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
3034 - Efficacy and safety of neoadjuvant chemotherapy plus trastuzumab and pertuzumab in non-metastatic HER2-positive breast cancer in real life: NEOPEARL STUDY
Presenter: Maria Agnese Fabbri
Session: Poster Display session 2
Resources:
Abstract
4772 - Real world comparison of the impact of adjuvant capecitabine in women with high-risk triple-negative breast cancer after neoadjuvant chemotherapy
Presenter: Maysa Vilbert
Session: Poster Display session 2
Resources:
Abstract
5627 - Influence of age on the indication of adjuvant chemotherapy in early breast cancer using Oncotype DX. An analysis of 240 patients treated in the Institut Catala d’Oncologia (ICO) hospitals
Presenter: Sabela Recalde
Session: Poster Display session 2
Resources:
Abstract
3917 - Impact of delayed neoadjuvant systemic chemotherapy on survival among breast cancer patients
Presenter: Mariana Chavez Mac Gregor
Session: Poster Display session 2
Resources:
Abstract
2246 - Clinical Confirmation of Higher Exposure to Niraparib in Tumor vs Plasma in Patients With Breast Cancer
Presenter: Laura Spring
Session: Poster Display session 2
Resources:
Abstract
581 - The rationale for the effectiveness of systemic treatment of breast cancer depending on the body weight index
Presenter: Mohammad Hojouj
Session: Poster Display session 2
Resources:
Abstract
5327 - Response to neoadjuvant chemotherapy in HER2 non-overexpressing breast cancer subtypes
Presenter: Silvia Mihaela Ilie
Session: Poster Display session 2
Resources:
Abstract
3613 - Pre-specified interim analysis of the SAFE trial (NCT2236806): a 4-arm randomized, double-blind, controlled study evaluating the efficacy and safety of cardiotoxicity prevention in non-metastatic breast cancer patients treated with anthracyclines with or without trastuzumab.
Presenter: Lorenzo Livi
Session: Poster Display session 2
Resources:
Abstract
3736 - Safety of hypofractionated whole breast irradiation after conservative surgery for patients aged less than 60 years: a multi-center comparative study.
Presenter: Icro Meattini
Session: Poster Display session 2
Resources:
Abstract
5085 - Usefulness of NT-ProBNP as a biomarker of cardiotoxicity in breast cancer patients treated with trastuzumab
Presenter: Isabel Blancas López-Barajas
Session: Poster Display session 2
Resources:
Abstract