The report was published on researchsquare.com as a preprint and has not yet been peer-reviewed.
Key Takeaway
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Cabazitaxel is more effective than androgen receptor-axis-targeted therapy (ARAT) for third-line treatment of metastatic castration-resistant prostate cancer (mCRPC) in a real-world setting, even when using lower doses than in the clinical trial setting and treating patients with more advanced disease.
Why This Matters
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Following progress on docetaxel followed by an ARAT regimen, the CARD trial demonstrated a 1.7-month progression-free survival and 2.6-month overall survival benefit with the taxane cabazitaxel instead of an additional ARAT regimen.
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The new findings confirm similar benefits in a real-world setting.
Study Design
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Investigators reviewed nationwide cabazitaxel postmarketing surveillance data in Japan.
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Participants had received docetaxel followed by a year or less of an ARAT regimen (abiraterone or enzalutamide) for mCRPC.
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The team compared outcomes of 247 men who subsequently received cabazitaxel with 288 who went on to receive an alternative ARAT.
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Among those receiving cabazitaxel, 73.3% had TNM classifications of M1 or MX and 78.5% had a Gleason score of 8-10; the mean PSA level was 483 ng/mL.
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In the ARAT group, 68.1% had a TNM classification of M1 or MX and 79.2% had a Gleason score of 8-10; the mean PSA level was 594 ng/mL.
Key Results
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The median time to treatment failure was 109 (94-108) days with cabazitaxel versus 58 (57-66) days for a second ARAT (hazard ratio [HR], 0.34 favoring cabazitaxel).
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Similar results were obtained after propensity-score matching (HR, 0.323 favoring cabazitaxel).
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Median overall survival was shorter in the current study compared with the CARD trial: 326 days with cabazitaxel versus 413 days with cabazitaxel in the CARD trial; the authors suggest the reasons could be that patients had more advanced disease or lower exposure to cabazitaxel in clinical practice compared with those in the CARD trial.
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Cabazitaxel was administered at a dose below 25 mg/m2 in 81.4% of men versus 21.4% in the CARD trial.
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Patients in both the cabazitaxel and ARAT arms had higher Gleason scores and serum PSA levels than those in the CARD arm.
Limitations
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The data are observational, nonblinded, nonrandomized, and noncontrolled, and limited to men in Japan.
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The proportions of patients receiving abiraterone and enzalutamide as a second ARAT were balanced in the CARD trial, but most patients in the current study received enzalutamide followed by abiraterone.
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The observation period was limited to 1 year.
Disclosures
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The work was funded by cabazitaxel maker Sanofi.
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Three investigators are Sanofi employees. Another investigator reported personal fees from the company.
This is a summary of a preprint research study, “Real-world effectiveness of third-line cabazitaxel in patients with metastatic castration-resistant prostate cancer: CARD-like analysis of data from a post-marketing surveillance in Japan,” led by Hideyasu Matsuyama of Yamaguchi University, Japan, provided to you by Medscape. The study has not been peer-reviewed. The full text can be found at researchsquare.com.
M. Alexander Otto is a physician assistant with a master’s degree in medical science and a journalism degree from Newhouse. He is an award-winning medical journalist who worked for several major news outlets before joining Medscape, and is also an MIT Knight Science Journalism fellow. Email: aotto@mdedge.com.
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