P3-16-01: Safety Profile and Clinical Activity of Single-Agent BKM120, a Pan-Class I PI3K Inhibitor, for the Treatment of Patients with Metastatic Breast Carcinoma

Background

Phosphatidylinositol 3-kinase (PI3K) is critical to cancer cell growth, survival, and metabolism. BKM120 is an oral pan-class I (α, β, γ, δ) PI3K inhibitor that has demonstrated in vitro and in vivo tumor cell growth inhibition in a range of cancer types including breast cancer.

Materials and methods: The Phase I study CBKM120X2101 investigating single-agent daily BKM120 in patients (pts) with advanced solid tumors has been recently completed with the maximum tolerated dose established at 100 mg/day. Here, we report the analysis of metastatic breast carcinoma (MBC) pts enrolled in this study.

Results: Overall, 83 pts have enrolled, 21 of whom have MBC. At the cut-off date of 25th February 2011, 20 MBC pts were evaluable: 1 pt at 80 mg, 1 pt at 150 mg and 18 pts at 100 mg. Patient characteristics were as follows: median age 55 years (range 37–71); performance status ECOG 0/1/2 for 7/12/1 pts, respectively; visceral disease was reported in 16 pts, including liver, 10 pts (50%); lung, 9 pts (45%); and pleura, 5 pts (25%); all pts had >3 lines of systemic therapy (3-12). The median time from last treatment and study entry was 46 days (29-235). The median duration of BKM120 treatment administered was 7.5 weeks (1.0−96.4). The most frequent grade 3 drug-related adverse events (AEs) were: transaminases increase, 4 pts; psychiatric disorders, 3 pts, consisting of anxiety, affective disorder, and mood alteration (1 pt each); diarrhea, 2 pts; fatigue, 2 pts; and hyperglycemia, 1 pt. The only grade 4 drug-related AE was hyperglycemia, reported in 1 pt at 150 mg. Most AEs were manageable with treatment interruption and dose reductions. Eighteen pts were evaluable for objective tumor response by RECIST. Two pts (11%) exhibited partial responses, which were confirmed in a triple-negative MBC pt, and unconfirmed in an ER+ HER2− MBC pt. For these 2 pts, the treatment duration was 29+ (ongoing) and 6 months, respectively. An additional 9 pts (50%) had stable disease, lasting >4 months in 7 pts (35%).

Conclusions: This preliminary analysis showed that BKM120 has single-agent activity in heavily pretreated pts with MBC, and an acceptable safety profile. Molecular profiling and updated pharmacokinetic results will be presented at the meeting.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-16-01.

A phase I dose escalation study of AUY922, a novel HSP90 inhibitor, in patients with advanced solid malignancies

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Background: AUY922, a novel isoxazole-based HSP90 inhibitor, causes the degradation of multiple cellular tumor promoting targets. Preclinical evidence suggests broad anti-tumor activity of AUY922, warranting clinical development. Methods: Single agent AUY922 was administered as IV infusion over 1h once a week to patients (pts) with advanced solid malignancies, utilizing a Bayesian design for dose-escalation. The primary endpoint was determination of the maximum tolerated dose of AUY922; secondary endpoints included safety, tolerability, preliminary activity, PK and PD. Results: Between Jul 2007 and Dec 2008, 44 pts with were treated at dose levels of 2 mg/m2 (3pts), 4 mg/m2 (4pts), 8 mg/m2 (5pts), 16 mg/m2 (7pts), 22 mg/m2 (11pts), 28 mg/m2 (7pts) and 40 mg/m2 (7pts). Median age was 56 years; 95% of pts had a WHO performance status 0 or 1. The most frequently reported adverse events were nausea in 19 patients (50.0 %), diarrhea in 18 patients (47.4 %), fatigue in 15 patients (39.5 %), and vomiting in 9 patients (23.7 %). Grade 1 and 2 diarrhea, fatigue, nausea and vomiting were suspected to be related to AUY922 at doses ≥ 8 mg/m2. Grade 3 events, including atrial flutter, 1pt, at 22 mg/m2, anorexia, fatigue and diarrhea, 2 pts, at 40 mg/m2, were reported as dose limiting toxicities. Expansion of the 40 mg/m2 cohort was initiated in Dec 2008. The median terminal half life of AUY922 at doses up to 28 mg/m2 was 56 h (24 to 108 h). Pharmacodynamic analyses show dose proportional induction of HSP70 in peripheral blood mononuclear cells by AUY922. Six pts achieved disease stabilization for at least 16 and up to 64 weeks. Conclusions: Single-agent AUY922, administered as a weekly infusion, is well tolerated at doses up to 40 mg/m2. Prolonged disease stabilization was seen in a subset of patients receiving AUY922 across dose levels.

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ASCO Conflict of Interest Policy and Exceptions

In compliance with the guidelines established by the ASCO Conflict of Interest Policy (J Clin Oncol. 2006 Jan 20;24[3]:519–521) and the Accreditation Council for Continuing Medical Education (ACCME), ASCO strives to promote balance, independence, objectivity, and scientific rigor through disclosure of financial and other interests, and identification and management of potential conflicts. According to the ASCO Conflict of Interest Policy, the following financial and other relationships must be disclosed: employment or leadership position, consultant or advisory role, stock ownership, honoraria, research funding, expert testimony, and other remuneration (J Clin Oncol. 2006 Jan 20;24[3]:520). The ASCO Conflict of Interest Policy disclosure requirements apply to all authors who submit abstracts to the Annual Meeting.

For clinical trials that began accrual on or after April 29, 2004, ASCO's Policy places some restrictions on the financial relationships of principal investigators (J Clin Oncol. 2006 Jan 20;24[3]:521). If a principal investigator holds any restricted relationships, his or her abstract will be ineligible for placement in the 2009 Annual Meeting unless the ASCO Ethics Committee grants an exception. Among the circumstances that might justify an exception are that the principal investigator (1) is a widely acknowledged expert in a particular therapeutic area; (2) is the inventor of a unique technology or treatment being evaluated in the clinical trial; or (3) is involved in international clinical oncology research and has acted consistently with recognized international standards of ethics in the conduct of clinical research. NIH-sponsored trials are exempt from the Policy restrictions. Abstracts for which authors requested and have been granted an exception in accordance with ASCO's Policy are designated with a caret symbol (^) in the Annual Meeting Proceedings.

For more information about the ASCO Conflict of Interest Policy and the exceptions process, please visit www.asco.org/conflictofinterest .

Pharmacodynamics and pharmacokinetics of AUY922 in a phase I study of solid tumor patients

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Background: AUY922 is a synthetic inhibitor of Heat Shock Protein 90. Disruption of the HSP90 chaperone hetero- complex results in the loss of repression of heat shock factor-1 (HSF1), and subsequent induction of HSP70. We evaluated HSP70 as a pharmacodynamic (PD) marker of AUY922 activity in a phase I/II clinical trial in patients (pts) with solid tumors. Methods: Single agent AUY922 was administered by IV infusion once a week to pts with advanced solid malignancies. HSP70 levels in PBMC were quantitated by ELISA in samples taken at baseline and multiple time-points post the 1st and 5th treatments over two cycles. Fold change of HSP70 induction was calculated and compared to dose level and AUY922 blood exposure obtained within the first week of treatment (single dose) at 6, 24, 48, and 168 hours post-treatment. Results: Of the 40 pts treated to date, HSP70 levels in PBMC has been evaluated in 36, encompassing seven dose levels ranging from 2 mg/m2 to 40mg/m2. Baseline levels of HSP70 in PBMC ranged from 26.0 to 95.1 ng/mg protein, with a median of 42.5ng/mg. The highest level of HSP70 induction obtained over two cycles was increasing with dose from 2 to 40 mg/m2, with a range of 1.4 to 12.1 fold, and the amount of HSP70 induction was frequently higher in the second cycle of treatment. In the first cycle of treatment, HSP70 induction is correlated to blood AUC. The degree of HSP70 upregulation in PBMCs at 40 mg/m2 exceeds the 8-fold upregulation seen in BT474 xenograft tumor tissue when treated with efficacious doses of AUY922. Conclusions: PK/PD analyses show that the highest level of HSP70 achieved post-treatment increases with dose, and at the highest dose tested thus far (40mg/m2), this pharmacodynamic effect has not yet reached a maximum response. Additionally, our analysis suggests that in humans, the PD effect of AUY922 is reaching the level corresponding to that required for anti-tumor effect in the BT474 xenograft model.

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Conventional radiograms for assessment of salm-calcitonin therapy for bone metastases from breast carcinoma

The effects of salm-calcitonin on breast cancer osteolytic skeletal metastases have been studied on conventional radiographs. Radiographic criteria for positive response have been defined. It is concluded that radiographs are inadequate for assessing the effects of salm-calcitonin.

A randomized clinical trial comparing systemic radiotherapy versus chemotherapy versus local radiotherapy in small cell lung cancer

Between 1982 and 1987 a prospectively randomized trial of sequential hemibody irradiation (SHBI) (A), a non-cross-resistant chemotherapy drug combination (B) and local and/or locoregional radiotherapy (C) in small cell lung cancer (SCLC) was conducted. Previously untreated patients with extensive SCLC were randomized into three arms: A = 31 patients, B = 37, C = 31. In the chemotherapy combination, the following were used: etoposide, doxorubicin, methotrexate (VAM) and procarbacine, vincristine, cyclophosphamide, lomustine (POCC) and prophylactic cranial irradiation (30 Gy). The results show that the median survival was significantly (P less than 0.01) better in chemotherapy (44 weeks) compared with 17 and 20 weeks in arms A and C, respectively. One year and 2 year survival rates were better for the chemotherapy arm. No differences were found between groups A and C. In comparing the total hospitalization time expressed as a percentage of overall survival, an advantage for group B was shown. In conclusion, high dose SHBI cannot be recommended as a standard therapy for extensive SCLC.