Addition of pentoxifylline plus nifedipine to chemotherapy in patients with cisplatin-resistant cancers of the lung and other sites.

Eight evaluable patients with cisplatin-resistant non-small cell lung cancer (6 patients), small cell lung cancer (1 patient), or both breast and ovarian cancer (1 patient) were entered on a study to determine whether the addition of nifedipine plus pentoxifylline to cisplatin-based chemotherapy would result in increased chemotherapy efficacy. No patient responded to treatment. Myelosuppression may have been augmented by the nifedipine and pentoxifylline (median granulocyte nadir, 0.3 x 10(9)/L). Two patients developed febrile neutropenia. Nifedipine and pentoxifylline had to be stopped in two evaluable patients due to hypotension, and three additional inevaluable patients withdrew from the study due to nifedipine-pentoxifylline toxicity before receiving their chemotherapy. There was no indication that other types of chemotherapy toxicity were increased by the addition of nifedipine and pentoxifylline. A major problem with the strategy followed in this protocol was that patients whose tumors had failed to respond to cisplatin-based regimens were often too ill to tolerate additional cisplatin, particularly when accompanied by nifedipine-associated hypotension.