Abstract 2211
Background
Trastuzumab stimulates HER2-specific T cell responses and increases tumour PD-L1 expression, and anti-PD-1 antibody can help enhance T cell-specific immunity of trastuzumab. We conducted a phase II trial of pembrolizumab with chemotherapy/trastuzumab.
Methods
Patients (pts) with previously untreated HER2 IHC 3+ or FISH+ tumours irrespective of PD-L1 status received intravenous P 200 mg flat dose, T 6 mg/kg (after 8 mg/kg load), O 130 mg/m2 every 3 weeks and oral C 850 mg/m2 2 weeks on/1 week off. 22 pts received 1 cycle of induction P/T prior to initiation of chemotherapy. The primary endpoint was 6-months PFS; with target accrual of 37 pts. Secondary endpoints included safety, OS, ORR, and biomarker analysis.
Results
Accrual completed and 100% of the 37 evaluable pts had tumour regression (ranging from -4% to -100%). The RECIST 1.1 ORR was 81% (27 PR, 3 CRs), and 12 (52%) of pts that received induction P/T x 1 cycle showed reduction in target lesions. Median PFS was 14.2 months (mo), with 70% 6 mo PFS. Median follow up was only 8 mo. In pts with available material, 14/36 (40%) had PD-L1 CPS >1 and median TMB was 4.4 mut/Mb (0-10.6). There was no correlation between PD-L1 status and PFS or OS. ERBB2 amplification was evident by tissue-NGS in 17/30 (63%) and ctDNA-NGS in 17/30 (58%) pre-treatment, while the remaining pts were ERBB2- by NGS likely due to tumour heterogeneity or low tumour content. CtDNA decreased in 16/24 tested pts after 1 cycle of induction T/P alone. irAEs included interstitial nephritis Gr4 (3%), transaminitis Gr3 (11%), Gr4 (3%), colitis Gr3 (3%).
Conclusions
40% remain on therapy, and so the primary endpoint should be reached by 9/19. Updated survival, correlative studies and will be presented. These promising preliminary safety and efficacy results led to initiation of a definitive phase III Keynote 811 trial (NCT03615326).
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Memorial Sloan Kettering Cancer Center.
Funding
Merck.
Disclosure
Y.Y. Janjigian: Advisory / Consultancy, Research grant / Funding (self): Bristol-Meyers; Advisory / Consultancy, Research grant / Funding (self): Eli Lily; Advisory / Consultancy: Daiichi Sankyo; Advisory / Consultancy: Pfizer; Advisory / Consultancy, Research grant / Funding (self): Merck; Research grant / Funding (self): Amgen; Advisory / Consultancy, Research grant / Funding (self): Bayer; Research grant / Funding (self): Boehringer Ingelhiem; Research grant / Funding (self): Genentech/Roche; Advisory / Consultancy: Merck Serono; Advisory / Consultancy: Imugene. S. Maron: Non-remunerated activity/ies, Research Collaboration Only: Guardant Health; Shareholder / Stockholder / Stock options: Calithera; Travel / Accommodation / Expenses: Merck; Licensing / Royalties, Non-remunerated activity/ies, Research Collaboration Only: Genentech. G.Y. Ku: Advisory / Consultancy, Research Support: Arog; Advisory / Consultancy, Research Support: Bristol-Myers Squibb; Advisory / Consultancy: Eli Lilly; Advisory / Consultancy, Research Support: Merck; Advisory / Consultancy, Research Support: Pieris; Advisory / Consultancy, Research Support: Zymeworks. D.H. Ilson: Advisory / Consultancy: Merck; Advisory / Consultancy: Astellas; Advisory / Consultancy: Bayer; Advisory / Consultancy: Pieris; Advisory / Consultancy: Roche; Advisory / Consultancy: AstraZeneca; Advisory / Consultancy: Eli Lilly; Advisory / Consultancy: Britsol Myers Squibb; Advisory / Consultancy, Contracted Research: Taiho. D. Solit: Advisory / Consultancy: Pfizer; Advisory / Consultancy, Shareholder / Stockholder / Stock options: Loxo Oncology; Advisory / Consultancy: Illumina; Advisory / Consultancy: Vivideon Therapeutics; Honoraria (institution), Speaker Bureau / Expert testimony: Lilly Oncology. J.F. Hechtman: Research grant / Funding (institution): Bayer; Honoraria (institution): Medscape; Advisory / Consultancy: Axiom Healthcare Strategies; Advisory / Consultancy: Cor2Ed. M. Lamendola-Essel: Advisory / Consultancy: Rockefeller University. All other authors have declared no conflicts of interest.
Resources from the same session
1988 - Molecular profiling reveals novel targetable biomarkers in neuroendocrine carcinoma of the uterine cervix
Presenter: Semir Vranic
Session: Poster Display session 2
Resources:
Abstract
2672 - Changes in clinico-pathological characteristics of vulvar cancer in Japan: increasing oldest-old, stage-shifting, and decreasing cohort-level survival
Presenter: Shin Nishio
Session: Poster Display session 2
Resources:
Abstract
4306 - Tumor Treating Fields (200 kHz) concomitant with weekly paclitaxel for platinum-resistant ovarian cancer: Phase 3 INNOVATE-3/ENGOT-ov50 study
Presenter: Ignace Vergote
Session: Poster Display session 2
Resources:
Abstract
5136 - Randomized, phase 1b/2 study of M6620 + avelumab + carboplatin vs standard care (sc) in patients (pts) with platinum-sensitive poly (ADP-ribose) polymerase inhibitor-(PARPi)-resistant ovarian cancer
Presenter: Susana Banerjee
Session: Poster Display session 2
Resources:
Abstract
2296 - An umbrella study of biomarker-driven targeted therapy in patients with platinum-resistant recurrent ovarian cancer: A Korean Gynecologic Oncology Group study (KGOG 3045), AMBITION
Presenter: Jung-Yun Lee
Session: Poster Display session 2
Resources:
Abstract
2732 - A phase 2 study of pembrolizumab in combination with doxorubicin in advanced, recurrent or metastatic endometrial cancer
Presenter: Ana Oaknin
Session: Poster Display session 2
Resources:
Abstract
4404 - ENGOT-EN9/LEAP-001: a phase 3, randomized, open-label study of pembrolizumab plus lenvatinib versus chemotherapy for first-line treatment of advanced or recurrent endometrial cancer
Presenter: Christian Marth
Session: Poster Display session 2
Resources:
Abstract
4564 - Phase 1/2 trial of tisotumab vedotin plus bevacizumab, pembrolizumab, or carboplatin in recurrent or metastatic cervical cancer (innovaTV 205/ENGOT-cx8)
Presenter: Ignace Vergote
Session: Poster Display session 2
Resources:
Abstract
4933 - Updated data of Epitopes-HPV02 trial and external validation of efficacy of DCF in prospective Epitopes-HPV01 study in advanced anal squamous cell carcinoma. Pooled analysis of 115 patients
Presenter: Stefano Kim
Session: Poster Display session 2
Resources:
Abstract
2301 - Pre-specified pilot analysis of a randomised pilot/phase II/III trial comparing standard dose vs dose-escalated concurrent chemoradiotherapy (CRT) in anal cancer (PLATO-ACT5)
Presenter: Alexandra Gilbert
Session: Poster Display session 2
Resources:
Abstract