Abstract
Abstract
Background: Early MDS becomes more advanced as immature myeloid cells proliferate, angiogenesis increases, genetic lesions accumulate, and tumor suppressor genes become inactivated through hypermethylation. Progression to acute myeloid leukemia (AML) may be prevented by targeting these defects through combination therapy, using an immunomodulatory, anti-angiogenic agent, lenalidomide (LEN), and a hypomethylating drug, azacitidine (AZA).
Methods: We conducted a multicenter, Phase I trial in patients (pts) with advanced MDS (IPSS score ≥1.5, or FAB or WHO classification with ≥5% myeloblasts) starting in 6/06, with results reported through 7/07. Pts were enrolled using a “3+3” design (See Table), and could not receive LEN or AZA previously. Cycles lasted 28 days, to a maximum of 7 cycles of therapy. The primary endpoint was to determine the maximum tolerated dose (MTD) and dose-limiting toxicities (DLTs, defined as Grade 3/4 non-hematologic toxicity or >50% neutrophil (ANC) or platelet (plt) drop without recovery by Day 56) of the combination. A secondary endpoint was response as defined by the Modified International Working Group.
Dose Level AZA Schedule LEN Schedule 1 75 mg/m2 SC days 1–5 5 mg PO days 1–14 2 75 mg/m2 SC days 1–5 5 mg PO days 1–21 3 75 mg/m2 SC days 1–5 10 mg PO days 1–21 4 50 mg/m2 SC days 1–5, 8–12 5 mg PO days 1–14 5 50 mg/m2 SC days 1–5, 8–12 5 mg PO days 1–21 6 50 mg/m2 SC days 1–5, 8–12 10 mg PO days 1–21
Results: Seven patients have been enrolled, 6 are evaluable for toxicity data. Median age was 64 years (range 52–70), 1 pt was female, and median follow-up is 5.5 months (range 1.5–13). All pts had RAEB-2; IPSS scores were 1.5 (4), 2.0 (2), and 3.0 (1), with IPSS cytogenetic risk categories of poor (1), intermediate (1), and good (5). No pt had a del (5q) lesion. Median time from MDS diagnosis was 3.5 wks (range 2–106). No DLTs occurred in Dose Levels 1 or 2, and MTD has not yet been reached. Grade 1/2 non-hematologic toxicities (n=6) included fatigue (4), injection site reaction (6), rash (3), pruritis (3), constipation or diarrhea (6), dizziness (1), and mucositis (1). Grade 3/4 non-hematologic toxicities included febrile neutropenia (1). Median ANC drop was 16.4% and plt drop was 10.4%. Although one patient was delayed 1 week in starting cycle 2 for neutropenia, there were no dose-reductions for toxicities. Four pts are evaluable for response: 2 had a complete response, 1 an erythroid response, and 1 progressive disease.
Conclusions: The combination of LEN and AZA is well-tolerated and early results suggest efficacy in advanced MDS. Responses and toxicity data from higher Dose Levels will be presented.