Brigatinib Versus Alectinib in ALK-Positive NSCLC After Disease Progression on Crizotinib: Results of Phase 3 ALTA-3 Trial

INTRODUCTION

This open-label, phase 3 trial (ALTA-3; NCT03596866) compared efficacy and safety of brigatinib versus alectinib for ALK+ NSCLC after disease progression on crizotinib.

METHODS

Patients with advanced ALK+ NSCLC that progressed on crizotinib were randomized 1:1 to brigatinib 180 mg once daily (7-d lead-in, 90 mg) or alectinib 600 mg twice daily, aiming to test superiority. The primary end point was blinded independent review committee-assessed progression-free survival (PFS). Interim analysis for efficacy and futility was planned at approximately 70% of 164 expected PFS events.

RESULTS

The population (N = 248; brigatinib, n = 125; alectinib, n = 123) was notable for long median duration of prior crizotinib (16.0-16.8 mo) and low rate of ALK fusion in baseline circulating tumor DNA (ctDNA; 78 of 232 [34%]). Median blinded independent review committee-assessed PFS was 19.3 months with brigatinib and 19.2 months with alectinib (hazard ratio = 0.97 [95% confidence interval: 0.66-1.42], p = 0.8672]). The study met futility criterion. Overall survival was immature (41 events [17%]). Exploratory analyses pooled across the treatment groups revealed median PFS of 11.1 versus 22.5 months in patients with versus without ctDNA-detectable ALK fusion at baseline (hazard ratio: 0.48 [95% confidence interval: 0.32-0.71]). Treatment-related adverse events in more than 30% of patients (brigatinib, alectinib) were elevated levels of blood creatine phosphokinase (70%, 29%), aspartate aminotransferase (53%, 38%), and alanine aminotransferase (40%, 36%).

CONCLUSIONS

Brigatinib was not superior to alectinib for PFS in crizotinib-pretreated ALK+ NSCLC. Safety was consistent with the well-established and unique profiles of each drug. The low proportion of patients with ctDNA-detectable ALK fusion may account for prolonged PFS with both drugs in ALTA-3.

A randomized phase 2 study of sapanisertib in combination with paclitaxel versus paclitaxel alone in women with advanced, recurrent, or persistent endometrial cancer

OBJECTIVE

This phase 2 study investigated sapanisertib (selective dual inhibitor of mTORC1/2) alone, or in combination with paclitaxel or TAK-117 (a selective small molecule inhibitor of PI3K), versus paclitaxel alone in advanced, recurrent, or persistent endometrial cancer.

METHODS

Patients with histologic diagnosis of endometrial cancer (1-2 prior regimens) were randomized to 28-day cycles on four treatment arms: 1) weekly paclitaxel 80 mg/m2 (days 1, 8, and 15); 2) weekly paclitaxel 80 mg/m2 + oral sapanisertib 4 mg on days 2-4, 9-11, 16-18, and 23-25; 3) weekly sapanisertib 30 mg, or 4) sapanisertib 4 mg + TAK-117 200 mg on days 1-3, 8-10, 15-17, and 22-24.

RESULTS

Of 241 patients randomized, 234 received treatment (paclitaxel, n = 87 [3 ongoing]; paclitaxel+sapanisertib, n = 86 [3 ongoing]; sapanisertib, n = 41; sapanisertib+TAK-117, n = 20). The sapanisertib and sapanisertib+TAK-117 arms were closed to enrollment after futility analyses. After a median follow-up of 14.4 (paclitaxel) versus 17.2 (paclitaxel+sapanisertib) months, median progression-free survival (PFS; primary endpoint) was 3.7 versus 5.6 months (hazard ratio [HR] 0.82; 95% confidence interval [CI] 0.58-1.15; p = 0.139); in patients with endometrioid histology (n = 116), median PFS was 3.3 versus 5.7 months (HR 0.66; 95% CI 0.43-1.03). Grade ≥ 3 treatment-emergent adverse event rates were 54.0% with paclitaxel versus 89.5% paclitaxel+sapanisertib.

CONCLUSIONS

Our findings support inclusion of chemotherapy combinations with investigational agents for advanced or metastatic disease. The primary endpoint was not met and toxicity was manageable.

TRIAL REGISTRATION

ClinicalTrials.gov number, NCT02725268.

Distribution and Detectability of EGFR Exon 20 Insertion Variants in NSCLC

INTRODUCTION

EGFR exon 20 insertion (ex20ins) mutations represent 5% to 10% of EGFR mutations in NSCLC. Identifying patients with EGFR ex20ins is challenging owing to the limited coverage of polymerase chain reaction (PCR) assays and the relatively recent use of next-generation sequencing (NGS). This study analyzes the spectrum of EGFR ex20ins variants in a large patient population from a global clinical trial and several real-world cohorts and the ability of PCR kits to identify these alterations.

METHODS

We conducted this retrospective analysis in patients with NSCLC who underwent NGS or other sequencing testing and had a known EGFR ex20ins mutation. Patients were gathered from a clinical trial (NCT02716116), a chart review study in Germany, and the LC-SCRUM-Japan, GENIE, and U.S. COTA databases. Proportions of patients with ex20ins variants that could have been detected by six commercially available and widely used PCR kits were calculated in each data set.

RESULTS

Overall, 636 patients with NSCLC harboring EGFR ex20ins mutations were included in this analysis and 104 unique EGFR ex20ins variants were identified across the data sources. The proportion of patients whose ex20ins could have been detected by any PCR test alone ranged from 11.8% to 58.9% across the data sources.

CONCLUSIONS

Our findings suggest that the PCR tests evaluated would have missed more than 40% of patients with NSCLC harboring EGFR ex20ins mutations. NGS-based genetic testing is preferable than standard PCR assays and can substantially improve the identification of the diverse profile of EGFR ex20ins variants in NSCLC.

Abstract 2781: De novo molecular mechanisms of resistance to mobocertinib

Mobocertinib is an oral tyrosine kinase inhibitor recently approved by the FDA for the treatment of patients (pts) with locally advanced or metastatic non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) exon 20 insertion mutations who have progressed on or after platinum-based chemotherapy. To understand the impact of co-occurring genetic alterations on the therapeutic response to mobocertinib, tumors from a subset of 72 platinum-pretreated pts with EGFR exon 20 insertions from the phase 1/2 study (NCT02716116) were collected before treatment and analyzed by next-generation sequencing. More than 200 co-occurring hotspot genetic alterations were detected in 43 pts, with some alterations detected with greater than 20% frequency, such as PTCH1 (67%), HNF1A (58%), TP53 (58%), and GNAQ (35%). In addition to EGFR exon 20 insertion mutations, co-occurring EGFR substitutions were also observed in the exon 20 loop following the C-helix (amino acid positions 770, 771, 772) in 4 pts and L858Q in 1 pt. The pt with the L858Q mutation had a confirmed partial response as assessed by an independent review committee, while the 4 pts with exon 20 substitutions were non-responders (2 had stable disease and 2 had progressive disease as best response). An abnormally high level of mutational burden was seen in 4 pts with EGFR exon 20 insertions, along with alterations in the mismatch repair gene MSH6 and/or the elongation factor MLLT3. Association analysis of mutations reported increased odds of association between the presence of PIK3CA, TP53, and EGFR alterations and a lack of mobocertinib response. Gene amplifications were observed in 12 pts (16%) affecting EGFR (6 pts), MYC (4 pts), CDK4 (3 pts), and CCND1 (2 pts). When assessed for association with lack of response (P values from the Fisher exact test), odds ratios were 2.47 (P=0.66) and 6.34 (P=0.085) for EGFR amplification and any-gene amplification, respectively. When combined, the presence of either PIK3CA mutations or any-gene amplification was associated with a lack of response to mobocertinib treatment with an odds ratio of 12.93. Following adjustment for selected clinical covariates in a multivariate model, the presence of either PIK3CA mutation or gene amplification was an independent predictor of lack of response to mobocertinib (P value of 0.047). Given the retrospective nature of these analyses and the insufficient control of statistical multiplicity, this finding should be considered exploratory. These data suggest that intrinsic genetic alterations, present at baseline in patients with NSCLC harboring an EGFR exon 20 insertion mutation, might impact the response to mobocertinib treatment. The presence of PIK3CA mutations, EGFR gene amplification, or cell cycle regulator MYC-CDK4-CCND1 amplification is associated with lack of response to mobocertinib, which might guide rational combinations for future clinical investigation.

Citation Format: Sylvie Vincent, Zhenqiang Su, Adarsh Joshi, Kalyani Penta, Pingkuan Zhang. De novo molecular mechanisms of resistance to mobocertinib [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 2781.

Molecular analysis of circulating tumor DNA (ctDNA) in patients (pts) with EGFR exon 20 insertion-positive (ex20ins+) advanced NSCLC treated with mobocertinib

9108

Background: ctDNA is an important tool to diagnose and monitor mutations in pts with non–small cell lung cancer (NSCLC). We evaluated epidermal growth factor receptor gene ( EGFR) ex20ins mutations in tumor vs plasma samples, assessed changes in EGFR ex20ins variant allele frequency (VAF) with mobocertinib treatment and correlation with response, and identified potential emerging variants of acquired resistance. Methods: Tumor tissue samples were collected at baseline (BL) from pts with EGFR ex20ins+ advanced NSCLC receiving mobocertinib 160 mg QD in a phase 1/2 study (NCT02716116); plasma samples were collected at BL, after 2 treatment cycles (Cycle 3, Day 1 [C3D1]) and at disease progression/end of treatment (DP/EOT). ctDNA samples were analyzed by next-generation sequencing for EGFR ex20ins to determine concordance rate detection between tissue and plasma ctDNA at BL. Changes in VAF for EGFR ex20ins from BL were analyzed at C3D1 and DP/EOT by confirmed response (RECIST v1.1) to mobocertinib per independent review committee. Emerging variants at DP/EOT were evaluated by elimination of germline variants seen in healthy populations (gnomAD databases and 1000 Genomes) and nonharmful variants predicted by PolyPhen and SIFT tools or annotated as benign in ClinVar database. Results: BL EGFR ex20ins mutations were detected by ctDNA sequencing in 29 of 38 pts (76%) with tissue-confirmed EGFR ex20ins+ NSCLC. VAFs for EGFR ex20ins significantly decreased at C3D1 in mobocertinib-treated pts with confirmed partial response (PR; P=0.0057) or stable disease (SD; P=0.0016), but not in pts with progressive disease (PD; P=0.14) (Table). ctDNA at EOT/DP analysis identified numerous genetic variants; EGFR, TP53, and DNMT3A were the most common genes with emerging variants. Twelve emerging missense mutations were identified in EGFR in 9 pts, including mutations located in the exon 20 loop following the C-helix (6), T790M (5), and D379E (1). Conclusions: Concordance between tissue and plasma ctDNA for EGFR ex20ins mutations at BL was 76%. EGFR ex20ins VAF decreased significantly after 2 treatment cycles in mobocertinib-treated patients with PR and SD. Plasma ctDNA longitudinal monitoring may be useful to assess mutation status and disease progression in pts with NSCLC treated with mobocertinib. Clinical trial information: NCT02716116. [Table: see text]

Sapanisertib plus Fulvestrant in Postmenopausal Women with Estrogen Receptor-Positive/HER2-Negative Advanced Breast Cancer after Progression on Aromatase Inhibitor

PURPOSE

This phase II study investigated daily or weekly sapanisertib (a selective dual inhibitor of mTOR complexes 1 and 2) in combination with fulvestrant.

PATIENTS AND METHODS

Postmenopausal women with estrogen receptor-positive (ER+)/HER2-negative (HER2-) advanced or metastatic breast cancer following progression during/after aromatase inhibitor treatment were randomized to receive fulvestrant 500 mg (28-day treatment cycles), fulvestrant plus sapanisertib 4 mg daily, or fulvestrant plus sapanisertib 30 mg weekly, until progressive disease, unacceptable toxicity, consent withdrawal, or study completion.

RESULTS

Among 141 enrolled patients, baseline characteristics were balanced among treatment arms, including prior cyclin-dependent kinase-4/6 (CDK4/6) inhibitor treatment in 33% to 35% of patients. Median progression-free survival (PFS; primary endpoint) was 3.5 months in the single-agent fulvestrant arm, compared with 7.2 months for fulvestrant plus sapanisertib daily [HR, 0.77; 95% confidence interval (CI), 0.47-1.26] and 5.6 months for fulvestrant plus sapanisertib weekly (HR, 0.88; 95% CI, 0.53-1.45). The greatest PFS benefits were seen in patients who had previously received CDK4/6 inhibitors. The most common adverse events were nausea, vomiting, and hyperglycemia, all occurring more frequently in the combination therapy arms. Treatment discontinuation due to adverse events occurred more frequently in the two combination therapy arms than with single-agent fulvestrant (32% and 36% vs. 4%, respectively).

CONCLUSIONS

Fulvestrant plus sapanisertib daily/weekly resulted in numerically longer PFS in patients with ER+/HER2- advanced or metastatic breast cancer, compared with single-agent fulvestrant. The combination was associated with increased toxicity. Further development of sapanisertib using these dosing schedules in this setting is not supported by these data.

Transverse Vaginal Septum Resection: Technique, Timing, and the Utility of Dilation. A Scoping Review of the Literature

STUDY OBJECTIVE

Transverse vaginal septae (TVS) are congenital, obstructive anomalies of the vagina typically presenting with abdominal pain and amenorrhea. Currently, the literature about surgical management is sparse. Postoperative complications are common. Vaginal dilation either pre- or postoperatively is sometimes recommended, the outcomes of which are poorly described. The aim of this scoping review was to guide surgical planning, namely, timing and postoperative care, to improve surgical outcomes.

DESIGN, SETTING, PARTICIPANTS, AND MAIN OUTCOME MEASURES

This scoping review followed the Joanna Briggs Institute framework. The population of interest was patients 21 years of age or younger with a TVS. MEDLINE, OVID and CINAHL databases were searched using the subject headings listed herein. Literature written in English and French were included. Excluded were reports on patients with concurrent urogenital anomalies or severe developmental disabilities. The resultant articles were reviewed by 2 independent researchers. A third researcher was used in cases of disagreement. Using a descriptive analytical method, data were extracted from the included articles.

RESULTS

We screened 1441 articles for eligibility; 41 articles met criteria, which described 152 cases of TVS. The most common management was simple vaginal excision. Five studies included outcomes from preoperative dilation, and 11 from postoperative dilation. There were 21 cases of postoperative vaginal stenosis; half (11/21) occurred without postoperative dilation.

CONCLUSION

The goal of this review was to describe how TVS are managed and provide guidance for management options. Although the literature was sparse, the authors believe that management in a tertiary center, and surgical delay until the patient is ready to participate in vaginal dilation will improve outcomes for patients with TVS. Further prospective studies are needed to guide surgical planning.

Treatment Outcomes and Safety of Mobocertinib in Platinum-Pretreated Patients With EGFR Exon 20 Insertion-Positive Metastatic Non-Small Cell Lung Cancer: A Phase 1/2 Open-label Nonrandomized Clinical Trial

IMPORTANCE

Metastatic non-small cell lung cancer (mNSCLC) with EGFR exon 20 insertion (EGFRex20ins) mutations is associated with a poor prognosis. Mobocertinib is an oral tyrosine kinase inhibitor designed to selectively target EGFRex20ins mutations.

OBJECTIVE

To evaluate treatment outcomes and safety of mobocertinib in patients with previously treated EGFRex20ins-positive mNSCLC.

DESIGN, SETTING, AND PARTICIPANTS

This 3-part, open-label, phase 1/2 nonrandomized clinical trial with dose-escalation/dose-expansion cohorts (28 sites in the US) and a single-arm extension cohort (EXCLAIM; 40 sites in Asia, Europe, and North America) was conducted between June 2016 and November 2020 (data cutoff date). The primary analysis populations were the platinum-pretreated patients (PPP) cohort and the EXCLAIM cohort. The PPP cohort included 114 patients with platinum-pretreated EGFRex20ins-positive mNSCLC who received mobocertinib 160 mg once daily from the dose-escalation (n = 6), dose-expansion (n = 22), and EXCLAIM (n = 86) cohorts. The EXCLAIM cohort included 96 patients with previously treated EGFRex20ins-positive mNSCLC (10 were not platinum pretreated and thus were excluded from the PPP cohort).

INTERVENTIONS

Mobocertinib 160 mg once daily.

MAIN OUTCOMES AND MEASURES

The primary end point of the PPP and EXCLAIM cohorts was confirmed objective response rate (ORR) assessed by independent review committee (IRC). Secondary end points included confirmed ORR by investigator, duration of response, progression-free survival, overall survival, and safety.

RESULTS

Among the PPP (n = 114) and EXCLAIM (n = 96) cohorts, the median (range) age was 60 (27-84) and 59 (27-80) years, respectively; most patients were women (75 [66%] and 62 [65%], respectively) and of Asian race (68 [60%] and 66 [69%], respectively). At data cutoff, median follow-up was 14.2 months in the PPP cohort (median 2 prior anticancer regimens; 40 [35%] had baseline brain metastases), with confirmed ORR of 28% (95% CI, 20%-37%) by IRC assessment and 35% (95% CI, 26%-45%) by investigator assessment; median duration of response by IRC assessment was 17.5 months (95% CI, 7.4-20.3). Median progression-free survival by IRC assessment was 7.3 months (95% CI, 5.5-9.2). Median overall survival was 24.0 months (95% CI, 14.6-28.8). In the EXCLAIM cohort, median follow-up was 13.0 months, with confirmed ORR by IRC assessment of 25% (95% CI, 17%-35%) and by investigator assessment of 32% (95% CI, 23%-43%). The most common treatment-related adverse events were diarrhea and rash.

CONCLUSIONS AND RELEVANCE

In this open-label, phase 1/2 nonrandomized clinical trial, mobocertinib was associated with clinically meaningful benefit in patients with previously treated EGFRex20ins-positive mNSCLC, with a manageable safety profile.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02716116.

Targeting HER2 Exon 20 Insertion-Mutant Lung Adenocarcinoma with a Novel Tyrosine Kinase Inhibitor Mobocertinib

No targeted treatments are currently approved for HER2 exon 20 insertion-mutant lung adenocarcinoma patients. Mobocertinib (TAK-788) is a potent irreversible tyrosine kinase inhibitor (TKI) designed to target human epidermal growth factor receptor 2 (HER2/ERBB2) exon 20 insertion mutations. However, the function of mobocertinib on HER2 exon 20 insertion-mutant lung cancer is still unclear. Here we conducted systematic characterization of preclinical models to understand the activity profile of mobocertinib against HER2 exon 20 insertions. In HER2 exon 20 insertion-mutant cell lines, the IC₅₀ of mobocertinib was higher than poziotinib and comparable with or slightly lower than afatinib, neratinib, and pyrotinib. Mobocertinib had the lowest HER2 exon 20 insertion IC₅₀/wild-type (WT) EGFR IC₅₀ ratio, indicating that mobocertinib displayed the best selectivity profile in these models. Also, mobocertinib showed strong inhibitory activity in HER2 exon 20^YVMA allograft and patient-derived xenograft models. In genetically engineered mouse models, HER2 exon 20^G776>VC lung tumors exhibited a sustained complete response to mobocertinib, whereas HER2 exon 20^YVMA tumors showed only partial and transient response. Combined treatment with a second antibody-drug conjugate (ADC) against HER2, ado-trastuzumab emtansine (T-DM1), synergized with mobocertinib in HER2 exon 20^YVMA tumors. In addition to the tumor cell autonomous effect, sustained tumor growth control derived from M1 macrophage infiltration and CD4⁺ T-cell activation. These findings support the ongoing clinical development of mobocertinib (NCT02716116) and provide a rationale for future clinical evaluation of T-DM1 combinational therapy in HER2 exon 20^YVMA insertion-mutant lung adenocarcinoma patients. SIGNIFICANCE: This study elucidates the potent inhibitory activity of mobocertinib against HER2 exon 20 insertion-mutant lung cancer and the synergic effect of combined mobocertinib and T-DM1, providing a strong rationale for clinical investigation.

Activity and Safety of Mobocertinib (TAK-788) in Previously Treated Non-Small Cell Lung Cancer with EGFR Exon 20 Insertion Mutations from a Phase I/II Trial

Mobocertinib, an oral epidermal growth factor receptor (EGFR) inhibitor targeting EGFR gene mutations, including exon 20 insertions (EGFRex20ins), in non-small cell lung cancer, was evaluated in a phase I/II dose-escalation/expansion trial (ClinicalTrials.gov NCT02716116). Dose escalation identified 160 mg/d as the recommended phase 2 dose and maximum tolerated dose. Among 136 patients treated with 160 mg/d, the most common any-grade treatment-related adverse events (TRAE; >25%) were diarrhea (83%), nausea (43%), rash (33%), and vomiting (26%), with diarrhea (21%) the only grade ≥3 TRAE >5%. Among 28 EGFRex20ins patients treated at 160 mg/d, the investigator-assessed confirmed response rate was 43% (12/28; 95% confidence interval, 24%-63%) with median duration of response of 14 months (5.0-not reached) and median progression-free survival of 7.3 months (4.4-15.6). Mobocertinib demonstrated antitumor activity in patients with diverse EGFRex20ins variants with a safety profile consistent with other EGFR inhibitors. SIGNIFICANCE: No oral EGFR-targeted therapies are currently approved for patients with EGFRex20ins NSCLC. Mobocertinib demonstrated antitumor activity with manageable toxicity in patients with advanced EGFRex20ins NSCLC in this study, supporting additional development of mobocertinib in this patient population.See related commentary by Pacheco, p. 1617.This article is highlighted in the In This Issue feature, p. 1601.

Sapanisertib Plus Exemestane or Fulvestrant in Women with Hormone Receptor-Positive/HER2-Negative Advanced or Metastatic Breast Cancer

PURPOSE

This open-label, multicenter, phase IB/II study evaluated sapanisertib, a dual inhibitor of mTOR kinase complexes 1/2, plus exemestane or fulvestrant in postmenopausal women with hormone receptor-positive (HR⁺)/HER2-negative (HER2^-) advanced/metastatic breast cancer.

PATIENTS AND METHODS

Eligible patients had previously progressed on everolimus with exemestane/fulvestrant and received ≤3 (phase IB) or ≤1 (phase II) prior chemotherapy regimens. Patients received sapanisertib 3 to 5 mg every day (phase IB), or 4 mg every day (phase II) with exemestane 25 mg every day or fulvestrant 500 mg monthly in 28-day cycles. Phase II enrolled parallel cohorts based on prior response to everolimus. The primary objective of phase II was to evaluate antitumor activity by clinical benefit rate at 16 weeks (CBR-16).

RESULTS

Overall, 118 patients enrolled in phase IB (n = 24) and II (n = 94). Five patients in phase IB experienced dose-limiting toxicities, at sapanisertib doses of 5 mg every day (n = 4) and 4 mg every day (n = 1); sapanisertib 4 mg every day was the MTD in combination with exemestane or fulvestrant. In phase II, in everolimus-sensitive versus everolimus-resistant cohorts, CBR-16 was 45% versus 23%, and overall response rate was 8% versus 2%, respectively. The most common adverse events were nausea (52%), fatigue (47%), diarrhea (37%), and hyperglycemia (33%); rash occurred in 17% of patients. Molecular analysis suggested positive association between AKT1 mutation status and best treatment response (complete + partial response; P = 0.0262).

CONCLUSIONS

Sapanisertib plus exemestane or fulvestrant was well tolerated and exhibited clinical benefit in postmenopausal women with pretreated everolimus-sensitive or everolimus-resistant breast cancer.

Mobocertinib (TAK-788) in EGFR exon 20 insertion (ex20ins)+ metastatic NSCLC (mNSCLC): Additional results from platinum-pretreated patients (pts) and EXCLAIM cohort of phase 1/2 study

9014

Background: No approved targeted therapies are available for EGFR ex20ins+ mNSCLC. Mobocertinib, a first-in-class, potent, oral TKI targeting EGFR ex20ins mutations, has Breakthrough Therapy Designation in the US and China for post-platinum-based chemotherapy pts with EGFR ex20ins+ mNSCLC. Methods: This 3-part, open-label, multicenter study (NCT02716116) has dose-escalation/expansion and extension (EXCLAIM) cohorts. Pts with EGFR ex20ins+ mNSCLC, ECOG status 0–1, and ≥1 prior line of therapy for locally advanced/metastatic disease received mobocertinib 160 mg QD. Primary endpoint was confirmed objective response rate (ORR; RECIST v1.1) assessed by independent review committee (IRC). We present additional efficacy and safety data for 114 platinum-pretreated pts (PPP) and 96 pts from EXCLAIM safety cohort. Results: Results are from Nov 1, 2020, data cutoff. Among PPP pts (n=114; median age 60 y [27–84 y]), 66% were female, 60% were Asian, and 59% had ≥2 prior systemic anticancer lines. Confirmed ORR per IRC was 28%, including 1 complete response (CR); disease control rate (DCR) was 78% [95% CI: 69–85]; median duration of response (DOR) was 17.5 mo (Table). In EXCLAIM (n=96; median age 59 y [27–80 y]), 65% were female, 69% were Asian, and 49% had ≥2 prior lines. Confirmed ORR per IRC was 25%, with 1 CR; DCR was 76% [95% CI: 66–84]; median DOR was not reached (Table). In EXCLAIM, baseline brain metastases were present in 33/96 pts (34%); the first site of disease progression by IRC was the brain in 40% of all pts and 73% of pts with baseline brain metastases. Confirmed responses were seen in all prespecified subgroups in PPP and EXCLAIM. Efficacy by EGFR ex20ins mutation variant will be presented. Treatment-related adverse events (TRAEs; >20%) in PPP were diarrhea (91%), rash (45%), paronychia (38%), decreased appetite (35%), nausea (34%), dry skin (31%), vomiting (30%), increased blood creatinine (25%), stomatitis (24%), and pruritus (21%); the only grade ≥3 TRAE in ≥5% was diarrhea (22%). AEs leading to discontinuation in >2% were diarrhea (4%) and nausea (4%). A similar safety profile was observed in EXCLAIM. Conclusions: Mobocertinib demonstrated clinically meaningful benefit for pts with EGFR ex20ins+ mNSCLC in PPP and EXCLAIM cohorts, with a manageable safety profile. Clinical trial information: NCT02716116. [Table: see text]

Mobocertinib (TAK-788): A Targeted Inhibitor of EGFR Exon 20 Insertion Mutants in Non-Small Cell Lung Cancer

Most EGFR exon 20 insertion (EGFRex20ins) driver mutations in non-small cell lung cancer (NSCLC) are insensitive to approved EGFR tyrosine kinase inhibitors (TKI). To address the limitations of existing therapies targeting EGFR-mutated NSCLC, mobocertinib (TAK-788), a novel irreversible EGFR TKI, was specifically designed to potently inhibit oncogenic variants containing activating EGFRex20ins mutations with selectivity over wild-type EGFR. The in vitro and in vivo activity of mobocertinib was evaluated in engineered and patient-derived models harboring diverse EGFRex20ins mutations. Mobocertinib inhibited viability of various EGFRex20ins-driven cell lines more potently than approved EGFR TKIs and demonstrated in vivo antitumor efficacy in patient-derived xenografts and murine orthotopic models. These findings support the ongoing clinical development of mobocertinib for the treatment of EGFRex20ins-mutated NSCLC. SIGNIFICANCE: No oral EGFR-targeted therapies are approved for EGFR exon 20 insertion (EGFRex20ins) mutation-driven NSCLC. Mobocertinib is a novel small-molecule EGFR inhibitor specifically designed to target EGFRex20ins mutants. Preclinical data reported here support the clinical development of mobocertinib in patients with NSCLC with EGFR exon 20 insertion mutations.See related commentary by Pacheco, p. 1617.This article is highlighted in the In This Issue feature, p. 1601.

Translational strategy using multiple nuclear imaging biomarkers to evaluate target engagement and early therapeutic efficacy of SAR439859, a novel selective estrogen receptor degrader

PURPOSE

Preclinical in vivo nuclear imaging of mice offers an enabling perspective to evaluate drug efficacy at optimal dose and schedule. In this study, we interrogated sufficient estrogen receptor occupancy and degradation for the selective estrogen receptor degrader (SERD) compound SAR439859 using molecular imaging and histological techniques.

MATERIAL AND METHODS

[¹⁸F]FluoroEstradiol positron emission tomography (FES-PET), [¹⁸F]FluoroDeoxyGlucose (FDG) PET, and [¹⁸F]FluoroThymidine (FLT) PET were investigated as early pharmacodynamic, tumor metabolism, and tumor proliferation imaging biomarkers, respectively, in mice bearing subcutaneous MCF7-Y537S mutant ERα+ breast cancer model treated with the SERD agent SAR439859. ER expression and proliferation index Ki-67 were assessed by immunohistochemistry (IHC). The combination of palbociclib CDK 4/6 inhibitor with SAR439859 was tested for its potential synergistic effect on anti-tumor activity.

RESULTS

After repeated SAR439859 oral administration over 4 days, FES tumoral uptake (SUVmean) decreases compared to baseline by 35, 57, and 55% for the 25 mg/kg qd, 12.5 mg/kg bid and 5 mg/kg bid treatment groups, respectively. FES tumor uptake following SAR439859 treatment at different doses correlates with immunohistochemical scoring for ERα expression. No significant difference in FDG uptake is observed after SAR439859 treatments over 3 days. FLT accumulation in tumor is significantly decreased when palbociclib is combined to SAR439859 (- 64%) but not different from the group dosed with palbociclib alone (- 46%). The impact on proliferation is corroborated by Ki-67 IHC data for both groups of treatment.

CONCLUSIONS

In our preclinical studies, dose-dependent inhibition of FES tumoral uptake confirmed target engagement of SAR439859 to ERα. FES-PET thus appears as a relevant imaging biomarker for measuring non-invasively the impact of SAR439859 on tumor estrogen receptor occupancy. This study further validates the use of FLT-PET to directly visualize the anti-proliferative tumor effect of the palbociclib CDK 4/6 inhibitor alone and in combination with SAR439859.

Randomized phase II study of sapanisertib (SAP) + paclitaxel (PAC) versus PAC alone in patients (pts) with advanced, recurrent, or persistent endometrial cancer

6087

Background: SAP (TAK-228, MLN0128) is a selective dual inhibitor of mammalian target of rapamycin complexes 1 and 2. In endometrial tumor xenograft models, SAP+PAC exhibited stronger antitumor efficacy than PAC alone. Methods: Female pts with histologic/cytologic diagnosis of endometrial cancer were randomized to receive SAP 4 mg by mouth (days [d] 2–4, 9–11, 16–18, 23–25) plus PAC 80 mg/m2 intravenously (d 1, 8, 15), or PAC alone, in 28-day cycles until unacceptable toxicity or disease progression. Randomization was stratified by histologic subtype, lines of prior chemotherapy (1 vs. 2), and prior taxane therapy. The primary endpoint was progression-free survival (PFS); secondary endpoints included overall survival (OS), overall response rate (ORR), clinical benefit rate (CBR; ORR + stable disease), and safety. Additional treatment arms of SAP alone (weekly dosing) and SAP+TAK-117 were closed after futility analyses. Results: 180 pts were randomized to SAP+PAC (n=90) or PAC (n=90); 86 and 87 pts received SAP+PAC and PAC, respectively; 3 pts from each arm were ongoing on treatment at data cut (30 July 2019). Baseline characteristics were balanced between arms. After a median follow-up of 17.2 vs. 14.4 mos with SAP+PAC vs. PAC, median PFS was 5.6 mos vs. 3.7 mos (hazard ratio [HR] 0.82; 95% CI 0.58–1.15). In pts with endometrioid histology (n=116), median PFS was 5.7 mos with SAP+PAC vs 3.3 mos with PAC (HR 0.66; 95% CI 0.43–1.03). In pts with nonendometrioid histology (n=64), median PFS was 3.6 mos with SAP+PAC vs. 5.4 mos with PAC (HR 1.09; 95% CI 0.62–1.90). Median OS was 13.7 mos with SAP+PAC vs. 14.6 mos with PAC (HR 1.01; 95% CI 0.67–1.53). Confirmed ORR was 24% with SAP+PAC vs. 18% with PAC (endometrioid, 23% vs. 16%; nonendometrioid, 28% vs. 22%); CBR was 80% vs. 58% (endometrioid, 84% vs. 55%; nonendometrioid, 72% vs. 63%). Median number of cycles received was 5 (range 1–23) with SAP+PAC and 4 (range 1–37) with PAC. Rates of grade ≥3 treatment-emergent adverse events (TEAEs) were 90% with SAP+PAC vs. 54% with PAC; the most common included anemia (21% vs.12%), neutropenia (12% vs. 3%), fatigue (12% vs. 5%), hypophosphatemia (12% vs. 1%), and pulmonary embolism (11% vs. 3%). Conclusions: Median PFS was longer with SAP+PAC vs. PAC in pts with endometrial cancer but did not reach statistical significance. PFS was particularly longer in the endometrioid subtype but again was not significant, and further studies are warranted. Incidence of grade ≥3 TEAEs was higher with SAP+PAC vs. PAC, but SAP+PAC toxicity was manageable, with no new safety signals. Clinical trial information: NCT02725268.

Antitumor activity of TAK-788 in NSCLC with EGFR exon 20 insertions

9007

Background: TAK-788 is an oral investigational EGFR/HER2 inhibitor under evaluation in NSCLC patients (pts) with EGFR exon 20 insertions. We report results of a phase 1/2 open-label, multicenter study (NCT02716116). Methods: Pts with advanced, previously treated NSCLC received daily TAK-788 in dose escalation and expansion cohorts based on tumor genotype. Antitumor activity was determined for pts with EGFR exon 20 insertions who received TAK-788 at the RP2D. Safety is reported for all pts across all doses and at 160 mg. Results: As of 14 Sep 2018, 101 pts (median age, 61 y; female, 70%; ≥2 prior anticancer therapies, 76%; brain metastases, 53%) were treated with TAK-788 at 5–180 mg qd. RP2D was determined to be 160 mg. 28 pts with EGFR exon 20 insertions were treated with 160 mg qd during dose escalation or in expansion cohort 1 (median 3.6 mo on treatment; median 3.8 treatment cycles); 24 pts remain on treatment. Antitumor activity in pts with EGFR exon 20 insertions is shown in Table. At data cutoff, 7/14 responses were confirmed with 6 awaiting confirmation and 1 unconfirmed PR at 160 mg qd; median time to response in these 14 pts was 56 days. 23/24 evaluable pts with EGFR exon 20 insertions treated at 160 mg qd had decreased target lesion measurements (median best percent change, -32.6% [-79.1%, 3.8%]). Rate of treatment discontinuation due to AEs was 10.7% in pts treated at 160 mg. Most common TEAEs (≥20%) in pts treated with 160 mg qd: diarrhea (85%), rash (43%), nausea (41%), vomiting (30%), decreased appetite (28%), and stomatitis (22%); gr ≥3 TEAEs (≥5%) were diarrhea (26%) and hypokalemia, nausea, and stomatitis (7% each). Median dose intensity for pts treated with 160 mg qd was 93%. There is no clear trend that response to TAK-788 is enriched in particular EGFR exon 20 insertion variants. Conclusions: In NSCLC pts with EGFR exon 20 insertions, TAK-788 demonstrated antitumor activity and an AE profile consistent with other EGFR TKIs. Clinical trial information: NCT02716116. [Table: see text]

Metallothionein Induced Time Dependent Histomorphometric Analysis of Clarias gariepinus Exposed to Cadmium

Cadmium (Cd), an extremely toxic heavy metal is extensively used in modern era because of its constructive chemical and physical properties. Recently Cd contamination was estimated in India's major cities fresh water ecosystem, which may have firm impact on human health. Hence, this study was aimed to detect the time dependent effect of cadmium in fresh water fish C. gariepinus, a bioindicator species of water pollution. In a controlled environment, fishes were exposed to cadmium for different duration and analyzed for Cd accumulation. Cd induced toxicity was assessed by estimating metallothionein biomarker protein of heavy metal toxicity and histomorphometric changes in liver and kidney. Our results revealed that fish exposed to Cd induced apoptosis in fish tissues via induction of caspases and in contrast the metallothionein was also increased consistently with different doses of Cd exposure. Hence we conclude Cd induced structural damages to fishes are attributed to induction of caspases and estimating MT level in tissues can be effective biomarker to analyze the effect of acute environmental exposure to Cd.

Abstract 943: SAR439859, an orally bioavailable selective estrogen receptor degrader (SERD) that demonstrates robust antitumor efficacy and limited cross-resistance in ER+ breast cancer

Despite resistance to endocrine therapies, estrogen receptor-positive (ER+) breast cancers (BC) still rely on ER. Eliminating ER by inducing its degradation with selective ER downregulators (SERD) should induce complete ablation of ER pathways. The clinical SERD fulvestrant, although it has demonstrated clinical benefits, is hampered by its poor drug properties and undesirable pharmacokinetics, undermining its optimal clinical activity. Therefore there is an unmet need for an improved therapy targeting ER. Here we describe SAR439859, a novel, nonsteroidal, orally bioavailable SERD currently in clinical trials. SAR439859 has a potent ER antagonist and ER degrading activity that translates in a robust inhibition of ER signaling in multiple ER+ breast cancer cell lines, including tamoxifen-resistant lines as well as cell lines harboring ER mutations. SAR439859 displays a broad and superior ER degradation activity across a large panel of ER+ cells. Importantly, based on its mechanism of action SAR439859 shows limited cross-resistance with other clinical SERD molecules. SAR439859 induces strong in vivo antitumor activity against a variety of BC cell lines and patient-derived xenografts, including models that harbor ERα mutations. The transcriptional profile analysis highlighted a crosstalk of ER mutant signaling and other oncogenic pathways. Interestingly, CDK4/6 inhibition by palbociclib induces partial activation of ER pathways as potential mechanism of tumor escape, which is completely abolished by the combination of SAR439859 with palbociclib. Finally, we demonstrate that SAR439859 in combination with palbociclib can lead to higher in vivo efficacy. This study highlights novel mechanism of ER degradation by SAR439859 that leads to profound inhibition of ER signaling as well as modulation of other oncogenic pathways and provides rationale for the ongoing clinical investigation of SAR439859 in ER+ breast cancer patients, both as a single agent and in combination with approved agents, such as CDK4 inhibitor.

Citation Format: Monsif Bouaboula, Maysoun Shomali, Jane Cheng, Natalia Malkova, Fangxian Sun, Malvika Koundinya, Zhuyan Guo, Stephane Poirier, Mikhail Levit, Dietmar Hoffman, Hui Cao, Laurent Bestret, Francisco Adrian, Christoph Winter, Youssef El-Ahmad, Sylvie Vincent, Frank Halley, Gary McCort, Laurent Schio, Vicky Richon, Hong Cheng, Karl Hsu, Chris Soria, Patrick Cohen, Joanne Lager, Carlos Garcia-Echeverria, Laurent Debussche. SAR439859, an orally bioavailable selective estrogen receptor degrader (SERD) that demonstrates robust antitumor efficacy and limited cross-resistance in ER+ breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 943.

Abstract LB-226: Exosomal liquid biopsy reveals mRNA and lincRNA biomarkers in early stage breast cancer patient plasma

Introduction

Breast cancer is the most prevalent cancer in women, with approximately 250,000 diagnoses per year in the US. Non-invasive detection of breast cancer is of critical importance but has proven challenging due to the rate of false-positive diagnoses with current tests. Liquid biopsies including circulating tumor cells (CTCs) or cell-free DNA (cfDNA) have struggled with the detection of early stage disease. For example, a recent multi-analyte (cfDNA+protein) analysis, ‘cancerSEEK', achieved a sensitivity of just 33% in breast cancer, highlighting the challenges facing the development of more sensitive and specific diagnostics for this disease.

Exosome-based liquid biopsy is a promising approach for minimally-invasive and highly sensitive diagnostics and it has been demonstrated that combining exosomal RNA and cfDNA greatly enhances mutation detection compared to profiling cfDNA alone. While most liquid biopsies profile mutations, studying RNA abundance in exosomes adds a new dimension to these non-invasive diagnostics. To date, much of the focus on exosomal RNA expression profiling has been on the small-RNA fraction. Here we demonstrate that whole-transcriptome profiling of mRNAs and lincRNAs greatly expands the landscape of potential biomarkers to clinically actionable genes.

Results

We have developed a novel platform designed to perform long-RNA sequencing on transcripts obtained from exosomes. We used this platform to compare expression profiles of total plasma exosomes versus subpopulations enriched for breast cancer-derived exosomes (CDE) versus depleted of non-cancer exosomes (NCE). The NCE-depleted and CDE-enriched exosomes equally outperformed total plasma exosomes, each detecting significantly more genes exhibiting breast cancer vs. healthy expression differences.

We performed NCE-depletion on 1.5 mL of input plasma from 15 stage I & II ER+/Her2- breast cancer patients and 12 healthy women matched for age & menopausal-status. RNA-seq data from these samples detected over 10,000 mRNAs and over 1,000 lincRNAs. Of these, we observed significantly increased abundance in over 100 mRNAs and lincRNAs in these early stage breast cancer patients. These mRNAs are enriched for gene-sets including those previously implicated in ‘breast cancer', ‘chromatin remodeling', and ‘immune response'.

We also performed RNA-seq on formalin-fixed paraffin-embedded (FFPE) samples from healthy and matched breast cancer tissue. The >100 genes found to be more abundant in breast cancer plasma exosomes significantly (p<0.05) separate the FFPE samples into two clusters corresponding to breast cancer patients and normal individuals, lending confidence to the exosomal signature.

Conclusions

This preliminary analysis highlights the exciting potential of exosomal long RNA based liquid biopsy for non-invasive early-stage detection of breast cancer. The platform is readily applicable to other disease areas and other biofluids such as urine or CSF.

Citation Format: Sudipto K. Chakrabortty, Robert R. Kitchen, Christine M. Coticchia, Vasisht R. Tadigotla, Erez Eitan, Elena Castellanos-Rizaldos, Lisa Bedford, Sunita Badola, Michael D. Valentino, Nicholas Colafemina, Hidefumi Uchiyama, Mario Morken, Miguel Williams, Sylvie Vincent, Hadi Danaee, Seth Yu, Johan Skog. Exosomal liquid biopsy reveals mRNA and lincRNA biomarkers in early stage breast cancer patient plasma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-226.

Abstract 5775: Identification of SAR439859, an orally bioavailable selective estrogen receptor degrader (SERD) that has strong anti-tumor activity in wild-type and mutant ER+ breast cancer models

Nearly 70% or more of newly diagnosed cases of breast cancer (BC) are estrogen receptor positive (ER+) where endocrine therapy is a primary treatment. However, substantial evidence describes a continued role of ER signaling in tumor progression, where approximately 40% of patients on endocrine therapy develop resistance that include mutations in the ER that drive a constitutively active receptor. Fulvestrant, an estrogen receptor degrader, is effective at shutting down ER signaling. However, fulvestrant efficacy studies report insufficient blockade of ER signaling in patients that may be a consequence of poor pharmaceutical properties.

Here we describe the discovery of SAR439859, a novel, orally bioavailable SERD with potent antagonist and degradative properties against ER both in vitro and in vivo. SAR439859 has robust inhibition of ER signaling activity in multiple ER+ breast cancer cell lines including tamoxifen resistant lines harboring ER mutations. Across a large panel of ER+ cells, SAR439859 demonstrated broad and superior ER degradation activity as compared to other SERDs including improved inhibition of ER signaling and inhibition of cell growth. Similarly, in vivo treatment with SAR439859 demonstrated significant tumor regression in ER+ BC models including MCF7-ESR1 mutant-Y537S model and endocrine therapy resistant patient-derived xenograft tumor transplantation.

Collectively, these results showed that SAR439859 is an oral, nonsteroidal, selective estrogen receptor antagonist and degrader that could provide therapeutic benefit to ER+ breast cancer patients. SAR439859 is currently being evaluated in a phase I clinical trial.

Citation Format: Maysoun Shomali, Youssef El-Ahmad, Frank Halley, Jane Cheng, Michael Weinstein, Muchun Wang, Fangxian Sun, Natalia Malkova, Mikhail Levit, Malvika Koundinya, Zhuyan Gou, Andrew Hebert, Jessica McManus, Dietmar Hoffman, Hui Cao, Joonil Jung, Jack Pollard, Sylvie Vincent, Timothy Ackerson, Francisco Adrian, Chris Winter, Victoria Richon, Hong Chen, Karl Hsu, Joanne Lager, Albane Courjaud, Rosalia Arrebola, Laurent Besret, Pierre-Yves Abecassis, Laurent Schio, Gary McCort, Michel Tabart, Victor Certal, Fabienne Thompson, Bruno Filoche-Rommé, Laurent Debussche, Patrick Cohen, Carlos Garcia-Echeverria, Monsif Bouaboula. Identification of SAR439859, an orally bioavailable selective estrogen receptor degrader (SERD) that has strong anti-tumor activity in wild-type and mutant ER+ breast cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5775.

Abstract P3-04-05: Identification of SAR439859, an orally bioavailable selective estrogen receptor degrader (SERD) that has strong antitumor activity in wild-type and mutant ER+ breast cancer models

Estrogen receptor positive (ER+) breast cancer accounts for 70% of all breast cancers and is primarily treated with endocrine therapy. Approximately 40% of patients on endocrine therapy will become resistant via a number of mechanisms. There is evidence that in many cases ER continues to play a central role, including mutations in ER leading to a constitutively active receptor. Estrogen receptor degraders like fulvestrant are effective in shutting down ER signaling; however, poor pharmaceutical properties limit fulvestrant clinical activity and prevent it from achieving maximum receptor blockade.

We describe the discovery of SAR439859, a novel, orally bioavailable SERD that is a potent antagonist and degrader of ER both in vitro and in vivo. SAR439859 has robust activity in multiple ER+ breast cancer cell lines including cells that are resistant to tamoxifen as well as cell lines harboring ER mutants. Across a large panel of ER+ cells, SAR439859 demonstrated broad and superior ER degradation activity than most SERDs undergoing clinical testing. This leads to a profound inhibition of ER signaling, better inhibition of cell growth and results in improved in vivo efficacy. SAR439859 demonstrated tumor regression in all ER+ BC models including MCF7-ESR1 mutant-Y537S model, as well as patient-derived xenograft model that is resistant to endocrine therapies. Furthermore, SAR439859 displays limited cross-resistance with other class of SERDs.

Taken together, these results suggest that SAR439859 would be of therapeutic benefit in metastatic BC setting for patients harboring wild type or mutant ER. SAR439859 is being advanced toward the clinic.

Citation Format: Shomali M, Cheng J, Koundinya M, Weinstein M, Malkova N, Sun F, Hebert A, Cindachao M, Hoffman D, McManus J, Levit M, Pollard J, Vincent S, Besret L, Adrian F, Winter C, El-Ahmad Y, Halley F, Hsu K, Lager J, Garcia-Echeverria C, Bouaboula M. Identification of SAR439859, an orally bioavailable selective estrogen receptor degrader (SERD) that has strong antitumor activity in wild-type and mutant ER+ breast cancer models [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-04-05.

Guidelines for May-Grünwald-Giemsa staining in haematology and non-gynaecological cytopathology: recommendations of the French Society of Clinical Cytology (SFCC) and of the French Association for Quality Assurance in Anatomic and Cytologic Pathology (AFAQAP)

OBJECTIVE

Since the guidelines of the International Committee for Standardisation in Haematology (ICSH) in 1984 and those of the European Committee for External Quality Assessment Programmes in Laboratory Medicine (EQALM) in 2004, no leading organisation has published technical recommendations for the preparation of air-dried cytological specimens using May-Grünwald-Giemsa (MGG) staining.

DATA SOURCES

Literature data were retrieved using reference books, baseline-published studies, articles extracted from PubMed/Medline and Google Scholar, and online-available industry datasheets.

RATIONALE

The present review addresses all pre-analytical issues concerning the use of Romanowsky's stains (including MGG) in haematology and non-gynaecological cytopathology. It aims at serving as actualised, best practice recommendations for the proper handling of air-dried cytological specimens. It, therefore, appears complementary to the staining criteria of the non-gynaecological diagnostic cytology handbook edited by the United Kingdom National External Quality Assessment Service (UK-NEQAS) in February 2015.

Androgen-regulated microRNA-135a decreases prostate cancer cell migration and invasion through downregulating ROCK1 and ROCK2

Androgen signaling, via the androgen receptor (AR), is crucial in mediating prostate cancer (PCa) initiation and progression. Identifying new downstream effectors of the androgens/AR pathway will allow a better understanding of these mechanisms and could reveal novel biomarkers and/or therapeutic agents to improve the rate of patient survival. We compared the microRNA expression profiles in androgen-sensitive LNCaP cells stimulated or not with 1 nM R1881 by performing a high-throughput reverse transcriptase-quantitative PCR and found that miR-135a was upregulated. After androgen stimulation, we showed that AR directly activates the transcription of miR-135a2 gene by binding to an androgen response element in the promoter region. Our findings identify miR-135a as a novel effector in androgens/AR signaling. Using xenograft experiments in chick embryos and adult male mice, we showed that miR-135a overexpression decreases in vivo invasion abilities of prostate PC-3 cells. Through in vitro wound-healing migration and invasion assays, we demonstrated that this effect is mediated through downregulating ROCK1 and ROCK2 expression, two genes that we characterized as miR-135a direct target genes. In human surgical samples from prostatectomy, we observed that miR-135a expression was lower in tumoral compared with paired adjacent normal tissues, mainly in tumors classified with a high Gleason score (⩾8). Moreover, miR-135a expression is lower in invasive tumors, showing extraprostatic extension, as compared with intraprostatic localized tumors. In tumor relative to normal glands, we also showed a more frequently higher ROCK1 protein expression determined using a semi-quantitative immunohistochemistry analysis. Therefore, in tumor cells, the lower miR-135a expression could lead to a higher ROCK1 protein expression, which could explain their invasion abilities. The highlighted relationship between miR-135a expression level and the degree of disease aggressiveness suggests that miR-135a may be considered as a prognostic marker in human PCa.

Superoxide production pathways in aortas of diabetic rats: beneficial effects of insulin therapy and endurance training

Superoxide (O 2 (·-) ) overproduction, by decreasing the nitric oxide ((·)NO) bioavailability, contributes to vascular complications in type 1 diabetes. In this disease, the vascular O 2 (·-) can be produced by the NADPH oxidase (NOX), nitric oxide synthase (NOS), and xanthine oxidase (XO). This study aimed to determine the contribution of each enzymatic pathway in hyperglycemia-induced O 2 (·-) overproduction, and the effects of an endurance training program and insulin therapy, associated or not, on the O 2 (·-) production (amount and related enzymes) in diabetic rats. Forty male Wistar rats were divided into diabetic (D), diabetic treated with insulin (D-Ins), diabetic trained (D-Tr), or diabetic insulin-treated and trained (D-Ins + Tr) groups. An additional healthy group was used as control. Insulin therapy (Glargine Lantus, Sanofi) and endurance training (treadmill run: 60 min/day, 25 m/min, 5 days/week) started 1 week after diabetes induction by streptozotocin (45 mg/kg), and lasted for 8 weeks. At the end of the protocol, the O 2 (·-) production in aorta rings was evaluated by histochemical analyses (DHE staining). Each production pathway was studied by inhibiting NOX (apocynin), NOS (L-Name), or XO (allopurinol) before DHE staining. Diabetic rats exhibited hyperglycemia-induced O 2 (·-) overproduction, resulting from NOX, NOS, and XO activation. Insulin therapy and endurance training, associated or not, decreased efficiently and similarly the O 2 (·-) overproduction. Insulin therapy reduced the hyperglycemia and decreased the three enzymatic pathways implicated in the O 2 (·-) production. Endurance training decreased directly the NOS and XO activity. While both therapeutic strategies activated different pathways, their association did not reduce the O 2 (·-) overproduction more significantly.

Physical inactivity, insulin resistance, and the oxidative-inflammatory loop

Epidemiological data indicate that physical inactivity, a main factor of global energetic imbalance, is involved in the worldwide epidemic of obesity and metabolic disorders such as insulin resistance. Although the complex pathogenesis of insulin resistance is not fully understood, literature data accumulated during the past decades clearly indicate that the activation of the oxidative-inflammatory loop plays a major role. By activating the oxidative-inflammatory loop in insulin-sensitive tissues, fat gain and adipose tissue dysfunction likely contribute to induce insulin resistance during chronic and prolonged physical inactivity. However, in the past years, evidence has emerged showing that early insulin resistance also occurs after very short-term exposure to physical inactivity (1-7 days) without any fat gain or energetic imbalance. The possible role of liver disturbances or endothelial dysfunction is suggested, but further studies are necessary to really conclude. Inactive skeletal muscle probably constitutes the primary triggering tissue for the development of early insulin resistance. In the present review, we discuss on the current knowledge about the effect of physical inactivity on whole-body and peripheral insulin sensitivity, and how local inflammation and oxidative stress arising with physical inactivity could potentially induce insulin resistance. We assume that early muscle insulin resistance allows the excess nutrients to shift in the storage tissues to withstand starvation through energy storage. We also consider when chronic and prolonged, physical inactivity over an extended period of time is an underestimated contributor to pathological insulin resistance and hence indirectly to numerous chronic diseases.

Abstract 1228: AV-203, a fully humanized ERBB3 inhibitory antibody, reverses ERBB3-induced resistance to targeted therapies

Targeted therapies have changed the treatment paradigm of cancer. Specifically, the use of tyrosine kinase inhibitors (TKIs) has improved therapeutic responses in a number of tumor types. However, initial response to TKIs is often followed by rapid relapse due to the acquisition of molecular features that lead to resistance. ERBB3, a receptor of the epidermal growth factor receptor (EGFR/ERBB1) family, has been linked to the development of resistance to multiple ERBB targeting TKIs. A proposed potential mechanism is the recruitment and activation of ERBB3 as a bypass mechanism to activate PI3K dependent pro-survival pathways. We investigated whether the inhibition of ERBB3 could reverse TKI resistance linked to ERBB3 activation. AV-203 is a humanized IgG1 antibody directed against ERBB3. AV-203 potently inhibits both ligand dependent and ligand independent activation of ERBB3. AV-203 was shown to inhibit the binding of NRG1 to ERBB3 and promote ERBB3 degradation. The tumor growth inhibitory activity of AV-203 was demonstrated in numerous xenograft models representing major human carcinomas (breast, lung, ovarian, kidney and pancreas). Here, we investigated the ability of AV-203 to restore TKI sensitivity in models with activated ERBB3. First, we demonstrated that ligand mediated (NRG1) activation of ERBB3 leads to acquired resistance to the EGFR TKI erlotinib in a lung cancer model bearing EGFR TKI sensitizing mutation, to the ERBB2/HER2 inhibitor lapatinib in a HER2 amplified breast cancer model, and to the EGFR inhibitory antibody cetuximab in head and neck cancer models. AV-203 was able to restore sensitivity to these RTK inhibitors. This data suggest that the combination of AV-203, with EGFR/HER2 targeted therapies could potentially extend the efficacy of these agents by preventing the emergence of ERBB3 mediated resistance. This hypothesis will be tested in future clinical trials. AV-203 is currently in Phase I development for the treatment of solid tumors.

Citation Format: Steven M. Tyler, Sylvie Vincent, Christina Fleet, Steve Bottega, Donna McIntosh, Kristan Meetze, Jeno Gyuris. AV-203, a fully humanized ERBB3 inhibitory antibody, reverses ERBB3-induced resistance to targeted therapies. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1228. doi:10.1158/1538-7445.AM2013-1228

Differential expression between PAX-6 and EN proteins in medulloblastoma

A collection of 28 medulloblastomas was analyzed for expression of the developmental control genes PAX-6 and EN by immunohistochemical staining. Sixteen medulloblastomas expressed both EN and PAX-6 but, when differentiation could be assessed in the positive areas, PAX-6 is expressed in the less differentiated cells. Since Drosophila en encodes a negative regulator, we overexpressed the chicken en-1 in retinal pigmented epithelium cells. This resulted in Pax-6 down regulation. These results suggest a regulatory loop between PAX-6 and EN, two molecular markers of medulloblastoma.