Wang, Xiaofei F.

Importance Outcomes for patients with unresectable stage III non–small cell lung cancer (NSCLC) treated with chemoradiation therapy (CRT) have improved with adjuvant immune checkpoint inhibitors, with a reported 5-year overall survival benefit of approximately 10% for adjuvant durvalumab vs placebo after completion of CRT without progression and with preserved performance status. Starting atezolizumab prior to CRT may allow more patients to benefit from immunotherapy. Objective To evaluate clinical outcomes of patients treated with atezolizumab before and after CRT for unresectable stage III NSCLC. Design, Setting, and Participants This single-cohort, phase II, nonrandomized controlled trial was conducted at 11 US sites. Patients with pathologically confirmed, unresectable stage III NSCLC who were treatment naive and had good performance status were enrolled between January 3, 2018, and July 24, 2019. Data were locked on March 21, 2023. Interventions Patients received four 21-day cycles of atezolizumab, 1200 mg intravenously, with therapy administered on day 1 of each cycle. Patients not experiencing tumor progression continued to CRT (60 Gy to involved fields) concurrent with weekly carboplatin area under the curve of 2 and paclitaxel, 50 mg/m 2 , followed by planned consolidation carboplatin area under the curve of 6 and paclitaxel, 200 mg/m 2 , for two 21-day cycles. Patients not experiencing progression continued atezolizumab, 1200 mg, every 21 days to complete 1 year of therapy. Main Outcomes and Measures The primary end point was the disease control rate at 12 weeks. Secondary end points were progression-free survival, overall survival, overall response rate, safety, and translational science end points. Results A total of 62 patients (median [range] age, 63.9 [38.1-86.5] years; 32 female [51.6%]) were enrolled and received at least 1 dose of atezolizumab. The disease control rate at 12 weeks was 74.2% (80% CI, 65.7%-81.4%). Median progression-free survival was 30.0 months (95% CI, 15.8 to not evaluable), and the median overall survival was not reached. The overall survival rate at 24 months was 73.7% (95% CI, 63.4%-85.7%), and the overall response rate was 66.2%. Seventeen patients (27.4%) experienced grade 3 or higher immune-related adverse events, including 1 with grade 5 pneumonitis and 1 with grade 4 Guillain-Barré syndrome. Thirty patients (48.4%) experienced grade 3 or higher treatment-related adverse events. Conclusions and Relevance These findings suggest that neoadjuvant atezolizumab merits further study based on safety and encouraging outcomes. Trial Registration ClinicalTrials.gov Identifier: NCT03102242

TPS8125 Background: Sarcomatoid mesothelioma is the most aggressive form of pleural mesothelioma and is associated with the worst prognosis of the histologic variants of this disease. In the Checkmate 743 clinical trial the patients with sarcomatoid mesothelioma who received ipilimumab and nivolumab had survival outcomes that were similar to those of patients with epithelioid mesothelioma. In comparison, the patients with sarcomatoid mesothelioma who received chemotherapy had the worst outcomes in this trial, highlighting the known limited efficacy of chemotherapy against this histologic variant. Checkmate 743 demonstrated that ipilimumab and nivolumab is a new standard of care for non-epithelioid mesothelioma. Surgery typically has not been offered to this group of patients given their historically poor outcomes. With the significant survival gains seen patients with sarcomatoid mesothelioma treated with immunotherapy, we hypothesized that surgery may extend the benefits seen with immunotherapy. Methods: Alliance for Clinical Trials in Oncology A082101 is a prospective, phase 2 nonrandomized clinical trial for patients with sarcomatoid mesothelioma. The co-primary objectives are to determine the percentage of patients with potentially resectable sarcomatoid mesothelioma able to proceed with surgery after neoadjuvant ipilimumab and nivolumab, and the progression-free survival (PFS) at 12 months (12-month PFS) after the initiation of ipilimumab and nivolumab. For sample size determination, we assumed that if the true rate of surgery is 75% or greater, it would indicate that neoadjuvant immunotherapy is feasible to be given prior to surgery. On the other hand, if the true rate of surgery is 50% or less it would indicate that neoadjuvant immunotherapy is not worthy of further investigation. Twenty-six (26) eligible patients will be needed to receive neoadjuvant immunotherapy. If 16 or fewer of the 26 eligible patients proceed to surgery, it will be concluded that the experimental therapy is not worthy of further investigation. Otherwise, it will be concluded that the experimental therapy is worthy of further investigation. Safety monitoring will be done through a 6-week run-in for the first 10 patients to assess for pre-operative and post-operative toxicities and complications. Sequential boundaries will be used to monitor severe toxicity and complication rates. Accrual will be halted if excessive numbers of severe toxicity and complications in pre-operative and post-operative phases are seen. The accrual and safety data will be summarized in reports for semiannual reviews by Alliance Data and Safety Monitoring Board. Tumor and blood-based biomarkers will be included as exploratory biomarkers. Support: U10CA180821, U10CA180882, U24 CA196171; https://acknowledgments.alliancefound.org . Clinical trial information: NCT05647265 .

TPS8123 Background: A minority of patients with unresectable stage III non-small cell lung cancer (NSCLC) may be cured by chemoradiotherapy (CRT). Adjuvant checkpoint inhibition through PD-L1 blockade after CRT improved survival compared to placebo in the PACIFIC trial (median progression-free survival (mPFS) 16.9 vs 5.6 months (mo), median overall survival (mOS) 47.5 vs 29.1 mo), but overall survival at 5 years remains below 50% (Spigel D, et al J Clin Oncol 2022, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9015199/ . Only patients completing CRT without progression and with good performance status were eligible for this approach. Neoadjuvant checkpoint inhibition would allow more patients the opportunity to benefit from immunotherapy and may attenuate tumor-related immunosuppression via depletion of regulatory T cells and clonal expansion of effector T cells, thereby improving tumor immunogenicity. Neoadjuvant atezolizumab had favorable outcomes compared to historic PACIFIC data in the phase II single arm trial, AFT-16 (mPFS 30 mo and mOS not reached). Whether combination immunotherapy therapy before CRT will improve outcomes in this setting is the question posed in the AFT-57 trial. Methods: This phase II randomized Alliance Foundation Trials study (AFT-57) will evaluate safety and efficacy of atezolizumab with or without the anti-TIGIT monoclonal antibody, tiragolumab, before and after definitive CRT with concurrent atezolizumab. The primary endpoint is PFS in the two experimental arms with a goal to select the most promising regimen for further study. AFT-57 will randomly assign 158 patients with stage III NSCLC (AJCC v8), Eastern Cooperative Oncology Group performance status 0-1, no active autoimmune disease and no underlying organ dysfunction to 2 cycles of neoadjuvant atezolizumab (1200 mg intravenously [IV] every 21 days) with or without tiragolumab (600 mg IV). Non-progressing patients will receive carboplatin and paclitaxel weekly with atezolizumab 1200 mg IV every 21 days concurrent with 60 Gray involved field thoracic radiation in 30 daily fractions (Monday - Friday) followed by atezolizumab with or without tiragolumab on the same schedule as the neoadjuvant doses, with a plan to complete one year of therapy. A pilot cohort of 20 patients for whom tiragolumab will be combined with atezolizumab during chemoradiotherapy is planned toward the end of accrual. Correlative science includes tissue and blood-based immune-related biomarkers at baseline and during therapy. This trial utilizes the Alliance Participant Engagement Portal, a patient-facing site designed to provide information and resources to Alliance clinical trial participants. The trial was activated on 12/7/23 with the first patient screened 1/19/24. Clinical trial information: NCT05798663 .

TPS8602 Background: Sarcomatoid mesothelioma is the most aggressive form of pleural mesothelioma and is associated with the worst prognosis of the histologic variants of this disease. In the Checkmate 743 clinical trial the patients with sarcomatoid mesothelioma who received ipilimumab and nivolumab had survival outcomes that were similar to those of patients with epithelioid mesothelioma. In comparison, the patients with sarcomatoid mesothelioma who received chemotherapy had the worst outcomes in this trial, highlighting the known limited efficacy of chemotherapy against this histologic variant. Checkmate 743 demonstrated that ipilimumab and nivolumab is a new standard of care for non-epithelioid mesothelioma. Surgery typically has not been offered to this group of patients given their historically poor outcomes. With the significant survival gains seen patients with sarcomatoid mesothelioma treated with immunotherapy, we hypothesized that surgery may extend the benefits seen with immunotherapy. Methods: Alliance for Clinical Trials in Oncology A082101 is a prospective, phase 2 nonrandomized clinical trial for patients with sarcomatoid mesothelioma. The co-primary objectives are to determine the percentage of patients with potentially resectable sarcomatoid mesothelioma able to proceed with surgery after neoadjuvant ipilimumab and nivolumab, and the progression-free survival (PFS) at 12 months (12-month PFS). For sample size determination, we assumed that if the true rate of surgery is 75% or greater, it would indicate that neoadjuvant immunotherapy is feasible to be given prior to surgery. On the other hand, if the true rate of surgery is 50% or less it would indicate that neoadjuvant immunotherapy is not worthy of further investigation. Twenty-six (26) eligible patients will be needed to receive neoadjuvant immunotherapy. If 16 or fewer of the 26 eligible patients proceed to surgery, it will be concluded that the experimental therapy is not worthy of further investigation. Otherwise, it will be concluded that the experimental therapy is worthy of further investigation. Safety monitoring will be done through a 6-week run-in for the first 10 patients to assess for pre-operative and post-operative toxicities and complications. Sequential boundaries will be used to monitor severe toxicity and complication rates. Accrual will be halted if excessive numbers of severe toxicity and complications in pre-operative and post-operative phases are seen. Tumor and blood-based biomarkers will be included as exploratory biomarkers. Clinical trial information: NCT05647265 .

TPS9082 Background: Limited stage small cell lung cancer (LS-SCLC) is treated with standard of care platinum/etoposide (EP) and thoracic radiation therapy (TRT) with curative intent, however the majority of patients are not cured and median overall survival is approximately 30 months. Addition of atezolizumab to chemotherapy in extensive stage SCLC has improved progression free and overall survival in a non-curative setting leading to hope that addition of an immune checkpoint inhibitor to standard chemoradiotherapy could benefit LS-SCLC patients. LU005 is a randomized phase II/III trial of standard concurrent chemoradiation with or without atezolizumab for patients with LS-SCLC. Methods: Patients are randomly assigned in a 1:1 ratio to standard EP chemotherapy with concurrent TRT (45 Gy BID or 66 Gy QD) with or without atezolizumab beginning concurrently with TRT, and continued every 3 weeks for up to 12 months. Eligible patients have LS-SCLC, PS 0-2, adequate organ function, no concerning comorbidities (including no active autoimmune disease) and are eligible for TRT. Patients are randomized prior to their second cycle of EP and thoracic radiation begins with the second overall cycle of chemotherapy (first cycle of study therapy) in both treatment arms. Prophylactic cranial radiation (PCI) is recommended for patients who respond to treatment. The phase II/III primary endpoints are progression free (PFS) and overall survival (OS) respectively. Secondary endpoints include objective response rates, local and distant disease control, and quality of life/patient reported outcomes assessment. Translational science component includes blood and tissue based immune related assays. This study activated in May 2019. 50 of 506 planned patients have been accrued as of 2/1/2020. Supported by grants U10CA180868 (NRG Oncology Operations), U10CA180822 (NRG Oncology SDMC), U23CA180803 (IROC) from the National Cancer Institute (NCI) and Genentech. *Authors Ross and Higgins are co-first authors and contributed equally to this work. Clinical trial information: NCT03811002.

9045 Background: A minority of the > 40,000 patients (pts) diagnosed with stage III NSCLC annually in the US are cured by CRT, more recently followed by adjuvant immune checkpoint inhibitors (ICI). PD-L1 blockade with CRT may attenuate tumor-related immunosuppression via depletion of regulatory T cells and clonal expansion of effector T cells. Further, CRT may expose otherwise hidden antigens that present additional targets to the reconstituting immune system. Adjuvant ICI has improved survival. Whether ICI before CRT will further improve outcomes is unknown. Methods: This Alliance Foundation Trials (AFT) study evaluated safety and efficacy of atezolizumab before and after CRT. 4 cycles of atezolizumab 1200 mg IV q 21 days with restaging after cycles 2 and 4 were followed by carboplatin and paclitaxel (C/P) weekly with 60 Gy radiation and C/P consolidation followed by atezolizumab for 1 year of therapy. Primary endpoint is disease control rate (DCR) (complete response + partial response (PR) + stable disease (SD)) at 12 weeks (wks). Secondary endpoints include overall response rate, progression-free survival, overall survival, safety and quality of life assessed by EORTC QLQ-30. Correlatives include PD-L1 and tumor mutation burden as predictive biomarkers. Tumor tissue was obtained at study entry; plasma and immune cells were isolated at multiple timepoints. Results: 64 pts with stage III NSCLC, performance status (PS) 0-1, no active autoimmune disease or significant organ dysfunction enrolled at 13 Alliance sites from 11/2017 to 7/2019. 62 pts received ≥ 1 dose of atezolizumab and are included in the primary analysis; median age 63.9 years (38.1-86.5), 51.6% female, 77.4% white, 61.3% former smokers, 56.5% PS 0. DCR at 12 wks was 77.4% (80% confidence interval 69.2-84.3%) (30.7% PR, 46.8% SD). 54 pts reported adverse events (AEs) during induction, mostly grade (gr) 1. There were 13 serious AEs, most unrelated to study treatment; 1 gr 3 anaphylactic reaction, 1 gr 3 colitis, and 1 gr 4 Guillain-Barre syndrome were attributable to atezolizumab. Baseline PD-L1 status was available for 49 pts. DCR was 82.4% for pts with PD-L1 negative and 90.9% for pts with PD-L1 positive tumors. Conclusions: Atezolizumab prior to and following CRT for stage III unresectable NSCLC was well tolerated with an encouraging 12-wk DCR. Analysis of secondary endpoints is ongoing. Further study of induction ICI therapy is warranted in patients with unresectable stage III NSCLC. Support: AFT, Genentech; Clinical trial information: NCT03102242.

7510 Background: We previously demonstrated that PFS may be a candidate surrogate endpoint for OS in ES-SCLC using data from 3 randomized trials (Foster, Cancer 2011). Here, we sought to formally assess the patient- and trial-level surrogacy of PFS using data from 9 additional randomized phase II and III trials conducted by the NCI-funded cancer cooperative groups since 1986. Methods: Individual patient data from all 12 trials (3178 patients: 9 phase III and 3 phase II) were pooled. OS was the primary endpoint in all phase III trials; 3 phase III and 1 phase II trial were positive per protocol. Patient-level surrogacy (Kendall’s tau) was assessed using the Clayton copula bivariate survival model. Trial-level surrogacy was assessed via association of the log hazard ratios on OS and PFS across trials, including: weighted (by trial size) least squares regression of Cox model effects (R² WLS) and weighted (by trial size) correlation of the copula effects (R² Copula). One trial had 4 treatment arms thus 14 total two-arm comparisons were made. Results: With a median follow-up of 41.8 months in the 106 patients still alive, the median OS and PFS across trials were 9.7 months (95% CI: 9.5, 9.9) and 5.7 months (95% CI: 5.5, 5.8), respectively. There were 3120 PFS events in total (2564 disease progressions and 556 deaths without progression). The median time from progression to death was 4.1 months (95% CI: 3.9, 4.3). PFS showed modest association with OS at the patient-level (tau= 0.56) and at the trial-level (R² WLS = 0.58; R² Copula (standard error) = 0.55 (0.29)). The 95% CIs for the predicted HR for OS given observed HR on PFS under a weighted leave-one-out prediction always included the observed HR for OS; however such intervals were wide, suggesting uncertainty on the practical use of PFS as a surrogate for OS in this setting. Conclusions: PFS failed to demonstrate surrogacy for OS in ES-SCLC based on this large pooled analysis. Given that the difference in the median PFS and OS is less than 6 months, we recommend using OS as the primary endpoint in phase III trials of previously untreated ES-SCLC.

Abstract Purpose: Assessing impact of poor accrual on premature trial closure requires a relevant metric. We propose defining accrual sufficiency on apparent ability to address primary endpoints (PE) rather than attaining accrual targets. Experimental Design: All phase III trials open January 1, 1993, to December 31, 2002, by five U.S. oncology Clinical Trials Cooperative Groups (CTCG) were evaluated for accrual sufficiency and scientific results. Sufficient accrual included meeting accrual target, CTCGs documentation attesting adequate accrual, or conclusive results at interim analysis; insufficient accrual included poor accrual as cited closure reason or other reasons rendering a trial unable to address its primary endpoints. Closure rates based on our accrual sufficiency definition are compared with rates of meeting accrual targets and addressing the primary endpoints. A percentage of target accrual above which trials commonly answer the intended scientific question was identified to serve as an alternative to meeting full target accrual in designating accrual success. Results: Of 238 eligible trials, 158 (66%) closed with sufficient accrual. Among 80 trials with insufficient accrual, 70 (29%) closed specifically because of poor accrual. Inadequate accrual rates are overemphasized when defining accrual success solely by meeting accrual targets. Nearly 75% of trials conclusively addressed the primary endpoints with positive results in 39% of trials. Exceeding 80% of target accrual serves as a reliable proxy for answering the intended scientific question. Conclusions: Approximately one third of phase III trials closed with insufficient accrual to address the primary endpoints, primarily due to poor accrual. Defining accrual sufficiency broader than meeting accrual targets represents a fairer account of trial closures. Clin Cancer Res; 18(1); 256–62. ©2011 AACR.