Artificial Intelligence-Powered Assessment of Pathologic Response to Neoadjuvant Atezolizumab in Patients With NSCLC: Results From the LCMC3 Study

INTRODUCTION

Pathologic response (PathR) by histopathologic assessment of resected specimens may be an early clinical end point associated with long-term outcomes with neoadjuvant therapy. Digital pathology may improve the efficiency and precision of PathR assessment. LCMC3 (NCT02927301) evaluated neoadjuvant atezolizumab in patients with resectable NSCLC and reported a 20% major PathR rate.

METHODS

We determined PathR in primary tumor resection specimens using guidelines-based visual techniques and developed a convolutional neural network model using the same criteria to digitally measure the percent viable tumor on whole-slide images. Concordance was evaluated between visual determination of percent viable tumor (n = 151) performed by one of the 47 local pathologists and three central pathologists.

RESULTS

For concordance among visual determination of percent viable tumor, the interclass correlation coefficient was 0.87 (95% confidence interval [CI]: 0.84-0.90). Agreement for visually assessed 10% or less viable tumor (major PathR [MPR]) in the primary tumor was 92.1% (Fleiss kappa = 0.83). Digitally assessed percent viable tumor (n = 136) correlated with visual assessment (Pearson r = 0.73; digital/visual slope = 0.28). Digitally assessed MPR predicted visually assessed MPR with outstanding discrimination (area under receiver operating characteristic curve, 0.98) and was associated with longer disease-free survival (hazard ratio [HR] = 0.30; 95% CI: 0.09-0.97, p = 0.033) and overall survival (HR = 0.14, 95% CI: 0.02-1.06, p = 0.027) versus no MPR. Digitally assessed PathR strongly correlated with visual measurements.

CONCLUSIONS

Artificial intelligence-powered digital pathology exhibits promise in assisting pathologic assessments in neoadjuvant NSCLC clinical trials. The development of artificial intelligence-powered approaches in clinical settings may aid pathologists in clinical operations, including routine PathR assessments, and subsequently support improved patient care and long-term outcomes.

Overall Survival by Response to First-line Induction Treatment with Atezolizumab plus Platinum-based Chemotherapy or Placebo plus Platinum-based Chemotherapy for Metastatic Urothelial Carcinoma

Standard-of-care first-line treatment for metastatic urothelial carcinoma (mUC) is platinum-based chemotherapy (CTx). Maintenance immunotherapy is a treatment option for patients without progressive disease (PD) after induction CTx. IMvigor130 was a randomised, phase 3 study evaluating atezolizumab plus platinum-based CTx (arm A), atezolizumab monotherapy (arm B), or placebo plus platinum-based CTx (arm C) as first-line treatment for mUC. The primary progression-free survival (PFS) analysis showed a statistically significant PFS benefit favouring arm A versus arm C, which did not translate into overall survival (OS) benefit at the final OS analysis. We report exploratory analyses based on response to combination induction treatment (arm A vs arm C) using final OS data. Post-induction OS was analysed for patients without PD during induction (4-6 CTx cycles) who received at least one dose of single-agent atezolizumab/placebo maintenance treatment. Post-progression OS was analysed for patients with PD during induction CTx. Addition of atezolizumab to CTx did not impact OS outcomes, regardless of response to induction CTx, with hazard ratios of 0.84 (95% confidence interval [CI] 0.63-1.10) for patients without PD and 0.75 (95% CI 0.54-1.05) for those with PD during induction CTx. Treatment effects appeared to be greatest for patients treated with cisplatin and for those with PD-L1-high tumours.

Patient summary

The IMvigor130 trial showed that addition of atezolizumab to chemotherapy (CTx) did not improve survival over CTx alone in patients with bladder cancer. Overall, patients whose cancer did not progress during initial treatment tended to live longer than patients whose cancer did progress, but addition of atezolizumab to CTx did not help either group live longer in comparison to CTx alone. However, the results suggest that patients who received a certain CTx drug (cisplatin) or who had high levels of a marker called PD-L1 in their tumour may get the most improvement from addition of atezolizumab to CTx.The IMvigor130 trial is registered on ClinicalTrials.gov as NCT02807636.

Pertuzumab plus high-dose trastuzumab for HER2-positive breast cancer with brain metastases: PATRICIA final efficacy data

The PATRICIA study (NCT02536339) examined the efficacy and safety of pertuzumab plus high-dose trastuzumab in patients with HER2-positive metastatic breast cancer (MBC) with progressive central nervous system (CNS) metastases following radiotherapy. Primary analysis confirmed CNS objective response rate (ORR) was 11% (95% confidence interval [CI]: 3-25); clinical benefit rate (CBR) was 68% (4 months) and 51% (6 months). We report final efficacy data after a further 21-months of follow-up, updated safety, survival, and patient-reported outcomes (PROs). Patients received standard-dose pertuzumab plus high-dose trastuzumab (6 mg/kg weekly) until CNS or systemic disease progression or unacceptable toxicity. Primary endpoint: confirmed ORR (CNS) per Response Assessment in Neuro-Oncology Brain Metastases criteria. Secondary endpoints were response duration, CBR, progression-free survival (PFS), overall survival (OS), safety, and PROs. By clinical cut-off, 39 patients had completed or discontinued treatment. Confirmed ORR (CNS) was 11% (95% CI: 3.0-25.4). Median CNS-PFS was 4.6 months (95% CI: 4.0-8.9), as was median CNS-PFS or systemic PFS (95% CI: 4.0-8.9); median OS was 27.2 months (95% CI: 16.1-not reached). CBR in the CNS was 51% (19 patients, 95% CI: 34.4-68.1) at 6 months. Two patients remained on treatment until study closure, achieving stable disease for 4.1 and 4.8 years. Treatment-related grade 3/4 adverse events occurred in 7.7% of patients. Patients with confirmed partial response or stable disease (≥4 months) in the CNS had stable PROs over time. Pertuzumab plus high-dose trastuzumab represents a reasonable non-chemotherapeutic treatment option for selected patients with HER2-positive MBC with CNS metastases.

Surgical results of the Lung Cancer Mutation Consortium 3 trial: A phase II multicenter single-arm study to investigate the efficacy and safety of atezolizumab as neoadjuvant therapy in patients with stages IB-select IIIB resectable non-small cell lung cancer

OBJECTIVE

Multimodality treatment for resectable non-small cell lung cancer has long remained at a therapeutic plateau. Immune checkpoint inhibitors are highly effective in advanced non-small cell lung cancer and promising preoperatively in small clinical trials for resectable non-small cell lung cancer. This large multicenter trial tested the safety and efficacy of neoadjuvant atezolizumab and surgery.

METHODS

Patients with stage IB to select IIIB resectable non-small cell lung cancer and Eastern Cooperative Oncology Group performance status 0/1 were eligible. Patients received atezolizumab 1200 mg intravenously every 3 weeks for 2 cycles or less followed by resection. The primary end point was major pathological response in patients without EGFR/ALK+ alterations. Pre- and post-treatment computed tomography, positron emission tomography, pulmonary function tests, and biospecimens were obtained. Adverse events were recorded by Common Terminology Criteria for Adverse Events v.4.0.

RESULTS

From April 2017 to February 2020, 181 patients were entered in the study. Baseline characteristics were mean age, 65.1 years; female, 93 of 181 (51%); nonsquamous histology, 112 of 181 (62%); and clinical stages IIB to IIIB, 147 of 181 (81%). In patients without EGFR/ALK alterations who underwent surgery, the major pathological response rate was 20% (29/143; 95% confidence interval, 14-28) and the pathological complete response rate was 6% (8/143; 95% confidence interval, 2-11). There were no grade 4/5 treatment-related adverse events preoperatively. Of 159 patients (87.8%) undergoing surgery, 145 (91%) had pathologic complete resection. There were 5 (3%) intraoperative complications, no intraoperative deaths, and 2 postoperative deaths within 90 days, 1 treatment related. Median disease-free and overall survival have not been reached.

CONCLUSIONS

Neoadjuvant atezolizumab in resectable stage IB to IIIB non-small cell lung cancer was well tolerated, yielded a 20% major pathological response rate, and allowed safe, complete surgical resection. These results strongly support the further development of immune checkpoint inhibitors as preoperative therapy in locally advanced non-small cell lung cancer.

Neoadjuvant atezolizumab for resectable non-small cell lung cancer: an open-label, single-arm phase II trial

In an ongoing, open-label, single-arm phase II study ( NCT02927301 ), 181 patients with untreated, resectable, stage IB-IIIB non-small cell lung cancer received two doses of neoadjuvant atezolizumab monotherapy. The primary end point was major pathological response (MPR; ≤10% viable malignant cells) in resected tumors without EGFR or ALK alterations. Of the 143 patients in the primary end point analysis, the MPR was 20% (95% confidence interval, 14-28%). With a minimum duration of follow-up of 3 years, the 3-year survival rate of 80% was encouraging. The most common adverse events during the neoadjuvant phase were fatigue (39%, 71 of 181) and procedural pain (29%, 53 of 181), along with expected immune-related toxicities; there were no unexpected safety signals. In exploratory analyses, MPR was predicted using the pre-treatment peripheral blood immunophenotype based on 14 immune cell subsets. Immune cell subsets predictive of MPR in the peripheral blood were also identified in the tumor microenvironment and were associated with MPR. This study of neoadjuvant atezolizumab in a large cohort of patients with resectable non-small cell lung cancer was safe and met its primary end point of MPR ≥ 15%. Data from this single-arm, non-randomized trial suggest that profiles of innate immune cells in pre-treatment peripheral blood may predict pathological response after neoadjuvant atezolizumab, but additional studies are needed to determine whether these profiles can inform patient selection and new therapeutic approaches.

Atezolizumab plus Bevacizumab versus Sorafenib for Unresectable Hepatocellular Carcinoma: Results from Older Adults Enrolled in the IMbrave150 Randomized Clinical Trial

INTRODUCTION

The efficacy of systemic first-line treatments in older adults with unresectable hepatocellular carcinoma (HCC) has not been well-studied. We compared the safety and efficacy of atezolizumab plus bevacizumab versus sorafenib as a first-line treatment in younger versus older patients with unresectable HCC.

METHODS

This global, phase 3, open-label, randomized clinical trial (IMbrave150) recruited patients aged ≥18 years with locally advanced metastatic or unresectable HCC, an Eastern Cooperative Oncology Group performance status score of 0 or 1, and Child-Pugh class A liver function who had not previously received systemic therapy for liver cancer. Patients received either 1,200 mg atezolizumab plus 15 mg/kg bevacizumab intravenously every 3 weeks or 400 mg sorafenib orally twice daily until loss of clinical benefit or unacceptable toxicity. Primary endpoints were overall survival (OS) and progression-free survival (PFS). Secondary outcomes were the incidence of adverse events and time to deterioration of patient-reported outcomes (PROs). This subgroup analysis evaluated safety and efficacy endpoints in patients <65 years, ≥65 to <75 years, and ≥75 years.

RESULTS

Of 501 patients, 165 patients were randomized to sorafenib and 336 were randomized to atezolizumab plus bevacizumab (175 patients <65 years; 106 patients ≥65 to <75 years; 55 patients ≥75 years). Across all age groups, patients receiving atezolizumab plus bevacizumab had longer median OS (<65: 18.0 vs. 12.2 months [HR, 0.57; 95% CI: 0.40-0.82]; ≥65 to <75: 19.4 vs. 14.9 months [HR, 0.80; 95% CI: 0.52-1.23]; ≥75: 24.0 vs. 18.0 months [HR, 0.72, 95% CI: 0.37-1.41]) and PFS than those receiving sorafenib. Time to deterioration for multiple PROs was delayed for patients receiving atezolizumab plus bevacizumab, including older adults. There were no clinically meaningful differences in toxicity between age groups.

CONCLUSION

Atezolizumab plus bevacizumab is safe and effective in adults <65, ≥65 to <75, and ≥75. Treatment was well-tolerated even in elderly patients.

Abstract CT112: AI-powered and manual assessment of PD-L1 are comparable in predicting response to neoadjuvant atezolizumab in patients (pts) with resectable non-squamous, non-small cell lung cancer (NSCLC)

Background: PD-L1 expression evaluated by immunohistochemistry (IHC) is a well-established predictor of anti-PD-L1/PD-1 cancer immunotherapy (CIT). The Phase II LCMC3 (NCT02927301) study evaluated pre-operative treatment (tx) with atezolizumab (anti-PD-L1) in pts with untreated early stage resectable NSCLC, achieving a 20% major pathologic response (MPR) rate (primary efficacy pts, n=143). A digital PD-L1 scoring method was developed to assess PD-L1 expression as a potential predictive marker for MPR in squamous and non-squamous tumor samples from LCMC3.

Methods: Manual scoring was used to determine PD-L1 status on pre-tx biopsy samples using the tumor proportion score (TPS) with a positive threshold of TPS≥50 (22C3). Binary results were correlated with MPR and stratified by squamous/non-squamous histology. A digital pathology workflow for automated PD-L1 scoring was developed to yield a precise continuous PD-L1 TPS. Deep convolutional neural networks trained using pathologist annotations were used to detect individual cells within the tumor and tumor microenvironment and quantify their PD-L1 expression. These cell type predictions were used to compute a digital PD-L1 TPS. LCMC3 pts with available digital and manual PD-L1 scores were then used to assess the role of PD-L1 expression in predicting MPR.

Results: PD-L1 scores were available for pre-tx biopsies from 108 pts. No significant difference in scores was seen between histological subtypes. At cutoff (Oct 15, 2021), TPS≥50 was seen in 41 (non-squamous, n=26 [39%]; squamous, n=15 [36%]) of 108 pts and was associated with MPR in non-squamous (odds ratio [OR], 28.6; P&lt;0.001; Fisher’s exact test) but not squamous histology (OR, 1.3; P=1.0). Continuous digital PD-L1 scores (range: 0-100) were highly correlated with local manual PD-L1 scores (range: 0-100) for squamous (n=42, Pearson r=0.90, P&lt;0.001) and non-squamous stained histology slides (n=66, Pearson r=0.90, P&lt;0.001). Continuous digital and manual PD-L1 TPS on pre-tx biopsies (n=108) were predictive of MPR (digital: area under the receiver operating curve (AUROC)=0.678, logistic regression [LR] P=0.01; manual: AUROC=0.675, LR P=0.003). Strikingly, when pts were stratified by histology, PD-L1 scores were predictive of MPR from pre-tx biopsies for non-squamous samples (n=66; digital: AUROC=0.821, LR P=0.002; manual: AUROC=0.819, LR P=0.001) but not for squamous samples (n=42; digital: AUROC=0.519, LR P=0.93; manual: AUROC=0.506, LR P=0.90), despite no significant difference in MPR rate between the 2 groups.

Conclusions: These findings support using digitally assessed PD-L1 IHC as a centralized and standardized scoring system and suggest that tumor histological subtype could be an important factor in the utility of PD-L1 as a predictive biomarker for neoadjuvant CIT in early stage NSCLC.

Citation Format: John Abel, Christopher Rivard, Filip Kos, Guillaume Chhor, Yi Liu, Jennifer Giltnane, Sara Hoffman, Murray Resnick, Cyrus Hedvat, Amaro Taylor-Weiner, Farah Khalil, Alan Nicholas, Gregory A. Fishbein, Lynette M. Sholl, Natasha Rekhtman, Stephanie Hennek, Ilan Wapinski, Ann Johnson, Michael Montalto, Katja Schulze, Bruce E. Johnson, David P. Carbone, Konstantin Shilo, Andrew H. Beck, Sanja Dacic, William D. Travis, Ignacio Wistuba. AI-powered and manual assessment of PD-L1 are comparable in predicting response to neoadjuvant atezolizumab in patients (pts) with resectable non-squamous, non-small cell lung cancer (NSCLC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT112.

Identifying mechanisms of acquired immune escape from sequential, paired biopsies

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Background: Resistance to immune checkpoint blockade (ICB) can manifest as disease progression either at the initiation of treatment (primary resistance) or after some initial response (acquired resistance). To better understand the mechanisms underlying acquired resistance, the imCORE Network is conducting a study (NCT03333655) to examine changes in tumor biology from pre-treatment to disease progression across cancer types. Methods: Eligible patients included those experiencing clinical benefit on ICB (defined as objective response or stable disease longer than 6 months) and had evaluable tissue samples from both pre-treatment and within 30 days of progression. Samples were subjected to whole exome sequencing (WES), RNA sequencing (RNA-Seq), and immunohistochemistry (IHC). Whole blood samples or adjacent normal tissue were used as a reference for tumor variant calling. Results: As of December 3rd, 2021, 24 enrolled patients have complete sample pairs. Of those, melanoma, bladder, and lung were most common (n = 7, 6 and 5 pairs, respectively), but our cohort also included patients with breast cancer, squamous head & neck, and renal cell carcinoma. IHC data unexpectedly showed a modest, but consistent increase in tumor infiltrating CD8+ T cells at progression. In addition, IHC evidence of a decrease in MHC-I proteins (HLA-A and B2M) suggest that in 5 out of 24 cases, key proteins needed for antigen presentation are lost. Global differential gene expression analysis showed that immune gene expression was significantly increased at progression, including numerous chemokines and significant enrichment in gene sets responsible for antigen presentation machinery. Protein-altering mutations at progression appeared in B2M in one patient, and CXCL9 in another. However, in most cases it is unclear what genetic alterations are responsible. We do not observe evidence of consistent IFNγ and Jak/stat signaling loss or antigen presentation loss. Conclusions: While ICB resistance is thought to be associated with a lack of immune response within the TME, we found that acquired resistance is usually associated with either maintenance or an increase in immune infiltration. Multiple alterations that are unique to individual patients also continue to emerge. Our data shows ICB resistance is multifactorial and associated with dynamic changes to markers amid immune activation and inhibition. Clinical trial information: NCT03333655.

Plasma-Based Measurements of Tumor Heterogeneity Correlate with Clinical Outcomes in Metastatic Colorectal Cancer

Sequencing circulating tumor DNA (ctDNA) from liquid biopsies may better assess tumor heterogeneity than limited sampling of tumor tissue. Here, we explore ctDNA-based heterogeneity and its correlation with treatment outcome in STEAM, which assessed efficacy and safety of concurrent and sequential FOLFOXIRI-bevacizumab (BEV) vs. FOLFOX-BEV for first-line treatment of metastatic colorectal cancer. We sequenced 146 pre-induction and 89 post-induction patient plasmas with a 198-kilobase capture-based assay, and applied Mutant-Allele Tumor Heterogeneity (MATH), a traditionally tissue-based calculation of allele frequency distribution, on somatic mutations detected in plasma. Higher levels of MATH, particularly in the post-induction sample, were associated with shorter progression-free survival (PFS). Patients with high MATH vs. low MATH in post-induction plasma had shorter PFS (7.2 vs. 11.7 months; hazard ratio, 3.23; 95% confidence interval, 1.85−5.63; log-rank p < 0.0001). These results suggest ctDNA-based tumor heterogeneity may have potential prognostic value in metastatic cancers.

Updated efficacy and safety data from IMbrave150: Atezolizumab plus bevacizumab vs. sorafenib for unresectable hepatocellular carcinoma

BACKGROUND & AIMS

IMbrave150 demonstrated that atezolizumab plus bevacizumab led to significantly improved overall survival (OS) and progression-free survival (PFS) compared with sorafenib in patients with unresectable hepatocellular carcinoma at the primary analysis (after a median 8.6 months of follow-up). We present updated data after 12 months of additional follow-up.

METHODS

Patients with systemic treatment-naive, unresectable hepatocellular carcinoma were randomized 2:1 to receive 1,200 mg atezolizumab plus 15 mg/kg bevacizumab intravenously every 3 weeks or 400 mg sorafenib orally twice daily in this open-label, phase III study. Co-primary endpoints were OS and PFS by independently assessed RECIST 1.1 in the intention-to-treat population. Secondary efficacy endpoints included objective response rates and exploratory subgroup efficacy analyses. This is a post hoc updated analysis of efficacy and safety.

RESULTS

From March 15, 2018, to January 30, 2019, 501 patients (intention-to-treat population) were randomly allocated to receive atezolizumab plus bevacizumab (n = 336) or sorafenib (n = 165). On August 31, 2020, after a median 15.6 (range, 0-28.6) months of follow-up, the median OS was 19.2 months (95% CI 17.0-23.7) with atezolizumab plus bevacizumab and 13.4 months (95% CI 11.4-16.9) with sorafenib (hazard ratio [HR] 0.66; 95% CI 0.52-0.85; descriptive p <0.001). The median PFS was 6.9 (95% CI 5.7-8.6) and 4.3 (95% CI 4.0-5.6) months in the respective treatment groups (HR 0.65; 95% CI 0.53-0.81; descriptive p < 0.001). Treatment-related grade 3/4 adverse events occurred in 143 (43%) of 329 and 72 (46%) of 156 safety-evaluable patients in the respective groups, and treatment-related grade 5 events occurred in 6 (2%) and 1 (<1%) patients.

CONCLUSION

After longer follow-up, atezolizumab plus bevacizumab maintained clinically meaningful survival benefits over sorafenib and had a safety profile consistent with the primary analysis.

GOV IDENTIFIER

NCT03434379.

LAY SUMMARY

The primary analysis of IMbrave150 showed that atezolizumab plus bevacizumab had significantly greater benefits than sorafenib in patients with advanced hepatocellular carcinoma, but survival data were not yet mature. At this updated analysis done 12 months later, median overall survival was 5.8 months longer with atezolizumab plus bevacizumab than sorafenib, and the severity profile of treatment-related side effects remained similar. These updated results confirm atezolizumab plus bevacizumab as the first-line standard of care for advanced hepatocellular carcinoma.

IMbrave150: Exploratory efficacy and safety in patients with unresectable hepatocellular carcinoma (HCC) treated with atezolizumab beyond radiological progression until loss of clinical benefit in a global phase III study

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Background: First-line atezolizumab (atezo) + bevacizumab (bev) has been approved in > 80 countries based on significantly longer survival vs sorafenib (sor) in systemic treatment (tx)–naive patients (pts) with unresectable HCC in IMbrave150 (NCT03434379; Finn NEJM 2020). This clinically meaningful tx benefit was maintained with an additional 12 months of follow-up (Finn ASCO GI 2021). We report the efficacy and safety in pts who received atezo beyond radiological progression until loss of clinical benefit. Methods: Pts were randomized 2:1 to receive atezo 1,200 mg IV + bev 15 mg/kg IV q3w or sor 400 mg bid until unacceptable toxicity or loss of clinical benefit per investigator (INV). In the presence of clinical benefit, pts with progressive disease (PD) per INV RECIST 1.1 (not at a critical anatomical site) could continue study tx. Pts from the atezo + bev arm who had PD and continued atezo were included. Results: Of the 336 pts who received atezo + bev, 236 had PD, of whom 130 continued atezo (± bev), 60 had other tx, and 46 received no tx on or after first PD. Of the pts who continued atezo, 78% were Barcelona Clinic Liver Cancer (BCLC) stage C and 80% Child-Pugh A5 vs pts receiving other tx (85% BCLC stage C, 72% Child-Pugh A5). Sor (13% and 53%) and lenvatinib (14% and 35%) were the most common other txs received post PD among pts who continued atezo or received other tx, respectively. At clinical cutoff (August 31, 2020), the median number of cycles of atezo received post PD was 5 (range, 1-33) and 41 (32%) pts received ≥ 10 cycles. 60 of 130 (46%) pts who continued atezo died vs 180 of 336 (54%) receiving atezo + bev in the ITT population. See Table for efficacy data from baseline (BL) and PD. Grade (Gr) 3/4 and tx-related Gr 3/4 AEs occurred in 30 (23%) and 21 (16%) pts who continued atezo, respectively. There were 6 (5%) Gr 5 AEs, none tx-related. Conclusions: Atezo + bev is the standard of care for pts with unresectable HCC. In IMbrave150, pts with maintained clinical benefit continuing atezo after PD may have further benefited from staying on tx, although interpretation is limited by selection bias (prespecified criteria excluding pts with loss of clinical benefit). These data suggest that tx with atezo until loss of clinical benefit may contribute to post-PD outcomes. Beyond this exploratory analysis in select pts, the value of tx with atezo beyond formal progression will be assessed prospectively in IMbrave251 (NCT04770896). Clinical trial information: NCT03434379. [Table: see text]

Abstract CT009: IMbrave150: Updated efficacy and safety by risk status in patients (pts) receiving atezolizumab (atezo) + bevacizumab (bev) vs sorafenib (sor) as first-line treatment for unresectable hepatocellular carcinoma (HCC)

Background: Based on the Ph III IMbrave150 trial, atezo + bev has been approved globally and is the standard of care for pts with unresectable HCC who have not received prior systemic therapy. With an additional 12 mo of follow-up from the primary analysis (median, 15.6 mo), atezo + bev showed consistent clinically meaningful treatment benefit and safety (Finn ASCO GI 2021). Here, we report results of updated analyses considering high-risk factors. Methods: Pts were randomized 2:1 to receive atezo 1200 mg IV q3w + bev 15 mg/kg IV q3w or sor 400 mg PO BID until loss of clinical benefit or unacceptable toxicity. High-risk pts were defined as those who had tumor invasion of the main trunk of the portal vein and/or the portal vein branch contralateral to the primarily involved lobe (Vp4), and/or bile duct invasion and/or tumor occupancy of ≥ 50% of liver. Results: In the ITT population, 64 (19%) pts randomized to atezo + bev and 37 (22%) pts randomized to sor were defined as high risk. 10 pts had bile duct invasion, 73 had Vp4 portal vein invasion and 31 had liver tumor occupancy of ≥ 50%. 9 pts in the atezo + bev arm and 4 pts in the sor arm had 2 high-risk factors. OS, PFS and ORR all favored atezo + bev over sor, in both non-high-risk and high-risk patients. See table for efficacy results. In safety-evaluable pts, Grade 3/4 treatment-related AEs (TRAEs) occurred in 122 (45%) of 269 non-high-risk and 21 (35%) of 60 high-risk atezo + bev pts. Grade 5 TRAEs occurred in 5 (2%) non-high-risk and 1 (2%) high-risk atezo + bev pt. Conclusions: Efficacy benefit was seen with atezo + bev vs sor regardless of the presence of high-risk features. HRs remained similar despite the numerical differences in median OS between non-high-risk and high-risk pts. Further, the overall safety data in the atezo + bev arm were comparable between non-high-risk and high-risk pts and in line with the known safety profile of each drug.

Non-High RiskHigh RiskITTAtezo + BevSorAtezo + BevSorAtezo + BevSorEvaluable for OS/PFS, n2721286437336165Median OS (95% CI), mo22.8 (19.1, 24.9)15.7 (13.2, 19.0)7.6 (6.6, 12.8)5.5 (4.1, 6.7)19.2 (17.0, 23.7)13.4 (11.4, 16.9)HR (95% CI)0.68 (0.51, 0.91)0.62 (0.39, 1.00)0.66 (0.52, 0.85)Median PFS (95% CI), moa7.2 (6.5, 9.6)4.4 (4.0, 5.8)5.4 (4.0, 6.9)2.8 (2.5, 5.3)6.9 (5.7, 8.6)4.3 (4.0, 5.6)HR (95% CI)0.61 (0.48, 0.78)0.74 (0.47, 1.17)0.65 (0.53, 0.81)Evaluable for ORR, n2631246335326159Confirmed ORR, n (%)a,b81 (31)13 (10)16 (25)5 (14)97 (30)18 (11)Complete response, n (%)a20 (8)05 (8)1 (3)25 (8)1 (1)Median DOR (95% CI), moa,c19.0 (14.6, NE)12.6 (4.9, 17.0)16.3 (13.5, NE)16.5 (3.9, NE)18.1 (14.6, NE)14.9 (4.9, 17.0)NCT03434379.Clinical cutoff date: Aug 31, 2020.DOR, duration of response; HR, hazard ratio; IRF, independent review facility; NE, not estimable; ORR, objective response rate; OS, overall survival; PFS, progression-free survival.aAssessed by an IRF per RECIST 1.1.bORR IRF RECIST 1.1-evaluable population was based on patients who presented with measurable disease at baseline.cDOR analysis was based on all confirmed responders.

Citation Format: Richard S. Finn, Shukui Qin, Masafumi Ikeda, Peter R. Galle, Michel Ducreux, Tae-You Kim, Masatoshi Kudo, Ho Yeong Lim, Valeriy Breder, Philippe Merle, Ahmed Kaseb, Daneng Li, Yin-Hsun Feng, Wendy Verret, Alan Nicholas, Lindong Li, Ning Ma, Andrew X. Zhu, Ann-Lii Cheng. IMbrave150: Updated efficacy and safety by risk status in patients (pts) receiving atezolizumab (atezo) + bevacizumab (bev) vs sorafenib (sor) as first-line treatment for unresectable hepatocellular carcinoma (HCC) [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 CT009.

IMbrave150: Exploratory analysis to examine the association between treatment response and overall survival (OS) in patients (pts) with unresectable hepatocellular carcinoma (HCC) treated with atezolizumab (atezo) + bevacizumab (bev) versus sorafenib (sor)

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Background: Based on IMbrave150 (NCT03434379) results, atezo + bev has been approved in > 60 countries for pts with unresectable HCC who have not received prior systemic therapy (Finn RS, NEJM 2020). OS and objective response rate (ORR) improvements with atezo + bev vs sor were maintained with an additional 12 mo of follow up since primary analysis. Updated median OS was 19.2 mo with atezo + bev vs 13.4 mo with sor (stratified HR, 0.66; 95% CI: 0.52, 0.85). Updated ORR was 30% with atezo + bev vs 11% with sor by independently-assessed (IRF) RECIST 1.1 (Finn RS, ASCO GI 2021). Here, we report an exploratory analysis examining the association of response by RECIST 1.1 with OS and independent predictors of survival. Methods: Pts in this Ph III study were systemic treatment–naive with unresectable HCC, ≥1 measurable untreated lesion (RECIST 1.1), Child-Pugh class A liver function and ECOG PS 0/1. Pts were randomized 2:1 to atezo 1200 mg IV q3w + bev 15 mg/kg IV q3w or sor 400 mg bid until unacceptable toxicity or loss of clinical benefit per investigator. ORR was determined by IRF RECIST 1.1. Kaplan-Meier analyses of OS by response status were conducted without landmark and with 4- and 6-mo landmarks. Multivariate analysis was conducted using Cox modeling with time-dependent covariate (responder [yes/no]) with backwards elimination. These analyses only included pts treated with atezo + bev. Results: IMbrave150 enrolled 501 pts, including 336 treated with atezo + bev. Median follow-up was 15.6 mo. OS was longer in pts with confirmed response per RECIST 1.1 (responders, CR + PR) vs non-responders by Kaplan-Meier analyses without landmark and with 4- and 6-mo landmarks (Table). By multivariate analysis, in addition to responder (yes/no), 5 of the 10 initially included predictors of OS remained in the final Cox model ( P< 0.10): ECOG PS (0/1), geographic region (Asia excluding Japan/rest of the world), etiology (hepatitis B/hepatitis C/non-viral), macrovascular invasion and/or extrahepatic spread (yes/no), and baseline alpha-fetoprotein ( < 400 ng/mL/≥400 ng/mL). Conclusions: Atezo + bev is the new standard of care for pts with previously untreated, unresectable HCC. Here we showed that in IMbrave150 pts treated with atezo + bev, response by RECIST 1.1 was associated with OS, suggesting that confirmed response is an independent predictor of OS in these pts. Clinical trial information: NCT03434379. [Table: see text]

Artificial intelligence (AI)–powered pathologic response (PathR) assessment of resection specimens after neoadjuvant atezolizumab in patients with non-small cell lung cancer: Results from the LCMC3 study

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Background: PathR is an efficacy endpoint in Phase II and III neoadjuvant trials and is proposed as a surrogate for disease-free survival (DFS) and overall survival. Machine learning (ML)–based, automated approaches standardize quantification of areas of tumor bed and residual viable tumor. Here we show that automation may provide a scalable alternative to or complementary tool for manual assessment. Methods: We determined inter-reader variability for PathR among pathologists in the LCMC3 (NCT02927301) study and developed an AI-powered digital PathR assessment tool in line with manual consensus recommendations. Study cases were reviewed for PathR by a local site pathologist and 3 central expert pathologists (n = 127). When determined manually, major PathR (MPR) was defined as ≤10% viable tumor averaged per case. ML models were trained and validated by the PathAI research platform using digitized H&E-stained tumor sections. The digital PathR model predicted percent viable tumor for each case as the sum of the cancer epithelium area from each slide divided by the sum of tumor bed area for each slide. DFS (clinical cutoff: Oct 23, 2020) was reported for patients with manual and digital PathR assessment (n = 135). For digital MPR, we used a prevalence-matched cutoff that maintained the same proportion of patients as manual MPR. Results: Inter-reader agreement among 1 local and 3 central pathologists for manual PathR was good (n = 127; ICC = 0.87; 95% CI: 0.84-0.90). Agreement was 91% (κ = 0.82) on manual MPR and 98% (κ = 0.88) on pathologic complete response (pCR). 6 patients had unanimous pCR. Digital and manual PathR were strongly correlated (n = 135, Pearson r = 0.78) and digital PathR demonstrated an outstanding predictability for manual MPR (AUROC = 0.975). The range was 0%-60% for digital PathR and 0%-100% for manual PathR with a regression line slope < 1.0 (m = 0.303) indicating systematic differences between the methods, consistent with digital PathR using a high-resolution segmentation of cancer epithelium from stroma across each slide. Longer DFS was observed for MPR yes vs no with both digital and manual assessment (Table). Conclusions: This analysis showed good inter-reader agreement for manual and strong correlation of AI-powered digital and manual PathR. Comparable DFS rates for manual MPR and digital MPR are encouraging in the preliminary data. These data support further studies of digital PathR as a standardized and scalable tool to determine PathR. Clinical trial information: NCT02927301. [Table: see text]

IMbrave150: Exploratory efficacy and safety results of hepatocellular carcinoma (HCC) patients (pts) with main trunk and/or contralateral portal vein invasion (Vp4) treated with atezolizumab (atezo) + bevacizumab (bev) versus sorafenib (sor) in a global Ph III study

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Background: Atezo + bev has been approved in >60 countries for pts with unresectable HCC who have not received prior systemic therapy, based on IMbrave150 (NCT03434379; Finn RS NEJM 2020). Due to their poor prognosis and the hemodynamic changes from increased portal vein pressure, pts with main portal vein tumor thrombus are often excluded from pivotal HCC trials. Here, we report exploratory efficacy and safety results of pts with Vp4 (presence of a tumor thrombus in the main trunk and/or contralateral portal vein) using updated IMbrave150 data (Finn RS ASCO GI 2021). Methods: Pts were randomized 2:1 to atezo 1200 mg IV q3w + bev 15 mg/kg IV q3w or sor 400 mg bid until unacceptable toxicity or loss of clinical benefit per investigator. IMbrave150 enrolled 501 systemic treatment (tx)–naive unresectable HCC pts, ≥1 measurable untreated lesion (RECIST 1.1), Child-Pugh class A liver function and ECOG PS 0/1, including 73 (15%) Vp4 pts. This post hoc exploratory analysis was conducted with a median follow-up of 15.6 mo in ITT pts. Results: Of the Vp4 pts, 48 received atezo + bev and 25 received sor. Median OS (mOS) was 7.6 vs 5.5 mo (HR, 0.62; 95% CI: 0.34, 1.11) and median PFS (mPFS) per independent review facility (IRF)–assessed RECIST 1.1 was 5.4 vs 2.8 mo (HR, 0.62; 95% CI: 0.35, 1.09) with atezo + bev and sor, respectively. ORR per IRF RECIST 1.1 was 23% (11/47) with atezo + bev (2 [4%] pts had CR) vs 13% (3/23) with sor (1 [4%] pt had CR). All-grade variceal bleeding was higher with atezo + bev in Vp4 (13.6%) vs rest of ITT pts (2.5%). See table for further efficacy and safety data. Conclusions: The benefits of atezo + bev over sor in Vp4 pts are consistent with those in ITT pts across all efficacy endpoints, despite the expected disease-intrinsic increase in variceal bleeding in Vp4 vs rest of ITT pts. The overall positive benefit-risk profile supports the use of atezo + bev in pts with Vp4. Clinical trial information: NCT03434379. [Table: see text]

Pertuzumab Plus High-Dose Trastuzumab in Patients With Progressive Brain Metastases and HER2-Positive Metastatic Breast Cancer: Primary Analysis of a Phase II Study

Effective therapies are needed for the treatment of patients with human epidermal growth factor receptor-2 (HER2)-positive metastatic breast cancer (MBC) with brain metastases. A trastuzumab radioisotope has been shown to localize in brain metastases of patients with HER2-positive MBC, and intracranial xenograft models have demonstrated a dose-dependent response to trastuzumab.

QOLP-02. PATIENT-REPORTED OUTCOMES FOLLOWING PERTUZUMAB PLUS HIGH-DOSE TRASTUZUMAB IN PATIENTS WITH HER2-POSITIVE METASTATIC BREAST CANCER (MBC) AND CENTRAL NERVOUS SYSTEM (CNS) PROGRESSION POST-RADIOTHERAPY

Effective therapies are needed for the treatment of patients with HER2-positive MBC who develop brain metastases. In the open-label, phase II PATRICIA study (NCT02536339), 40 patients with HER2-positive MBC with CNS metastases and CNS progression post-radiotherapy (median age 48 years [range, 34–69]; prior CNS treatment [whole brain radiotherapy 71%, stereotactic radiosurgery 59%, both 31%]) were enrolled to receive pertuzumab plus high-dose trastuzumab (6-mg/kg weekly) until CNS or systemic disease progression or unacceptable toxicity. Following a median (range) treatment duration of 4.5 (0.3–37.3) months, the CNS-confirmed objective response rate per Response Assessment in Neuro-Oncology Brain Metastases criteria (primary endpoint) was 11% (95% confidence interval: 3.03, 25.42), and the clinical benefit rate at 4 months was 68%, indicating sustained clinical stability. Patient-reported outcomes (PROs) were evaluated using the MD Anderson Symptom Inventory-Brain Tumor (MDASI-BT), which includes sub-scales for symptom severity (average of 13 core symptom and 9 brain-tumor specific items) and symptom interference (average of 6 interference-with-life items representing overall symptom distress). Among 36 patients included in the PRO analyses, mean (standard deviation [SD]) symptom severity scores at baseline and weeks 12 and 28 were 1.65 (1.62), 2.24 (2.14), and 1.94 (2.55), respectively. Mean (SD) symptom interference scores at baseline and weeks 12 and 28 were 2.51 (2.63), 2.81 (3.39), and 1.76 (2.43), respectively. Mean (SD) changes in symptom severity and interferences scores from baseline to week 12 were 0.34 (1.54) and 0.33 (3.08), respectively. On average, patients who did not achieve stable disease or better in the CNS following treatment had worsened symptom severity and symptom interference scores over 12 weeks, while those with stable disease or better in the CNS exhibited stable or improving scores. Pertuzumab plus high-dose trastuzumab provided clinical benefit to the majority (68%) of patients in PATRICIA, without a decrement in quality of life.

Disease Monitoring Using Post-induction Circulating Tumor DNA Analysis Following First-Line Therapy in Patients with Metastatic Colorectal Cancer

PURPOSE

We assessed plasma circulating tumor DNA (ctDNA) level as a prognostic marker for progression-free survival (PFS) following first-line metastatic colorectal cancer (mCRC) therapy.

EXPERIMENTAL DESIGN

The Sequencing Triplet With Avastin and Maintenance (STEAM) was a randomized, phase II trial investigating efficacy of bevacizumab (BEV) plus 5-fluorouracil/leucovorin/oxaliplatin (FOLFOX) and 5-fluorouracil/leucovorin/irinotecan (FOLFIRI), administered concurrently or sequentially, versus FOLFOX-BEV in first-line mCRC. Evaluation of biomarkers associated with treatment outcomes was an exploratory endpoint. Patients in the biomarker-evaluable population (BEP) had 1 tissue sample, 1 pre-induction plasma sample, and 1 post-induction plasma sample collected ≤60 days of induction from last drug date.

RESULTS

Among the 280 patients enrolled in STEAM, 183 had sequenced and evaluable tumor tissue, 118 had matched pre-induction plasma, and 54 (BEP) had ctDNA-evaluable sequencing data for pre- and post-induction plasma. The most common somatic variants in tumor tissue and pre-induction plasma were TP53, APC, and KRAS. Patients with lower-than-median versus higher-than-median post-induction mean allele fraction (mAF) levels had longer median PFS (17.7 vs. 7.5 months, HR, 0.33; 95% confidence interval, 0.17-0.63). Higher levels of post-induction mAF and post-induction mean mutant molecules per milliliter (mMMPM), and changes in ctDNA (stratified by a 10-fold or 100-fold reduction in mAF between pre- and post-induction plasma), were associated with shorter PFS. Post-induction mAF and mMMPM generally correlated with each other (ρ = 0.987, P < 0.0001).

CONCLUSIONS

ctDNA quantification in post-induction plasma may serve as a prognostic biomarker for mCRC post-treatment outcomes.

Abstract P1-18-03: Pertuzumab (P) plus high-dose trastuzumab (H) for the treatment of central nervous system (CNS) progression after radiotherapy (RT) in patients (pts) with HER2-positive metastatic breast cancer (MBC): Primary efficacy analysis results from the phase II PATRICIA study

Background: There is an unmet need for evidence-based systemic therapies for pts with HER2-positive MBC and progressive brain metastases. Despite assumptions that monoclonal antibodies do not cross the blood-brain barrier, molecular imaging in pts shows localization of 89Zr-trastuzumab to brain metastases. Furthermore, preclinical data support dose-dependent activity of H in intracranial tumor models. The PATRICIA study (NCT02536339) evaluated safety and efficacy of P plus high-dose H in pts with HER2-positive MBC with CNS metastases and CNS progression after RT. Herein, we present results from the primary efficacy analysis of PATRICIA. Methods: PATRICIA was a US-based, phase II, open-label, single arm study. Eligible pts had measurable (≥10 mm) CNS disease that had progressed after CNS-directed RT, in the setting of stable extracranial disease. CNS-directed RT included whole-brain RT (WBRT) or stereotactic radiosurgery (SRS) and must have been completed ≥60 days before study entry. Pts received P (840 mg loading dose, then 420 mg every 3 weeks) and high-dose H (6 mg/kg weekly), which continued until progression (CNS or systemic) or unacceptable toxicity. Pts could continue their existing systemic anti-cancer therapy during the study, with the exception of trastuzumab emtansine (T-DM1) or lapatinib. Switch of other anti-cancer therapy was not permitted during the study. Restaging evaluations including brain MRI were completed every 2 cycles. The primary efficacy endpoint was confirmed objective response rate (ORR) in the CNS per Response Assessment in Neuro-Oncology Brain Metastases (RANO-BM) criteria. Secondary endpoints included duration of response (DOR), clinical benefit rate (CBR) in the CNS, and safety. Samples were collected for exploratory pharmacokinetic analyses on Day 1 of weeks 1, 4, 10, and 16. Results: From 15 Dec 2015 to 18 May 2017, 40 pts were enrolled across 16 sites. Median age was 48 (range 34–69) years, with 33% and 67% of pts having an Eastern Cooperative Oncology Group Performance Status score of 0 or 1, respectively. 41% of pts had received prior WBRT only, 28% had received prior SRS only, and 31% had received both. At the data cut off (1 May 2019), of 39 treated pts, 2 remained on study treatment and 37 discontinued treatment, most commonly due to CNS progression (n=27). Median treatment duration was 4.5 (range 0.3–37.3) months. Four pts in the efficacy population (N=37) experienced a confirmed partial response (Table), leading to an ORR of 11% (95% confidence interval [CI], 3–25%). Response durations were 3.2, 3.3, 4.6, and 5.6 months (median DOR 4.6 months). The CBR (complete response + partial response + stable disease [SD] of ≥4 or ≥6 months) was 68% (SD ≥4 months) and 51% (SD ≥6 months). Results from exploratory pharmacokinetic analyses confirmed greater H exposure with the high-dose schedule. The adverse event profile was similar to that previously reported for P and H, with no new safety signals. One pt discontinued treatment due to an adverse event (grade 3 left ventricular dysfunction, considered related to study treatment). No Grade 5 adverse events were reported. Conclusions: The CNS ORR of 11%, ≥6-month CBR of 51%, and lack of any new safety signals suggest that P plus high-dose H may have clinical utility in some pts with HER2-positive MBC with progressive CNS metastases.

Table. Efficacy within the CNS per RANO-BM criteriaEfficacy population (N=37)n (%)95% CIORR*4 (11)3, 25CBR (CR + PR + stable disease [SD] ≥4 months)25 (68)50, 82CBR (CR + PR + SD ≥6 months)19 (51)34, 68Confirmed best response (SD ≥4 months)CR0—PR4 (11)—SD ≥4 months21 (57)—Pts without clinical benefit12 (32)—Confirmed best response (SD ≥6 months)CR0—PR4 (11)—SD ≥6 months15 (41)—Pts without clinical benefit18 (49)—*Confirmed complete response (CR) or confirmed partial response (PR).

Citation Format: Nancy U Lin, Priya Kumthekar, Solmaz Sahebjam, Nuhad Ibrahim, Anita Fung, Anna Cheng, Alan Nicholas, Bei Wang, Mark Pegram. Pertuzumab (P) plus high-dose trastuzumab (H) for the treatment of central nervous system (CNS) progression after radiotherapy (RT) in patients (pts) with HER2-positive metastatic breast cancer (MBC): Primary efficacy analysis results from the phase II PATRICIA study [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-18-03.

IgE-Mediated Systemic Anaphylaxis And Its Association With Gene Polymorphisms Of ACE, Angiotensinogen And Chymase

BACKGROUND

The renin-angiotensin system (RAS) protects the circulation against sudden falls in systemic blood pressure via generation of angiotensin II (AII). Previously, we demonstrated that patients with anaphylaxis involving airway angioedema and cardiovascular collapse (AACVS) had significantly increased "I" gene polymorphisms of the angiotensin-converting-enzymes (ACE). This is associated with lower serum ACE and AII levels and was not seen in anaphylaxis without collapse nor atopics and healthy controls.

OBJECTIVES

To examine the angiotensinogen (AGT-M235T) and chymase gene (CMA-1 A1903G) polymorphisms in these original subjects.

METHOD

122 patients with IgE-mediated anaphylaxis, 119 healthy controls and 52 atopics had polymorphisms of the AGT gene and chymase gene examined by polymerase chain reactions and gel electrophoresis. Their previous ACE genotypes were included for the analysis.

RESULTS

AGT-MM genes (associated with low AGT levels) were significantly increased in anaphylaxis (Terr's classification). When combined with ACE, anaphylaxis showed increased MM/II gene pairing (p<0.0013) consistent with lower RAS activity. For chymase, there was increased pairing of MM/AG (p<0.005) and AG/II and AG/ID (p<0.0073) for anaphylaxis consistent with lower RAS activity. A tri-allelic ensemble of the 6 commonest gene combinations for the healthy controls and anaphylaxis confirmed this difference (p=0.0001); for anaphylaxis, genes were predominately MM/AG/II or ID, while healthy controls were DD/MT/AG or GG patterns.

CONCLUSION

Our gene polymorphisms show lower RAS activity for anaphylaxis especially AACVS. Animal models of anaphylaxis are focused on endothelial nitric oxide (eNO) which is shown to be the mediator of fatal shock and prevented by eNO-blockade. The interaction of AII and eNO controls the microcirculation in man. High serum AII levels reduce eNO activity, so higher RAS-activity could protect against shock. Our data shows low RAS activity in anaphylaxis especially AACVS, suggesting the influence of these genes on shock are via AII levels and its effects on eNO.

Neoadjuvant atezolizumab in resectable non-small cell lung cancer (NSCLC): Interim analysis and biomarker data from a multicenter study (LCMC3)

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Background: Small pilot studies (e.g., N Engl J Med. 2018;378:1976) have shown that preoperative immune checkpoint inhibitor therapy may be of benefit in early-stage NSCLC. This large multicenter trial assesses the benefit of neoadjuvant treatment with atezolizumab (atezo; NCT02927301). Methods: Patients (pts) with stages IB to selected IIIB resectable NSCLC receive 2 cycles of atezo 1200 mg (days 1, 22) then undergo resection (day 40 ± 10). Primary tumor +/- node biopsies and blood samples are obtained before atezo and at surgery for biomarker studies. The primary endpoint is major pathological response (MPR), defined as ≤ 10% viable tumor cells in the resection specimen. Secondary endpoints include safety and correlation of response with PD-L1 expression, tumor mutation burden (TMB) and gene expression signatures. Results: For this interim efficacy analysis (5 Sep 2018 data cut), we report on the first 101 of 180 planned pts: 47 males, median age, 64 y; all ECOG PS 0-1; 23 current and 68 former smokers; 66 non-squamous NSCLC; clinical stages IB/IIA/IIB/IIIA/IIIB n = 11/16/28/39/7. There were 2 treatment-unrelated Gr 5 AEs (cardiac death post surgical resection; death due to disease progression), 29 Gr 3-4 AEs (6 [6%] treatment related). 90 pts had surgery. Excluding 8 pts who had driver mutations (7 EGFR, 1 ALK, no MPR), MPR rate was 15/82 (18%, 95% CI 11%-28%), 4 pts had pathological complete response (pCR). By RECIST, 6/82 pts had PR, 72 had SD and 4 had PD. Two of 26 (8%) PD-L1− (TC0 and IC0, clone SP142) and 10 of 35 (29%) PD-L1+ had MPR ( P= 0.055). Five of 44 (11%) TPS < 50 (PD-L1 clone 22C3) and 7 of 20 (35%) TPS > 50 had MPR ( P= 0.040). Exome sequencing data was available for 47/101 pts. Median TMB was 10.4 (range, 1.5-46.5) mutations per Mb and was not different in those with MPR compared with those without MPR. Further analysis of TMB, mutation signatures, and gene expression profiling is ongoing. Conclusions: Atezo in the neoadjuvant setting was well tolerated, and pCR and MPR rates are encouraging in this large multicenter trial. Efficacy interim analysis passed its futility boundary, and study enrollment continues. Safety, efficacy results and ongoing correlative analyses will be presented. Clinical trial information: NCT02927301.

Neoadjuvant atezolizumab in resectable NSCLC patients: Updated clinical and immunophenotyping results from a multicenter trial

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Background: Targeting PD-L1/PD-1 to activate anti-tumor immunity is associated with improved response and survival compared to chemo in NSCLC pts. We present a preliminary analysis of the clinical efficacy, safety and peripheral blood (PB) immunophenotyping from an ongoing multicenter atezolizumab (atezo) neoadjuvant immunotherapy study in resectable NSCLC. Methods: Pts received 2 cycles of atezo, 1200mg, days 1, 22 before resection. Tumor biopsies and PB were obtained pre-atezo & pre-surgery. The biomarker evaluable population (BEP) included pts with paired PB analyzed within 72 hrs by 10-color flow cytometry (IMMUNOME) and major pathological response (MPR) assessment (defined as ≤ 10% residual tumor). The primary endpoint was MPR. Secondary endpoints included safety, MPR by PD-L1, OS, and DFS. Immunophenotypic analyses were correlated with treatment, MPR and PD-L1 expression. Results: 116 patients have been enrolled as of October 31, 2018 and here we report on 54 of 180 planned pts with follow-up through surgery. 15 pts had Gr 3-4 AEs (3 treatment related), one Gr 5 AE (sudden death) was unrelated. By RECIST there were 3 PR, 49 SD, and 2 PD. 50/54 pts underwent the planned surgery, 47 pts had MPR assessment: 4 pts discontinued study preop (2 radiographic PD, 2 other reasons); 3 were unresectable. Excluding 5 pts with EGFR or ALK mutations, MPR rate was 10/45 (22%, 95% CI 11-37%). Baseline PD-L1 status was evaluable in 44/54 pts; BEP included 31 pts, 23 had tissue PD-L1 status: 16 PD-L1+. We observed significant increases in natural killer (NK) cells, CD8+ T-cells, Th1-response related dendritic cells (DC), and decreases in B-cells after atezo. Non-MPR pts showed significant increases in late activated NK cells, monocytic myeloid cells and Th2 and Th17-response–related DCs. PD-L1+ pts showed significant decreases of senescent T cells, monocytic myeloid cells, and increases of Th1-response–related DCs. We analyzed 22/54 tumor pairs, PD-L1+ cells increased in most pts after atezo treatment. Conclusions: Neoadjuvant atezo was well tolerated and the MPR rate is encouraging. Preliminary immunophenotyping data showed significant changes in PB with immunotherapy. Clinical trial information: NCT02927301.

Phase II Randomized Trial of Sequential or Concurrent FOLFOXIRI-Bevacizumab Versus FOLFOX-Bevacizumab for Metastatic Colorectal Cancer (STEAM)

BACKGROUND

First-line treatment for metastatic colorectal cancer (mCRC) typically entails a biologic such as bevacizumab (BEV) with 5-fluorouracil/leucovorin/oxaliplatin (FOLFOX) or 5-fluorouracil/leucovorin/irinotecan (FOLFIRI). STEAM (NCT01765582) assessed the efficacy of BEV plus FOLFOX/FOLFIRI (FOLFOXIRI), administered concurrently (cFOLFOXIRI-BEV) or sequentially (sFOLFOXIRI-BEV, FOLFOX-BEV alternating with FOLFIRI-BEV), versus FOLFOX-BEV for mCRC.

PATIENTS AND METHODS

Patients with previously untreated mCRC (n = 280) were randomized 1:1:1 to cFOLFOXIRI-BEV, sFOLFOXIRI-BEV, or FOLFOX-BEV and treated with 4-6-month induction followed by maintenance. Coprimary objectives were overall response rate (ORR; first-line cFOLFOXIRI-BEV vs. FOLFOX-BEV) and progression-free survival (PFS; pooled first-line cFOLFOXIRI-BEV and sFOLFOXIRI-BEV vs. FOLFOX-BEV). Secondary/exploratory objectives included overall survival (OS), liver resection rates, biomarker analyses, and safety.

RESULTS

ORR was 72.0%, 72.8%, and 62.1% and median PFS was 11.9, 11.4, and 9.5 months with cFOLFOXIRI-BEV, sFOLFOXIRI-BEV, and FOLFOX-BEV, respectively. OS was similar between arms. ORR between cFOLFOXIRI-BEV and FOLFOX-BEV did not significantly differ (p = .132); thus, the primary ORR endpoint was not met. cFOLFOXIRI-BEV and sFOLFOXIRI-BEV numerically improved ORR and PFS, regardless of RAS status. Median PFS was higher with pooled concurrent and sequential FOLFOXIRI-BEV versus FOLFOX-BEV (11.7 vs. 9.5 months; hazard ratio, 0.7; 90% confidence interval, 0.5-0.9; p < .01). Liver resection rates were 17.2% (cFOLFOXIRI-BEV), 9.8% (sFOLFOXIRI-BEV), and 8.4% (FOLFOX-BEV). Grade ≥ 3 treatment-emergent adverse events (TEAEs) were observed in 91.2% (cFOLFOXIRI-BEV), 86.7% (sFOLFOXIRI-BEV), and 85.6% (FOLFOX-BEV) of patients, with no increase in serious chemotherapy-associated TEAEs.

CONCLUSION

cFOLFOXIRI-BEV and sFOLFOXIRI-BEV were well tolerated with numerically improved ORR, PFS, and liver resection rates versus FOLFOX-BEV, supporting triplet chemotherapy plus BEV as a first-line treatment option for mCRC. IMPLICATIONS FOR PRACTICE: The combination of first-line FOLFIRI with FOLFOX and bevacizumab (concurrent FOLFOXIRI-BEV) improves clinical outcomes in patients with metastatic colorectal cancer (mCRC) relative to FOLFIRI-BEV or FOLFOX-BEV, but it is thought to be associated with increased toxicity. Alternating treatment of FOLFOX and FOLFIRI (sequential FOLFOXIRI-BEV) could improve tolerability. In the phase II STEAM trial, which is the largest study of FOLFOXIRI-BEV in patients in the U.S., it was found that both concurrent and sequential FOLFOXIRI-BEV are active and well tolerated in patients with previously untreated mCRC, supporting the use of these regimens as potential first-line treatment options for this population.

Developmental Change in the Influence of Domain-General Abilities and Domain-Specific Knowledge on Mathematics Achievement: An Eight-Year Longitudinal Study

The contributions of domain-general abilities and domain-specific knowledge to subsequent mathematics achievement were longitudinally assessed (n = 167) through 8^th grade. First grade intelligence and working memory and prior grade reading achievement indexed domain-general effects and domain-specific effects were indexed by prior grade mathematics achievement and mathematical cognition measures of prior grade number knowledge, addition skills, and fraction knowledge. Use of functional data analysis enabled grade-by-grade estimation of overall domain-general and domain-specific effects on subsequent mathematics achievement, the relative importance of individual domain-general and domain-specific variables on this achievement, and linear and non-linear across-grade estimates of these effects. The overall importance of domain-general abilities for subsequent achievement was stable across grades, with working memory emerging as the most important domain-general ability in later grades. The importance of prior mathematical competencies on subsequent mathematics achievement increased across grades, with number knowledge and arithmetic skills critical in all grades and fraction knowledge in later grades. Overall, domain-general abilities were more important than domain-specific knowledge for mathematics learning in early grades but general abilities and domain-specific knowledge were equally important in later grades.

Correlation of pre- and post-induction plasma mutant allele fraction with progression-free survival (PFS) in STEAM, a prospective, randomized, multicenter study in metastatic colorectal cancer (mCRC)

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Background: STEAM (NCT01765582) evaluated the efficacy and safety of concurrent (c) and sequential (s) FOLFOXIRI-bevacizumab (BEV) versus FOLFOX-BEV for first-line treatment of mCRC. Methods: The AVENIO ctDNA Expanded Kit (Research Use Only) was used to identify somatic mutations in 77 cancer-related genes by next-generation sequencing (NGS) in both pre- and post-induction plasma samples (n = 118 for both groups) from STEAM. Demographics for patient tested were similar to the overall cohort. The mutant allele fraction (mAF) represents the mutation frequency in ctDNA for single nucleotide variants (SNVs) and indels detected per patient. Results: Overall, patients with a pre-induction mAF below the median had longer PFS compared to patients with mAF above the median (13.4 vs 9.5 mo, HR 0.49, p = 0.002). A similar trend was seen for overall survival (OS). Within the below median mAF group, longer PFS was observed in patients treated with cFOLFOXIRI-BEV versus FOLFOX-BEV (25.2 vs 9.5 mo, HR 0.34, p = 0.020). In contrast, no differences in PFS were observed in the treatment arms in the above median mAF group. Patients with a post-induction mAF below the median had longer PFS compared to patients with mAF above the median (15.3 vs 8.1 mo, HR 0.51, p = 0.0064). Correlations of post-induction genomic changes with outcomes, according to treatment groups, will also be presented. Conclusions: The level of pre- and post-induction mAF appears to correlate with PFS in STEAM overall. Furthermore, a lower median pre-induction mAF suggests PFS benefit for cFOLFOXIRI-BEV versus FOLFOX-BEV. Thus, plasma analysis of mAF via the AVENIO ctDNA Expanded Kit may identify patients who benefit from specific treatment in mCRC. These results are hypothesis generating and require further clinical validation. Clinical trial information: NCT01765582.

Evaluation of clinical outcomes by analysis of mutations in tumor tissue and circulating plasma DNA using next-generation sequencing (NGS) from STEAM, a prospective, randomized, multicenter study in metastatic colorectal cancer (mCRC)

11510

Background: STEAM (NCT01765582) assessed the efficacy and safety of concurrent (c) and sequential (s) FOLFOXIRI-bevacizumab (BEV) vs FOLFOX-BEV for first-line treatment of mCRC. Methods: The AVENIO ctDNA Expanded Kit (Research Use Only) was used to assess somatic mutations in 77 cancer-related genes by NGS in tissue, and both pre- and post-induction plasma samples (n = 182, 150 and 118 respectively) from STEAM. Four mutation classes including single-nucleotide variants (SNVs), indels, copy number amplifications (CNAs) and fusions were identified. SNVs and indels were called in tissue and plasma at allele frequencies of 5% and 0.25% respectively. Results: Overall concordance of mutations in pre-induction plasma with tissue was 83%. Concordance for the seven most mutated genes ranged from 91.5%-100%. In pts with matched samples (n = 118), RAS WT pts showed significantly longer progression-free survival (PFS) in both cFOLFOXIRI-BEV (A) and sFOLFOXIRI-BEV (B) arms versus FOLFOX-BEV (C), using genotyping of either tissue or plasma. This was not seen in RAS MUT pts. In contrast, TP53 WT showed no significant treatment differences while TP53 MUT showed longer PFS for cFOLFOXIRI-BEV versus FOLFOX-BEV. A list of mutation frequencies for all samples, as well as hierarchical clustering analysis of tissue mutations will be presented. Conclusions: The AVENIO ctDNA Expanded Kit identified mutations in 77 cancer-related genes, in both plasma and tissue, with high overall concordance. Compared to FOLFOX-BEV, longer PFS was observed for c- or s- FOLFOXIRI-BEV in RAS WT pts and for cFOLFOXIRI-BEV in TP53 MUT pts, irrespective of sample type. These results are hypothesis generating and require further clinical validation. Clinical trial information: NCT01765582. [Table: see text]

Planned interim analysis of PATRICIA: An open-label, single-arm, phase II study of pertuzumab (P) with high-dose trastuzumab (H) for the treatment of central nervous system (CNS) progression post radiotherapy (RT) in patients (pts) with HER2-positive metastatic breast cancer (MBC)

2074

Background: There is currently no clear standard of care to address the management of recurring/multiple intracranial metastases post RT in HER2-positive MBC. The ongoing PATRICIA study (NCT02536339) is evaluating the safety and efficacy of P in combination with high-dose h for patients with HER2-positive MBC with CNS metastases who have CNS progression following RT. Reported herein are results from the protocol-specified interim analysis of PATRICIA. Methods: All eligible patients must have measurable (≥10 mm) CNS progression post RT, and stable non-CNS disease. Patients receive P (840-mg loading dose, then 420 mg every 3 weeks) and high-dose h (6 mg/kg weekly). The primary efficacy endpoint is objective response rate (ORR) in the CNS per Response Assessment in Neuro-Oncology Brain Metastases (RANO-BM) criteria. The interim analysis was planned after 15 patients were enrolled and had ≥2 left ventricular ejection fraction (LVEF) measurements, 2 cycles of study drugs, and 2 response measurements. The study would proceed to full enrollment (n=40) if objective response or stable disease in the CNS was observed in ≥1 of 15 patients and <2 of 15 patients develop congestive heart failure (CHF) related to P or H. Results: As of Sept 6, 2016, 15 patients had been enrolled across 9 sites. Median treatment duration was 4.4 (range 1.2−8.3) months. Six patients discontinued treatment (5 for disease progression; 1 for symptomatic deterioration). Range for duration of response was 1.4−3.3 months. There were no new safety signals for P combined with high-dose h treatment. No patients had CHF or a clinically significant drop in LVEF. Conclusions: Based on early evidence of clinical benefit (ORR 20%) and a lack of new safety signals, the safety and futility boundaries for PATRICIA have been passed and study enrollment continues. Clinical trial information: NCT02536339. [Table: see text]

Updated efficacy, safety, and biomarker analyses of STEAM, a randomized, open-label, phase II trial of sequential (s) and concurrent (c) FOLFOXIRI-bevacizumab (BV) vs FOLFOX-BV for first-line (1L) treatment (tx) of patients with metastatic colorectal cancer (mCRC)

657

Background: STEAM (NCT01765582) assessed efficacy and safety of 1L cFOLFOXIRI-BV and sFOLFOXIRI-BV vs FOLFOX-BV. Updated efficacy, safety, and exploratory biomarker data are reported. Methods: 280 tx-naive pts with mCRC were randomized 1:1:1 to BV-containing (5 mg/kg q2w) arms (cFOLFOXIRI, sFOLFOXIRI [alternating FOLFOX and FOLFIRI every 4 weeks {q4w}], or FOLFOX) in a 4–6 month (mo) induction phase, followed by maintenance. Primary objectives include progression-free survival (PFS). Secondary objectives include overall survival (OS). Tumor-relevant biomarker evaluations were exploratory. Results: Median PFS significantly improved and median OS showed a positive trend with cFOLFOXIRI-BV vs FOLFOX-BV. PFS significantly improved with cFOLFOXFIRI-BV vs FOLFOX-BV in BRAF wild type (WT); there was a positive trend in RAS WT and mutant (MUT) pts; no tx difference observed in BRAF MUT pts. In the safety pop., (n = 271), 88% had Grade ≥ 3 tx emergent AEs: 91% cFOLFOXIRI-BV; 87% sFOLFOXIRI-BV; 86% FOLFOX-BV. Conclusions: Improved PFS and a positive trend in OS were observed for cFOLFOXIRI-BV vs FOLFOX-BV. A positive PFS trend was seen in RAS WT and MUT pts, with significantly improved PFS in BRAF WT. The small number of BRAF MUT pts precluded estimation of tx effects. AEs for all 3 txs were consistent with previous reports. Clinical trial information: NCT01765582. [Table: see text]

The foliar trichomes of Hypoestes aristata (Vahl) Sol. ex Roem. & Schult var aristata (Acanthaceae) a widespread medicinal plant species in tropical sub-Saharan Africa: with comments on its possible phylogenetic significance

The micromorphology of foliar trichomes of Hypoestes aristata var. aristata was studied using stereo, light and scanning microscopy (SEM). This genus belongs to the advanced angiosperm family Acanthaceae, for which few micromorphological leaf studies exist. Results revealed both glandular and non-glandular trichomes, the latter being more abundant on leaf veins, particularly on the abaxial surface of very young leaves. With leaf maturity, the density of non-glandular trichomes decreased. Glandular trichomes were rare and of two types: long-stalked capitate and globose-like peltate trichomes. Capitate trichomes were observed only on the abaxial leaf surface, while peltate trichomes were distributed on both adaxial and abaxial leaf surfaces.

Age-related gene-specific changes of A-to-I mRNA editing in the human brain

A-to-I editing is an adenosine-to-inosine modification of mRNA particularly widespread in the human brain, where it affects thousands of genes. A growing body of evidence suggests that A-to-I RNA editing is necessary for normal development and maintenance in mammals and that its deficiencies contribute to a number of pathological states. In this study, we examined whether mRNA editing levels of two mRNA species, CYFIP2 and GABRA3, change with aging. CYFIP2 has been implicated in synaptic maintenance, while GABRA3 is a GABA receptor subunit, a part of the major inhibitory neurotransmitter system in the CNS. The levels of mRNA editing were assessed in cortex samples of 20 subjects 22-102 years old. The data show an age-dependent statistically significant decrease in editing in CYFIP2. GABRA3 editing remained much more stable with age, implying that age-related decline of RNA editing is gene-specific. This is the first report of age-dependent decline in A-to-I editing. Further examination of these and other vulnerable genes may reveal specific RNA editing mechanisms that contribute to the aging phenotype.