2373P - Outcomes by retrospective eligibility for maintenance therapy of patients (pts) with advanced urothelial carcinoma (UC): Post hoc analysis of KEYNOTE-361

Background

The phase 3 KEYNOTE-361 trial (NCT02853305) of 1L pembrolizumab + chemotherapy (chemo) or pembrolizumab vs chemo alone in pts with advanced UC completed enrollment prior to approval of PD-L1 maintenance therapy after 1L chemo. This post hoc exploratory analysis evaluated pts who received chemo by eligibility for post-chemo maintenance therapy.

Methods

Pts who received chemo alone were retrospectively categorized as eligible (received ≥4 cycles of chemo and either did not have PD or died within 0-10 wk after completion of chemo or did have a PD or died >10 wk after completion of chemo) or ineligible (received ≥4 cycles of chemo and had a PD or died while on chemo or within 0-10 wk after completion of chemo) for post-chemo maintenance. Pts who received <4 cycles of chemo, were censored before end of chemo, or had nonevaluable or missing scans within 10 wk of chemo were excluded. Exploratory end points were PFS, landmark PFS (time from last non-PD assessment within 0-10 wk of chemo completion to PD per RECIST v1.1 by BICR), OS, and landmark OS (time from last non-PD assessment within 0-10 wk of chemo completion to death).

Results

Median follow-up was 31.7 mo (range, 22.0-42.3). Among 342 pts in the chemo arm, 172 (50.3%) were eligible for maintenance, 108 (31.6%) were ineligible, and 62 (18.1%) were excluded; 85/172 pts (49.4%) received subsequent anti–PD-1/L1 therapy. Results for pts eligible for post-chemo maintenance are reported (Table). For maintenance-ineligible pts, median (95% CI) PFS and OS were 5.1 mo (4.2-6.0) and 10.2 mo (9.1-11.6), respectively.

Conclusions

This post hoc exploratory analysis demonstrates that pts who are eligible for post-chemo maintenance therapy have a favorable prognosis. About 50% of pts who initiated chemo on a clinical trial were considered eligible for maintenance therapy. To our knowledge, these are the first exploratory data describing outcomes of maintenance-eligible pts from the initiation of chemo. Table: 2373P

Clinical trial identification

NCT02853305; Release date: August 2, 2016.

Editorial acknowledgement

Medical writing and/or editorial assistance was provided by Matthew Grzywacz, PhD of ApotheCom (Yardley, PA, USA).

Legal entity responsible for the study

Merck Sharp & Dohme Llc, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.

Funding

Merck Sharp & Dohme Llc, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.

Disclosure

R. Mamtani: Non-Financial Interests, Institutional, Research Grant: Merck, Astellas; Non-Financial Interests, Personal, Advisory Board: Seagen, BMS. N. Matsubara: Financial Interests, Personal, Invited Speaker: Sanofi; Financial Interests, Personal, Other, Consultancy (including expert testimony): Janssen, MSD, Eli Lilly; Financial Interests, Institutional, Research Grant: Janssen, AstraZeneca, Bayer, MSD, Taiho, Astellas, Amgen, Eisai, Eli Lilly, Takeda, Pfizer, Seagen, Chugai, AbbVie, Novartis. A. Montesa Pino: Financial Interests, Personal, Advisory Board: Pfizer, Merck, Astellas, MSD, AstraZeneca; Financial Interests, Personal, Speaker’s Bureau: Pfizer, Merck, Astellas, MSD, AstraZeneca. M.A.N. Sendur: Financial Interests, Personal, Invited Speaker: Astellas, Roche, Takeda, Pfizer, Novartis, Bayer; Financial Interests, Personal, Advisory Board: Astellas, Roche, Takeda, Pfizer, Novartis, Bayer, BMS. U. Anido Herranz: Financial Interests, Personal, Invited Speaker: Advanced Accelerator Applications, Ipsen, AstraZeneca, Merck, Pfizer, Astellas, Bayer, Eisai, BMS, Kyowa Kirin, Rovi; Financial Interests, Personal, Advisory Board: Advanced Accelerator Applications, Ipsen, AstraZeneca, Merck, Pfizer, Bayer. G. Gravis: Financial Interests, Institutional, Invited Speaker: AAA, Amgen, Astellas, BMS, Janssen, MSD, Pfizer, Ipsen, AstraZeneca, Alliance Merck-Pfizer, Bayer, Eisai; Financial Interests, Institutional, Advisory Board: Alliance Merck-Pfizer, BMS, Janssen, Pfizer, Ipsen, Bayer, Eisai; Financial Interests, Institutional, Funding: Janssen; Financial Interests, Institutional, Coordinating PI: BMS; Non-Financial Interests, Principal Investigator: Ipsen, BMS, Merck. O. Huillard: Financial Interests, Personal, Invited Speaker: Sanofi, Ipsen, Novartis; Financial Interests, Personal, Advisory Board: Janssen, Bristol Myers Squibb, AstraZeneca, Pfizer, Eisai, Bayer, AAA. R. Gafanov: Financial Interests, Personal, Speaker’s Bureau: Janssen, Astellas, Roche, Ipsen, Eisai, Pfizer, Merck, AstraZeneca, MSD; Financial Interests, Personal, Advisory Board: Janssen, Astellas, Roche, Ipsen, Eisai, Pfizer, Merck, AstraZeneca, MSD; Financial Interests, Personal, Research Grant: Janssen, Astellas, Roche, AstraZeneca, MSD. F. Joly Lobbedez: Financial Interests, Personal, Advisory Board: GSK, AstraZeneca, MSD, Janssen, Ipsen, BMS, Bayer, Eisai; Financial Interests, Personal, Invited Speaker: GSK, AstraZeneca, MSD, Janssen, Ipsen, Amgen, Astellas; Financial Interests, Institutional, Coordinating PI: GSK, AstraZeneca; Financial Interests, Institutional, Research Grant: BMS; Other, travel: MSD, GSK. J. Bedke: Financial Interests, Personal, Advisory Board: AstraZeneca, Astellas, Eisai; Financial Interests, Personal, Advisory Board, Advisory Board and Speaker´s Bureau: BMS, Ipsen, MSD, Merck Serono, Pfizer, Roche, Janssen; Financial Interests, Institutional, Advisory Board: BMS, Pfizer; Financial Interests, Institutional, Local PI: AstraZeneca, Eisai, Novartis, Nektar; Financial Interests, Institutional, Coordinating PI: Astellas, BMS, MSD, Ipsen, Pfizer, Roche, Seagen; Financial Interests, Institutional, Steering Committee Member: BMS, MSD, Pfizer, Seagen; Other, Member of the Renal Cell Carcinoma Guidelines Panel: European Association of Urology. A. Sella: Financial Interests, Personal and Institutional, Advisory Board: Shamir, Asaf Harofe Medical Center; Financial Interests, Personal and Institutional, Invited Speaker: Shamir, Asaf Harofe Medical Center; Financial Interests, Personal and Institutional, Research Grant: Shamir, Asaf Harofe Medical Center. K. Imai: Financial Interests, Personal, Full or part-time Employment: Merck & Co Inc; Financial Interests, Personal, Stocks/Shares: Merck & Co Inc. B. Homet Moreno: Financial Interests, Institutional, Stocks/Shares: Merck; Financial Interests, Institutional, Full or part-time Employment: Merck. J. Xu: Financial Interests, Institutional, Stocks or ownership: Merck; Financial Interests, Institutional, Full or part-time Employment: Merck. A. Alva: Financial Interests, Personal, Advisory Role: AstraZeneca, Merck, Pfizer, BMS; Financial Interests, Institutional, Research Funding: Genentech, Bristol Myers Squibb, Merck Sharp & Dohme, Prometheus Laboratories, Mirati Therapeutics, AstraZeneca, Roche, Bayer, Astellas Pharma, Arcus Biosciences, Progenics, Celgene, Janssen; Financial Interests, Personal, Other, Travel, Accommodations, Expenses: Merck, BMS. T.B. Powles: Financial Interests, Personal, Advisory Board: AstraZeneca, Bristol Myers Squibb, Exelixis, Incyte, Ipsen, Merck, Novartis, Pfizer, Seattle Genetics, Merck Serono, Astellas, Johnson & Johnson, Eisai, Roche, MSD; Financial Interests, Personal, Other, Travel/Accommodation/Expenses: Roche, Pfizer, MSD, AstraZeneca, Ipsen; Financial Interests, Personal, Other, Sponsorship for Uromigos Podcast: Mashup Ltd; Financial Interests, Institutional, Research Grant: AstraZeneca, Roche, Bristol Myers Squibb, Exelixis, Ipsen, Merck, MSD, Seattle Genetics, Novartis, Pfizer, Merck Serono, Astellas, Johnson & Johnson, Eisai. All other authors have declared no conflicts of interest.