Ladle, Brian H.

We previously reported initial results of the pivotal phase II trial of atezolizumab for patients with alveolar soft part sarcoma (ASPS; ClinicalTrials.gov identifier: NCT03141684 ). Here, we report on three additional years of observation. Fifty-three patients with ASPS received atezolizumab. Median duration of response increased to 37.0 months. Objective response rate (ORR) and median progression-free survival (mPFS) remained essentially as previously reported (35.8% [95% CI, 23.1 to 50.2] and 20.8 months [IQR, 7.6-not reached], respectively). ASPSCR1::TFE3 fusion type was determined for 47/53 patients; ORR and mPFS were higher among the 41 patients expressing type 1 (43.9% [95% CI, 28.5 to 60.2] and 28.3 months [IQR, 9.2-not reached], respectively) than the six patients expressing type 2 (0% [95% CI, 0 to 45.9] and 7.5 months [IQR, 3.9-not reached], respectively, PFS HR, 3.2 [95% CI, 1.01 to 10.2]). Eleven patients chose a per-protocol drug holiday (range, 3.5-26.4 months) after ≥2 years of treatment; two experienced disease progression during the holiday. Nine eligible patients elected to receive bevacizumab plus atezolizumab after progressing on monotherapy; ORR was 0% and mPFS was 18.5 months (IQR, 7.9-21.1) in this small cohort. Long-term results support using atezolizumab to treat ASPS, even for several years; a drug holiday with careful monitoring may be an option for some patients.

Abstract Background: Letetresgene autoleucel (lete-cel; GSK3377794) is an autologous T-cell therapy expressing a genetically modified T-cell receptor (TCR) to improve recognition of cancer cells expressing NY-ESO-1 and/or LAGE-1a. Next generation NY-ESO-1 TCR T-cell therapies, including GSK3901961 and GSK3845097, incorporate further genetic modifications to enhance anticancer activity. GSK3901961 co-expresses the CD8α chain to stabilize TCR-human leukocyte A (HLA) class I interactions on CD4+ T cells, enhancing T-cell persistence and increasing helper functions such as Type 1 T-helper anti-tumor responses. GSK3845097 co-expresses a dominant negative transforming growth factor-β (TGF-β) type II receptor to reduce TGF-β pathway activation and maintain T-cell proliferation, cytokine production, and cytotoxicity in the tumor microenvironment. A first-time-in-human master protocol (NCT04526509) will evaluate the safety, tolerability, and recommended Phase 2 dose (RP2D) of these two therapies and possible subsequent ones. Substudy 1 will assess GSK3901961 in patients with advanced non-small cell lung cancer (NSCLC) or synovial sarcoma (SS). Substudy 2 will assess GSK3845097 in patients with advanced SS. Methods: Each substudy includes a dose confirmation stage to assess RP2D and a dose expansion stage. Table 1 lists eligibility criteria. Primary endpoints are safety (adverse events) and tolerability (dose-limiting toxicities). Secondary endpoints include investigator-assessed overall response rate, duration of response, and maximum expansion/persistence and phenotype of infiltrating transduced T cells. Exploratory endpoints include laboratory parameters, overall survival, and anti-GSK3901961 and anti-GSK3845097 titers for the respective substudies. The substudies are open and recruiting. Funding: GSK (209012; NCT04526509) Initial screening criteriaInclusion criteriaExclusion criteriaSubstudies 1 and 2 (SS and NSCLC)≥18 years of agePrior malignancy that is not in complete remission or clinically significant systemic illnessMeasurable disease per RECIST v1.1 criteriaPrevious treatment with genetically modified NY-ESO-1-specific T cells, NY-ESO-1 vaccine, or NY-ESO-1 targeting antibodyExpression of HLA-A*02:01, A*02:05, or A*02:06Prior gene therapy using an integrating vectorExpression of NY-ESO-1/LAGE-1a in tumor archival or fresh biopsyPrevious allogeneic hematopoietic stem cell transplant within the last 5 years or solid organ transplantSubstudies 1 and 2 (SS only)Histologically confirmed advanced (metastatic or unresectable) SS diagnosisCentral nervous system metastasesPresence of t(X;18) translocation(Allowed for NSCLC participants on a case-by-case basis)Received, completed, or intolerant to treatment with anthracycline or anthracycline with ifosfamide for advanced (metastatic or unresectable) disease and has progressedSubstudy 1 (NSCLC only)Histologically or cytologically confirmed Stage IV NSCLCReceived or failed ≥3 lines of systemic therapyReceiving or previously received ≥1 prior line(s) of standard of care treatment including programmed death receptor-1/programmed death ligand-1 checkpoint blockade therapy, and received or be intolerant to doublet taxane and platinum chemotherapyPresence of actionable genetic aberration (activation epithelial growth factor receptor, anaplastic lymphoma kinase/c-ros oncogene 1) per NCCN guidelines Citation Format: Adam J. Schoenfeld, Mehmet Altan, Taofeek K. Owonikoko, Sandra D'Angelo, Brian H. Ladle, Jonathan Noujaim, Kai He, David Liebner, Adrian G. Sacher, John B.A.G. Haanen, Jeffrey Yachnin, Chao Huang, Brian A. Van Tine, Aisha Hasan, Thomas Faitg, Emily Butler, Aiman Shalabi, Steven Attia, Dejka M. Araujo. Master protocol to assess the safety and recommended Phase 2 dose of next generation NY-ESO-1-specific TCR T-cells in HLA-A*02 patients with synovial sarcoma and non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT219.

TPS2661 Background: Letetresgene autoleucel (lete-cel; GSK3377794) is an autologous T-cell therapy using a genetically modified T-cell receptor (TCR) to improve recognition of cancer cells expressing NY-ESO-1/LAGE-1a. Next generation NY-ESO-1 TCR T-cell therapies, such as GSK3901961 and GSK3845097, integrate added genetic modifications to enhance anticancer activity. GSK3901961 co-expresses the CD8α chain to stabilize TCR-human leukocyte A (HLA) class I interactions on CD4+ T cells, improving T-cell persistence and helper functions such as Type 1 T-helper antitumor responses. GSK3845097 co-expresses a dominant negative transforming growth factor-β (TGF-β) type II receptor to reduce TGF-β pathway activation and maintain T-cell proliferation, cytokine production, and cytotoxicity in the tumor microenvironment. A first-time-in-human master protocol (NCT04526509) will evaluate safety, tolerability, and recommended phase 2 dose (RP2D) of these and possible subsequent therapies. Substudy 1 will assess GSK3901961 in patients (pts) with advanced non-small cell lung cancer (NSCLC) or synovial sarcoma (SS). Substudy 2 will assess GSK3845097 in pts with advanced SS. Methods: Each substudy includes a dose confirmation stage to assess RP2D and a dose expansion stage. Key inclusion criteria are age ≥18 y; measurable disease per RECIST v1.1; HLA-A*02:01, A*02:05, or A*02:06 positivity; NY-ESO-1/LAGE-1a tumor expression; advanced (metastatic/unresectable) SS with t(X;18) translocation and anthracycline-based therapy receipt/completion/intolerance (SS only); and Stage IV NSCLC, receipt of ≥1 prior line(s) of standard of care (SOC) therapy including programmed death receptor- or ligand-1 inhibitors, and SOC chemotherapy receipt/intolerance (Substudy 1 only). Key exclusion criteria are prior malignancy that is not in complete remission or clinically significant systemic illness; prior receipt of gene/NY-ESO-1–specific therapy or allogenic stem cell/solid organ transplant; central nervous system metastases (SS only); and actionable genetic aberration and receipt/failure of ≥3 systemic therapy lines (Substudy 1 only). Primary endpoints are safety (adverse events) and tolerability (dose-limiting toxicities). Secondary endpoints include investigator-assessed overall response rate, duration of response, and maximum expansion/persistence and phenotype of infiltrating transduced T cells. Exploratory endpoints include laboratory parameters, overall survival, and anti-GSK3901961 or -GSK3845097 titers as applicable. Analyses will be descriptive. The substudies are enrolling. Funding: GSK (209012; NCT04526509). Editorial support was provided by Eithne Maguire, PhD, of Fishawack Indicia, part of Fishawack Health; funded by GSK. Previously presented at AACR 2021 (CT219). Clinical trial information: NCT04526509.