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Anti-CD22 immunotoxin RFB4(dsFv)-PE38 (BL22) for CD22-positive hematologic malignancies of childhood: preclinical studies and phase I clinical trial.

ABSTRACT: PURPOSE:Although most children with B-lineage acute lymphoblastic leukemia (ALL) and non-Hodgkin lymphoma are cured, new agents are needed to overcome drug resistance and reduce toxicities of chemotherapy. We hypothesized that the novel anti-CD22 immunotoxin, RFB4(dsFv)-PE38 (BL22, CAT-3888), would be active and have limited nonspecific side effects in children with CD22-expressing hematologic malignancies. We conducted the first preclinical and phase I clinical studies of BL22 in that setting. EXPERIMENTAL DESIGN:Lymphoblasts from children with B-lineage ALL were assessed for CD22 expression by flow cytometry and for BL22 sensitivity by in vitro cytotoxicity assay. BL22 was evaluated in a human ALL murine xenograft model. A phase I clinical trial was conducted for pediatric subjects with CD22+ ALL and non-Hodgkin lymphoma. RESULTS:All samples screened were CD22+. BL22 was cytotoxic to blasts in vitro (median IC(50), 9.8 ng/mL) and prolonged the leukemia-free survival of murine xenografts. Phase I trial cohorts were treated at escalating doses and schedules ranging from 10 to 40 microg/kg every other day for three or six doses repeated every 21 or 28 days. Treatment was associated with an acceptable safety profile, adverse events were rapidly reversible, and no maximum tolerated dose was defined. Pharmacokinetics were influenced by disease burden consistent with rapid drug binding by CD22+ blasts. Although no responses were observed, transient clinical activity was seen in most subjects. CONCLUSIONS:CD22 represents an excellent target and anti-CD22 immunotoxins offer therapeutic promise in B-lineage hematologic malignancies of childhood.

SUBMITTER: Wayne AS

PROVIDER: S-EPMC2840067 | biostudies-literature | 2010 Mar

REPOSITORIES: biostudies-literature

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Anti-CD22 immunotoxin RFB4(dsFv)-PE38 (BL22) for CD22-positive hematologic malignancies of childhood: preclinical studies and phase I clinical trial.

Wayne Alan S AS Kreitman Robert J RJ Findley Harry W HW Lew Glen G Delbrook Cynthia C Steinberg Seth M SM Stetler-Stevenson Maryalice M Fitzgerald David J DJ Pastan Ira I

Clinical cancer research : an official journal of the American Association for Cancer Research 20100309 6

<h4>Purpose</h4>Although most children with B-lineage acute lymphoblastic leukemia (ALL) and non-Hodgkin lymphoma are cured, new agents are needed to overcome drug resistance and reduce toxicities of chemotherapy. We hypothesized that the novel anti-CD22 immunotoxin, RFB4(dsFv)-PE38 (BL22, CAT-3888), would be active and have limited nonspecific side effects in children with CD22-expressing hematologic malignancies. We conducted the first preclinical and phase I clinical studies of BL22 in that s ...[more]

PMID: 20215554

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Project description:BackgroundBrentuximab vedotin is a CD30-directed antibody-drug conjugate. Retreatment with brentuximab vedotin monotherapy was investigated in patients with CD30-positive Hodgkin lymphoma (HL) or systemic anaplastic large cell lymphoma (ALCL) who relapsed after achieving complete or partial remission (CR or PR) with initial brentuximab vedotin therapy in a previous study (ClinicalTrials.gov NCT00947856).MethodsTwenty-one patients with HL and 8 patients with systemic ALCL were retreated; 3 patients with systemic ALCL were retreated twice. Patients generally received brentuximab vedotin 1.8 mg/kg intravenously approximately every 3 weeks over 30 minutes as an outpatient infusion. The primary objectives of this study were to assess safety and to estimate antitumor activity of brentuximab vedotin retreatment.ResultsThe objective response rate was 60% (30% CR) in HL patients and 88% (63% CR) in systemic ALCL patients. The estimated median duration of response for patients with an objective response was 9.5 months (range, 0.0+ to 28.0+ months) at the time of study closure. Of the 19 patients with objective response, 7 patients had not had an event of disease progression or death at the time of study closure; duration of response for these patients ranged from 3.5 to 28 months. Of the 11 patients with CR, 45% had response durations of over 1 year.Adverse events (AEs) occurring in ≥25% of patients during the retreatment period were generally similar in type and frequency to those observed in the pivotal trials of brentuximab vedotin monotherapy, with the exception of peripheral neuropathy, which is known to have a cumulative effect. Grade 3 or higher events were observed in 48% of patients; these were generally transient and managed by dose modifications or delays. Deaths due to AEs occurred in 3 HL patients; none were considered to be related to brentuximab vedotin retreatment.DiscussionWith the exception of a higher rate of peripheral motor neuropathy, retreatment with brentuximab vedotin was associated with similar side effects seen in the pivotal trials.ConclusionsRetreatment with brentuximab vedotin monotherapy is associated with response rates in 68% (39% CR) of patients with relapsed HL and systemic ALCL.Trial registrationUnited States registry and results database ClinicalTrials.gov NCT00947856.

Dataset Information

Anti-CD22 immunotoxin RFB4(dsFv)-PE38 (BL22) for CD22-positive hematologic malignancies of childhood: preclinical studies and phase I clinical trial.

Publications

Anti-CD22 immunotoxin RFB4(dsFv)-PE38 (BL22) for CD22-positive hematologic malignancies of childhood: preclinical studies and phase I clinical trial.

Similar Datasets

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