Abstract 5927
Background
Heat shock protein 90 (HSP90) is a molecular chaperone required for proper folding and stabilization of proteins. Client proteins of HSP90 include many oncogenic proteins known to be over-activated in triple negative breast cancer (TNBC) such as AKT, EGFR and members of RAS/MAPK signaling pathway. Over-expression of HSP90 client proteins such as AKT and c-RAF has also been implicated in paclitaxel resistance. Onalespib (AT13387) is a potent non-ansamycin small molecule inhibitor of HSP90.
Methods
Patients (pts) with inoperable or metastatic, TNBC were treated with onalespib and paclitaxel on days 1, 8, 15 every 28 days. Paclitaxel was given at a dose of 80 mg/m2 while the dose of onalespib was gradually increased from 120 mg/m2 to 260 mg/m2 in dose levels (DL) 1-4 using standard 3 + 3 design. In order to assess the effect of each drug on pharmacokinetics (PK) of the other drug, onalespib was given on day -7 prior to cycle 1 and skipped on day 1 of cycle 1. The primary objective was to determine dose limiting toxicities (DLT) and maximum tolerated dose (MTD). The secondary objectives were PKs of each agent, overall response rate (ORR), response duration and progression-free survival.
Results
20 pts were enrolled to dose escalation part (5, 3, 7 and 6 to DL 1-4 respectively). One pt in DL 1 did not start therapy due history of severe paclitaxel hypersensitivity and 2 pts (DL1 and DL 3) had to be replaced due to disease progression in cycle 1. One DLT occurred in 1 pt in DL3 (grade 3 nausea, vomiting and abdominal pain). No DLTs were noted in the highest DL testing onalespib at 260 mg/m2. The most common grade 3 or higher adverse events included diarrhea (55%), fatigue (55%), anemia (14%), leukopenia (24%) and neutropenia (41%). Diarrhea was self limiting, lasting 24-48 hrs post infusion and responded well to loperamide. ORR and clinical benefit rate in 16 evaluable pts was 25% and 62.5% respectively. Preliminary PK analysis showed no evidene of interaction between onalespib and paclitaxel.
Conclusions
Study regimen demonstrated acceptable safety profile. MTD of onalespib in combination with standard dose and schedule of paclitaxel was determined to be 260 mg/m2. Dose expansion study at MTD is currently ongoing.
Clinical trial identification
NCI 9876 (NCT02474173).
Editorial acknowledgement
Not applicable
Legal entity responsible for the study
Robert Wesolowski, MD.
Funding
Cancer Therapy Evaluation Program at the National Cancer Institute.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
2107 - Role of Individualized Intervention(s) on Quality of Life (QOL) and Adherence to Adjuvant Endocrine Therapy in Premenopausal Women with Early-Stage Breast Cancer (BC): MyChoice Study
Presenter: Shahid Ahmed
Session: Poster Display session 2
Resources:
Abstract
5812 - Correlation between the density of tumor-infiltrating lymphocytes, immune cell subsets in tumor stroma and response to systemic therapy in breast cancer
Presenter: Cvetka Grasic Kuhar
Session: Poster Display session 2
Resources:
Abstract
4734 - BRCA1/2 Testing in HER2- Advanced Breast Cancer (ABC): Results from the European Component of a Multi-Country Real World Study
Presenter: Michael Patrick Lux
Session: Poster Display session 2
Resources:
Abstract
1686 - In vitro and in vivo rescue of resistance to BET inhibitors by targeting PLK1 in triple negative breast cancer.
Presenter: Cristina Nieto-jiménez
Session: Poster Display session 2
Resources:
Abstract
5020 - Neoadjuvant endocrine therapy in combination with melatonin and metformin in locally advanced breast cancer
Presenter: Tatiana Semiglazova
Session: Poster Display session 2
Resources:
Abstract
5082 - Melatonin and metformin in neoadjuvant chemotherapy in locally advanced breast cancer
Presenter: Tatiana Semiglazova
Session: Poster Display session 2
Resources:
Abstract
2642 - Patient-tailored tamoxifen dosing based on an increased quantitative understanding of its complex pharmacokinetics: A novel integrative modelling approach
Presenter: Anna Mueller-Schoell
Session: Poster Display session 2
Resources:
Abstract
2461 - Lack of benefit of neoadjuvant pertuzumab in high risk HER2 positive breast cancer. A retrospective case-control study of 355 cases with biomarker analysis.
Presenter: Manuela Tiako Meyo
Session: Poster Display session 2
Resources:
Abstract
4776 - Targeting CDCA3 to improve chemotherapy response in triple-negative breast cancer patients
Presenter: Kenneth O'Byrne
Session: Poster Display session 2
Resources:
Abstract
1674 - Activity of BET-proteolysis targeting chimeric (PROTAC) compounds in triple negative breast cancer
Presenter: María Del Mar Noblejas López
Session: Poster Display session 2
Resources:
Abstract