title: Phase I clinical trial and pharmacodynamic evaluation of combination hydroxychloroquine and doxorubicin treatment in pet dogs treated for spontaneously occurring lymphoma.
abstract: Autophagy is a lysosomal degradation process that may act as a mechanism of survival in a variety of cancers. While pharmacologic inhibition of autophagy with hydroxychloroquine (HCQ) is currently being explored in human clinical trials, it has never been evaluated in canine cancers. Non-Hodgkin lymphoma (NHL) is one of the most prevalent tumor types in dogs and has similar pathogenesis and response to treatment as human NHL. Clinical trials in canine patients are conducted in the same way as in human patients, thus, to determine a maximum dose of HCQ that can be combined with a standard chemotherapy, a Phase I, single arm, dose escalation trial was conducted in dogs with spontaneous NHL presenting as patients to an academic, tertiary-care veterinary teaching hospital. HCQ was administered daily by mouth throughout the trial, beginning 72 h prior to doxorubicin (DOX), which was given intravenously on a 21-d cycle. Peripheral blood mononuclear cells and biopsies were collected before and 3 d after HCQ treatment and assessed for autophagy inhibition and HCQ concentration. A total of 30 patients were enrolled in the trial. HCQ alone was well tolerated with only mild lethargy and gastrointestinal-related adverse events. The overall response rate (ORR) for dogs with lymphoma was 93.3%, with median progression-free interval (PFI) of 5 mo. Pharmacokinetic analysis revealed a 100-fold increase in HCQ in tumors compared with plasma. There was a trend that supported therapy-induced increase in LC3-II (the cleaved and lipidated form of microtubule-associated protein 1 light chain 3/LC3, which serves as a maker for autophagosomes) and SQSTM1/p62 (sequestosome 1) after treatment. The superior ORR and comparable PFI to single-agent DOX provide strong support for further evaluation via randomized, placebo-controlled trials in canine and human NHL.
authors.affiliation: Department of Clinical Sciences; Colorado State University; Fort Collins, CO USA.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Barnard
authors.affiliation: Department of Clinical Sciences; Colorado State University; Fort Collins, CO USA.
authors.forename: Luke A
authors.initials: LA
authors.lastname: Wittenburg
authors.affiliation: Department of Medicine Hematology Oncology Division; Pearlman School of Medicine; University of Pennsylvania; Philadelphia, PA USA.
authors.forename: Ravi K
authors.initials: RK
authors.lastname: Amaravadi
authors.affiliation: Department of Clinical Sciences; Colorado State University; Fort Collins, CO USA.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Gustafson
authors.affiliation: Department of Pharmacology; University of Colorado School of Medicine; Aurora, CO USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Thorburn
authors.affiliation: Department of Clinical Sciences; Colorado State University; Fort Collins, CO USA.
authors.forename: Douglas H
authors.initials: DH
authors.lastname: Thamm
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use*; D018572:Disease-Free Survival; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004317:Doxorubicin / Q000009:adverse effects / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D006886:Hydroxychloroquine / Q000009:adverse effects / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use*; D008223:Lymphoma / Q000097:blood / Q000188:drug therapy* / Q000662:veterinary*; D008297:Male; D057805:Pets; D016896:Treatment Outcome
chemical_list: D006886:Hydroxychloroquine; D004317:Doxorubicin
keywords: autophagy; canine model; doxorubicin; hydroxychloroquine; lymphoma