Safety and activity of DCR-MYC, a first-in-class Dicer-substrate small interfering RNA (DsiRNA) targeting MYC, in a phase I study in patients with advanced solid tumors.

Article Tools Tumor Biology Article Tools OPTIONS & TOOLS Export Citation Track Citation Add To Favorites Rights & Permissions COMPANION ARTICLES No companion articles ARTICLE CITATION DOI: 10.1200/jco.2015.33.15_suppl.11006 Journal of Clinical Oncology - published online before print May 20, 2015 Safety and activity of DCR-MYC, a first-in-class Dicer-substrate small interfering RNA (DsiRNA) targeting MYC, in a phase I study in patients with advanced solid tumors. Anthony W. TolcherxAnthony W. TolcherSearch for articles by this author , Kyriakos P. PapadopoulosxKyriakos P. PapadopoulosSearch for articles by this author , Amita PatnaikxAmita PatnaikSearch for articles by this author , Drew Warren RascoxDrew Warren RascoSearch for articles by this author , Dorothy MartinezxDorothy MartinezSearch for articles by this author , Debra L WoodxDebra L WoodSearch for articles by this author , Barbara FielmanxBarbara FielmanSearch for articles by this author , Manish SharmaxManish SharmaSearch for articles by this author , Linda A. JanischxLinda A. JanischSearch for articles by this author , Bob D BrownxBob D BrownSearch for articles by this author , Pankaj BhargavaxPankaj BhargavaSearch for articles by this author , Mark J. RatainxMark J. RatainSearch for articles by this author Show More START, San Antonio, TX; START Center for Cancer Care, San Antonio, TX; Nadler Pharma Associates, LLC, Randolph, NJ; Dicerna Pharmaceuticals, Cambridge, MA; The University of Chicago Medicine, Chicago, IL; University of Chicago, Chicago, IL; The University of Chicago, Chicago, IL Abstract Disclosures https://doi.org/10.1200/jco.2015.33.15_suppl.11006 Abstract Abstract 11006 Background: MYC, an oncoprotein deregulated in over half of all human malignancies, has thus far been considered "undruggable" with conventional approaches. RNA interference (RNAi), a therapeutic approach that can be used to silence the MYC oncogene, has been shown to inhibit cancer growth in animal models. Synthetic DsiRNA with specificity for MYC have demonstrated highly potent activity in vitro (picomolar IC50), and anti-MYC DsiRNA formulated in EnCore lipid nanoparticles (DCR-MYC) have demonstrated activity in vivo across various tumor models. DCR-MYC is the first MYC-targeting siRNA to enter clinical trials. Methods: This phase I, dose-escalation study (3+3 design) evaluated the safety, pharmacokinetics (PK), pharmacodynamics (PD) and clinical activity of DCR-MYC in patients (pts) with advanced solid tumors, multiple myeloma or lymphoma. DCR-MYC is administered as a 2-hr IV infusion on Day 1 and 8 of a 21 day cycle. Given the role of MYC in tumor metabolism, FDG-PET is obtained after cycle 1 to assess early metabolic response, while RECIST response is assessed after every 2 cycles. Results: Nineteen pts have been treated across 5 dose levels (0.1, 0.125, 0.156, 0.2, 0.3 mg/kg): 8M/11F, median age 58 yrs, ECOG PS 0(5), 1(14). Tumor types include NET (4), MBC (4), CRC (3), Ovarian (2), Appendiceal (2), other (4). The most common treatment-related AEs (all grades/grade 3) include fatigue (7/0), nausea (5/0) and infusion reactions (3/1). A pt with PNET treated at 0.1 mg/kg experienced DLT (transient grade 3 AST) and fatigue. This pt experienced a complete metabolic response (based on FDG-PET) after cycle 1 which has been sustained for > 8 months without further treatment. Metabolic responses after cycle 1, as well as evidence of tumor shrinkage have been observed in multiple patients. Preliminary PK analysis from the first two dose levels shows dose proportional changes in AUC and Cmax. Conclusions: DCR-MYC, a novel MYC inhibitor, is well tolerated and shows promising initial clinical and metabolic responses across various dose levels. These data support early validation of MYC as a therapeutic target. Updated results from the ongoing study will be presented. Clinical trial information: NCT02110563. © 2015 by American Society of Clinical Oncology