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An analysis to quantify the overall survival (OS) benefit of sipuleucel-T accounting for the crossover in the control arm of the IMPACT study.

Publication ,  Journal Article
Nabhan, C; Gomella, LG; DeVries, T; Whitmore, JB; Frohlich, MW; George, DJ
Published in: Journal of Clinical Oncology
February 10, 2012

144 Background: Sipuleucel-T is an autologous cellular immunotherapy approved for the treatment of asymptomatic or minimally symptomatic metastatic castrate resistant prostate cancer (mCRPC). Our previous analyses on the effect of salvage crossover treatment with a product constructed from previously frozen cells (APC8015F) on OS in the control arms of mCRPC studies of sipuleucel-T suggested a positive treatment effect with salvage therapy (George DJ et al. JCO 2011;29:abstr 139). To quantify how treatment with APC8015F might have impacted the OS of the IMPACT study, we performed an exploratory analysis adjusting for the potential bias that salvage APC8015F might have had in estimating the OS advantage of sipuleucel-T. Methods: After objective disease progression, patients (pts) in the control arm were offered 3 infusions of APC8015F, an autologous immunotherapy made from cells cryopreserved at the time of control generation. A rank-preserving structural failure time (RPSFT) model, as previously described, was applied to adjust the sipuleucel-T treatment effect. Results: In the 512-pt IMPACT study, there was a 4.1-month median improvement in OS (25.8 vs 21.7 months) for sipuleucel-T compared to control (HR=0.78; 95% CI: 0.61, 0.98; p=0.032). 109/171 (64%) of control pts received APC8015F; other post-progression interventions were balanced. Median OS was 23.8 months for control pts receiving APC8015F and 11.6 months for control pts not receiving APC8015F. Using the RPSFT model, and assuming APC8015F was equally as effective as sipuleucel-T, the estimate of median OS for control was 18.0 months (HR=0.60, 95% CI: 0.41, 0.95), representing a 7.8-month median improvement in OS in favor of sipuleucel-T. Results from extensions of the RPFST model, where APC8015F is assumed to have less treatment effect than sipuleucel-T, will be presented. Conclusions: Adjusting for a positive effect of APC8015F in the control arm resulted in a sipuleucel-T OS treatment benefit in the IMPACT study ranging from 4.1 to 7.8 months. These results support a greater treatment effect of sipuleucel-T than reported in the IMPACT study and should be factored into future studies without APC8015F crossover.

Duke Scholars

Published In

Journal of Clinical Oncology

DOI

EISSN

1527-7755

ISSN

0732-183X

Publication Date

February 10, 2012

Volume

30

Issue

5_suppl

Start / End Page

144 / 144

Publisher

American Society of Clinical Oncology (ASCO)

Related Subject Headings

  • Oncology & Carcinogenesis
  • 3211 Oncology and carcinogenesis
  • 1112 Oncology and Carcinogenesis
  • 1103 Clinical Sciences
 

Citation

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MLA
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Nabhan, C., Gomella, L. G., DeVries, T., Whitmore, J. B., Frohlich, M. W., & George, D. J. (2012). An analysis to quantify the overall survival (OS) benefit of sipuleucel-T accounting for the crossover in the control arm of the IMPACT study. Journal of Clinical Oncology, 30(5_suppl), 144–144. https://doi.org/10.1200/jco.2012.30.5_suppl.144
Nabhan, Chadi, Leonard G. Gomella, Todd DeVries, James Boyd Whitmore, Mark Walter Frohlich, and Daniel J. George. “An analysis to quantify the overall survival (OS) benefit of sipuleucel-T accounting for the crossover in the control arm of the IMPACT study.Journal of Clinical Oncology 30, no. 5_suppl (February 10, 2012): 144–144. https://doi.org/10.1200/jco.2012.30.5_suppl.144.
Nabhan C, Gomella LG, DeVries T, Whitmore JB, Frohlich MW, George DJ. An analysis to quantify the overall survival (OS) benefit of sipuleucel-T accounting for the crossover in the control arm of the IMPACT study. Journal of Clinical Oncology. 2012 Feb 10;30(5_suppl):144–144.
Nabhan, Chadi, et al. “An analysis to quantify the overall survival (OS) benefit of sipuleucel-T accounting for the crossover in the control arm of the IMPACT study.Journal of Clinical Oncology, vol. 30, no. 5_suppl, American Society of Clinical Oncology (ASCO), Feb. 2012, pp. 144–144. Crossref, doi:10.1200/jco.2012.30.5_suppl.144.
Nabhan C, Gomella LG, DeVries T, Whitmore JB, Frohlich MW, George DJ. An analysis to quantify the overall survival (OS) benefit of sipuleucel-T accounting for the crossover in the control arm of the IMPACT study. Journal of Clinical Oncology. American Society of Clinical Oncology (ASCO); 2012 Feb 10;30(5_suppl):144–144.

Published In

Journal of Clinical Oncology

DOI

EISSN

1527-7755

ISSN

0732-183X

Publication Date

February 10, 2012

Volume

30

Issue

5_suppl

Start / End Page

144 / 144

Publisher

American Society of Clinical Oncology (ASCO)

Related Subject Headings

  • Oncology & Carcinogenesis
  • 3211 Oncology and carcinogenesis
  • 1112 Oncology and Carcinogenesis
  • 1103 Clinical Sciences