You are here
An exploratory analysis of bone scan lesion area (BSLA), circulating tumor cell (CTC) change, pain reduction, and overall survival (OS) in patients (pts) with castration-resistant prostate cancer (CRPC) treated with cabozantinib (cabo): Updated results of a phase II nonrandomized expansion (NRE) cohort.
J Clin Oncol 31, 2013 (suppl; abstr 5026)
Abstracts that were granted an exception in accordance with ASCO's Conflict of Interest Policy are designated with a caret symbol (^).
Background: The results of 144 pts with metastatic CRPC treated in a phase II NRE cohort with daily cabo 100 mg and 40 mg starting doses have been previously reported. Substantial rates of bone scan improvement, reductions in CTC counts and pain relief were observed. To better understand the implication of these effects, the association with OS was explored. Methods: Relevant baseline variables (LDH, BSLA, visceral disease, pain, hemoglobin, CTCs) and post-treatment changes at week 6: ≥30% reduction in BSLA using computer-aided assessment, CTC conversion (>5 vs. 4 or less/7.5 ml of blood), and pain intensity (7 day averaged worst pain score; BPI scale; using an IVR system) were associated with OS in 144 CRPC pts with bone metastasis who progressed within 6 months of docetaxel (D) treatment (≥225 mg/m2) in either bone or soft tissue. Median OS was compared between responders and non-responders for each of the above outcomes categories using a Cox proportional hazard model. The findings were examined further after adjusting for significant baseline covariates selected from a stepwise Cox regression model. Results: See Table. Conclusions: Recognizing the limitations of associating response with survival, this retrospective analysis of decreases in BSLA, CTC conversions and reductions in pain intensity support further study in ongoing phase III trials. Clinical trial information: NCT00940225.
|Median age||66||Sites of disease, %|
|Prior therapies, %||Bone||100|
|≥2 prior lines therapy including docetaxel||73||Visceral||31|
|Cabazitaxel||24||Moderate to severe pain (BPI≥4), %||47|
|Abiraterone||43||Median CTC count||37|
|Progression <1 mo from last taxane dose, %||36||CTC count ≥5, %||80|
|Median overall survival, mos||10.8 (CI, 9.1-13.0)|
|Univariate analysis||Analysis adjusted for covariates|
||HR (95% CI)||P||HR (95% CI)||P|
|Bone scan response||0.62 (0.38-1.00)||0.054||0.47 (0.28-0.79)||0.005|
|CTC conversion||0.40 (0.21-0.78)||0.007||0.42 (0.19-0.92)||0.031|
|Pain||0.65 (0.34-1.24)||0.186||0.51 (0.24-1.11)||0.090|
Abstracts by H. I. Scher:
Association of alkaline phosphatase (ALP) with clinical outcomes in chemotherapy-naive patients (pts) with metastatic castration-resistant prostate cancer (mCRPC): Results from COU-AA-302.
Characterization of immune-related adverse events (irAEs) in a phase 3 trial of ipilimumab (Ipi) versus placebo (Pbo) in post-docetaxel mCRPC.
Clinical characteristics and outcomes of patients with prostate cancer and parenchymal brain metastases (PBM).
Presentations by H. I. Scher:
Impact of on-study corticosteroid use on efficacy and safety in the phase III AFFIRM study of enzalutamide (ENZA), an androgen receptor inhibitor.Session: General Poster Session A: Prostate Cancer (General Poster Session)
Impact of on-study corticosteroid use on efficacy and safety in the phase III AFFIRM study of enzalutamide (ENZA), an androgen receptor inhibitor.Session: Oral Abstract Session A: Prostate Cancer (eQ&A) (Oral Abstract Session)
Effect of MDV3100, an androgen receptor signaling inhibitor (ARSI), on overall survival in patients with prostate cancer postdocetaxel: Results from the phase III AFFIRM study.Session: General Poster Session A: Prostate Cancer (General Poster Session)