Author of

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  MO09 - Mesothelioma I (ID 120)

  • Event: WCLC 2013
  • Type: Mini Oral Abstract Session
  • Track:
  • Presentations: 1
  • Moderators:K. Suzuki, S.G. Armato III
  • Coordinates: 10/28/2013, 16:15 - 17:45, Bayside 204 A+B, Level 2

  • 11331

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    MO09.02 - A Randomised Phase II trial of Pegylated Arginine Deiminase in patients with Malignant Pleural Mesothelioma (ID 1355)

    16:20 - 16:25  |  Author(s): S. Ellis
    • Abstract
    • Presentation
    • Slides

    Background
    Preclinically, arginine deprivation has shown activity as a novel antimetabolite strategy for MPM patients who are deficient for the rate-limiting enzyme in arginine biosynthesis argininosuccinate synthetase (ASS1). Here, we examine the efficacy and safety of the arginine-lowering agent ADI-PEG20 (Polaris Group, San Diego, US) among patients with MPM.

    Methods
    We performed a multicentre randomised phase II clinical trial, based on patients with good performance status (0 or 1), non-resectable disease, ASS1-deficient MPM, and measurable disease. Patients were randomized 1:2 to receive best supportive care (BSC) or BSC+ADI-PEG20, stratified by: gender, histology (sarcomatoid versus non-sarcomatoid), prior treatment (chemonaive or previous platinum combination therapy), and centre. The primary endpoint, progression-free survival (PFS), is assessed by modified RECIST, and secondary endpoints include overall survival, tumor response rate, and toxicity. Translational endpoints included measurement of plasma arginine, citrulline and ADI-PEG20 antibody levels, assessment of metabolic response by [18F]Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) and ASS1 methylation status using Illumina’s 450K DNA methylation array. The target sample size was estimated to detect a PFS hazard ratio of 0.60. [Trial funded by Cancer Research UK].

    Results
    ASS1 deficiency was detected in 98 of 214 patients (46%) of which 68 were randomized on the trial (44 ADI-PEG20+BSC and 24 BSC alone). 66 patients have progressed so far (42 ADI-PEG20+BSC vs. 24 BSC alone), and 32 patients were alive (23 ADI-PEG20+BSC vs. 9 BSC alone). The hazard ratio for PFS was 0.53 (95%, CI 0.31 to 0.90, p=0.02) with a median PFS of 98 days for patients randomized to ADI-PEG20+BSC compared with 59 days for patients receiving BSC alone. ADI-PEG20 toxicity in patients with MPM has been consistent with previous trials of ADI-PEG20 in melanoma and liver cancer: commonly skin injection site reactions (grade 1-2), infrequent episodes of neutropenia (range: grade 1-4), anaphylactoid reactions (2 patients with grade 3 episodes) and serum sickness (1 patient). The best response by modified RECIST was stable disease. Metabolic responses (in 39 evaluable ADI-treated patients) were as follows: 46% with partial response (18/39), 31% with stable disease (12/39), 15% progressive metabolic disease (6/39) and 8% mixed metabolic response (3/39) by FDG-PET assessment. There was a significant difference between IHC assessed ASS1-negative and ASS1-positive patients and the methylation status of the ASS1 gene (p=0.025).

    Conclusion
    ADI-PEG20 is generally well tolerated and shows evidence of clinically significant activity in patients selected for arginine-dependent MPM demonstrating differential methylation of ASS1. Arginine deprivation may have a role in the future management of MPM either alone or in combination with selected therapies.

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