PALO ALTO, Calif., June 8 /PRNewswire-FirstCall/ -- Telik, Inc. (Nasdaq: TELK) today announced positive results from a Phase 2 multicenter trial of ezatiostat hydrochloride (TELINTRA, TLK199) tablets in patients with an International Prognostic System Score (IPSS) low to intermediate-1 risk myelodysplastic syndrome (MDS).
The primary objective of the study was to determine the Hematologic Improvement (HI) rate according to the International Working Group criteria (IWG, 2006). Since MDS comprises a spectrum of heterogeneous disorders with multiple molecularly distinct diseases and overlapping clinical features, an additional goal of this study was to identify those patients whose disease characteristics may allow us to prospectively target patients most likely to respond to Telintra treatment.
Eighty-seven patients were randomized and treated at 23 investigational sites. After initial dose ranging in 14 patients, two dose levels were selected for further study. Subsequently, 37 patients were treated at 3 gm daily for two weeks followed by a one week rest period, and 36 patients were treated at 2 gm daily for three weeks followed by a one week rest period. The data on these 73 patients was pooled for this preliminary analysis.
The median age was 72 years, with a patient population distribution of IPSS low risk (23 patients, 32%) and intermediate-1 risk (50 patients, 68%). Patients had received a median of three prior MDS therapies including 34 patients (47%) with prior Revlimid® (lenalidomide), and 28 patients (38%) with prior DNA methyltransferase inhibitors (DMTI) [azacitadine, decitabine].At the time of preliminary analysis, 8 patients remain on treatment for continuing clinical benefit. The overall Hematologic Improvement - Erythroid (HI-E) rate was 22%, 13 of 60 evaluable patients, (95% CI, 12.1–34.2). The median duration of HI-E response was 46 weeks (range 2–51). The median hemoglobin level increased by 2.0 gm/dL in responders. Eleven of 38 red blood cell (RBC) transfusion-dependent patients (29%) had clinically significant RBC transfusion reductions (reduction of 4U/8 weeks, IWG 2006) with 4 patients (11%) achieving RBC transfusion independence and 3 patients continuing on treatment. In addition, one patient continues in remission for more than 12 months following discontinuation of therapy (Quddus, et. al., J. Hem. and Onc. Apr. 2010, 3:15). Telintra continues to demonstrate multilineage hematologic improvement. There was a 15% Hematologic Improvement - Neutrophil (HI-N) rate observed in 3 of 20 patients, (95% CI, 3.2–37.9), and the bilineage HI rate (HI-E and HI-N) was 11%, 2 of 19 patients, (95% CI, 1.3–33.1).