ol- tz - t\ approved METC EUR/AZR 16 October2002 approved METC EURyMR 20 December 2002 approved METC Erasmus MC,

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1 HOVON 5t CML Version: O5 F)ecemher 2Ol 1 A dose-ranging phase l/llstudy of STl571 (lmatinib) in combination with Cytarabin in patients with first chronic phase Chronic Myeloid Leukemia PROTOCOL Study Coordinators Consultant Statistician Datamanager Registration Novartis studynr. First version Final version Date of activation Approved Amendment 1 Amendment 2 Amendment 3 Amendment 4 Adjustment Amendment 5 Amendment 6 Amendement 7./ t.1 J.J. Cornelisg n,.,/ t' -"' G.J. Osse&ofpele G.E.G. Verhoef B. Druker B. van der Holt HOVON Data Center HOVON Data Center ol- tz - t\ University Hospital Rofterdam - Daniel P.O.Box OO8AE ROTTERDAM The Netherlands tel fax +31jO.7O41O28 CSTI571ANLO1 1 December May August 2001 CKTO , 9 July 2001 METC EURyAZR /166, 2 August November 2001 approved METC EUR/AZR 14March2002 approved METC EUR/AZR 16 October2002 approved METC EURyMR 20 December 2002 approved METC Erasmus MC, 20 February January March 2005 approved METC Erasmus MC, 11 April March 2008 approved METC Erasmus MC, 27 May 2OO8 17 March 2009 approved METC Erasmus MC, 19 May 2009 Page 1 of 75

2 Amendement8 : 04 August 2009 approved METC Erasmus MC, 28 Sepember 2009 Amendment 9 : 23 March 2011 approved METC Erasmus MC, 18 May 2011 Amendment 10 : 05 December 2011 Page 2 of 75

3 1 Scheme of study CML Philadelphia-positive First chronic phase Age years REGISTRATION PRE-PHASE STI mg, days 1-21 COMBINATION THERAPY Patients will receive 2 cycles of combination therapy, according to the Dose Level which has been assigned at registration DOSE LEVEL I DOSE LEVEL II DOSE LEVEL III-A DOSE LEVEL IV-A STI mg daily until start of maintenance STI mg daily until start of maintenance STI mg daily until start of maintenance STI mg daily until start of maintenance Cytarabin 200 mg/m 2 i.v. days 1-7 in cycles I and II Cytarabin 200 mg/m 2 i.v. days 1-7 in cycles I and II Cytarabin 200 mg/m 2 i.v. days 1-7 in cycles I and II Cytarabin 200 mg/m 2 i.v. days 1-7 in cycles I and II DOSE LEVEL III-B DOSE LEVEL IV-B DOSE LEVEL V STI mg daily until start of maintenance STI mg daily until start of maintenance STI mg daily until start of maintenance Cytarabin 1000 mg/m 2 i.v. days 1-7 in cycles I and II Cytarabin 1000 mg/m 2 i.v. days 1-7 in cycles I and II Cytarabin 1000 mg/m 2 i.v. days 1-7 in cycles I and II MAINTENANCE The dose of STI571 during maintenance depends on the Dose Level of combination therapy STI mg daily until progression (Dose Levels I, II, III-B) STI mg daily until progression (Dose Levels III-A, IV-B) STI mg daily until progression (Dose Levels IV-A, V) Page 3 of 75

4 CML Philadelphia-positive First chronic phase receiving IM maintenance according to HOVON 51-protocol Complete molecular response 2 yr age years Stop imatinib maintenance Molecular relapse Resume Imatinib maintenance; dosage identical to dosage received before in IM Continue Stringent BCR-ABL QPCR follow-up Page 4 of 75

5 2 Table of contents Page 1 Scheme of study Table of contents Table of contents Synopsis Investigators and study administrative structure Introduction CML Allogeneic bone marrow transplantation Interferon- and low dose Cytarabin Intensified Cytarabin STI571 (Imatinib) Discontinuation of imatinib in patients with a complete molecular response Study objectives Study design Eligibility Registration and study treatment Allogeneic transplantation Discontinuation of Imatinib Study population Eligibility for registration Inclusion criteria Exclusion criteria Eligibility for discontinuation of IM maintenance Inclusion criteria Exclusion criteria Treatments STI571 monotherapy pre-phase Dose adjustments during STI571 monotherapy STI571 and Cytarabin combination therapy Dose adjustments during STI571 and Cytarabin combination therapy Special management orders in conjunction with combination therapy Dose limiting toxicities Number of patients per Dose Level and decision rules STI571 maintenance therapy Dose adjustments during STI571 maintenance therapy Stopping Imatinib during maintenance End of protocol treatment Required clinical evaluations Time of clinical evaluations Required investigations at entry, during treatment and during follow up Medical history...31 Page 5 of 75

6 Physical examination Hematology Blood chemistry Bone marrow Cytogenetic analysis Molecular analysis (see also appendix C) Specific investigations Additional investigations Additional observations during hospitalisation for Cytarabin treatment Required extra investigation for randomized patients Required extra investigations for patients randomized for discontinuation of IM maintenance Evaluation of response Toxicities Reporting serious adverse events Endpoints Endpoints after registration Endpoints after discontinuation Forms and procedures for collecting data CRF s and schedule for completion Registration Registration for treatment Discontinuation of imatinib Statistical considerations Patient numbers and power considerations Statistical analysis Feasibility analysis Statistical consideration (discontinuation of imatinib) Patient numbers Ethics Independent ethics committee or Institutional review board Ethical conduct of the study Patient information and consent Trial insurance Publication policy Glossary of abbreviations References A. Diagnostic Criteria Chronic Myeloid Leukemia B. CML risk assessment C. Response Criteria for Chronic Myeloid Leukemia D. Flowsheet sampling during maintenance and follow up Flowsheet sampling after discontinuation imatinib E. Common Toxicity Criteria Page 6 of 75

7 F. ZUBROD-ECOG-WHO Performance Status Scale G. NYHA* scoring list H. Patiënteninformatie I. Additional investigation J. Patiënteninformatie aanvullend onderzoek Page 7 of 75

8 3 Synopsis Study phase Study objectives Patient population Study design Duration of treatment Number of patients Adverse events Planned start and end of recruitment Phase I/II To determine the feasibility of STI571(Imatinib) in combination with Cytarabin in a dose-ranging study Patients with Chronic Myeloid Leukemia in first chronic phase 6 months from diagnosis, age inclusive Prospective, multicenter, dose-ranging Expected duration of induction treatment is about 3 months. STI571 will be continued as maintenance until progression. Depending on feasibility, patients Adverse events will be documented if observed, and reported immediately Start of recruitment: IV 2001 End of recruitment: I 2004 Page 8 of 75

9 4 Investigators and study administrative structure Responsibility Name Affiliation/Address Study Coordinators J.J. Cornelissen G.J. Ossenkoppele G.E.G. Verhoef Writing Committee M.J. Kersten A. van Leeuwenhoek Hospital, Amsterdam R. Willemze Leiden University Medical Center A.V.M.B. Schattenberg L.F. Verdonck, A.W. Dekker M.H.J. van Oers P.C. Huijgens, G.J. Ossenkoppele University Hospital St. Radboud, Nijmegen University Medical Center Utrecht Academic Medical Center, Amsterdam University Hospital Free University, Amsterdam W. Smit Medical Spectrum Twente, Enschede J.J. Cornelissen, B. Löwenberg E. Vellenga, J.C. Kluin-Nelemans P.W. Wijermans University Hospital Rotterdam- Daniel/Dijkzigt University Hospital Groningen Leyenburg Hospital, The Hague S. Wittebol Hospital Eemland, Amersfoort M. van Marwijk Kooy Isala Clinic Sophia, Zwolle Belgium CML Study Group G.E.G. Verhoef University Hospital, Leuven A. Louwagie St-Jan Hospital, Brugge Ph. Martiat Institut Jules Bordet, Brussels N. Straetmans UCL St. Luc, Brussels A. Bosly Cliniques Univ. de Mont-Godinne Statistician B. van der Holt HOVON Data Center, Rotterdam Datamanagement HOVON Data Center HOVON Data Center, Rotterdam Serious Adverse Events (SAEs) notification HOVON Data Center fax: Page 9 of 75

10 5 Introduction 5.1 CML Chronic myeloid leukemia (CML) is a hematological stem cell disorder associated with a specific chromosomal translocation known as the Philadelphia (Ph) chromosome, detected in 95% of patients. 1,2 The molecular consequence of the translocation is the fusion of the ABL protooncogene to the BCR gene resulting in the production of an activated form of the ABL proteintyrosine kinase. 3,4 The BCR-ABL protein is capable of inducing leukemias in mice, implicating the protein as the cause of the disease. 5,6 Clinically, CML progresses through three distinct phases of increasing refractoriness to therapy: chronic phase (CP) (median duration 3-4 years), accelerated phase (median duration 3-9 months), and blast crisis (median survival 3-6 months) Allogeneic bone marrow transplantation Allogeneic bone marrow transplantation (BMT) is the only curative treatment available, but is only applicable in a minority of patients (15-20%) for whom an HLA identical (sibling) donor can be identified and who are under the age of years. 7 The overall 5 year survival is 55% for patients transplanted in CP according to data analyzed by the International Bone Marrow Transplantation Registry (IBMTR). Results have improved over the last years and 5 years survival was 50% for patients transplanted in and 60% for those transplanted in This difference is largely due to a reduction of transplant related mortality (TRM) Interferon- and low dose Cytarabin Several randomized as well as non-randomized studies have shown that survival of patients treated with Interferon- (IFN- ) may be significantly longer than that of patients receiving Hydroxyurea (HU) However, the beneficial effect of IFN- appears to be restricted to a subgroup of patients (10-15%) who achieve a partial or complete cytogenetic response after IFN- treatment. The actuarial survival at 5 years for these patients is nearly 90%, while survival for patients without a major cytogenetic response is probably not different from that observed after Hydroxyurea and in the order of 40-50% at 5 years. The combination of Interferon and low-dose Cytarabin was initially investigated by Guilhot 15 and subsequently confirmed in a multicenter randomized trial. 16 Among the 625 analyzed patients, survival was significantly better in the Interferon-Cytarabin group (311 patients), as compared to the Interferon group (314 patients) (P 0.006). At 3 years the survival rate was 88 percent for those treated with Interferon and Cytarabin and 76 percent with IFN- alone. A major cytogenetic response was obtained within 12 months Page 10 of 75

11 after randomization in 39 percent of 248 patients with Cytarabin and IFN- and in 22 percent out of IFN- treated patients (P < 0.001). Based on these favorable results, the combination of IFN- and low-dose Cytarabin became standard initial treatment for CML patients without a sibling donor. 5.4 Intensified Cytarabin Cytosine arabinoside (ARA-C, Cytarabin) is a very active, if not the most important drug in leukemias of myeloid origin (AML). 17, 18 Mayer et al compared Cytarabin as post remission therapy in three different dosages in patients with AML and showed a dose response effect. In CML, intensive chemotherapy programs including Cytarabin have produced a significant Ph + suppression (to less than 35% Ph + metaphases) in 30% to 50% of first CP CML patients in earlier studies. 19, 20 This phenomenon, however, was transient, without IFN- therapy. In a pilot study, Kantarjian and Talpaz et al treated 32 patients with intensive chemotherapy followed by IFN- maintenance. 21 Overall, 60% of patients showed a major cytogenetic response, which was maintained in 25%. 6 year survival rate was 58%, compared with 36% for a matched historic control group. The HOVON study group has evaluated intensive Cytarabin in a pilot study involving a group of 19 patients with newly diagnosed CML in chronic phase. Chemotherapy consisted of two consecutive courses of chemotherapy combining Cytarabin with Idarubicin (first course), or Amsacrin (second course). The dosages of Cytarabin were, respectively, 200 mg/m 2 for 7 days (1 st course) and 2000 mg/m 2 for 6 days (2 nd course). Major cytogenetic responses were observed in 60% of the patients. The median number of days of neutropenia (< 0.5 x 10 9 /l) were, respectively, 17 and 22 days following the first and second course of chemotherapy. It was concluded from the pilot study that intensive chemotherapy was associated with acceptable toxicity and an encouraging response rate ensued. 22 The pilot study was followed by a prospective randomized trial studying the effect of intensified Cytarabin chemotherapy preceding IFN- therapy on response and survival as compared to the combination of IFN- and low-dose Cytarabin. Preliminary findings in 25 patients treated in the intensified treatment arms confirm the high response rate observed in the pilot study. A formal analysis will follow upon closure of the study. The Swedish CML study groups has prospectively evaluated chemotherapy and added further support that Cytarabin based chemotherapy may produce favorable responses in previously untreated patients with CML in CP followed by long-term disease free survival (median overall survival of 8 years: Simonsson, personal communication). Page 11 of 75

12 5.5 STI571 (Imatinib) STI571 is an inhibitor of the protein-tyrosine kinases associated with BCR-ABL, the platelet-derived growth factor (PDGF) receptor and c-kit. 23, 24 Inhibiting the activity of the BCR-ABL kinase with STI571 represents a novel, highly selective approach to the therapy of CML given the dominant role that BCR-ABL plays in the deregulated cell proliferation in this disease. STI571 shows selectivity for ABL protein-tyrosine kinase at the in vitro, cellular and in vivo level. 24, 25 The compound specifically inhibits proliferation of BCR-ABL expressing cells. In colony forming assays using ex vivo peripheral blood and bone marrow samples, STI571 shows selective inhibition of BCR-ABL positive colonies from CML patients. 25 In animal models, the compound shows potent anti-tumor activity against BCR-ABL and v-abl expressing cells at tolerated doses STI571 is currently in phase II/III clinical testing. Encouraging results were observed in patients with CML resistant to IFN- and in patients with advanced CML as well. 27, 28 Kantarjian et al presented updated results to evaluate the efficacy and safety of STI571 in patients, who are either resistant to or intolerant for IFN-. 29 Five hundred and thirty-two patients were included. With a median followup of 254 days, 47% of the patients developed a major cytogenetic response including a complete cytogenetic response in 28% and a partial response in 19%. These responses continued to improve during the first year of treatment with a median number of Ph + metaphases upon cytogenetic evaluation of bone marrow of 55% at 3 months, 38% at 6 months and 18% at 9 months. 29 Talpaz reported treatment results of 233 patients with accelerated CML. 30 A complete hematological response was observed in 63% and cytogenetic responses were observed in 40% including 21% major cytogenetic responses. A randomized phase III-study was started in June 2000 in order to compare STI571 with current standard treatment (IFN- and low-dose Cytarabin). First results comparing hematological and cytogenetic response rates are expected to be reported early The most commonly reported adverse event related to STI571 administrations has been nausea, which has been observed in approximately 40% of patients and which has mostly been mild. Arthralgias, myalgias and periorbital edema have each been observed in 10% of chronic phase patients. Interstitial edema and weight gain poorly responsive to diuretics have been seen in some patients treated with daily doses of 600 mg and 750 mg. Although STI571 has been shown to induce a relatively high rate of cytogenetic response in different phases of CML, little is known about the long-term durability of the responses observed. Patients treated for CML in blast crisis showed a high relapse rate and patients treated in accelerated phase showed a median progression-free survival of approximately 12 months, whereby progression was defined as the development of blast crisis, death or discontinuation of the drug for any reason. Longer follow-up is needed for patients treated in chronic phase to obtain a reliable picture of duration of response. Paschka et al very recently reported a study evaluating minimal residual disease by PCR in 14 patients with a complete cytogenetic response to STI Page 12 of 75

13 None of these patients became negative by PCR and the number of BCR-ABL transcripts in these patients was higher than observed in a large number of complete cytogenetic responders to IFN-. In addition, experimentally, Wolff et al showed prolonged survival by STI571 in a murine model of CML, but BM harvesting of responding mice followed by BM transplantation into syngeneic mice resulted in overt CML in all recipient mice. 32 These experimental and clinical results suggest that STI571, as a single drug, might not be sufficient to eradicate all Ph + -progenitor cells. In-vitro studies exploring the combination of STI571 and different other cytotoxic agents have already been reported. Druker et al showed additive effect of the combination of STI571 with IFN- or daunorubicin, but synergism of cytotoxicity towards BCR-ABL positive cell lines was observed when STI571 was combined with Cytarabin. 33 Others, however, showed additive effects in-vitro. 34 Based on the efficacy of Cytarabin in previous clinical studies and the observed synergistic effects of STI571 and Cytarabin in-vitro, a clinical study combining STI571 and standard or intermediate dose Cytarabin appears warranted. It is assumed that such a synergistic combination of Cytarabin and STI571 may permit the induction of molecular responses at greater frequency and, as a consequence, may allow for prolonged disease free survival. Therefore, the current study aims to evaluate oral STI571 in conjunction with i.v. Cytarabin. A stepwise increase of the dosage of STI571 and the dosage of Cytarabin guided by dose-limiting toxicity criteria may allow to determine the feasibility and the efficacy of the combination of STI571 and intermediate dose Cytarabin. If efficacious and feasible, a phase III trial could follow comparing STI571 alone versus STI571 combined with i.v. intermediate dose Cytarabin. 5.6 Discontinuation of imatinib in patients with a complete molecular response. Imatinib is a very effective therapy and has changed the treatment and prospects for CML patients dramatically. A phase 3 study (the IRIS study) designed to compare IM 400mg d.d. with the combination of interferon-alfa and low dose cytarabine in previously untreated patients with chronic phase CML, showed superior efficacy of IM 7. With 66 months of follow up, the estimated best rates of complete hematological remission (CHR) and complete cytogenetica responses (CCR) were 98% and 87% respectively. The overall estimated survival rate at 66 months was 95% (after the censoring of data for patients who died from causes unrelated to CML or transplantation). In most patients, the achievement of CCR is followed by a continuous decline in bcr-abl transcript levels, which continues after 30 months. The risk of disease progression in complete cytogenetic responders was inversely correlated with the reduction of BCR-ABL mrna levels. Progression free survival was 100% at 24 months in patients who achieved a log 3 (i.e fold) reduction of bcrabl transcripts. However, using IM only, complete molecular response rate, defined as undetectable bcr-abl using RQ-PCR was less than 10% in the IRIS study. In general, responding patients continue IM indefinitely. However, a recently published study demonstrated that after Page 13 of 75

14 discontinuation of IM in 100 patients who had had a complete molecular response for at least two years almost 40% did not relapse within a follow-up period of at least two years. All patients who relapsed did so within the first seven months after discontinuation and all relapses were completely sensitive to reinitiation of the drugref. The recurrence of disease within 6 months probably reflects the kinetics of undetectable dividing leukemic stem cells. This observation does suggest the possibility that long-term continuous IM treatment might eradicate residual leukemia in selected patients. With the intent to improve cytogenetic and molecular response rates in CML, the HOVON cooperative study group evaluated whether the combination of escalated IM and intravenous cytarabine in patients with first chronic phase chronic myeloid leukemia (CML) would be feasible and efficacious. We aimed at development of a therapy that would induce an early, preferably complete molecular response, thereby preventing resistance. One hundred and sixty-five patients with CML in early chronic phase entered the study. Patients received two cycles of intravenous cytarabine (200 mg/m2 or 1000mg/m2 days 1-7) in conjunction with IM (200 mg, 400 mg, 600 mg or 800 mg), according one of seven predefined, successive dose levels. All dose levels proved feasible. IM was continued as maintenance therapy. Seven dose limiting toxicities (DLTs) were observed in 302 cycles of chemotherapy, which were accompanied by streptococcal bacteremia in five cases. Intermediate dose cytarabine (1000mg/m2) prolonged neutrophil recovery and platelets recovery as compared to standard dose cytarabine (200 mg/m2). High dose IM (600 mg or 800 mg) extended time to platelet recovery as compared to standard dose IM (400 mg). Common Toxicity Criteria grade 3-4 non-hematological and non-infectious toxicities appeared similar in patients receiving different dosages of cytarabine and IM. Early response data evaluated immediately after completion of combination therapy included a complete hematological response in 92% of patients, a complete cytogenetica response in 46% of patients and a major molecular response in 30% of patients. These results have recently been published (Deenik Haematologica)ref. Longer follow-up showed a continuing improvement of molecular responses. The probability of obtaining a complete molecular response (CMR) was estimated at 55% at 18 months after a median follow-up of 2 years. Higher responses were observed in patients receiving a higher dose of IM19. As results continued to improve during IM maintenance, updated results with longer follow-up are expected to show an even higher CMR rate. It was concluded that combination therapy of escalating dosages of IM and cytarabine is feasible and initial data show a very promising molecular response rate. The initial results of the French imatinib discontinuation study were the rationale behind the previous amendment to the HOVON51 study, according to which patients in CMolR for at least two Page 14 of 75

15 years were randomized to either stop or continue imatinib. The updated and published results of the Stop Imatinib study now justify another amendment to the HOVON51 study. All patients who are in complete molecular response for more than two years will be offered discontinuation of imatinib. As described above, in a large number of CML patients who are in a long lasting CMR, discontinuation of IM does not result in the immediate recurrence of the disease. It would be highly relevant to be able to stop IM continuously and to predict the successful withholding of IM. In this study proposal we will stop IM in a selected group of CML patients, all treated with a combination of IM and cytarabine, a combination thought to be capable of more effective eradication of the malignant stem cell pool. We hope to prove that this is indeed the case by demonstrating a reduced relapse rate. Besides, we aim at developing tools to predict in which patients IM can successfully be withheld. 6 Study objectives To assess the feasibility of STI571 combined with i.v. Cytarabin in a dose-ranging study To determine the rate and duration of molecular response in adult patients with newly diagnosed CML treated with STI571 in conjunction with 2 courses of standard dose i.v. Cytarabin, and STI571 combined with 2 cycles of intermediate-dose i.v. Cytarabin To determine the rate and duration of complete hematological response To determine the rate and duration of complete cytogenetic response To determine the time to treatment failure To determine overall survival To assess wether Imatinib can effectively be stopped in patients, who were treated with Imatinib and cytarabine and obtained a longlasting (> 2 years) complete molecular response. 7 Study design This is a dose-ranging feasibility study. A stepwise increase of dosage of STI-571 and Cytarabin is allowed if a prior dose level meets the criteria of feasibility. Enrollment at each dose level will consist of a minimum of 5 and a maximum of 20 patients. After the final patient of a dose level is enrolled, the study will remain closed to further enrollment until the last patient in that dose level has completed induction therapy and feasibility has been evaluated. Feasibility is defined by: Treatment related mortality occurring in 5% of patients; Dose limiting toxicities (including TRM) occurring in 20% of patients. Page 15 of 75

16 Dose limiting toxicities, dose escalation criteria, and numbers of patients needed at each dose level are described in detail in and Details of all treatments (dose and schedule) are given in Eligibility Patients with newly diagnosed Ph + -CML in first chronic phase meeting all eligibility criteria (see 8.1) are eligible if a diagnosis of CML was made within 6 months of registration and no other treatment than Hydroxyurea has been used. Patients with an HLA-identical sibling donor who are planned to receive an allogeneic stem cell transplantation upfront, are not eligible for this study (see also 7.3). Patients must be registered before start of STI571 monotherapy pre-phase. 7.2 Registration and study treatment After cessation of preceding therapy with HU and upon registration, treatment will start with STI571 once daily 400 mg orally, for 2-3 weeks until clinical admission. At that time, oral STI571 is continued at 200 mg daily and the first cycle of i.v. Cytarabin is added (200 mg/m 2, days 1-7). Clinical admission is continued until resolution of mucosal and hematological toxicity. Prophylaxis for prevention of fungi and gram-negative bacteria is prescribed until resolution of granulocytopenia. After completion of procedures for evaluation, patients may be discharged for a maximum period of 14 days, during which period STI571 is continued. A second cycle of Cytarabin (in conjunction with STI571) is given upon re-admission with similar preventive measures and continuation of oral STI571. After completion of both cycles, maintenance with STI571 will be continued at a dose of 400 mg daily until progression of disease. If results of the first cohort of patients meet the criteria for acceptable safety and toxicity, a second cohort will be included. These patients will receive oral STI571 at a dose of 400 mg once daily until progression of disease. Two successive cycles of Cytarabin will be added in a similar way as performed in the first cohort: Cytarabin (200 mg/m 2 ) for 7 consecutive days. If results of that cohort meet the criteria of acceptable toxicity and safety, a third and fourth cohort will be included simultaneously and treated with either STI571 at a dose of 600 mg once daily combined with 2 courses of Cytarabin (200 mg/m 2 ) or STI571 at a dose of 400 mg once daily combined with 2 courses of intermediate-dose Cytarabin (1000 mg/m 2 ) for 7 days. Both cohorts will then continue with STI571 maintenance, at the same dose as given during Cytarabin treatment (400 or 600 mg once daily). If results of both cohorts meet the criteria of acceptable toxicity and safety, a fifth and sixth cohort will be included simultaneously and treated with either STI571 at a dose of 800 mg once daily combined with 2 courses of Cytarabin (200 mg/m 2 ) or STI571 at a dose of 600 mg once daily Page 16 of 75

17 combined with 2 courses of intermediate-dose Cytarabin (1000 mg/m 2 ) for 7 days. Both cohorts will then continue with STI571 maintenance, at the same dose as given during Cytarabin treatment (600 or 800 mg once daily). If results of both cohorts meet the criteria of acceptable toxicity and safety, a seventh cohort will be included and treated with STI571 at a dose of 800 mg once daily combined with 2 courses of intermediate-dose Cytarabin (1000 mg/m 2 ) for 7 days. This cohort will then continue with STI571 maintenance, at the same dose as given during Cytarabin treatment (800 mg once daily). Criteria of dose limiting toxicity, feasibility, and number of patients required are described in paragraphs and Allogeneic transplantation Patients with an HLA-A, B, DR-matched sibling donor who are planned to receive an allogeneic transplantation upfront, are not eligible for this study. Once patients have been included in the study, allogeneic transplantation with a sibling donor or MUD is only allowed as off protocol treatment. For patients who entered the present study an allogeneic transplantation or search for a MUD donor may be considered when: Repeated cytogenetic bone marrow examinations indicate complete loss of a previously established cytogenetic response; A patient does not acquire any cytogenetic response 12 months after start of study treatment. 7.4 Discontinuation of Imatinib. All patients who have attained a CMolR that was durable for at least two years may, after registration, stop imatinib. For the study, they will be considered as patients who will receive imatinib maintenance therapy at a dosage of 0 mg. In case the quantitative PCR (qpcr) results of these patients becomes positive (i.e. < 4.5 log reduction) and this is confirmed by a second positive qpcr these patients will restart imatinib maintenance therapy in the same dose as they received before discontinuation of the drug. The patients stay on protocol. 8 Study population 8.1 Eligibility for registration All eligible patients have to be registered before start of treatment (see 16.1). Page 17 of 75

18 8.1.1 Inclusion criteria Newly diagnosed patients with CML in first chronic phase 6 months; Presence of Philadelphia chromosome or BCR-ABL rearrangement; Age years inclusive; WHO performance status 2; Written informed consent Exclusion criteria Hepatic dysfunction (serum bilirubin 2 x N, and/or ALAT 4 x N); Renal dysfunction (creatinin 200 mol/l or 2.3 mg/dl); Severe cardiac dysfunction (NYHA classification II-IV, see appendix G) ; Severe pulmonary or neurologic disease; Pregnant or lactating females; Patients with a history of active malignancy during the past 5 years with the exception of basal carcinoma of the skin or stage 0 cervical carcinoma; Patients known to be HIV-positive; Patients with active, uncontrolled infections; Previous treatment other than Hydroxyurea 6 months; 8.2 Eligibility for discontinuation of IM maintenance Inclusion criteria Written informed consent Receiving Imatinib maintenance as HOVON-51 protocol treatment Having achieved a complete molecular response (>4.5 log reduction by quantitative PCR and confirmed by negative Rt-PCR), which persists for at least 2 years WHO < 2 Page 18 of 75

19 8.2.2 Exclusion criteria Unable to visit outpatient clinic at regular one-monthly intervals during the first 6 months after stopping imatinib. 9 Treatments 9.1 STI571 monotherapy pre-phase Following registration and study entry, preceding therapy is stopped and STI571 is started after 48 hours (yielding an interval of 2 days without therapy). STI571 is started at a dose of 400 mg once daily and continued at that dose until the addition of Cytarabin i.v., which should be planned within days from start of therapy. This period of STI571 only is needed to avoid cumulative toxicity of Hydroxyurea and Cytarabin. Agent Dose/day Route Days STI mg p.o. Once daily, until start combination therapy after days Novartis will supply STI571 as 100 mg capsules packaged in bottles. STI571 should be administered each morning during breakfast. Grapefruit or grapefruit juice must be avoided. STI571 is a local irritant and must be taken in a sitting position with a large glass of water (250 ml/8 oz) Dose adjustments during STI571 monotherapy Dose adjustments during this period of STI571 monotherapy are according the guidelines as described under 9.3.1, detailing the modifications during STI571 maintenance. 9.2 STI571 and Cytarabin combination therapy Following the period of days STI571 monotherapy, patients are admitted clinically to receive the first cycle of Cytarabin i.v. in conjunction with oral STI571. During combination therapy patients will receive STI571 once daily until full hematological recovery (platelets > 100 x 10 9 /l and WBC > 2.0 x 10 9 /l) after the second cycle of i.v. Cytarabin, at which timepoint maintenance therapy with STI571 will be started. Cytarabin is added as a 7 day course of i.v. chemotherapy. The second cycle of Cytarabin will be started if there is evidence of hematopoietic recovery (platelets > 100 x 10 9 /l and WBC > 2.0 x Page 19 of 75

20 10 9 /l) and when evaluation procedures after cycle I have been performed. Cycle II should preferably be started after 28 days but within 42 days from the start of cycle I. Deleted: Dose Level I Patients treated at Dose Level I will receive STI571 at a dose of 200 mg once daily. Cytarabin is given at a dose of 200 mg/m 2 /day in 500 ml NaCl 0.65% (or 0.9%) as 1-2 hours infusion, once daily on days 1-7. Dose Level II Patients treated at Dose Level II will receive STI571 at a dose of 400 mg once daily. Cytarabin is given at a dose of 200 mg/m 2 /day in 500 ml NaCl 0.65% (or 0.9%) as 1-2 hours infusion, once daily on days 1-7. Dose Level III-A Patients treated at Dose Level III-A will receive STI571 at a dose of 600 mg once daily. Cytarabin is given at a dose of 200 mg/m 2 /day in 500 ml NaCl 0.65% (or 0.9%) as 1-2 hours infusion, once daily on days 1-7. Dose Level III-B Patients treated at Dose Level III-B will receive STI571 at a dose of 400 mg once daily. Cytarabin is given at a dose of 1000 mg/m 2 /day in 1000 ml NaCl 0.65% (or 0.9%) in a 3 hours infusion, once daily on days 1-7. Dose Level IV-A Patients treated at Dose Level IV-A will receive STI571 at a dose of 800 mg once daily. Cytarabin is given at a dose of 200 mg/m 2 /day in 500 ml NaCl 0.65% (or 0.9%) as 1-2 hours infusion, once daily on days 1-7. Dose Level IV-B Patients treated at Dose Level IV-B will receive STI571 at a dose of 600 mg once daily. Cytarabin is given at a dose of 1000 mg/m 2 /day in 1000 ml NaCl 0.65% (or 0.9%) in a 3 hours infusion, once daily on days 1-7. Dose Level V Patients treated at Dose Level V will receive STI571 at a dose of 800 mg once daily. Cytarabin is given at a dose of 1000 mg/m 2 /day in 1000 ml NaCl 0.65% (or 0.9%) in a 3 hours infusion, once daily on days 1-7. Page 20 of 75

21 Agent Dose/day Route Days Dose Level I STI mg p.o. Day 1 until start STI571 maintenance Cytarabin 200 mg/m 2 i.v. 1-2 hr infusion Cycle I 1-7 Cycle II 1-7 Dose Level II STI mg p.o. Day 1 until start STI571 maintenance Cytarabin 200 mg/m 2 i.v. 1-2 hr infusion Cycle I 1-7 Cycle II 1-7 Dose Level III-A STI mg p.o. Day 1 until start STI571 maintenance Cytarabin 200 mg/m 2 i.v. 1-2 hr infusion Cycle I 1-7 Cycle II 1-7 Dose Level III-B STI mg p.o. Day 1 until start STI571 maintenance Cytarabin 1000 mg/m 2 i.v. 3 hr infusion Cycle I 1-7 Cycle II 1-7 Dose Level IV-A STI mg p.o. Day 1 until start STI571 maintenance Cytarabin 200 mg/m 2 i.v. 1-2 hr infusion Cycle I 1-7 Cycle II 1-7 Dose Level IV-B STI mg p.o. Day 1 until start STI571 maintenance Cytarabin 1000 mg/m 2 i.v. 3 hr infusion Cycle I 1-7 Cycle II 1-7 Dose Level V STI mg p.o. Day 1 until start STI571 maintenance Cytarabin 1000 mg/m 2 i.v. 3 hr infusion Cycle I 1-7 Cycle II 1-7 Assessment of response during combination therapy is described in paragraph 11 and appendix C. Page 21 of 75

22 9.2.1 Dose adjustments during STI571 and Cytarabin combination therapy No dose modifications will be made for Cytarabin. No dose modifications of STI571 will be done for CTC grade 1, 2 and 3 toxicity (except for grade 3 liver toxicity). If a patient experiences any of the following toxicities, STI571 must be withheld until toxicity has resolved < grade 2 and then be resumed at the targeted dose of that specific cohort of patients: grade 4 stomatitis which persists for longer than 1 week; grade 3 or 4 liver toxicity; any other grade 4 toxicity (except hematological toxicity, nausea and vomiting). Patients who experience any Dose Limiting Toxicities (see 9.2.3) during or following cycle I, will not receive a second cycle of Cytarabin, but will continue with STI571 maintenance Special management orders in conjunction with combination therapy Infections should be controlled before start of chemotherapy Anti-bacterial prophylaxis and anti-fungal prophylaxis should be given, for example oral Ciprofloxacin 500 mg (2 x) and oral Fluconazole tablets 200 mg (1 x), or according to local protocols Patients experiencing CTC grade 4 neutropenia (ANC < 0.5 x 10 9 /l) for longer than 1 week may receive granulocyte colony-stimulating factor (G-CSF, Neupogen Singleject ) until neutropenia has resolved (ANC > 1.0 x 10 9 /l). G-CSF should be given at a dose of 5 g/kg s.c. once daily. During Cytarabin therapy 1000 mg/m 2 /day, methylcellulose (0.5%) or corticosteriod eye drops should be prescribed (6 times daily, days 1-7) During Cytarabin therapy 1000 mg/m 2 /day, special attention should be given to prevent bacteremias by -hemolytic Streptococci, for example, by i.v. penicillin (6 x 10 6 U/daily, at days 8-20) Cytarabin 1000 mg/m 2 /day should be discontinued in case of nystagmus or cerebellar symptoms. If those symptoms resolve within 24 hours, Cytarabin may be resumed. After interruption of the cycle, it should not be prolonged after day 7. Page 22 of 75

23 9.2.3 Dose limiting toxicities Dose Limiting Toxicities (DLT) are defined as toxicities with onset within 42 days after the start of cycle I and II of the following type and grade : CTC grade 4 mucosal toxicity lasting > 2 weeks from onset; CTC grade 4 hepatic enzyme and/or bilirubin evaluations lasting > 2 weeks from onset; Any other CTC grade 4 toxicity, except for hematological toxicity, nausea and vomiting, since these are expected during Cytarabin treatment; Any treatment related mortality (TRM) occuring after start of cycle I. Judgment of the relationship of these deaths with the combination treatment STI571 and Cytarabin is made by the responsible local investigator Number of patients per Dose Level and decision rules Initially 5 patients will be treated according to Dose Level I. Once 5 patients have been entered, the study will be temporarily closed for patient entry until these patients are evaluable for DLT. Decision rules for recruitment of additional patients at the same Dose Level or entry of new patients at the next Dose Level are specified in the table below. The study will remain closed for patient entry until all patients in the current cohort are evaluable for DLT and completed case report forms of all patients have been received at the HDC. A patient is considered evaluable for DLT if: cycle I of combination therapy has been completed and evaluated; the patient experiences DLT during cycle I or II. A patient is considered not evaluable for DLT and will be replaced if: the patient goes off treatment before start of cycle I, for whatever reason; the patient goes off treatment before completion of cycle I chemotherapy for reasons not related to DLT. The highest feasible Dose Level will always contain 20 patients. The feasibility of this Dose Level will be evaluated when all 20 patients have completed combination therapy, i.e. cycle I and cycle II have been completed and evaluated or cycle I has been completed and evaluated and the patient goes off treatment, for whatever reason. Page 23 of 75

24 Current Nr. of Nr. Of patients with Dose evaluable Action Level patients DLT TRM I AND 0 Go to Dose Level II with entry of 5 patients I 5 5 OR 2 STOP; Dose Level I not feasible I OR 1 Enter 5 more patients at Dose Level I I AND 0 Go to Dose Level II with entry of 5 patients I 10 5 OR 2 STOP; Dose Level I not feasible I OR 1 Enter 10 more patients at Dose Level I I AND 0-1 Go to Dose Level II with entry of 5 patients I 20 5 OR 2 STOP; Dose Level I not feasible II AND 0 Enter 10 more patients at Dose Level II II 5 5 OR 2 STOP; Dose Level II not feasible 1) II OR 1 Enter 5 more patients at Dose Level II II AND 0 Go to Dose Levels III-A and III-B with entry of 5 patients at each level II 10 5 OR 2 STOP; Dose Level II not feasible 1) II OR 1 Enter 10 more patients at Dose Level II II AND 0 Go to Dose Levels III-A and III-B with entry of 5 patients at each level II 15 5 OR 2 STOP; Dose Level II not feasible 1) II 15 4 OR 1 Enter 5 more patients at Dose Level II II AND 0-1 Go to Dose Levels III-A and III-B with entry of 5 patients at each level II 20 5 OR 2 STOP; Dose Level II not feasible 1) III-A/B AND 0 Enter 10 more patients at current Dose Level III-A/B 5 5 OR 2 STOP; current Dose Level not feasible 2) III-A/B OR 1 Enter 5 more patients at current Dose Level III-A/B AND 0 III-A/B 10 5 OR 2 STOP; current Dose Level not feasible 2) III-A/B OR 1 Enter 10 more patients at current Dose Level III-A/B AND 0 3) 3) Page 24 of 75

25 III-A/B 15 5 OR 2 STOP; current Dose Level not feasible 2) III-A/B 15 4 OR 1 Enter 5 more patients at current Dose Level III-A/B AND 0-1 III-A/B 20 5 OR 2 STOP; current Dose Level not feasible 2) 3) IV-A/B AND 0 Enter 10 more patients at current Dose Level IV-A/B 5 5 OR 2 STOP; current Dose Level not feasible 4) IV-A/B OR 1 Enter 5 more patients at current Dose Level IV-A/B AND 0 IV-A/B 10 5 OR 2 STOP; current Dose Level not feasible 4) IV-A/B OR 1 Enter 10 more patients at current Dose Level IV-A/B AND 0 IV-A/B 15 5 OR 2 STOP; current Dose Level not feasible 4) IV-A/B 15 4 OR 1 Enter 5 more patients at current Dose Level IV-A/B AND 0-1 IV-A/B 20 5 OR 2 STOP; current Dose Level not feasible 4) 5) 5) 5) V AND 0 Enter 10 more patients at Dose Level V V 5 5 OR 2 STOP; Dose Level V not feasible 6) V OR 1 Enter 5 more patients at Dose Level V V AND 0-1 Enter 10 more patients at Dose Level V V 10 5 OR 2 STOP; Dose Level V not feasible 6) V AND 0-1 Enter 5 more patients at Dose Level V V 15 5 OR 2 STOP; Dose Level V not feasible 6) V AND 0-1 STOP; Dose Level V feasible V 20 5 OR 2 STOP; Dose Level V not feasible 6) 1) Enter in this case a total of 20 patients at Dose Level I; entry will be according to the decision rules for Dose Level I. 2) When both Dose Levels III-A and III-B are not feasible, enter in this case a total of 20 patients at Dose Level II; entry will be according to the decision rules of Dose Level II. When one of the dose levels III-A or III-B is not yet considered as not feasible, continue entry in that Dose Level according to the corresponding decision rules. 3) When both Dose Levels III-A and III-B have reached such a stage, go to Dose Levels IV-A and IV-B with entry of 5 patients at each level. When one of Dose Levels III-A or III-B has reached such a stage and the other one is not yet considered as not feasible, continue entry in that other Dose Level. Page 25 of 75

26 When Dose Level III-A has reached this stage and Dose Level III-B is not feasible, go to Dose Level IV-A with entry of 5 patients. When Dose Level III-B has reached this stage and Dose Level III-A is not feasible, enter in this case a total of 20 patients in Dose Level III-B ; entry will be according to the decision rules of Dose Level III-B. 4) When both Dose Levels IV-A and IV-B are not feasible, enter in this case a total of 20 patients at Dose Levels III-A and III-B; entry will be according to the decision rules of those Dose Levels. When one of the dose levels IV-A or IV-B is not yet considered as not feasible, continue entry in that Dose Level according to the corresponding decision rules. 5) When both Dose Levels IV-A and IV-B have reached such a stage, go to Dose Level V with entry of 5 patients. When one of Dose Levels IV-A or IV-B has reached such a stage and the other one is not yet considered as not feasible, continue entry in that other Dose Level. When one of Dose Levels IV-A and IV-B has reached such a stage and the other Dose Level is not feasible, enter in this case a total of 20 patients in the Dose Level that is still feasible; entry will be according to the decision rules of that Dose Level. When Dose Level IV-A is feasible and Dose Level IV-B is not feasible, enter in this case a total of 20 patients in Dose Level III-B ; entry will be according to the decision rules of Dose Level III-B. 6) Enter in this case a total of 20 patients at the Dose Levels IV-A and IV-B; entry will be according to the decision rules of those Dose Levels. Allocation to either Dose Level III-A or Dose Level III-B, as well as to Dose Level IV-A or Dose Level IV-B, will be alternating as long as both levels are open for recruitment. Page 26 of 75

27 9.3 STI571 maintenance therapy Following full hematological recovery after the second cycle of i.v. Cytarabin and when evaluation procedures have been completed, maintenance therapy is started. Patients in Dose Levels I, II and III-B will receive STI571 at a dose of 400 mg, patients in Dose Levels III-A and IV-B will continue with STI571 at a dose of 600 mg and patients in Dose Levels IV-A and V will continue with STI571 at a dose of 800 mg orally once daily until progression of disease (either accelerated CML, blast crisis, or death), intolerance of treatment, or eligibility for allogeneic stem cell transplantation (see 7.3), whichever occurs first. Agent Dose/day Route Days Dose Level I, II, III-B STI mg p.o. Once daily until going off protocol treatment Dose Level III-A, IV-B STI mg p.o. Once daily until going off protocol treatment Dose Level IV-A, V STI mg p.o. Once daily until going off protocol treatment Assessment of response during STI maintenance is described in paragraph 11 and appendix C Dose adjustments during STI571 maintenance therapy Hematological Toxicity No dose adjustments for hematological toxicity will be made. Non-hematological Toxicity Grade 1: No dose adjustments for grade 1 toxicity will be made. Grade 2: If a patient experiences a grade 2 non-hematological toxicity that does not resolve despite therapeutic intervention, STI571 must be withheld until the toxicity has resolved to grade 1. STI571 may then be resumed at the previous dose of 400 mg (Dose Levels I, II, III-B), 600 mg (Dose Levels III-A, IV-B) or 800 mg (Dose Levels IV-A, V) daily. If the grade 2 toxicity recurs, STI571 must again be withheld until the toxicity has resolved to grade 1, and the dose of STI571 must be reduced when resumed; for Dose Levels I, II and III-B to 300 mg, for Dose Levels III-A and IV-B to 400 mg and for Dose Levels IV-A and V to 600 mg. Page 27 of 75

28 Grade 3-4: If a patient experiences grade 3 non-hematological toxicity, STI571 must be withheld until the toxicity has resolved to grade 1. STI571 may then be continued at a reduced dose of 300 mg (Dose Levels I, II, III-B), 400 mg (Dose Levels III-A, IV-B) or 600 mg (Dose Levels IV-A, V) daily. A documented grade 3 non-hematological toxicity that recurs despite dose reduction or is lifethreatening such that re-treatment with STI571 would be deemed medically inappropriate is considered intolerance of treatment. Treatment with STI571 should then be discontinued and the patient proceeds to off protocol treatment. Toxicity Action Dose / day STI when resumed Hematological Any grade No dose adjustment Non-hematological Grade 1 Grade 2, resolved by therapeutic intervention Grade 2, not resolved by therapeutic intervention Grade 3 Life-threatening or grade 3 recurring No dose adjustment No dose adjustment Withhold STI until resolved to grade 1 Withhold STI until resolved to grade 1 End STI maintenance Resolved: 400 mg (I, II, III-B) or 600 mg (III-A, IV-B) or 800 mg (IV-A, V) Recurring: 300 mg (I, II, III-B) or 400 mg (III-A, IV-B) or 600 mg (IV-A, V) Resolved: 300 mg (I, II, III-B) or 400 mg (III-A, IV-B) or 600 mg (IV-A, V) Recurring: end STI maintenance 9.4 Stopping Imatinib during maintenance Patients who have achieved a complete molecular response that lasted for at least two years, and who meet the eligibility criteria for discontinuation of IM maintenance (see 8.2) will abruptly stop their IM maintenance therapy. Following discontinuation of IM patients will undergo monthly qpcr for BCR-ABL on peripheral blood and two-monthly qpcr for BCR-ABL on bone marrow during the first half year. After the first six months, peripheral blood and bone marrow testing will be performed every two and three months, respectively until one year after discontinuation. Thereafter, qpcr will be performed on peripheral blood every three months and on bone marrow every six months. The evaluation procedures are detailed below (see ). Page 28 of 75