A Phase II Study of Intravenous Azacitidine Alone in Patients with Myelodysplastic Syndromes NCT00384956.

Rationale: 5-Azacytidine (Aza), a DNA hypomethylating agent, has now been shown in 2 clinical trials involving high-risk MDS patients to provide a survival benefit over supportive/conventional care regimens. While one phase II study used a continuous 7-day IV infusion, Aza was administered subcutaneously (SQ) in most pre-approval studies. However, injection site reactions are not uncommon with SQ dosing, especially in thrombocytopenic patients. Aza given as a short intravenous (IV) infusion is anticipated to be efficacious from pharmacokinetic profiling and is FDA approved, but prospective efficacy data for short IV infusion are lacking.

Study aim and design: To determine the efficacy of IV Aza when given as a short infusion, we have undertaken an open-label, single-arm, single-center phase II study of Aza in patients with MDS, either de novo or secondary, defined by FAB classification. Previously treated subjects were ineligible if they had already received Aza or decitabine. Treatment consisted of Aza 75 mg/m² given as a 20 minute IV infusion once daily on Days 1–5 of a 28-day cycle. Response was evaluated by IWG 2000 criteria. After two cycles at the 75 mg/m² dose, patients failing to achieve a CR were eligible for an increased dose of 100 mg/m². After 6 cycles of therapy, patients must have demonstrated at least a hematologic improvement to continue on study. Study endpoints include determination of the complete response (CR) and partial response (PR) rates, and secondary endpoints examined the rates of hematological improvement, time to progression, and cytogenetic response.

Results: Accrual began 8/17/06 with a target of 21 subjects. As of 7/31/07, 15 subjects have accrued with a median follow-up of 77 days (range 4 to 246). Subjects consisted of 9 males and 6 females with a median age of 69.6 yr (range 53 to 82). The median time from diagnosis is 213 days (range 0 days to 4 yr). By FAB criteria, subjects consist of 4 RA, 9 RAEB, 1 RAEB-t, and 1 CMML, and subjects are categorized by IPSS risk as 1 Low, 4 Int-1, and 10 Int-2. Two patients had therapy related MDS. The data remain preliminary with subjects having completed a mean of 3 cycles (range 1 to 6). None of the 5 subjects who have completed at least 4 cycles of therapy have achieved a CR. However, 2 (40%) of these subjects achieved a PR. Additionally, 1 (20%) patient had a major erythroid response, while another had a minor erythroid response. Median time to response was 2 months. Ten subjects remain on study, 1 patient withdrew due to progressive disease (in first week of therapy), and 4 deaths have occurred on study (2 due to sepsis, 1 each due to pneumonia and acute MI). No deaths were attributed to study drug. Common adverse events include nausea, emesis, and hematologic toxicities. Grade 2–3 nausea and grade 2–3 emesis each occurred in 5 subjects. Observed grade 3 or 4 hematologic toxicities included: anemia (n=7), thrombocytopenia (n=4), leukopenia (n=3), neutropenia (n=7), and febrile neutropenia (n=1). Hematologic toxicities have resulted in transient treatment delays (< 4 weeks) and dose reduction, but hematologic toxicities have not prevented subsequent treatment on study.

Conclusions: Although follow-up is short for assessment of efficacy, this is the first prospective study to report on efficacy and toxicity of short infusional Aza in the treatment of MDS.