Clofarabine Research Articles

333: Preliminary Results of Phase II Trial of Clofarabine with Parenteral Busulfan Followed by Allogeneic Related or Unrelated Donor Transplantation for the Treatment of Hematologic Malignancies and Diseases

333: Preliminary Results of Phase II Trial of Clofarabine with Parenteral Busulfan Followed by Allogeneic Related or Unrelated Donor Transplantation for the Treatment of Hematologic Malignancies and Diseases

Phase I Study of Clofarabine with Standard-Dose Infusional Cytarabine (Ara-C) as Intensive Induction Therapy for Newly-Diagnosed De Novo Acute Myeloid Leukemia in Older Adults Age ≥60 Years.

Background The median age of AML is approximately 70 years, and the survival of older adults age ≥60 years remains poor with standard therapy. Clofarabine (CLO) has significant single agent activity in AML, and in vitro studies demonstrate synergy with Ara-C. We therefore performed a phase I study to determine the maximum tolerated dose (MTD) of CLO with standard dose Ara-C (100mg/m2/day D1-7 by 24hr continuous infusion) as AML induction therapy. CLO was administered daily × 5 days beginning D2 to allow for pharmacokinetic (PK) & pharmacodynamic (PD) studies.Methods Enrollment was restricted to newly-diagnosed de novo AML patients age ≥60 years considered candidates for intensive therapy; those with prior MDS or hypoplastic AML (<20% bone marrow cellularity) were excluded. Pts were treated in cohorts of 3–6 to determine MTD of CLO with standard dose infusional Ara-C (100mg/m2 × 7). DLT was defined as grade III/IV non-hematologic toxicity occurring in >1 pt per cohort. The CLO starting dose was 30mg/m2/day ×5 (dose level 1), with the intention to increase to CLO 40mg/m2 if tolerated. However, CLO dose reductions of 25% (CLO 22.5 mg/m2/day × 5, dose level -1) & 50% (CLO 15mg/m2/day ×5, dose level -2) were allowed in the event of dose-limiting toxicity (DLT). Pts achieving complete remission (CR) received 2 cycles consolidation with CLO ×5 & Ara-C 100mg/m2 × 5.Results A total of 13 pts (median age 69 yrs, range 61–77; 10 male) have been treated. DLT was observed at dose level 1 (Table 1), and the protocol was amended to mandate additional hydration with CLO, and antibiotic/antifungal prophylaxis. At dose level -1, 1 pt died from PE on D27 after hematologic recovery, considered treatment-related per protocol, mandating dose de-escalation to dose level -2. Pt 13 is in active induction therapy, and not yet evaluable for response, although DLT has not been encountered. Febrile neutropenia occurred in 11/13 pts. The MTD in this study is CLO 15mg/m2/day × 5 with standard infusional Ara-C (dose level -2). Significant clinical activity was observed, particularly at higher CLO doses, including CR in 2 pts with complex karyotype. In contrast, only 1/5 evaluable pts at dose level-2 achieved CR. PK & PD studies are in progress.Conclusions In contrast to prior reports using intermediate dose bolus Ara-C (1g/m2), the MTD of CLO combined with standard dose infusional Ara-C in older adults with AML is lower, and the toxicity profile appears different. Significant clinical activity was noted at higher CLO dose levels & with complex karyotype. Based on this observation an escalation to CLO 20mg/m2 is now planned.CLO & Standard Dose Infusional Ara-C: Toxicity & EfficacyPatientCLO Dose LevelAgeCytogeneticsResponse (CR Duration)DLT11 (30mg)66−7DeathInfection/Renal2161−7, complexCR (15 mths)none3169intermediateCR (2 mths)none41775q-, complexDeathInfection/Renal/Vasc Leak5−1 (22.5mg)75+8DeathPneumonia6−167diploidCR (5 mths)none7−1719q-DeathPulm Embolism Day 278−2 (15mg)745q-, complexFailnone9−264diploidFailnone10−263diploidFailnone11−273complexCR (5 mths)none12−272diploidFailnone13−263diploid--Fail - failure to achieve CR

Results of an Exploratory Study of Oral (po) and Intravenous (iv) Clofarabine in Patients with Myelodysplastic Syndrome.

Clofarabine (CLO) is an adenosine nucleoside analog with activity in adult acute myeloid leukemia (AML). Its activity in MDS is less well defined. To evaluate the activity and safety of CLO in MDS we designed two phase II studies with iv CLO and po CLO, respectively. Pts were eligible if they had MDS with ≥ 5% blasts, fell into IPSS intermediate-2 and high-risk groups, or had CMML. No prior intensive chemotherapy or high-dose cytarabine was allowed. Hematopoietic growth factor support was permitted. In the iv study pts were adaptively randomized to receive CLO 15 or 30 mg/m2 iv daily x 5 every 4–6 weeks. The second study used a starting dose of CLO 40 mg/m2 orally daily x 5 every 4–6 weeks (assuming oral bioavailability about 50%), which was then decreased to 30 mg/m2 orally daily x 5. Thirty pts (18 RAEB, 6 RAEB-T, 6 CMML) have been treated. Assignment by IPSS for RAEB and RAEB-T pts: 10 high-risk, 10 intermediate-2, and 4 intermediate-1. Fifteen pts received iv CLO and 15 po CLO. Median age was 68 yrs (range 57–86). Median number of prior therapies was 1 (0–4). Twenty (67%) pts received prior decitabine or azacitidine. Karyotype was abnormal in 24 (80%) pts, including 10 pts with −5/−7 abnormalities. Responses were determined according to International Working Group criteria (IWG). Twenty-seven pts were evaluable for response (2 pts too early, one refused further treatment on day 4 of first course). Eleven (41%) pts responded [7 (26%) CR, 2 (7%) HI, 2 (7%) clinical benefit (CB)] (see table).Response (%)RouteDose (mg/m2)NCRHICBpo406--1 (17)3061(17)2 (33)1 (17)iv3062 (33)--1594 (44)--Response by IPSS: 67% intermediate-1, 44% intermediate-2, 40% high. Twenty-seven pts are evaluable for toxicities. Grade ≥ 3 toxicities occurred in 8 of 13 pts on iv CLO (rash, hyperbilirubinemia, elevated transaminases, elevations of creatinine, acute renal failure) and 4 of 14 pts with po CLO (rash, hyperbilirubinemia, elevated transaminases). Myelosuppression resulting in febrile episodes and hospitalizations with both iv and po CLO was ubiquitous, but prolonged myelosuppression (> 42 days) was rare. In summary, CLO has activity in pts with higher-risk MDS. The optimal dose and schedule for po and iv CLO have not been defined yet. Lower doses of CLO are associated with responses. Correlative PK studies may help to provide further support for optimal dose and route of administration of CLO in pts with MDS.

Clofarabine (CLO) Is Active in Patients (pts) with Refractory and/or Relapsed Non-Hodgkin's Lymphoma (NHL): A Phase I/II Study.

There is no known standard of care for pts with relapsed and/or refractory NHL who cannot undergo stem cell transplantation (SCT) or have relapsed after SCT. Such pts are candidates for new therapies. CLO is a novel nucleoside analogue with known activity in acute leukemia and myelodysplasia. Previous clinical trials with CLO have established safety and potential activity in a variety of tumors. We performed a phase I/II study of CLO in a heavily pretreated pt population with refractory and/or relapsed NHL regardless of cell type, histology, or grade. Eligible pts were adults over 18 years of age who have relapsed and/or refractory NHL with measurable disease. Pts were required to have adequate performance status, bone marrow function (unless cytopenias were related to disease involvement), renal, cardiac, and liver functions. Pts with bulky disease (>10 cm at any site), known HIV, or immune-related cytopenias were excluded. CLO was given as a 1-hour intravenous infusion for 5 consecutive days every 28 days for a maximum of 6-cycles. All enrolled pts received anti-viral and anti-pneumocystis carinii prophylaxis. Growth factors were administered at the investigator's discretion. Pts were divided into cohorts of 3 each. CLO was given at 4 mg/m2 to the first cohort with escalated doses by 2 mg/m2 increments for each cohort. Once the dose-limiting toxicity (DLT) was reached, the phase II portion of this study was initiated at the dose below the DLT level. All pts were followed until disease progression. To date, 13 pts have been enrolled with 7 on the phase I portion and 6 on the phase II portion. For the phase I portion, the median age was 79 (range: 27–81); the median number of prior therapies was 5 (range: 2–6) with 3 pts having relapsed after prior SCT. The median number of given CLO cycles in the phase I portion was 2 (range: 1–5). The DLT at 6 mg/m2 was thrombocytpenia establishing 4 mg/m2 as the appropriate dose for phase II. For the phase II portion, the median age was 78 (range: 50–83), median number of prior therapies was 2 (range: 1–8). Taken all together (phase I and II pts), 9 out of 13 pts are evaluable for response. (All received at least 1 cycle). There was 1 complete response (CR) and 4 partial responses (PR) for an overall response rate (OR) of 55%. Four patients demonstrated stable disease (SD) with one of them progressing shortly after 2 months. Eight patients remain alive (overall survival: 61%) at a median follow up of 4 months (range: 1–13). Median times to progression and duration of response have not been reached in responding pts. [Display omitted] CLO is active in heavily pretreated refractory and/or relapsed NHL. The drug has an acceptable toxicity profile. Myelosuppresion is the major adverse event in this heavily pretreated population. The study continues to accrue patients and will be updated at the meeting.

Phase I/II Study of Clofarabine Plus Cyclophosphamide in Adults with Relapsed and Refractory Acute Lymphoblastic Leukemia (ALL).

Clofarabine (CLO) is a nucleoside analog with activity in pediatric ALL salvage where it has received FDA approval. Less experience with CLO exists in adult ALL. As CLO inhibits DNA repair following exposure to DNA damaging agents, we designed a phase I/II study of the combination of CLO with cyclophosphamide (CY) for therapy of adult patients (pts) with primary refractory or relapsed ALL. Pts with NYHA class ≥ 3 and a cardiac ejection fraction < 45% were excluded. The continual reassessment method (CRM) was applied to determine MTD from 4 dose levels. The starting dose level was CLO 40 mg/m2 i.v. daily x 3d and CY 200 mg/m2 i.v. q12h x 3d. For cohort 2, the dose of CY was increased to 300 mg/m2. Cohorts 3 and 4 maintained these doses with the treatment duration extended to 4 and 5 days, respectively. Additional samples for clinical pharmacology were obtained from consenting pts prior to and following CY on d1 and d2 and prior to CLO on d2.Thirteen pts have been enrolled. Median age was 34 yrs (range 21–72 yrs). Eight pts had pre-B ALL, 2 pts T ALL/LL, 1 pt mature B ALL, and 2 pts biphenotypic acute leukemias. Karyotype was abnormal in 9 pts (no Ph). Median number of prior regimens was 2 (1–6). Two (15%) pts were primary refractory. Median remission duration to initial induction was 11 mos (0–29.8 mos). Three patients were treated in cohort 1 and 10 in cohort 2. Four pts in cohort 2 experienced DLTs (≥ grade 3): elevation of creatinine/renal failure (1), diarrhea (1), transaminase elevations (2), and hyperbilirubinemia (2). Twelve patients were evaluable for response. One pt (70 yrs, prim. refr. pre-B ALL, complex karyotype) of cohort 1 achieved CR after 2 courses, which lasted for 10.3 months. Four pts died on study from infectious complications (days 2, 15, 34, and 41, respectively). Although no MTD has been defined yet and accrual continues in cohort 2, it appears unlikely that the MTD will exceed the dose levels of cohort 2. More information on efficacy will be obtained in the phase II extension part of the study.

Preliminary Results of Phase II Trial of Clofarabine with Parenteral Busulfan Followed by Allogeneic Related or Unrelated Donor Transplantation for the Treatment of Hematologic Malignancies and Diseases.

Background: Nonablative transplant regimens are useful to treat patients who are elderly or too ill to undergo a full-intensity ablative allogeneic transplant regimen. However, this approach is limited by a higher relapse rate in some situations. We developed a novel conditioning regimen using the nucleoside analogue clofarabine (CLO) with busulfan (BU) to treat elderly patients with acute leukemia or high risk MDS who are not in remission or are at high risk of relapse.Methods: Five patients were enrolled on this single institution; phase II, IRB-approved trial, so far. The diagnoses at the time of transplant were two with AML, one with ALL, and two with MDS. All patients received CLO 40mg/m2/day iv on d-7 through d-4 followed by BU 3.2 mg/m2/day iv on d-3 and -2, followed by infusion of HLA matched related or unrelated donor PBSC on day 0. GVHD prophylaxis consisted of oral FK506 and MTX 5mg/m2 iv d + 1, +3 and +6. BU and CLO pharmacokinetic samples were collected on all patients for later PK analysis.Results: Primary endpoints included toxicity and response to therapy. There were no cases of hepatic, cardiac, or renal toxicity attributed to the conditioning regimen by d+30. Acute toxicities included hand/foot syndrome, n=2 (one grade 1, and one grade 3 by CTCAE v 3.0); fluid retention, n=3 (2 grade 1 and 1 grade 2). All patients had hematologic nadirs lasting 12 to 15 days. GCSF was used in 4 of 5 subjects. 5 of 5 patients achieved allogeneic engraftment with myeloid cells by day +30. Response to therapy was documented in 4 patients by d+30, one is not yet evaluated. One (1) patient relapsed by d+62. 3 of 4 remain in remission with follow up ranging from 60 to 117 days.Conclusions: CLO + BU is a novel allogeneic conditioning regimen that seems to be well tolerated by the small number of subjects treated so far at our institution. The follow up is not long enough to conclude more at this time. The study continues to accrue patients and will be updated at the meeting.

In vitro cytotoxicity of nelarabine, clofarabine and flavopiridol in paediatric acute lymphoblastic leukaemia

The in vitro efficacies of three new drugs--clofarabine (CLOF), nelarabine (NEL) and flavopiridol (FP) - were assessed in a panel of acute lymphoblastic leukaemia (ALL) cell lines. The 50% inhibitory concentration (IC50) for CLOF across all lines was 188-fold lower than that of NEL. B-lineage, but not T-lineage lines, were >7-fold more sensitive to CLOF than cytosine arabinoside (ARAC). NEL IC50 was 25-fold and 113-fold higher than ARAC in T- and B-lineage, respectively. T-ALL cells were eightfold more sensitive to NEL than B-lineage but there was considerable overlap. FP was more potent in vitro than glucocorticoids and thiopurines and at doses that recent phase I experience predicts will translate into clinical efficacy. Potential cross-resistance of CLOF, NEL and FP was observed with many front-line ALL therapeutics but not methotrexate or thiopurines. Methotrexate sensitivity was inversely related to that of NEL and FP. Whilst NEL was particularly effective in T-ALL, a subset of patients with B-lineage ALL might also be sensitive. CLOF appeared to be marginally more effective in B-lineage than T-ALL and has a distinct resistance profile that may prove useful in combination with other compounds. FP should be widely effective in ALL if sufficient plasma levels can be achieved clinically.

Limited Phase I Trial of Sequential High Dose Cytarabine and Clofarabine (HiDAC→CLOF) in Relapsed or Refractory Acute Myeloid Leukemia.

High dose cytarabine (HiDAC) is the most effective single agent for the treatment of acute myeloid leukemia (AML); clofarabine (CLOF) is also an active agent in AML. Preclinical data suggest synergy between cytarabine and clofarabine. We conducted a two step limited phase I trial of sequential HiDAC (2g/m2 over 3 hours) followed by CLOF (30 or 40 mg/m2 infused over 2 hours), each given daily for 5 days, in adults with AML in first or second relapse or refractory to initial induction chemotherapy. Patients with persistent leukemia on day 12–14 received a second course of HiDAC→CLOF; phase I toxicity evaluation was based on cycle 1 data only. Nine patients (6 men and 3 women) were treated. The median age was 55.5 years (range 29.2 – 68.1). All had relapsed AML; two had prior autologous stem cell transplant. The initial cohort of 3 patients received clofarabine 30 mg/m2 with one dose limiting toxicity (DLT); an additional 3 patients were treated in cohort 1. The second cohort was treated with CLOF 40 mg/m2, the target dose for a planned phase II trial of HiDAC→CLOF. Hematologic toxicities and infections were not considered DLT. In the first cohort (30 mg/m2; n = 6) there was 1 DLT - grade 4 skin rash in a patient who subsequently died on day 17 with sepsis-related multi-organ failure; 3 patients had reversible grade 3 elevations in AST/ALT, 1 had grade 3 skin toxicity. In cohort 2 (40 mg/m2 ; n = 3) there was no DLT; 1 patient had grade 3 AST/ALT; 2 had grade 3 skin. Three of nine patients received a second course of induction HiDACCLOF. Two of six patients in cohort 1 achieved complete remission (CR), 1/3 patients in cohort 2 achieved CRi(CRp). Two of three CR/CRi patients received one course and one received two courses of HiDAC→CLOF induction. Conclusion: HiDAC→CLOF was associated with transient elevation in AST/ALT (4/9) and skin rash (3/9; primarily extensive palmar/plantar); skin toxicity appeared especially prominent in patients with palmar/plantar toxicity during prior therapy with HiDAC. Toxicities (other than skin) were comparable to other salvage regimens for relapsed and refractory AML. This combination is active in relapsed AML with 3/9 CR/CRp. A phase II trial of HiDAC→CLOF is underway; prophylactic intravenous hydrocortisone has been incorporated in an attempt to decrease skin toxicity.

Clofarabine Plus Anthracycline Combinations in Acute Myeloid Leukemia (AML) Salvage.

Clofarabine (CLO) is a second-generation nucleoside analog with activity in acute leukemias. Whereas it has received FDA approval in children with relapsed acute lymphoblastic leukemia, the focus of clinical research in adults has shifted to AML. To improve single agent activity, various CLO combinations are being studied. Here we present the results of two dose-finding phase I studies, exploring combinations of CLO with idarubicin (IDA) [CI] and CLO+IDA+Ara−C [CIA] in patients (pts) with relapsed or refractory AML and high-risk MDS. Eligibility for CI required previous Ara-C and primary refractory disease, or relapsed AML with first remission duration (CRD1) < 12 mos. Eligibility for CIA required either no previous Ara-C or Ara-c with CRD1 ≥ 12 mos. Maximum tolerated dose (MTD) was determined by “3+3” method. Forty-four pts (CI 23; CIA 21) have been accrued and are evaluable. The median age of pts on CI was 56 yrs (range 24–71), 9 were primary refractory and 14 in first relapse (median CRD1 2 mos. [0–9]). Fifteen pts had abnormal cytogenetics (including 6 with -5, -7, or 11q23). Sixteen pts had intermediate- or high-dose Ara-C-based prior therapy, 2 relapsed from allogeneic transplant (SCT). The median age of pts on CIA was 56 yrs (23–78), 8 were primary refractory and 13 in first relapse (median CRD1 9 mos [0–61]). Twelve pts had an abnormal karyotype (-5, -7, or 11q23 in 6 pts). Twelve pts received intermediate dose Ara-C-based prior therapy and 2 failed unrelated donor SCT. The starting dose level of the CI group was CLO 22.5 mg/m2 iv daily x 5d and IDA 12 mg/m2 iv daily x 3d. Three DLTs occurred (diarrhea, rash, ↑ bilirubin) requiring dose de-escalation to CLO 15 mg/m2/d x 5d and IDA 8 mg/m2/d x 3d. Gradual re-escalation led to CLO 30 mg/m2/d x 5d and IDA 10 mg/m2/d x 3d where 2/5 pts experienced DLTs (↑ SGPT, ↑ bilirubin, headache). MTD was defined by the next lower dose level: CLO 22.5 mg/m2/d x 5d and IDA 10 mg/m2/d x 3d. Three (13%) CR occurred. The CIA group started at CLO 22.5 mg/m2/d x 5d, IDA 8 mg/m2/d x 3d, and Ara-C 1g/m2/d x 5d. Two pts developed DLTs (diarrhea, ↑ bilirubin, renal failure) requiring de-escalation to CLO 15 mg/m2/d x 5d, IDA 6 mg/m2/d x 3d, and Ara-C 0.75 g/m2/d x 5d. Re-escalation to CLO 30mg/m2/d x 5d, IDA 6mg/m2/d x 3d, and Ara-C 0.75 g/m2/d x 5d revealed DLTs in 2/6 pts (diarrhea, mucositis, ↑ bilirubin). MTD was thus defined at next lower dose level of CLO 22.5 mg/m2/d x 5d, IDA 6 mg/m2/d x 3d, and Ara-C 0.75 g/m2/d x 5d. Ten (48%) responses (9 CR, 1 CRp) occurred. The higher response rate of CIA may be due to the difference in pt characteristics between the two trials. A phase II study is now in progress adaptively randomizing patients with AML relapse to CI versus CIA versus CLO (40 mg/m2/d x 5d) plus Ara-C (1 g/m2/d x 5d) (as established in an earlier study) to assess activity of the combinations.

Phase I Clinical-Laboratory Trial of Clofarabine (CLO) Followed by Cyclophosphamide (CY) for Adults with Refractory Acute Leukemias: Evidence for Enhanced DNA Damage.

CLO is a nucleoside analog with ribonucleotide reductase inhibitory activity. As such, CLO has the ability to impede repair of damaged DNA. We designed a Phase I clinical trial of CLO followed by CY for adults with refractory acute leukemias, with escalating doses of CLO (beginning10 mg/m2/day) and CY (beginning 400 mg/m2/day) days 1–3 and 8–10. The first CY dose was split between Day 0 and Day 1 at 200 mg/m2/dose to test the hypothesis that CLO could increase CY-induced DNA damage in leukemic blasts. Peripheral blood blasts were obtained prior to CY (Pre), at end Day 0 CY 2 hr infusion (Day 0 EOI), 2 hrs after Day 0 CY EOI (Day 0 Post), and Day 1 2 hrs after CLO-CY EOI (Day 1 Post). DNA damage was measured serially by flow cytometry of cells stained with antibody to phosphorylated histone H2AX (γH2AX). Apoptosis was measured at each time point by propidium iodide (PI) staining as sub2N DNA. To date, we have studied peripheral blood blasts from 9 patients at 2 CLO doses (10 and 20 mg/m2/day) and CY total daily dose 400 mg/m2. γH2AX was detected in a median 1.32% of Pre cells (range 0–6.1). Relative to Pre, there was median 2-fold increase in γH2AX (range 0.3–6) in Day 0 EOI cells with less damage detected in Day 0 Post cells (median 1.1, range 0–3.3). Day 1 Post cells evinced median 6.3-fold increase in γH2AX staining (range 1.5–38) relative to Pre, with 6/9 patients have a >2-fold increase, and median 9.2-fold increase (range 0.9–38) relative to Day 0 Post with >2-fold increase in 7/9 patients. Relative to Pre cells, there was no increase in the fraction of cells exhibiting sub2N DNA (median 0.9, range 0.34–22, >1.2-fold increase in 4/9) in Day 0 Post samples. In contrast, Day 1 Post samples had median 1.4-fold (range 0.3–61) increase in cells with sub2N DNA, with 7/9 patients having >1.2 fold increases. In this small number of patients, there was no clear relationship between CLO dose and magnitude of DNA damage or apoptosis induced in Day 1 Post cells. In 5 patients with complete tumor clearance in Day 14 marrow, there was median 11-fold increase (range 0.3–62) in γH2AX staining in Day 1 Post cells relative to Pre cells and median 5.7-fold increase (range 0.9–33) over Day 0 Post cells. In 3 patients who had residual leukemia present on Day 14, the median increase in γH2AX over Pre was 1.7-fold (1.5,1.7,38). WBC nadir was 0 (range 0–50) occurred on median day 12 (range 10–20). WBC recovery to >500/mm3 occurred in 7 patients on median day 32 (range 27–75), 1 patient with refractory AML died Day 14 of multi-organ failure, and 1 patient with refractory ALL post autologous transplant died on day 100 in marrow aplasia. Two patients with refractory AML achieved responses: 1 CR, 1 PR. Interestingly, the patient who achieved CR had the highest Pre γH2AX and Day 1 Post levels (38.6%). In summary, our in vivo correlative data suggest that DNA damage that occurs following CY, as measured by γH2AX, is augmented by prior CLO administration and correlates with tumor clearance by Day 14. With accrual and study of additional patients, we should be able to determine any relationship between magnitude of increase in DNA damage and clinical outcomes.

Bioenvision has announced that it will formally launch its clofarabine [Evoltra] throughout Europe

Bioenvision has announced that it will formally launch its clofarabine [Evoltra] throughout Europe

FDA gives accelerated approval to clofarabine

FDA gives accelerated approval to clofarabine