubicin and Cisplatin antitumor activity has been evaluated in sensitive and resistant P388 and L1210 murine leukemias. A reversal of both Doxorubicin or Cisplatin resistance has been observed when P388/Dx or L1210/CP tumor bearing mice received multiple treatments of the antitumor agent plus 30 mg/Kg of RO 11-2933. No modification of Doxorubicin or Cisplatin effect has been observed in sensitive tumors. The results obtained indicate that RO 11-2933 might represent a promising agent for the reversal of multidrug resistance.