Randomized Comparison of Cladribine Containing Regimens and COP in Previously Untreated Patients with Small Lymphocytic, Marginal Zone and Follicular Lymphoma.

The aim of the study was to comparatively assess first-line treatment with cladribine alone or in combination with cyclophosphamide (CCR, cladribine-containing regimens) and COP (cyclophosphamide, vincristine, prednisone) in different subtypes of low-grade lymphoma. End points were complete remission (CR), overall response rate (ORR), incidence of chemotherapy-related side effects as well as freedom from progression (FFP) and overall survival (OS). From June’2000 to June’2005, 178 previously untreated patients (pts) were randomly allocated to receive 6 monthly courses of either CCR or COP in 17 centers in Poland. This analysis included 107 pts who have completed scheduled chemotherapy, including 45 pts with small lymphocytic (SLL, median age=64 years), 26 marginal zone (MZL, median age=58 years) and 36 follicular (FL, median age=65 years) lymphoma. Compared to COP, CCR induced higher CR rates in all treated groups (65% vs 15%, p=.005; 57% vs 10%, p=.02; 58% vs 12%, p=.03, respectively) but differences in ORR were not significant (92% vs 69%; 92% vs 60%; 79% vs 62%, respectively). Incidence of side effects did not differ significantly in CCR- as compared to COP-treated pts, e.i. infections (10% vs 7%; 14% vs 20%; 15% vs 0%, respectively), myelosuppression (31% vs 7%; 21% vs 20%; 30% vs 0%, respectively), and non-hematological adverse events (10% vs 14%; 7% vs 30%; 7% vs 22%, respectively). With a median follow-up of 12 months, median FFP was superior in CCR- as compared to COP-treated treated pts with SLL (43 vs 12 months, log-rank p<.03) or MZL (37 vs 7 months, log-rank p<.03) but not with FL (17 vs 22 months). Although the median OS has not been reached in any of the histological group so far, no difference in its duration is detected between CCR- or COP-treated pts. In summary, for pts with SLL, MZL and FL, first-line CCR regimens provided better CR and similar toxicity rates as compared to COP, which translated into longer FFP in SLL and MZL but not in FL pts. Although these results warrant larger number of pts and longer follow-up, they might suggest the choice of different front-line chemotherapy with or without immunotherapy in particular histological subtypes of low-grade lymphoma.