Clofarabine monotherapy in aggressive, relapsed and refractory Langerhans cell histiocytosis

Over 50% of patients with systemic LCH are not cured with front-line therapies, and data to guide salvage options are limited. We describe 58 patients with LCH who were treated with clofarabine. Clofarabine monotherapy was active against LCH in this cohort, including heavily pretreated patients with a systemic objective response rate of 92.6%, higher in children (93.8%) than adults (83.3%). BRAFV600E+ variant allele frequency in peripheral blood is correlated with clinical responses. Prospective multicentre trials are warranted to determine optimal dosing, long-term efficacy, late toxicities, relative cost and patient-reported outcomes of clofarabine compared to alternative LCH salvage therapy strategies.

Combination of clofarabine, etoposide, and cyclophosphamide in adult relapsed/refractory acute lymphoblastic leukemia: a phase 1/2 dose-escalation study by the Japan Adult Leukemia Study Group

This phase 1/2 study aimed to identify the maximum tolerated dose, the recommended phase 2 dose (RP2D), and efficacy of the clofarabine, etoposide, and cyclophosphamide combination regimen in adult patients with relapsed/refractory acute lymphoblastic leukemia (ALL). Patients aged ≥ 15 years with relapsed/refractory ALL were enrolled. Escalating doses of clofarabine (20-30 mg/m²/day × 5 days), etoposide (50-100 mg/m²/day × 5 days), and cyclophosphamide (200-440 mg/m²/day × 5 days) were administered. Dose-limiting toxicity was defined as Grade 3 or more non-hematological toxicities and others. A total of 18 patients (B-ALL; n = 13, T-ALL; n = 5) were recruited in phase 1; however, the protocol was amended to close study without proceeding to phase 2. Three patients were enrolled in cohort 1, three in cohort 2, six in cohort 3, and six in cohort 4. The RP2D of clofarabine, etoposide, and cyclophosphamide was 30, 100, and 440 mg/m² daily, respectively. Complete remission (CR) was achieved in four patients (22%) and CR without platelet recovery in four patients (22%), with an overall response rate of 44%. The RP2D of the combination therapy was successfully determined in this study.

Toxicity associated with intensive postinduction therapy incorporating clofarabine in the very high-risk stratum of patients with newly diagnosed high-risk B-lymphoblastic leukemia: A report from the Children's Oncology Group study AALL1131

BACKGROUND

Children, adolescents, and young adults with very high-risk (VHR) B acute lymphoblastic leukemia (B-ALL) have poor outcomes, and novel therapies are needed for this subgroup. The AALL1131 study evaluated postinduction therapy using cyclophosphamide (CPM), etoposide (ETOP), and clofarabine (CLOF) for patients with VHR B-ALL.

METHODS

Patients who were 1 to 30 years old and had VHR B-ALL received modified Berlin-Frankfurt-Münster therapy after induction and were randomized to 1) CPM, cytarabine, mercaptopurine, vincristine (VCR), and pegaspargase (control arm), 2) CPM, ETOP, VCR, and pegaspargase (experimental arm 1), or 3) CPM, ETOP, CLOF (30 mg/m2 /d × 5), VCR, and pegaspargase (experimental arm 2) during the second half of consolidation and delayed intensification.

RESULTS

The rates of grade 4/5 infections and grade 3/4 pancreatitis were significantly increased in experimental arm 2. The dose of CLOF was, therefore, reduced to 20 mg/m2 /d × 5, and myeloid growth factor was required after CLOF administration. Despite these changes, 4 of 39 patients (10.3%) developed grade 4 infections, with 1 of these patients developing a grade 5 acute kidney injury attributed to CLOF, whereas only 1 of 46 patients (2.2%) in experimental arm 1 developed grade 4 infections, and there were no grade 4/5 infections in the control arm (n = 20). Four patients in experimental arm 2 had prolonged cytopenias for >60 days, whereas none did in the control arm or experimental arm 1. Counts failed to recover for 2 of these patients, one having a grade 5 acute kidney injury and the other removed from protocol therapy; both events occurred 92 days after the start of consolidation part 2.

CONCLUSIONS

In AALL1131, CLOF, administered with CPM and ETOP, was associated with unacceptable toxicity. Cancer 2018;124:1150-9. © 2017 American Cancer Society.

A Phase I Dose-Escalation Study of Clofarabine in Patients with Relapsed or Refractory Low-Grade or Intermediate-Grade B-Cell or T-Cell Lymphoma

LESSONS LEARNED

Clofarabine can be active in relapsed and refractory lymphoid malignancies on a weekly dosing schedule.Responses were seen in patients with T-cell lymphomas, including cutaneous T-cell lymphoma, but not in patients with aggressive B-cell lymphomas.

BACKGROUND

Clofarabine is a second-generation purine nucleoside analog currently approved for the treatment of pediatric relapsed or refractory acute lymphoblastic leukemia. In adults, clofarabine has been investigated in several phase I and II trials as a single agent and in combination for relapsed or refractory acute leukemia. These studies have shown that clofarabine has activity and an acceptable safety profile in patients with hematological malignancies. In this phase I dose escalation trial, clofarabine was evaluated in patients with relapsed or refractory, low-grade or intermediate-grade, B-cell or T-cell lymphoma.

METHODS

The starting dose of 10 mg/m² per week was administered intravenously (IV) for 3 consecutive weeks every 28 days, and doses were escalated in cohorts of three. The study objectives were to determine the maximum tolerated dose (MTD), characterize and quantify the toxicity profile, and determine the overall response rate of clofarabine administered once a week for 3 weeks and repeated every 4 weeks. Eligible patients were over the age of 18, had a histologically confirmed low-grade or intermediate-grade B-cell or T-cell lymphoma, and must have previously been treated with one standard chemotherapy regimen, excluding single-agent rituximab. The primary objectives included in statistical analyses were MTD, toxicity, and overall response rate (ORR). Four patients were enrolled in cohort 1 (clofarabine 10 mg/m²), four in cohort 2 (clofarabine 15 mg/m²), three in cohort 3 (clofarabine 20 mg/m²), two in cohort 4 (clofarabine 30 mg/m²), and one in cohort 5 (clofarabine 40 mg/m²) (Table 2).

RESULTS

MTD was not reached in the study. The most common toxicity observed was myelosuppression. A total of four (29%) patients experienced grade 3 leukopenia, with three (21%) patients experiencing grade 4 neutropenia. The myelosuppression was not considered to be a dose-limiting toxicity, as it resolved within 7 days.Fourteen patients were enrolled: 10 patients with T-cell non-Hodgkin lymphoma (NHL) and 4 patients with B-cell NHL (see Table 1). All 14 patients received at least one dose of clofarabine and were evaluable for response. One patient with cutaneous T-cell lymphoma (CTCL) had a partial response; five (36%) had stable disease, and eight patients (57%) had no response. The one patient with a response had stage III erythroderma and was treated in the 10 mg/m² cohort; a nodal complete response by positron emission tomography scan was observed with a partial response of the skin.

CONCLUSION

In this study, weekly administration of clofarabine was demonstrated to be safe and associated with minimal hematologic toxicity at doses ranging from 10-40 mg/m². In prior studies when dosed daily for 5 consecutive days, the MTD was shown to be 4 mg/m². Weekly dosing within this dose range did not result in dose modifications, and the MTD was not reached. Clinical efficacy was observed in one patient with CTCL who was treated in the lowest-dose cohort.