2nd Line Setting Research Articles

T-DM1 efficacy in trastuzumab-pertuzumab pre-treated HER2 positive metastatic breast cancer patients: a meta-analysis

BackgroundCurrent guidelines consider T-DM1 the standard 2nd line therapy for HER2 positive metastatic breast cancer (MBC) patients following trastuzumab (T) + pertuzumab (P) and taxane 1st line treatment. Despite this, there are no prospective studies supporting this sequence.MethodsWe performed a meta-analysis using real world data to determine the efficacy of T-DM1 after 1st line TP in HER2 positive MBC patients. We used a random-effect model to find differences in the rate of 1-year progression free survival (PFS) between TP pre-treated population and the EMILIA phase III pivotal trial.ResultsSeven studies were eligible. The meta-analysis showed a combined 1-year PFS risk difference for T-DM1 efficacy after TP in 2nd or more lines of -0.122, with lower and upper limits of -0.253 and 0.010, respectively (p = 0.07), with low heterogeneity among studies (I2 0.01%, p = 0.836). Considering the four studies on T-DM1 in 2nd line setting, 1-year PFS risk was -0.034 (95% CI -0.207 – 0,139; p = 0.701) (I2 0.01%, p = 0.91).ConclusionOverall, the efficacy of T-DM1 after TP seems to be similar to that previously reported in the EMILIA trial. In the second line setting, data are not mature enough to confirm T-DM1 efficacy in TP pre-treated population.

Phase 1b study of vactosertib in combination with oxaliplatin with 5FU/LV (FOLFOX) in patients with metastatic pancreatic cancer who have failed first-line gemcitabine/nab-paclitaxel.

e16299 Background: TGF-β is strongly involved in the tumor microenvironment of PDAC, and dysregulation of TGF-β signaling is a frequent molecular disturbance in pancreatic ductal adenocarcinoma (PDAC) progression and metastasis. Vactosertib is an orally bioavailable TGF-β signaling inhibitor that targets the TGF-β type I receptor kinase. In preclinical studies, vactosertib in combination with FOLFOX improves pancreatic cancer survival by suppressing cell migration, invasion, and epithelial-mesenchymal transition (EMT), highlighting a potential clinical application of this approach for PDAC patients. We performed a phase 1b study to determine the recommended phase 2 dose (RP2D) and to evaluate the safety of vactosertib in combination with FOLFOX in patients with metastatic PDAC who have failed first-line gemcitabine/ nab-paclitaxel. Methods: Eligible patients have histologically confirmed PDAC who have failed first-line gemcitabine/ nab-paclitaxel with adequate organ function and performance status. This study is composed of two parts; dose escalation and dose expansion. In the dose escalation part (phase 1b), different dose levels of vactosertib (50 mg bid, 100 mg bid, and 200 mg bid) for escalation were tested, starting with dose level 0 (DL 0, 100 mg bid) with 3 to 6 subjects recruited in each cohort. DL -1 was only planned to test when DL 0 was unacceptable. In the dose expansion part, an additional backfill cohort was planned to open for determination of the final RP2D. Patients in each cohort were planned to receive vactosertib 50-200 mg orally twice per day 1-5 & day 8-12 with oxaliplatin 85 mg/m2 on day 1, LV 200mg/m2 IV on day 1, 5FU 200mg/m2 bolus on day 1 and continuous 5-FU 2400mg/m2 infusion over 48 hours every 2 weeks. The primary endpoints were to determine RP2D and to evaluate safety of this combination. The key secondary endpoints were progression free survival (PFS), overall response rate (ORR), disease control rate (DCR) based on RECIST 1.1 and overall survival. Results: A total of 16 patients were enrolled, 3 in DL 0, 4 in DL 1 and 9 in DL 1 backfill cohort. No dose limiting toxicities (DLTs) were observed and the RP2D was established as vactosertib 200 mg orally twice per day 1-5 & day 8-12 with FOLFOX. The vactosertib related adverse events (AEs) of any grade included fatigue, nausea, vomiting and anorexia. Three of 13 patients (23.1%) had partial response and 5 (38.5%) stable disease as best response, with clinical benefit rate of 61.5 % in DL 1, while there were no PR or SD in DL 0. Median PFS was 5.6 months [95% confidence interval (CI), 2.27–8.93]. Conclusions: In this phase Ib study, we demonstrated the feasibility and safety of adding vactosertib to FOLFOX in 2nd line setting, which needs to be further investigated. Updated results, including PK analyses, safety profiles, ORR, PFS and overall survival, will be presented. Clinical trial information: NCT03666832.

Overall survival from a phase II randomized study of ramucirumab plus pembrolizumab versus standard of care for advanced non–small cell lung cancer previously treated with immunotherapy: Lung-MAP nonmatched substudy S1800A.

9004 Background: Resistance to immune checkpoint inhibitor (ICI) therapy develops in most patients (pts) with advanced non-small cell lung cancer (NSCLC). Tumors that develop resistance to ICI constitute a major unmet need. Combined ICI and VEGF/VEGF receptor inhibition have shown benefit in multiple tumor types through immune modulation. We evaluated pembrolizumab and ramucirumab (P+R) in advanced, ICI-exposed NSCLC, under the aegis of Lung-MAP, a master protocol for pts with stage IV, previously treated NSCLC. Pt characteristics and treatment toxicities were presented at ASCO 2021. Methods: S1800A was a randomized phase II trial for pts ineligible for a biomarker-matched substudy with acquired resistance to ICI defined as previous ICI therapy for at least 84 days with progressive disease (PD) on or after therapy. Eligibility stipulated PD on prior platinum-based doublet therapy (sequential or in combination with ICI) and ECOG PS of 0-1. Pts were stratified by PD-L1 expression, histology, and intent to receive ramucirumab in the standard of care (SOC) arm and were randomized to P+R or SOC (investigator’s choice of docetaxel+R; docetaxel, pemetrexed, gemcitabine). With a goal of 144 total/130 eligible pts, the primary objective was to compare overall survival (OS) between the arms using a 1-sided 10% level log-rank test upon 90 deaths. Secondary endpoints included response, duration of response, investigator assessed-progression free survival and toxicity. Results: From May 17, 2019 to November 16, 2020, 166 pts were enrolled with 137 eligible (69 P+R; 68 SOC [45 +R, 23 w/o R]). Main causes for ineligibility were lack of PD on ICI or chemotherapy (6 SOC, 6 P+R), > 1 line of ICI (2 P+R), ICI discontinued due to toxicity (2 SOC), or lack of measurable disease (2 SOC, 1 P+R). OS was significantly improved with P+R (HR: 0.61 [0.38-0.97], 1-sided p-value = 0.019; median [95% CI] OS of 15.0 (13.2-17) months (mo) for P+R and 11.6 (8.5-13.8) mo in SOC arm). Progression-free survival (PFS) was not different between the arms (HR: 0.86 [0.57-1.31], 1-sided p-value=0.25; median PFS (95% CI) of 4.5 (4.0-6.9) mo for P+R and 5.2 (4.0-6.6) mo in SOC arm). ORR was not different between the arms (p=0.28). OS benefit for P+R was seen in most subgroups. Analysis of survival based on genomic alterations, tumor mutational burden and PD-L1 will be presented. Conclusions: Pembrolizumab + ramucirumab in pts with advanced NSCLC previously treated with chemotherapy and immunotherapy led to improved OS compared to SOC. Discordance of ORR and PFS from OS has been reported in prior ICI trials (Rittmeyer et al. Lancet 2017). This is the first trial in the 2nd line setting without a chemotherapy backbone to demonstrate a potential survival benefit compared to SOC regimens including docetaxel and ramucirumab using the Lung-MAP platform. Clinical trial information: NCT03971474.

Adverse health outcomes (AHO) in testis cancer survivors (TCS) following high-dose chemotherapy (HDCT) and autologous stem cell transplant.

12083 Background: Patients with relapsed/refractory germ cell tumors are often cured with tandem platinum-based HDCT followed by autologous stem cell transplant in the ≥2nd line treatment setting. A comprehensive assessment of long-term AHO (adverse health outcomes) in TCS cured with HDCT has not been previously described. Methods: Testis cancer survivors (TCS) at least 1 year after HDCT and treated at Indiana University were eligible. TCS were asked to complete a comprehensive, well validated survey regarding 19 different AHO. TCS demographics, disease characteristics, treatment received, and AHO were collected. Results: From 2/2021-1/2022, 118 eligible TCS were invited. 70 TCS completed the survey (59.3% completion rate). TCS received HDCT followed by autologous stem cell transplant in the 2nd (91.4%), 3rd (7.1%) or 4th line (1.4%) setting. At the time of survey completion, 93% of respondents were at least two years from HDCT (range 1.6-16.2 y) with a median age of 42 y (range 24.8-66.6 y). Median age at the time of original germ cell tumor diagnosis was 32 y (range 17.4-56.8 y). TCS reported a median of 3 AHO with 37% of participants reporting 5 or more AHO. 90% of participants reported tinnitus, 91% experienced hearing impairment, and 52% required the use of hearing aids. Additionally, 46% TCS noted peripheral neuropathy and 26% reported problems with balance/vertigo/dizziness. Prevalence of kidney disease was 10%, and 24% TCS experienced erectile dysfunction. In regards to physical activity, 47% of participants were not participating in vigorous physical activity (defined as > 6 mets/week). 16% TCS reported use of medications to treat anxiety and/or depression, and 19% required testosterone replacement therapy. The prevalence of hypertension, coronary artery disease, Raynaud phenomenon, hypercholesterolemia, diabetes, and thyroid disease were 13%, 1%, 17%, 12%, 4%, and 6% respectively. Conclusions: Despite the high cure rate of HDCT, TCS report a substantial burden of morbidity with the majority experiencing ototoxicity, and with half of the TCS requiring hearing aids. Special attention to these AHO and efforts to develop ototoxicity prevention approaches are urgently needed for this patient population.

Liquidscan mediated HER2 amplification detection in patient samples study.

e13016 Background: Overexpression of HER2 serves as an oncogenic driver in breast cancer which can result in tumor progression and distant metastases. Amplification or overexpression of HER2 occurs in approximately 15–30% of breast cancers and serves as a therapeutic, prognostic and predictive biomarker. There have been tremendous advances in HER2+ breast cancer management and there is an need to identify patients with HER2+ early breast cancer who may benefit from de-escalation or escalation of treatment. In addition, selection of HER2 therapies beyond the 2nd line setting for HER2+ metastatic breast cancer is currently unclear. Therefore, rapid monitoring tests for treatment response are needed. Liquid biopsy may provide a cost effective, sensitive, and non-invasive approach to monitor response. Methods: Whole blood (8ml) from 20 consenting patients with confirmed stage 3 or 4 metastatic breast cancer with clinical Her2 status identified by solid tissue biopsy (10 HER2+ and 10 HER2-) were collected. Circulating tumor cells were isolated on the LiquidScan system, were probed by HER2 FISH, analyzed using automated and visual microscopy. Results: Protocols were optimized to obtain morphology and cellularity of the tumor cells allowing conclusive HER2 identification for all samples. All samples from patients identified as Her2+ by standard invasive solid tumor biopsies could be identified (100% concordance), whereas for one sample that was reported as HER2-, cells were identified with the liquid biopsy having HER2+ FISH morphology. Further molecular analysis on this patient is under way. Conclusions: We were able to demonstrate that non-invasive liquid biopsy with the LiquidScan identifies HER2 status. The method has high concordance with conventional solid biopsy approach and may be a promising for patient monitoring. We will expand to larger sample sets to explore the full capacity of liquid biopsy to monitor and diagnose HER2 related diseases.

A multicenter real-life U.K. study of use of immunotherapeutic agents in metastatic urothelial cancer.

504 Background: First-line chemotherapy for patients with cisplatin-ineligible metastatic urothelial carcinoma (mUC) is associated with short response duration and high toxicity. Pembrolizumab(PEM) and atezolizumab (ATZ) are associated with long-term, durable remissions as a first-line treatment of cisplatin-ineligible, PD-L1-positive patients with mUC. For patients who progressed during or after platinum-based chemotherapy, Immunotherapy also prolongs survival with less toxicity and better quality of life compared with further lines of chemotherapy. There have been no studies directly comparing the effectiveness of PEM to ATZ in mUC patients. Methods: A cohort of 112 patients from 3 UK centres were included. 62, previously untreated cisplatin ineligible mUC patients who showed PDL1 positivity were given either ATZ or PEM once every 3 weeks until progression. 49 patients who had initial platinum based chemotherapy subsequently had ATZ or PEM as second line treatment following their disease progression The primary endpoint was Overall Survival(OS) and secondary endpoints included objective rate(ORR), response duration and safety. Results: The median age was 69 ( Interquartile range 43-91) and 23% were female and 77% were male. Among, patients who received immunotherapy 1st line, 82% had baseline renal impairment(GFR < 60), and 18% had Eastern Cooperative Oncology Group performance status 2. For chemo naïve patients, median OS was 11.5 months for PEM and 5 months for ATZ respectively. ORR was 22 % for ATZ vs 50% for PEM and median duration of treatment was 4.5 and 2.5 months for PEM and ATZ respectively. When used in 2nd line median OS is 7 months for ATZ irrespective of PDL1 status and not reached for PEM yet. Grade 2 and above toxicities were reported in 18 % ATZ patients vs 10% in PEM patients, commonest were pneumonitis, tiredness, hepatitis and dermatitis. No treatment related deaths were reported. Conclusions: This study suggests that pembrolizumab has higher response rate and better survival compared to atezolizumab in cisplatin-ineligible patients with mUC and also in the 2nd line setting after disease progression following platinum based agents. Both agents were well tolerated.

Randomized phase 2 trial of maintenance oral etoposide or observation following high-dose chemotherapy for relapsed metastatic germ cell tumor.

TPS429 Background: High-dose chemotherapy (HDCT) and peripheral-blood stem-cell transplant (PBSCT) is effective salvage therapy in patients with relapsed germ-cell tumors (GCT). Utilizing HDCT and PBSCT in the 2nd line setting, cures can be achieved in about 60% of patients with relapsed non-seminoma. Maintenance daily oral etoposide after salvage therapy has been shown effective in inducing remissions (J Clin Oncol 1995;13:1167-9). We evaluate the efficacy and safety of maintenance daily oral etoposide after HDCT+PBSCT in patients with relapsed non-seminoma. Methods: This randomized phase II open label trial is evaluating maintenance oral etoposide after HDCT+PBSCT. Eligible patients are adults with metastatic non-seminomatous GCT who have progressive disease after first-line cisplatin-based combination chemotherapy. All patients will complete initial salvage with HDCT+PBSCT with the carboplatin/etoposide Indiana protocol x2 tandem cycles. All patients should have normal or declining tumor markers (AFP and/or hCG) at time of randomization and absence of progressive disease on imaging. Adverse events from prior therapy, including hematologic toxicity, should be recovered to grade≤2 at time of randomization. Randomization should occur within ≤16 weeks from time of the 2nd cycle of HDCT. Patients with primary mediastinal non-seminoma are eligible. Patients with relapsed pure seminoma are excluded. Patients are randomized in 1:1 ratio to receive maintenance etoposide vs. standard of care surveillance post HDCT. Randomization will be stratified by platinum refractory status defined as progression within 4 weeks of first-line chemotherapy (yes vs no). Patients randomized to treatment arm will receive oral etoposide 50mg/m2 daily for 21 consecutive days of 28 day cycles. A total of 3 cycles will be delivered. Weekly labs including CBC w differential will be checked to detect hematological toxicity. The primary objective is to compare the 12-month progression-free survival (PFS) for maintenance etoposide vs observation in patients with relapsed non-seminoma post HDCT. Secondary objectives include to assess the toxicity and tolerability of maintenance etoposide, and 12-month overall survival. Exploratory analysis of the biomarker micro-RNA371 at time of randomization and correlation with disease progression/relapse will be performed. As of September 20, 2021, 5 of the total sample (N = 64) have been enrolled and randomized. Clinical trial information: NCT04804007.

MOUNTAINEER-02: Phase 2/3 study of tucatinib, trastuzumab, ramucirumab, and paclitaxel in previously treated HER2+ gastric or gastroesophageal junction adenocarcinoma—Trial in progress.

TPS371 Background: Tucatinib (TUC), a highly selective HER2-directed tyrosine kinase inhibitor (TKI) approved in multiple regions for HER2+ metastatic breast cancer, is being developed as a novel therapy for patients (pts) with GI tumors including gastric or gastroesophageal junction adenocarcinoma (GEC). While trastuzumab (Tras) with chemotherapy is standard in the 1st-line setting for metastatic HER2+ GEC, no anti-HER2 therapy has demonstrated an OS benefit over chemotherapy as 2nd-line therapy, possibly due to loss of HER2 expression following Tras-based therapy. In GEC xenograft models, dual targeting of HER2 with TUC and Tras showed superior activity to either agent alone.(Kulukian 2020) Interim results from the MOUNTAINEER study have shown promising activity for TUC and Tras for HER2+ mCRC.(Strickler 2019) The MOUNTAINEER-02 study is evaluating the efficacy and safety of TUC with Tras, ramucirumab (Ram), and paclitaxel (Pac) in pts with HER2+ GEC in the 2nd-line setting. Methods: MOUNTAINEER-02 (NCT04499924) is a phase 2/3 study evaluating TUC + Tras with Ram and Pac. Pts receive TUC 300 mg or placebo PO BID, Tras (6 then 4 mg/kg) or placebo (IV on Days 1 and 15 of each 28-day cycle), Pac (IV on Days 1, 8, 15), and Ram (IV on Days 1 and 15). Eligible pts have locally-advanced unresectable or metastatic HER2+ GEC and have received a HER2-directed antibody and 1 prior line of therapy for advanced disease. Pts must be ≥18 years of age, with an ECOG ≤1, and have had no prior exposure to Ram, anti-HER2 or anti-EGFR TKI, HER2-directed antibody-drug conjugates, or taxanes ≤12 months before enrollment. Due to the potential impact of TUC on Pac metabolism, the study will include an initial Pac dose optimization stage. The open-label phase 2 part will determine the recommended dose of Pac (60 or 80 mg/m²) combined with TUC, Tras, and Ram in 6-18 pts, and evaluate safety and activity of the regimen in Cohorts 2A and 2B (30 pts each). The randomized, double-blind, phase 3 part will compare the efficacy and safety of TUC and Tras (Arm 3A; ̃235 pts) vs. placebo (Arm 3B; ̃235 pts), both in combination with Ram and Pac, and also evaluate activity of TUC with Ram and Pac (Arm 3C; ̃30 pts). The dual primary phase 3 endpoints are OS and PFS per investigator, with confirmed ORR as a key secondary endpoint. HER2 status is determined at baseline using a blood-based NGS assay, and IHC/ISH of fresh or archival tumor biopsies, if available. Pts must be HER2+ by blood-based NGS in Cohort 2A and phase 3; in Cohort 2B, pts must be HER2+ in a biopsy taken post-progression during/after 1st-line therapy, but HER2-negative by blood-based NGS. Disease assessments per RECISTv1.1 will occur q6 weeks for 36 weeks, then q9 weeks. The pharmacokinetics of TUC, Pac, and their metabolites will be evaluated in a subset of pts, including a cohort with gastrectomies. Enrollment in phase 2 is ongoing. Clinical trial information: NCT04499924.

Immuno-oncology therapy in metastatic bladder cancer: A systematic review and network meta-analysis.

Three first line and three second-line clinical trials tested the effect of immunotherapy (IO) relative to standard chemotherapy (CT) on overall survival. However, network meta-analysis-based comparisons have not yet been presented. We addressed this void. To provide comparisons of overall survival (OS), progression-free survival (PFS), complete response (CR), partial response (PR), stable disease (SD), objective response rates (ORR), disease control rates (DCR) and adverse events (AEs) associated with 1st and 2nd line IO-based regimens. PubMed was searched for phase III randomized controlled trials from 2016 to 2021, including conference abstracts. We identified three first line [IMvigor130 (atezolizumab + CT vs atezolizumab vs CT), DANUBE (durvalumab vs durvalumab + tremelimumab vs CT), and KEYNOTE-361 (pembrolizumab + CT vs pembrolizumab vs CT)] and two second line [KEYNOTE-045 (pembrolizumab vs CT) and IMvigor211 (atezolizumab vs CT)] RCTs. Overall, 3255 and 1452 patients were respectively included in the first- and second-line settings. In 1st line setting, compared with CT, no IO-based regimen exhibited survival benefit. However, all exclusive IO regimens resulted in lower rates of grade 3+ AEs. In 2nd line setting, compared with CT, only pembrolizumab improved OS benefit. Conversely, atezolizumab only showed OS benefit in exploratory analyses. Compared to second-line CT, no experimental regimen (atezolizumab or pembrolizumab) exhibited statistically significant ORR benefit. Both pembrolizumab and atezolizumab resulted in lower rates of grade 3+ AEs compared to 2nd line CT. In metastatic UC, IO-based regimens do not hold a survival benefit relative to CT in 1st line setting. However, pembrolizumab holds a survival benefit in 2nd line compared to CT. Several IO-based clinical trials are ongoing and will provide more and possibly better treatment alternatives for locally advanced and metastatic UC.

HER2-Directed Therapy in Advanced Gastric and Gastroesophageal Adenocarcinoma: Triumphs and Troubles.

Gastric and gastroesophageal junction (GEJ) cancers represent the third leading cause of malignancy-associated death worldwide. Approximately 15-20% of these adenocarcinomas overexpress the human epidermal growth factor receptor 2 (HER2), a pro-proliferative receptor tyrosine kinase that has been therapeutically exploited in other disease contexts. The landmark ToGA trial demonstrated that trastuzumab, an anti-HER2 antibody, could improve overall survival for patients with HER2 overexpressing advanced gastric and GEJ adenocarcinomas. In the ensuing decade, great effort has been made to refine and expand this therapeutic strategy through a variety of avenues including optimization of chemotherapy backbones, identifying potential synergy with immune checkpoint inhibition, deployment of alternative HER2-targeted antibodies, use of small molecule inhibitors, and development of HER2-directed antibody drug conjugates. While the results of these efforts have had variable success, they have led to a greater understanding of the mechanisms of both primary and acquired resistance to HER2-directed therapies, laying the groundwork for future investigations. Recently, KEYNOTE-811 and DESTINY-Gastric01 have led to the FDA approvals of pembrolizumab in combination with trastuzumab and chemotherapy in the 1st-line advanced setting and trastuzumab deruxtecan (fam-trastuzumab deruxtecan-nxki) in the 2nd-line setting, respectively. Herein, we review these significant works as well as discuss the ongoing investigations they have inspired, which aim to find and utilize additional means for targeting HER2 in gastric and GEJ cancers.

Abstract CT239: ENVASARC: A Pivotal Trial of Envafolimab, and Envafolimab in Combination with Ipilimumab, in Patients with Advanced or Metastatic Undifferentiated Pleomorphic Sarcoma or Myxofibrosarcoma who have Progressed on Prior Chemotherapy

Abstract Background: Metastatic undifferentiated pleomorphic sarcoma (UPS) and the genetically related myxofibrosarcoma (MFS) are soft tissue sarcoma (STS) subtypes with poor prognoses. While responses to front line chemotherapy can approach 20%, in the 2nd line setting and beyond, efficacy remains limited. Pazopanib, the only approved treatment in the refractory setting has demonstrated an objective response rate (ORR) of 4%. Envafolimab is a single domain PD-L1 antibody administered rapidly by subcutaneous (SQ) injection that is being studied in two additional pivotal trials: MSI-H cancer and biliary tract cancer. The activity of envafolimab is similar to other PD-1 antibodies administered intra-venously. Envafolimab demonstrated a 32% ORR in MSI-H colorectal cancer that failed three approved chemotherapeutics, similar to the ORR of 28% and 33%, with nivolumab and pembrolizumab, respectively. The rationale for the ENVASARC trial is based on the previously reported efficacy of checkpoint inhibition in UPS/MFS. Single agent pembrolizumab demonstrated a 23% ORR, while the combination of nivolumab and ipilimumab demonstrated a 29% ORR in refractory UPS/MFS. Methods: ENVASARC (NCT 04480502) is a pivotal multicenter (at ~25 U.S. centers) open-label, randomized, non-comparative, parallel cohort study of treatment with envafolimab 300 mg every 3 weeks by SQ injection (cohort A; n=80) or envafolimab 300 mg every 3 weeks by SQ injection combined with ipilimumab 1 mg/kg every 3 weeks intra-venously for four doses (cohort B; n=80) in patients with locally advanced, unresectable or metastatic UPS/MFS who have progressed on one or two lines of prior therapy. The primary objective of each of parallel cohort is to demonstrate an ORR with a lower limit of the 95% confidence interval that excludes 5.0% in each cohort. If ≥ 9 responders are observed of the 80 patients enrolled in each cohort, then the lower bound of the 95% confidence interval will exclude 5.0%. Secondary endpoints include duration of response (DOR), PFS and OS. Key inclusion criteria: ≤ 2 prior lines of therapy (neoadjuvant and adjuvant therapy excluded), ECOG ≤ 1. Citation Format: Sandra D'Angelo, Steven Robinson, Joelle Lam, Bonne Adams, James Freddo, Charles P. Theuer, Robert Maki. ENVASARC: A Pivotal Trial of Envafolimab, and Envafolimab in Combination with Ipilimumab, in Patients with Advanced or Metastatic Undifferentiated Pleomorphic Sarcoma or Myxofibrosarcoma who have Progressed on Prior Chemotherapy [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 CT239.

Molecular Responses after Switching from a Standard-Dose Twice-Daily Nilotinib Regimen to a Reduced-Dose Once-Daily Schedule in Patients with Chronic Myeloid Leukemia: A Real Life Observational Study (NILO-RED)

IntroductionStandard dosing regimen for the BCR-ABL1 tyrosine kinase inhibitor (TKI) nilotinib in chronic myeloid leukemia (CML) is 300mg twice daily (BID) in the frontline setting and 400mg BID in the 2nd line setting or beyond. Patients (pts) are instructed to fast within 2 hours before and 1 hour after medication intake due to significant high-fat food effects on drug bioavailability. On-label dose adjustments to a lower-dose once-daily (QD) regimen are recommended solely in case of significant toxicity.Study goalThe primary aim of our observational two-center study was to ask whether nilotinib-treated adult CML pts were able to maintain major molecular responses (MMR) within 1 year after conversion to a more convenient nilotinib QD regimen at reduced doses, regardless of reasons for tapering nilotinib. Pts with minor transcripts or a history of blast crisis or allogeneic stem cell transplantation were excluded.PatientsEighty one pts in chronic phase were identified and included and results from the first 67 pts with a follow-up of at least 12 months after the switch to the once-daily dose-reduced nilotinib regimen are presented. Median age at study entry was 52 years (range: 19-82). There were 25 males (37.3%) and the Sokal score was low, intermediate, high or unknown in 43.3%, 37.3%, 13.4% and 6% of pts, respectively. All pts had major-type BCR-ABL1 transcripts. Nilotinib was started as 1st line TKI at 300mg BID in 68.6% of pts and as 2nd or subsequent line TKI at 400 or 300 mg BID in 31.4% of pts due to intolerance, warning, resistance or absence of a deep molecular response on prior therapy. Median duration of nilotinib prior switching to a reduced QD dosing was 29 months (range: 1-94) and median duration of MMR was 25 months (range: 3-212). Primary reason for the switch to a reduced QD nilotinib dosing was non-serious adverse events in 37.3% of pts and improvement in pts convenience in 62.7% of pts. Nilotinib was reduced down to 450mg QD, 400mg QD or 300mg QD in 86.6%, 10.4% and 3% of pts, respectively. A 2nd dose reduction from 450mg to 300mg QD was performed in 30 pts after a median time of 18 months (range: 4-37). The median duration of low-dose nilotinib QD was 24 months (5-54). No severe tolerance issues were encountered and no ischemic cardiovascular events occurred. Eleven pts stopped nilotinib due to treatment-free remission attempt (n=10) or persistent adverse event (n=1). All pts were alive at last follow-up.Evolution of molecular responsesAt baseline, the number of pts in MMR, MR4 and ≥MR4.5 was 9 (13.4%), 17 (25.4%) and 41 (61.2%), respectively and 32 pts (47.8%) had undetectable BCR-ABL1 transcripts. Median BCR-ABL1/ABL1 % IS was 0.006% (range: 0.0007-0.063) and median ABL1 copy number in pts with undetectable transcripts was 87259 (range: 36018-921339). Only 2 pts treated with 1st line nilotinib lost MMR 4 and 6 months after QD dose reduction of nilotinib with BCR-ABL1/ABL1 % IS at 0.13 and 0.11%, respectively. Both pts spontaneously regained MMR 4 months later without any treatment modification. Kaplan-Meier analysis of survival without unconfirmed MMR loss was 97% (95% CI: 92.9-100) at 12 months and analysis by molecular response category showed that none of the pts who were at least in MR4 at baseline lost MMR (Figure 1). At last follow-up on low-dose QD nilotinib, the number of pts in MMR, MR4 and ≥MR4.5 was 4 (6.3%), 11 (16.4%) and 52 (77.6%), respectively and 37 pts had undetectable transcripts (55.2%). Median BCR-ABL1/ABL1 % IS was 0.0035% (range: 0.00025-0.058) and median ABL1 copy number in pts with undetectable transcripts was 96000 (range: 23285-472000).Ten pts in long-lasting deep molecular response stopped nilotinib without further treatment after a median duration of TKI and of nilotinib of 60 months (range: 50-149) and 56 months (range: 42-87), respectively. Their follow-up after nilotinib discontinuation was 18 months (range: 5-33). Only 1 of them lost MMR and restarted therapy 5 months later while the others remained treatment-free.ConclusionSwitching to a nilotinib QD regimen at reduced doses as maintenance therapy after achievement of a MMR on standard-dose nilotinib BID schedule is feasible and safe in chronic phase CML pts regardless of prior treatment history and does not compromise the anti-leukemic efficacy of nilotinib. Our results may pave the way for clinical trials aiming at systematic avoidance of overtreatment and improvement of pts convenience in treatment with nilotinib. [Display omitted] DisclosuresRea:Pfizer: Honoraria; BMS: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Incyte: Honoraria. Cayuela:BMS: Honoraria; Novartis: Honoraria. Etienne:BMS: Speakers Bureau; Incyte: Speakers Bureau; Novartis: Consultancy, Research Funding.

JUPITER-02: Randomized, double-blind, phase III study of toripalimab or placebo plus gemcitabine and cisplatin as first-line treatment for recurrent or metastatic nasopharyngeal carcinoma (NPC).

LBA2 Background: Gemcitabine-cisplatin (GP) chemotherapy is the standard 1st line treatment for locally advanced, recurrent or metastatic (r/m) NPC. Toripalimab, a humanized IgG4K monoclonal antibody specific for PD-1, provided durable responses in patients (pts) with r/m NPC as monotherapy in the ≥2nd line setting (POLARIS-02 study). The results of JUPITER-02, a randomized, placebo-controlled, double-blinded Phase III trial of toripalimab in combination with GP chemotherapy as first-line treatment for r/m NPC are summarized. Methods: Pts with advanced NPC with no prior chemotherapy in the r/m setting were randomized (1:1) to receive toripalimab 240 mg or placebo d1 in combination with gemcitabine 1000 mg/m2 d1, d8 and cisplatin 80 mg/m2 d1 every 3 weeks (Q3W) for up to 6 cycles, followed by monotherapy with toripalimab or placebo Q3W until disease progression, intolerable toxicity, or completion of 2 years of treatment. Stratification factors were ECOG PS (0 vs. 1) and extent of disease (recurrent vs. primary metastatic) at enrollment. Progression-free survival (PFS) and response were assessed by independent review committee (IRC) per RECIST v1.1. The primary endpoint was PFS by IRC in the ITT population. Secondary end points included ORR, DOR and OS. There was one prespecified interim analysis of PFS at 130 PFS events with a planned final analysis at 200 PFS events. Results: 289 pts were randomized: 146 to the toripalimab arm and 143 to the placebo arm. By May 30, 2020 as the interim analysis cutoff date, the median treatment duration was 39 weeks in the toripalimab arm and 36 weeks in the placebo arm. A significant improvement in PFS was detected for the toripalimab arm compared to the placebo arm (HR = 0.52 [95% CI: 0.36-0.74] two-sided p = 0.0003), with median PFS of 11.7 vs. 8.0 months. The 1-year PFS rates were 49% and 28% respectively. An improvement in PFS was observed across relevant subgroups, including all PD-L1 subgroups. The ORR was 77.4% vs. 66.4% (P = 0.033) and the median DOR was 10.0 vs. 5.7 months (HR = 0.50 [95% CI: 0.33-0.78]). As of Jan 15, 2021, OS was not mature, with 25 deaths in the toripalimab arm and 35 in the placebo arm (HR = 0.68 [95% CI: 0.41-1.14], P = 0.14). The incidence of Grade ≥3 adverse events (AEs) (89.0% vs 89.5%); AEs leading to discontinuation of toripalimab/placebo (7.5% vs 4.9%); and fatal AEs (2.7% vs 2.8%) were similar between two arms; however, immune-related (irAEs) (39.7% vs. 18.9%) and Grade ≥3 irAEs (7.5% vs. 0.7%) were more frequent in the toripalimab arm. Conclusions: The addition of toripalimab to GP chemotherapy as 1st-line treatment for pts with advanced NPC provided superior PFS and ORR and longer DOR than GP alone with a manageable safety profile. These results support the use of toripalimab with GP chemotherapy as the new standard care for this population. Clinical trial information: NCT03581786.

Systemic treatment of patients with inoperable and metastatic Merkel cell carcinoma: A multicenter study.

e21521 Background: Merkel cell carcinoma (MCC) is an uncommon, aggressive neuroendocrine skin cancer. The prognosis in the unresectable and metastatic setting is very poor. Distant metastases develop in more than 30%. Chemotherapy (CHT), the previous mainstay of treatment, is associated with the high response rates (RR) of limited duration. The main cytotoxic drugs have been platinum derivatives, taxoids, anthracyclines, and etoposide. The standard systemic treatment for this disease has changed in the last few years. Immunotherapy (IO) is currently the basis of systemic therapy in the metastatic setting. This study aimed to analyze outcomes for unresectable and metastatic MCC pts treated in routine clinical practice, mostly before the era of IO availability. Methods: We conducted the retrospective analysis of data from 36 MCC pts in unresectable (n= 23) and metastatic (n=13) settings treated in three oncological centers, diagnosed between 01/2010 and 12/2019, with data cut-off on 31/12/2020. The data collected included epidemiological and clinical information. Survival analyses were performed using the Kaplan-Meier method and log-rank test. Results: The median patient age at diagnosis was 72 years (57-88); 58.3% were male. The most common primary tumor (PT) locations were lower limbs (41.7%), head and neck (30.6%), and upper limbs (16.7%). In 63.9% the PT was located in the sun-exposed skin. The most common location of distant metastases were nonregional lymph nodes (n=9) and lungs (n=3). Thirty-six pts received 1st line CHT with the median progression-free survival (mPFS) of 5.3 months (95%CI 2.88-7.7) and objective response of 61.1%, with 13.9% complete responses (CR). The most commonly used regimens were platinum-based and anthracycline-based regimens (n=26). Disease progression (PD) was observed in 91.7% of pts treated with 1st line CHT. Twenty-one pts received 2nd line therapy, IO (n=14), or CHT (n=7), with PD in 19 pts (90.6%), mPFS 2.83 months (95% CI 0.59-5.06) and RR of 33.3% (0% CR). 13 pts were treated with avelumab (AVE), all in the 2nd line, with RR of 38.5% (0% CR). The mPFS in the 2nd line was 5 months (95%CI 0-11.46) on AVE compared to 2.82 (95%CI 0.46-5.19) on CHT (HR 0.65, 95%CI 0.25-1.70, p=0.378). During 1st line systemic therapy, 16 pts underwent palliative surgery (n=7, 19.4%) or received radiation therapy (RT) (n=9, 25%), and during 2nd line, one patient was treated with surgery, and five pts received RT. The median overall survival was 10.38 months (95% CI 2.90-17.87). Local treatment did not improve the treatment outcomes in the 1st (p=0.119) nor 2nd line (p=0.821). Conclusions: Our results confirm the poor prognosis of pts with unresectable and metastatic MCC. The response rates and median PFS for CHT in the 1st and 2nd line setting are consistent with historical data. The treatment with AVE in the 2nd line allows achieving better results, similar to the results reported in the clinical trials.

Overall survival comparison in patients with and without brain metastases treated with osimertinib for metastatic EGFR mutation positive non-small cell lung cancer (NSCLC).

e21216 Background: With the development of Epidermal Growth factor receptor (EGFR) tyrosine kinase inhibitors such as Osimertinib, the landscape of lung cancer treatment and outcomes has changed. We aimed to describe the outcomes of patients treated with Osimertinib who have brain metastasis compared to those without brain metastases. Methods: This study involved patients diagnosed with metastatic non-small cell lung cancer (NSCLC) with EGFR mutation, from January 2010 to December 2018, who had treatment with Osimertinib at a dose of 80 mg daily. Retrospective data was collected through the electronic medical records from Sunnybrook Health Sciences Centre. Descriptive statistics were used to summarize the population characteristics. The log rank test was used to compare the survival distributions. Results: A total of 56 patients were included, the mean age at initial diagnosis was 63 years (range 27 – 85 years). Overall, 82.2% of this patient population received Osimertinib in 2nd line setting. A total of 50% (n = 28) had brain metastasis, and14.3% (n = 8) had leptomeningeal metastasis. Of the patients with brain metastasis, 14.3% (n = 4) had brain surgery. All patients with brain metastasis received central nervous system (CNS) radiation. With respect to radiotherapy modalities, 67.9% (n = 19) of patients with brain metastasis received gamma knife radiation, 42.85% (n = 12) were treated with stereotactic radiosurgery (SRS), and whole brain radiation was given to 57.1% (n = 16). Of those with brain metastasis, equal numbers of patients, 46.4% (n = 13), had EGFR mutations with exon 19-deletion and exon 21-L858R, 7.1% (n = 2) had unknown gene location EGFR mutation. The median OS for patients without brain metastasis was 38.6 months (95% confidence interval [CI] 37.5 – 39.8 months], compared to 35.9 months (95% [CI] 28.3 – 43.5 months] for those with brain metastasis ; log Rank (Mantel-Cox) p = 0.874. The median OS for patients diagnosed with leptomeningeal metastasis was 21 months (95% [CI] 2.9 – 39.0 months); log rank (mantel-cox). When brain metastasis was examined by EGFR mutation sub-groups, the median OS for patients with EGFR-exon 19-deletion was 26.4 months (95% CI [14.3 – 38.4 months], compared to 36.8 months, 95% CI [34.3 – 39.2 months] for those with EGFR-Exon 21-L858R; log Rank (Mantel-Cox) p = 0.49. Conclusions: Although there is an equivalent prevalence of brain metastasis between the two NSCLC EGFR mutation populations, in unadjusted analyses, no difference in OS was seen between patients with brain metastases compared to those without brain metastases. However, in the small number of patients with leptomeningeal disease, survival was shorter and a larger population should be studied to further explore this finding.

ESMO Magnitude of Clinical Benefit Scale (MCBS): An evaluation of systemic treatment trials for soft tissue sarcomas (STS).

11553 Background: Patients with STS have poor prognosis in the metastatic setting. Although some treatment options are associated with improved outcomes, such as progression-free (PFS) or overall survival (OS), the overall magnitude of clinical benefit can be unclear. The ESMO MCBS is a validated and reproducible tool developed to quantify the clinical benefit of treatments evaluated in trials ( www.esmo.org/guidelines/esmo-mcbs ). Herein, we report the application of ESMO MCBS to systemic treatment trials involving metastatic STS patients. Methods: A systematic search of Medline, Embase and Cochrane databases for adult phase II and III trials in advanced STS (01/1998 to 12/2020) was carried out. Gastrointestinal stromal tumor trials were excluded. Outcomes, including but not limited to OS, PFS, objective response rate (ORR), toxicity and quality of life (QoL) data were extracted and analyzed. Studies with outcomes that met the criteria for ESMO MCBS v1.1 were evaluated to generate a score of 1 to 5 (score of ≥ 4: substantial benefit). MCBS scoring of each study was performed by at least 2 co-authors for consensus. Results: Among 3454 abstracts screened, a total of 140 Phase II and 28 phase IIII trials were identified. A total of 41 studies fulfilled the criteria for ESMO MCBS scoring. These include 5 phase III studies, as well as 9 randomized and 27 single-arm phase II trials. Fifteen studies involved specific histology, while remaining 26 studies were of all STS subtypes. Chemotherapy, alone or in combination was evaluated in 29 trials, while molecular-targeted agents (MTA) and immune checkpoint inhibitors (IO) were evaluated in 11 and 3 studies, respectively (Table). The median MCBS score was 2 (range 1-4), regardless of drug class or combination. Only 3 studies, all randomized in design, had a MCBS score of 4. All three trials were in the 2nd line setting or beyond, where there is no standard control treatment. None of the trials, irrespective of drug class had a score of 5 and no study showed evidence of significant improvement in QoL. The observed MCBS scores were low, partly because the trials evaluated mainly comprise single-arm studies without QoL assessments, restricting to a maximum MCBS score of 3. Conclusions: Most systemic therapy trials in advanced STS did not confer substantial clinical benefit when evaluated using MCBS. Although randomized phase 3 trials remain the gold standard of treatment evaluation, clinical benefit evaluation of STS trials using tools such as MCBS may be useful. Incorporation of QoL evaluation, even in single-arm studies should be prioritized in metastatic STS trials.[Table: see text]

ENVASARC: A pivotal trial of envafolimab, and envafolimab in combination with ipilimumab, in patients with advanced or metastatic undifferentiated pleomorphic sarcoma or myxofibrosarcoma who have progressed on prior chemotherapy.

TPS11581 Background: Metastatic undifferentiated Pleomorphic Sarcoma (UPS) and the genetically related myxofibrosarcoma (MFS) are soft tissue sarcoma (STS) subtypes with poor prognoses. While responses to front line chemotherapy can approach 20%, efficacy remains limited in the 2nd line setting and beyond. Pazopanib, the only approved treatment in the refractory setting, has demonstrated an objective response rate (ORR) of 4%. Envafolimab is a single domain PD-L1 antibody administered rapidly by subcutaneous (SQ) injection that is being studied in two additional pivotal trials: microsatellite instability-high (MSI-H) cancer and biliary tract cancer. The activity of envafolimab appears to be similar to other PD-1 antibodies administered i.v. Envafolimab demonstrated a 32% objective response rate (ORR) in MSI-H colorectal cancer patients who failed three approved chemotherapeutics, similar to the ORR of 28% and 33% with nivolumab and pembrolizumab in these patient populations, respectively. The rationale for the ENVASARC trial is based on the previously reported activity of checkpoint inhibition in UPS/MFS. Single agent pembrolizumab demonstrated a 23% ORR, while the combination of nivolumab and ipilimumab demonstrated a 29% ORR in refractory UPS/MFS. Methods: ENVASARC (NCT 04480502) is a pivotal multicenter (at ̃25 U.S. centers) open-label, randomized, non-comparative, parallel cohort study of treatment with envafolimab 300 mg every 3 weeks by SQ injection (cohort A; n = 80) or envafolimab 300 mg every 3 weeks by SQ injection combined with ipilimumab 1 mg/kg every 3 weeks i.v. for four doses (cohort B; n = 80) in patients with locally advanced, unresectable or metastatic UPS/MFS who have progressed on one or two lines of prior therapy. The primary objective of each of parallel cohort is to demonstrate an ORR with a lower limit of the 95% confidence interval that excludes 5.0% in each cohort. If ≥ 9 responders are observed of the 80 patients enrolled in each cohort, then the lower bound of the 95% confidence interval will exclude 5.0%. Secondary endpoints include duration of response (DOR), PFS and OS. Key inclusion criteria: ≤ 2 prior lines of therapy (neoadjuvant and adjuvant therapy excluded), ECOG ≤ 1. Clinical trial information: NCT 04480502.

Efficacy and tolerability of the combination of nano-liposomal irinotecan and 5-fluorouracil/leucovorin in advanced pancreatic adenocarcinoma: post-approval clinic experience.

Nano-liposomal irinotecan (nal-IRI) plus 5-fluorouracil/leucovorin (5-FU/LV) is the regimen of choice in the 2nd line setting for advanced pancreatic adenocarcinoma (PAC). However, real-world data is limited. Our objectives were to elicit the real-word effectiveness and safety of this combination as an advanced line of therapy in pancreatic cancer patients and analyze the impact of prior lines of therapy on survival outcomes with this regimen. We conducted a retrospective cohort study of 58 patients with locally advanced unresectable or metastatic PAC, who were treated with at least one dose of nal-IRI + 5-FU/LV following cancer progression on prior therapies between August 2015 and December 2018 at the Kansas University Medical Center (KUMC) and University of Alabama at Birmingham (UAB). Median OS was 5.4 (range, 4.2-7) months. Disease control rate (DCR) was highest (84%) for patients given nal-IRI + 5-FU/LV as 2nd line agent after progression on a 1st line gemcitabine-based regimen. However, no significant survival difference was observed between those given nal-IRI + 5-FU/LV after 1st line or beyond the 2nd line (P=0.17). Among those given nal-IRI + 5-FU/LV as 2nd line, use of gemcitabine-inclusive chemotherapy as the 1st line agent did not impact survival (P=0.68). Prior irinotecan exposure and baseline CA 19-9 level did not affect the overall survival (OS) but patients with a higher CA 19-9 level had a significant risk of progression (HR =3.2, P=0.02). Grade 3/4 toxicities were reported in only 19% patients. Our report suggests that nal-IRI + 5-FU/LV offers a modest survival benefit with a tolerable safety profile as an advanced line of treatment in patients with advanced PAC.

Abstract PS10-40: Real life efficacy of palbociclib and endocrine therapy in HR positive, HER2 negative advanced breast cancer

Abstract BackgroundPalbociclib, a highly selective inhibitor of CDK4/6, is indicated for the treatment of hormone receptor-positive (HR+), HER2-negative (HER2-) advanced breast cancer (ABC), in combination with an aromatase inhibitor or with fulvestrant for patients who have progressed with an aromatase inhibitor, and in premenopausal women with a luteinising-hormone-releasing-hormone (LH-RH) agonist. Emerging real world data suggest that the efficacy of a palbociclib-based therapy is highly conserved. We report here the Institut Curie (IC) experience. Patients and methodsWe retrospectively reviewed all patients with HR+ HER2- ABC treated with a palbociclib-based therapy as 1st or 2nd line of therapy for ABC, from November 2016 to December 2018. Clinical, biological and imaging data were retrieved from IC electronic health record system. Data lock was December 31st 2020. Descriptive analyses, univariate and multivariate Cox regression analyses were performed. ResultsWe included 310 consecutive premenopausal (24.5%) and menopausal (75.5%) women. Median age was 61.8 years-old [23.5-92.1]. Among them, Eastern Cooperative Oncology Group (ECOG) performance status was 0 in 59.7%, 1 in 32.1%, and 2 in 8.2% of patients (pts). The ABC diagnosis was de novo for 26.8%. There was at least one visceral lesion in 51.0% of pts, only bone lesions in 30.3%, 28.1% had three metastatic sites or more, and none of them have brain lesions. Previous treatments were chemotherapy (49.4%) and endocrine therapy (60.7%). Among pts pretreated by at least one endocrine therapy, 51.1% had shown prior sensibility, as defined by an absence of recurrence during adjuvant endocrine therapy or during 24 months after its completion, or an absence of progression during 6 months after the beginning of an endocrine therapy for a metastatic disease. Palbociclib was prescribed in the 1st line setting for 72.6% of pts and in the 2nd line setting for 27.4% of pts. The initial dose was 125 mg daily (95.2%). It was associated with an aromatase inhibitor (66.8%) or with fulvestrant (33.2%). LH-RH agonist was prescribed in 19.7% of pts. Denosumab was prescribed in 68.5% of pts with bone lesions. Median follow-up was 20.7 months (m). At 12 m from the initiation of palbociclib, 94.5% of the pts were alive. Median progression free survival was 23.4 m (95%CI: 21.6-NR) for pts without previous endocrine therapy, 22.7 m (95%CI: 14.7-NR) for pts who have shown endocrine sensibility, HR=1.2 (95%CI: 0.81-1.77), p=0.0027 and 13.4 m (95%CI: 10.7-20.8) for pts who have not shown endocrine sensibility, HR=1.88 (95%CI: 1.29-2.73), p=0.003. Although sensibility to previous endocrine therapy was a prognostic factor for progression free survival with the univariate analyse, it was not with the multivariate analysis. Three independent poor prognostic factors for progression free survival were identified: previous chemotherapy, HR=1.6 (95%CI: 1.12-2.29), p<0.001; initial ECOG performance status 2, HR=2.72 (95%CI: 1.55-4.79), p<0.001; and three or more metastatic sites, HR=1.61 (95%CI: 1.152.26), p<0.001. Hematologic grade 3-4 adverse events were neutropenia (72.3%), leukopenia (43.9%), anemia (3.2%) and thrombocytopenia (2.9%). Other adverse events observed (all grades) were infections (16.5%), stomatitis (13.9%) or alopecia (13.9%). At least one dose reduction occurred in 29.4% of pts and permanent discontinuation because of treatment toxicity was observed in 5.7% of pts. ConclusionIn a non-selected population of patients with HR+ HER2- ABC, the efficacy and safety data are strikingly similar to those previously reported. Palbociclib, in combination with hormone therapy, is a cornerstone treatment of HR+ HER2- metastatic breast cancer. Citation Format: Baptiste Porte, Matthieu Carton, Delphine Loirat, François-Clement Bidard, Linda Haroun, Audrey Bellesoeur, Youlia Kirova, Paul Cottu. Real life efficacy of palbociclib and endocrine therapy in HR positive, HER2 negative advanced breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS10-40.

CMTM6 expression as a potential biomarker for immunotherapy in metastatic renal cell carcinoma.

The introduction of immune checkpoint inhibitors (ICIs) has revolutionized the treatment of metastatic renal cell carcinoma (mRCC) [1]. The expression of programmed death-ligand 1 (PD-L1) as assessed by immunohistochemistry (IHC) has been extensively studied as predictive biomarker for patients receiving ICIs. However, results in clinical RCC trials concerning the predictive value of PD-L1 expression were highly controversial [2]. In the Checkmate 214 trial [3], patients with PD-L1 positivity were found to benefit most from ICI combination. On the contrary, PD-L1 expression was not found to be predictive for nivolumab in the 2nd line setting [4]. Thus, all ICIs (combination and monotherapy) were approved in mRCC, irrespective of PD-L1 status.