Drug resistance resulting from emergence of Imatinib-resistant BCR-ABL clones is a significant problem in Ph positive ALL patients because after a very good initial response to one TKI inhibitor, many patients relapse within one year, relapse being almost always associated with a BCR-ABL kinase domain point mutation. The patients who relapse after treatment with one TKI can be rescued to remission with another TKI, but the second remission is usually shorter than the previous one. A more potent TKI inhibitor, and pan-active not only on all the BCR-ABL variants (including the second generation TKI resistant T315I mutant), but also on others molecular targets can do better. In this context, Ponatinib is a novel synthetic orally active tyrosine kinase inhibitor (TKI), specifically developed to inhibit BCR-ABL, the fusion protein that is the product of the Philadelphia chromosome (Ph) in chronic myeloid leukemia (CML) and in a subset of acute lymphoblastic leukemia (Ph+ ALL). It potently inhibits the BCR-ABL protein as well as mutated forms of the protein that arise in patients resistant to prior therapies with TKIs. Ponatinib has been demonstrated to inhibit all the mutations that have been detected so far, in vitro and in vivo and to uniformly suppress the emerge of single-mutant clones in a mutagenesis assay. In the Phase II study, 41% of Philadelphia chromosome positive acute lymphoblastic leukemia patients treated with Ponatinib achieved major hematologic response, 47% had a major cytogenetic response, 38% obtained a complete cytogenetic response, showing that Ponatinib provides significant benefit despite previous intolerance or refractoriness to other TKIs. The Phase I trial showed that patients with a more recent diagnosis had increased rates of major molecular response: 79% for 14 patients with 0 to 5 years since diagnosis vs. 29% for 14 patients with more than 5 to 9 years since diagnosis (P=0.02) and 27% for 15 patients with more than 9 to 24 years since diagnosis (P=0.009). These characteristics support the hypothesis for a role of Ponatinib not only in patients resistant to prior TKI therapy but also in untreated ALL Ph+ patients, in order to prevent the emergence of resistant caused by the selection of mutated Ph+ clones and in order to avoid rapid progression of the disease.
Description: The primary endpoint is the proportion of patients who are in CHR at 6 months, calculated on the total number of patients who have been enroled and have received at least one dose of the first drug (prednisone).Measure: Proportion of patients who are in Complete Hematological Response (CHR). Time: At 6 months from study entry.
Description: CHR requires that all of the following are present: Bone marrow with less than 5% blast cells Peripheral blood differential without blasts PMN ≥ 1.5 x 109/L PLT ≥ 100 x 109/L No evidence of extramedullary involvement from leukemiaMeasure: The rate of Complete Hematological Response (CHR). Time: At 6, 12, 24, 36 and 48 weeks from study entry.
Description: CgR is defined based on the percentage of Ph pos metaphases, as evaluated by chromosome banding analysis (CBA) of at least 20 marrow cell metaphases: Complete (CCgR) if Ph pos 0 Partial (PCgR) if Ph pos 1-34% Minor (mCgR) if Ph pos 35-65% Minimal or none (min/none CgR) if Ph pos > 65% If only interphase FISH data are available, the response can be defined only as non-complete or complete - to be complete by FISH, it is required that less than 1% of nuclei (minimum number 200) have a positive signal.Measure: The rate of complete Cytogenetic Response (CgR). Time: At 6, 12, 24, 36 and 48 weeks from study entry.
Description: Duration of CCgR is measured by the date of the achievement of CCgR to the date of CCgR loss.Measure: Duration of Complete Cytogenetic Response (CCgR). Time: After four years from study entry.
Description: Molecular response is classified as: • Complete if by RT-Q-PCR the BCR-ABL: ABL ratio is below 0.01, with a sensitivity of at least 30,000 molecules of ABL.Measure: The rate of Complete Molecular Response (CMoIR). Time: At 12, 24, 36 and 48 weeks from study entry.
Description: Molecular response (MR) is classified as: • Major (MMolR) if by RT-Q-PCR the BCR-ABL: ABL ratio is lower than 0.10, with a sensitivity of at least 30,000 molecules of ABL.Measure: The rate of major molecular response. Time: At 12, 24, 36 and 48 weeks from study entry.
Description: Duration of CMR is measured by the date of the achievement of CMR to the date of CMR loss.Measure: Duration of Complete molecular response (CMR). Time: After four years from study entry.
Description: Events are induction failure, relapse and death whichever comes first.Measure: Event Free Survival. Time: After four years from study entry.
Description: Overall survival is measured in all patients from the data of enrolment to the date of death, by any causes.Measure: Overall survival Time: At the end of study. After four years from enrolment.
Single Group Assignment
There is one SNP
A more potent TKI inhibitor, and pan-active not only on all the BCR-ABL variants (including the second generation TKI resistant T315I mutant), but also on others molecular targets can do better. --- T315I ---