Reversion of Chemoresistance in Aggressive Lymphoma by Quinine. A Phase II Trial.

Abstract

Multidrug resistance has been one of the most studied mechanisms of cancer cell resistance to chemotherapy. Evidence of its involvement in hematological malignancies is known since many years. One well-designed phase I trial showed that about 20 to 25% of patients strictly resistant to EPOCH schedule could become responsive again by the addition of Dex-verapamil (J Clin Oncol 1995; 13: 1995–2004). We decided to perform a phase II trial to evaluate whether quinine could reverse resistance to chemotherapy in aggressive lymphoma. Methods: Patients included had all received at least two lines of chemotherapy including CEOP (cyclophosphamide 750mg/m2, epirubicine 60mg/m2, vincristine 1.4mg/m2 IV day 1 and prednisone 40mg/m2 orally day1 to day 7) and were demonstrated as strictly refractory to CEOP i.e. either no change or progression. Q-CEOP was administered as follows: quinine 30-mg/kg/day for two days from d0 to d1 as a continuous infusion, CEOP at the beginning of d1. Results: 15 patients have been included with the following characteristics: median age: 52 years (32–64), 66% stage III–IV, 60% elevated LDH. The median number of previous regimens was 3 (2–5). 13 patients had diffuse large B cell lymphoma including 3 with previous history of follicular lymphoma. Two had mantle cell lymphoma. Seven patients were included directly since they were initially refractory to CEOP while eight were shown refractory after two further cycles of CEOP. Epirubicin pharmacokinetics was not influenced by quinine. Mean dose intensity of epirubicin was 94%. Toxicity was mild. 4 responses were observed at the end of treatment including 2 complete and 2 partial responses (26%, IC 95%: 8–55%). Only the 2 CR patients are still alive with no evidence of disease at 35+ and 61+ months. Conclusion: These results add further arguments to confirm that MDR1 plays a significant role in resistance to chemotherapy in lymphoma. Quinine allowed unexpected long term remission in 2 responding patients.