Adjusting Overall Survival Estimates for Treatment Switching in Metastatic, Castration-Sensitive Prostate Cancer: Results from the LATITUDE Study
Susan Feyerabend, Fred Saad, Nolen Joy Perualila, Suzy Van Sanden, Joris Diels, Tetsuro Ito, Peter De Porre, Karim Fizazi, Susan Feyerabend, Fred Saad, Nolen Joy Perualila, Suzy Van Sanden, Joris Diels, Tetsuro Ito, Peter De Porre, Karim Fizazi
Abstract
Background: LATITUDE was the first phase 3 trial examining the survival benefit of adding abiraterone acetate (AA) + prednisone (P) to androgen-deprivation therapy (ADT) in newly diagnosed metastatic, castration-sensitive prostate cancer (mCSPC). Due to significant improvement in overall survival after the first interim analysis, patients in the placebos + ADT arm could switch to AA + P + ADT during an open-label extension. As in other studies where switching is allowed, statistical adjustments are needed to assess the real benefit of new drugs.
Patients and methods: This was a post hoc analysis to estimate the true survival benefit of AA + P + ADT in patients with newly diagnosed mCSPC by applying statistical adjustments commonly used to adjust for treatment switching.
Results: Of 112 patients still receiving placebos + ADT at the first interim analysis, 72 switched to AA + P + ADT during the open-label extension. Final analysis was conducted after median follow-up of 51.8 months. Compared to the placebos + ADT arm, the risk of death in the AA + P + ADT arm was 34% lower [hazard ratio (HR) = 0.663 (95% confidence interval 0.566-0.778)] by unadjusted intent-to-treat analysis, 37% lower [HR = 0.629 (95% confidence interval 0.526-0.753)] by rank preserving structure failure time modeling, and 38% lower [HR = 0.616 (95% confidence interval 0.524-0.724)] by inverse probability of censoring weights.
Conclusions: Analyses adjusting for treatment switching using two different statistical approaches confirm the improved survival benefit of adding AA + P to ADT in patients with newly diagnosed mCSPC.
Trial registration: ClinicalTrials.gov identifier NCT01715285.
Conflict of interest statement
S Feyerabend has nothing to disclose. F. Saad reports grants, personal fees, and non-financial support from Janssen and Sanofi related to the conduct of the study, and grants, personal fees, and non-financial support from Astellas and Bayer unrelated to the submitted work. N.J. Perualila, S. Van Sanden, J. Diels, T. Ito, and P. De Porre are employees of Janssen. S. Van Sanden, T. Ito, and P. De Porre are shareholders of Janssen’s parent company, Johnson & Johnson. K. Fizazi reports financial support for participation in advisory boards for Amgen, AstraZeneca, Astellas, Bayer, Janssen, Sanofi, Orion, and CureVac.
Figures
References
- Ferlay J, Soerjomataram I, Dikshit R, Eser S, Mathers C, Rebelo M, et al. Cancer incidence and mortality worldwide: sources, methods and major patterns in GLOBOCAN 2012. Int J Cancer. 2015;136:E359–E386. doi: 10.1002/ijc.29210.
- Li J, Siegel DA, King JB. Stage-specific incidence rates and trends of prostate cancer by age, race, and ethnicity, United States, 2004–2014. Ann Epidemiol. 2018;28:328–330. doi: 10.1016/j.annepidem.2018.03.001.
- Jack RH, Davies EA, Moller H. Prostate cancer incidence, stage at diagnosis, treatment and survival in ethnic groups in South-East England. BJU Int. 2010;105:1226–1230. doi: 10.1111/j.1464-410X.2009.08940.x.
- Oakley-Girvan I, Kolonel LN, Gallagher RP, Wu AH, Felberg A, Whittemore AS. Stage at diagnosis and survival in a multiethnic cohort of prostate cancer patients. Am J Public Health. 2003;93:1753–1759. doi: 10.2105/AJPH.93.10.1753.
- Dong L, Zieren RC, Xue W, de Reijke TM, Pienta KJ. Metastatic prostate cancer remains incurable, why? Asian J Urol. 2019;6:26–41. doi: 10.1016/j.ajur.2018.11.005.
- Purshouse K, Protheroe AS. Abiraterone acetate in combination with prednisone in the treatment of metastatic hormone-sensitive prostate cancer: clinical evidence and experience. Ther Adv Urol. 2019;11:1756287218820804. doi: 10.1177/1756287218820804.
- Cassinello J, Arranz JA, Piulats JM, Sanchez A, Perez-Valderrama B, Mellado B, et al. SEOM clinical guidelines for the treatment of metastatic prostate cancer (2017) Clin Transl Oncol. 2018;20:57–68. doi: 10.1007/s12094-017-1783-2.
- Fizazi K, Tran N, Fein L, Matsubara N, Rodriguez-Antolin A, Alekseev BY, et al. Abiraterone plus prednisone in metastatic, castration-sensitive prostate cancer. N Engl J Med. 2017;377:352–360. doi: 10.1056/NEJMoa1704174.
- James ND, de Bono JS, Spears MR, Clarke NW, Mason MD, Dearnaley DP, et al. Abiraterone for prostate cancer not previously treated with hormone therapy. N Engl J Med. 2017;377:338–351. doi: 10.1056/NEJMoa1702900.
- Feyerabend S, Saad F, Li T, Ito T, Diels J, Van Sanden S, et al. Survival benefit, disease progression and quality-of-life outcomes of abiraterone acetate plus prednisone versus docetaxel in metastatic hormone-sensitive prostate cancer: a network meta-analysis. Eur J Cancer. 2018;103:78–87. doi: 10.1016/j.ejca.2018.08.010.
- Vale CL, Fisher DJ, White IR, Carpenter JR, Burdett S, Clarke NW, et al. What is the optimal systemic treatment of men with metastatic, hormone-naive prostate cancer? A STOPCAP systematic review and network meta-analysis. Ann Oncol. 2018;29:1249–1257. doi: 10.1093/annonc/mdy071.
- European Society for Medical Oncology. eUpdate—Cancer of the prostate treatment recommendations. 2019. . Accessed 19 Nov 2019.
- European Association of Urology. Prostate cancer. 2019. . Accessed 19 Nov 2019.
- Janssen Pharmaceutical Company. ZYTIGA® Prescribing Information. 2019. . Accessed 19 Sep 2019.
- Chi KN, Protheroe A, Rodriguez-Antolin A, Facchini G, Suttman H, Matsubara N, et al. Patient-reported outcomes following abiraterone acetate plus prednisone added to androgen deprivation therapy in patients with newly diagnosed metastatic castration-naive prostate cancer (LATITUDE): an international, randomised phase 3 trial. Lancet Oncol. 2018;19:194–206. doi: 10.1016/S1470-2045(17)30911-7.
- Fizazi K, Tran N, Fein L, Matsubara N, Rodriguez-Antolin A, Alekseev BY, et al. Abiraterone acetate plus prednisone in patients with newly diagnosed high-risk metastatic castration-sensitive prostate cancer (LATITUDE): final overall survival analysis of a randomised, double-blind, phase 3 trial. Lancet Oncol. 2019;20:686–700. doi: 10.1016/S1470-2045(19)30082-8.
- Latimer NR. Treatment switching in oncology trials and the acceptability of adjustment methods. Expert Rev Pharmacoecon Outcomes Res. 2015;15:561–564. doi: 10.1586/14737167.2015.1037835.
- European Medicines Agency. Question and answer on adjustment for cross-over in estimating effects in oncology trials. EMA/845963/2018. London (UK): EMA; 2018.
- Latimer NR, Abrams KR, Lambert PC, Crowther MJ, Wailoo AJ, Morden JP, et al. Adjusting survival time estimates to account for treatment switching in randomized controlled trials—an economic evaluation context: methods, limitations, and recommendations. Med Decis Making. 2014;34:387–402. doi: 10.1177/0272989X13520192.
- Robins JM, Tsiatis AA. Correcting for non-compliance in randomized trials using rank preserving structural failure time models. Commun Stat Theory Methods. 1991;20:2609–2631. doi: 10.1080/03610929108830654.
- Robins JM, Finkelstein DM. Correcting for noncompliance and dependent censoring in an AIDS Clinical Trial with inverse probability of censoring weighted (IPCW) log-rank tests. Biometrics. 2000;56:779–788. doi: 10.1111/j.0006-341X.2000.00779.x.
- Latimer NR, Bell H, Abrams KR, Amonkar MM, Casey M. Adjusting for treatment switching in the METRIC study shows further improved overall survival with trametinib compared with chemotherapy. Cancer Med. 2016;5:806–815. doi: 10.1002/cam4.643.
- Latimer NR, Amonkar MM, Stapelkamp C, Sun P. Adjusting for confounding effects of treatment switching in a randomized phase II study of dabrafenib plus trametinib in BRAF V600 + metastatic melanoma. Melanoma Res. 2015;25:528–536. doi: 10.1097/CMR.0000000000000193.
- Latimer NR, Abrams KR, Amonkar MM, Stapelkamp C, Swann RS. Adjusting for the confounding effects of treatment switching—the BREAK-3 trial: dabrafenib versus dacarbazine. Oncologist. 2015;20:798–805. doi: 10.1634/theoncologist.2014-0429.
- Skaltsa Konstantina, Ivanescu Cristina, Naidoo Shevani, Phung De, Holmstrom Stefan, Latimer Nicholas R. Adjusting Overall Survival Estimates after Treatment Switching: a Case Study in Metastatic Castration-Resistant Prostate Cancer. Targeted Oncology. 2016;12(1):111–121. doi: 10.1007/s11523-016-0472-3.
- Saad F. Importance of early treatment in metastatic prostate cancer: a question of life or death. Lancet Oncol. 2019;20:609–611. doi: 10.1016/S1470-2045(19)30155-X.
Source: PubMed