A phase II study of alpha-interferon and oral arabinosyl cytosine (YNK01) in chronic myeloid leukemia.

YNK01 (Starasid) is a prodrug that is adsorbed in the gut and is transformed in the liver in arabinosyl cytosine (AC). Low-dose AC (LDAC) is useful for the treatment of Philadelphia positive (Ph+) chronic myeloid leukemia (CML), especially in combination with alpha-interferon (alphaIFN). The use of YNK01 can avoid the daily s.c. injection of conventional AC. To assess the safety and the efficacy of alphaIFN and YNK01, we enrolled 86 consecutive previously untreated chronic phase Ph+ CML patients in a phase II study of alphaIFN (Intron-A) 5 MIU/m(2) daily and YNK01 600 mg daily 14 days a month. The 6-month complete hematologic response and the 12-month major cytogenetic response rates were 78 and 28%, respectively. In a prior study of alphaIFN and conventional LDAC, they were 62 and 22%, respectively. However, the compliance to the treatment was poor, with 25% of cases discontinuing the treatment within the first year. This was not because of the severity of the side effects but because of the frequency, duration and repetition of the side effects, for an overall frequency of 13.17 adverse events, mostly grade 1 and 2, per patient per year. Therefore, the study of this effective combination is being pursued, testing lower doses of alphaIFN and YNK01.

Chronic myeloid leukemia and interferon-alpha: a study of complete cytogenetic responders.

Achieving a complete cytogenetic response (CCgR) is a major target in the treatment of chronic myeloid leukemia (CML) with interferon-alpha (IFN-alpha), but CCgRs are rare. The mean CCgR rate is 13%, in a range of 5% to 33%. A collaborative study of 9 European Union countries has led to the collection of data on 317 patients who were first seen between 1983 and 1997 and achieved CCgRs with IFN-alpha alone or in combination with hydroxyurea. The median time to first CCgR was 19 months (95% CI, 17-21; range, 3-84 months). At last contact, 212 patients were still alive and in continuous CCgR; 105 patients had lost CCgR, but 53% of them were still alive and in chronic phase. IFN-alpha treatment was discontinued permanently in 23 cases for response loss, in 36 cases for chronic toxicity (15 are still in unmaintained continuous CCgR), and in 8 cases because it was believed that treatment was no longer necessary (7 of these 8 patients are still in unmaintained continuous CCgR). The 10-year survival rate from first CCgR is 72% (95% CI, 62%-82%) and is related to the risk profile. High-risk patients lost CCgR more frequently and more rapidly and none survived more than 10 years. Low-risk patients survived much longer (10-year survival probability 89% for Sokal low risk and 81% for Euro low risk). These data point out that a substantial long-term survival in CCgRs is restricted mainly to low-risk and possibly intermediate-risk patients and occurs significantly less often in high-risk patients.

Real-time quantification of different types of bcr-abl transcript in chronic myeloid leukemia.

BACKGROUND AND OBJECTIVES: The most common translocation in chronic myeloid leukemia (CML) t(9;22) (q34;q22) produces the BCR/ABL fusion gene. We set up and evaluated a rapid and reliable real-time reverse-transcription-polymerase chain reaction (RT-PCR) approach using TaqMan technology for detection and quantification of bcr-abl transcripts in CML patients at diagnosis and during therapy. DESIGN AND METHODS: A pair of primers and probe complementary to ABL exon 2 were designed, enabling detection of the most frequent bcr-abl transcripts, and also of the normal ABL-Ia transcript as an internal control. Conditions were established to amplify less than 1(-10) target molecules/reaction and detect one CML cell in 10(6) cells from healthy donors. To determine the utility of the assay, we quantified the bcr-abl/ABL-Ia ratio in 59 bone marrow samples (45 samples with evidence of different Ph+ chromosome percentages and 14 samples in complete cytogenetic remission) from 48 CML patients, 34 of them at diagnosis and 14 in clinical remission (CR). In 14 cases, this ratio was compared with results obtained by a competitive-quantitative RT-PCR/capillary electrophoresis method from contemporary specimens. RESULTS: By real-time RT-PCR, the median value of bcr-abl/ABL-Ia ratio at diagnosis was 15.334 (range 3.3-28.81) and fell to 0.9 (range 0.003-26.1) in CR. The median value of bcr-abl/ABL-Ia ratio at cytogenetic remission was 0.7 (range 0.003-2.83). The real-time bcr-abl/ABL-Ia ratios correlated with those obtained by competitive RT-PCR (p < 0.0001) and the percentage of Ph+ metaphases (p < 0.0001). The high sensitivity and specificity of the real-time RT-PCR procedure was confirmed in all 14 patients with minimal residual disease. INTERPRETATION AND CONCLUSIONS. We conclude that this real-time RT-PCR procedure is a reliable and sensitive method of monitoring CML patients after therapy, and that the bcr-abl/ABL-Ia ratio correlates strongly with cytogenetic analysis.

Testing Sokal's and the new prognostic score for chronic myeloid leukaemia treated with alpha-interferon. Italian Cooperative Study Group on Chronic Myeloid Leukaemia.

As it has been shown that alpha-interferon (alphaIFN) treatment modifies the survival of chronic myeloid leukaemia (CML) patients in comparison with conventional chemotherapy, a new prognostic score was devised with the aim of providing a treatment-adapted risk evaluation. We have tested the new prognostic score (the Euro score) in an independent series of 272 patients less than 56 years old with previously untreated, chronic phase, Philadelphia (Ph)-positive CML who had been assigned prospectively to alphaIFN treatment between 1989 and 1991. The Sokal score system was used as a reference. The new Euro score predicted the response to alphaIFN as the Sokal score. The median survival of low-risk, intermediate-risk and high-risk patients was similar using the Euro score (105, 65 and 45 months) and Sokal score (105, 76 and 45 months) but, by multivariate analysis, the Euro was more potent than Sokal for predicting survival time. The new Euro score identified more low-risk cases (59% vs. 48%) and fewer high-risk cases (9% vs. 23%) than the Sokal score. The main differences between the Euro and Sokal scores concerned age (it is more important in the Euro than in Sokal), spleen size and the percentage of myeloblasts in peripheral blood (more important in Sokal than in Euro). We conclude that the new Euro score marks an improvement in the prognostic evaluation of CML treated with alphaIFN. By comparison with the Sokal score, the Euro was more potent and identified more low-risk patients but left only a small number of cases in the high-risk group.