Anti-TIGIT antibody improves PD-L1 blockade through myeloid and Treg cells

Tiragolumab, an anti-TIGIT antibody with an active IgG1κ Fc, demonstrated improved outcomes in the phase 2 CITYSCAPE trial (ClinicalTrials.gov: NCT03563716 ) when combined with atezolizumab (anti-PD-L1) versus atezolizumab alone1. However, there remains little consensus on the mechanism(s) of response with this combination2. Here we find that a high baseline of intratumoural macrophages and regulatory T cells is associated with better outcomes in patients treated with atezolizumab plus tiragolumab but not with atezolizumab alone. Serum sample analysis revealed that macrophage activation is associated with a clinical benefit in patients who received the combination treatment. In mouse tumour models, tiragolumab surrogate antibodies inflamed tumour-associated macrophages, monocytes and dendritic cells through Fcγ receptors (FcγR), in turn driving anti-tumour CD8+ T cells from an exhausted effector-like state to a more memory-like state. These results reveal a mechanism of action through which TIGIT checkpoint inhibitors can remodel immunosuppressive tumour microenvironments, and suggest that FcγR engagement is an important consideration in anti-TIGIT antibody development.

Analysis of risk factors for complications following transurethral resection of the prostate

OBJECTIVE

This study investigates the risk factors for complications following transurethral resection of the prostate and provides a reference for reducing postoperative complications.

PATIENTS AND METHODS

A retrospective analysis was conducted on 322 patients with benign prostatic hyperplasia who underwent transurethral resection of the prostate from April 2015 to January 2022. Among them, 214 patients had complete clinical and follow-up data. Clinical and follow-up data were collected, and both univariate and multivariate logistic regression analyses were performed to identify factors influencing the occurrence of postoperation transurethral resection of the prostate complications.

RESULTS

The incidence of complications after transurethral resection of the prostate was 19.16% (41/214). Among them, the incidence of Grade I-II complications was 14.96% (32/214), and Grade III-IV complications were 4.2% (9/214). The preoperative Quality of Life score (p<0.001) was identified as an independent risk factor for the occurrence of Grade I-II complications after transurethral resection of the prostate. The International Prostate Symptom Score (p=0.006) was identified as an independent risk factor for the occurrence of Grade III-IV complications after transurethral resection of the prostate.

CONCLUSIONS

The preoperative Quality of Life score is an independent risk factor for the occurrence of Grade I-II complications after transurethral resection of the prostate. The International Prostate Symptom Score is an independent risk factor for the occurrence of Grade III-IV complications after transurethral resection of the prostate.

SKYSCRAPER-02: Tiragolumab in Combination With Atezolizumab Plus Chemotherapy in Untreated Extensive-Stage Small-Cell Lung Cancer

PURPOSE

The phase III SKYSCRAPER-02 study determined whether the benefits of atezolizumab plus carboplatin and etoposide (CE) could be enhanced by the addition of tiragolumab in untreated extensive-stage small-cell lung cancer (ES-SCLC). We report final progression-free survival (PFS) and overall survival (OS) analyses.

METHODS

Patients received tiragolumab 600 mg/placebo, plus atezolizumab 1,200 mg and CE (four cycles), then maintenance tiragolumab/placebo plus atezolizumab. Primary end points were investigator-assessed PFS and OS in patients without history/presence of brain metastases (primary analysis set [PAS]). Additional end points included PFS and OS in all patients regardless of brain metastases status (full analysis set [FAS]), response, and safety.

RESULTS

Four hundred ninety patients were randomly assigned (FAS): 243 to tiragolumab arm and 247 to control arm. At the cutoff date (February 6, 2022; median duration of follow-up, 14.3 months [PAS] and 13.9 months [FAS]), final analysis of PFS in the PAS (n = 397) did not reach statistical significance (stratified hazard ratio [HR], 1.11; P = .3504; median, 5.4 months tiragolumab v 5.6 months control). At the cutoff date (September 6, 2022; median duration of follow-up, 21.2 months [FAS]), median OS in the PAS at final OS analysis was 13.1 months in both arms (stratified HR, 1.14; P = .2859). Median PFS and OS in the FAS were consistent with the PAS. The proportion of patients with immune-mediated adverse events (AEs) in the tiragolumab and control arms was 54.4% and 49.2%, respectively (grade 3/4: 7.9% and 7.7%). AEs leading to treatment withdrawal occurred in 8.4% and 9.3% of tiragolumab- and control-treated patients, respectively.

CONCLUSION

Tiragolumab did not provide additional benefit over atezolizumab and CE in untreated ES-SCLC. The combination was well tolerated with no new safety signals.

Comparison of anal function and quality of life after conformal sphincter preservation operation and intersphincteric resection of very low rectal cancer: a multicenter, retrospective, case-control analysis

PURPOSE

Conformal sphincter preservation operation (CSPO) is a sphincter preservation operation for very low rectal cancers. Compared to intersphincteric resection (ISR), CSPO retains more dentate line and distal rectal wall, and also avoids damaging the nerves in the intersphincteric space. This study aimed to compare the postoperative anal function and quality of life between the CSPO and ISR.

METHOD

Patients with low rectal cancer undergoing CSPO (n = 117) and ISR (n = 66) were included from Changhai and Huashan Hospital, respectively, between 2011 and 2020. A visual analog scale (range 0-10) was utilized to evaluate satisfaction with anal function and quality of life. The anal function was evaluated with Wexner scores and low anterior resection syndrome (LARS) score. Quality of life was evaluated with the EORTC QLQ-C30 and QLQ-CR38.

RESULTS

The CSPO group had more male patients (65.8% vs. 50%, p = 0.042), more preoperative chemoradiotherapy (33.3% vs. 10.6%, p < 0.001), lower tumor position (3.45 ± 1.13 vs. 4.24 ± 0.86 cm, p < 0.001), and more postoperative chemotherapy (65% vs. 13.6%, p < 0.001) compared to the ISR group. In addition, CSPO patients had shorter postoperative stay (6.63 ± 2.53 vs. 7.85 ± 4.73 days, p = 0.003) and comparable stoma reversal rates within 1 year after surgery (92.16% vs. 96.97%, p = 0.318). Multivariable analysis showed that CSPO significantly contributed to higher satisfaction with anal function (beta = 1.752, 95% CI 0.776-2.728) and with quality of life (beta = 1.219, 95% CI 0.374-2.064), but not to Wexner, LARS score, or EORTC QLQ-C30 and QLQ-CR38.

CONCLUSION

CSPO improved the satisfaction with anal function and quality of life but utilized more preoperative chemoradiotherapy. CSPO may be an alternative choice for patients with very low rectal cancers in better physical health and with higher requirements for anal function and quality of life.

Anti-TIGIT Antibody Tiragolumab Alone or With Atezolizumab in Patients With Advanced Solid Tumors: A Phase 1a/1b Nonrandomized Controlled Trial

Importance

Inhibition of the T-cell immunoreceptor with Ig and ITIM domains (TIGIT)/poliovirus receptor pathway may amplify the antitumor immune response of atezolizumab in programmed death ligand 1-selected tumors.

Objective

To evaluate the safety and antitumor activity of the anti-TIGIT antibody tiragolumab and its combination with atezolizumab in patients with advanced solid tumors.

Design, Setting, and Participants

The GO30103 open-label, first-in-human phase 1a/1b dose-escalation and dose-expansion nonrandomized controlled trial was conducted at 13 sites in 6 countries (Australia, Canada, France, Korea, Spain, and the US). The start dates were May 23, 2016, for phase 1a and October 11, 2016, for phase 1b. Patients were aged 18 years or older with measurable disease at baseline. The clinical cutoff date was October 1, 2021. Data analysis was performed on January 24, 2022.

Interventions

Patients received fixed-dose intravenous tiragolumab on day 1 of each 21-day cycle (2 mg escalating to 1200 mg) in phase 1a, plus fixed-dose intravenous atezolizumab (1200 mg every 3 weeks) in phase 1b. Patients were treated until disease progression, loss of clinical benefit, or development of unacceptable toxicity.

Main Outcomes and Measures

The primary end points included the safety, tolerability, and recommended phase 2 dose (RP2D) of tiragolumab or combination tiragolumab plus atezolizumab. The secondary end point included the investigator-assessed objective response rate (ORR). Counts and percentages are used for categorical variables, and medians and ranges are used for continuous variables.

Results

Among the phase 1a (n = 24) and 1b (n = 49) dose-escalation cohorts, the median age was 60 (range, 40-77) and 54 (range, 25-81) years, respectively. More than half of patients were women (14 of 24 [58%] and 25 of 49 [51%]), and more than a third (10 [42%] and 18 [37%]) had received 4 or more prior cancer therapies. No dose-limiting toxicities occurred, and the maximum tolerated dose of tiragolumab was not reached (NR). The most frequent treatment-related adverse events (AEs) were fatigue (5 of 24 [21%]) in phase 1a and pruritus (5 of 49 [10%]) in phase 1b; the majority of AEs were grade 1 or 2. Immune-mediated AEs occurred in 4 of 24 (17%) and 29 of 49 (59%) patients during phases 1a and 1b, respectively (primarily grade 1 or 2). The RP2D of tiragolumab was 600 mg intravenously every 3 weeks, which was tested in phase 1b dose expansion. The confirmed ORR was 0% during phase 1a, with evidence of antitumor activity in 6% of patients (n = 3) during phase 1b. The safety profile of combination tiragolumab plus atezolizumab in phase 1b was similar in the dose-escalation and dose-expansion cohorts. The confirmed ORR was 46% (6 of 13) in the non-small cell lung cancer (NSCLC) cohort (median duration of response [DOR], NR) and 28% (5 of 18) in the esophageal cancer (EC) cohort (median DOR, 15.2 [95% CI, 7.0 to NR] months).

Conclusions and Relevance

In this nonrandomized controlled trial, tiragolumab was well tolerated with or without atezolizumab; no new safety signals were observed. Preliminary antitumor activity was demonstrated for the combination regimen in patients with cancer immunotherapy-naive metastatic NSCLC or EC.

Trial Registration

ClinicalTrials.gov Identifier: NCT02794571.

PD-L1 Inhibitors Combined with Thoracic Radiotherapy in First-Line Treatment of Extensive Stage Small Cell Lung Cancer: A Propensity Score-Matched, Real-World Study

PURPOSE/OBJECTIVE(S)

The CREST study showed that the addition of thoracic radiotherapy (TRT) could improve the survival of extensive stage small cell lung cancer (ES-SCLC), but whether TRT can bring survival benefit in the era of immunotherapy is controversial. This study aims to explore the efficacy and safety of adding TRT to the combination of PD-L1 inhibitors and chemotherapy.

MATERIALS/METHODS

Thepatients who received PD-L1 inhibitors combined with platinum-based chemotherapy as the first-line treatment of ES-SCLC from January 2019 to December 2021 were retrospectively collected. According to whether they received TRT, they were divided into two groups, and the follow-up analysis was performed. Propensity score matching (PSM) in with a 1:1 ratio was performed to balance the baseline characteristics of the two cohorts. The endpoints were progression-free survival (PFS) and OS.

RESULTS

A total of 211 patients with ES-SCLC were enrolled, of whom 70 (33.2%) patients received standard therapy plus TRT as first-line treatment, and 141 (66.8%) patients in the control group received PD-L1 inhibitors plus chemotherapy. After PSM, a total of 65 pairs of patients were enrolled in the analysis. There were no significant differences in baseline characteristics between the two groups of patients who received TRT and those who did not. In all patients, the median PFS (mPFS) in the TRT group and the non-TRT groupwere 9.5 months and 7.2 months, respectively, with HR = 0.60 (95% CI 0.41-0.87, p = 0.007). The median OS (mOS) in the TRT group was also significantly longer than that in the non-TRT group (24.1 months vs. 18.5 months, HR = 0.53, 95% CI 0.32-0.85, p = 0.009). Multivariable analysis showed that baseline liver metastasis and bone metastasis were independent prognostic factors for OS. In terms of safety, immunotherapy combined with thoracic radiotherapy increased the incidence of treatment-related pneumonia (p<0.001), most of which were grade 1-2.

CONCLUSION

This real-world study shows that adding TRT to durvalumab or atezolizumab plus chemotherapy significantly improves survival in ES-SCLC. It leads to more treatment-related pneumonia, but most of them can be relieved after symptomatic treatment. This treatment model deserves to be explored in prospective clinical trials.

Abstract 5712: Anti-TIGIT antibody tiragolumab leverages myeloid cells and regulatory T cells to improve PD-L1 checkpoint blockade

Background: TIGIT is a co-inhibitory receptor and immune checkpoint associated with T cell and natural killer (NK) cell dysfunction in cancer. Tiragolumab is an anti-TIGIT antibody with an active IgG1/kappa Fc. In a randomized double-blind phase 2 clinical trial in non-small cell lung cancer (NSCLC), tiragolumab + atezolizumab (anti-PD-L1) combination treatment demonstrated significant improvement relative to atezolizumab alone. However, the mechanisms underlying the efficacy of this combination are not well understood.

Methods: In CITYSCAPE (phase 2, NCT03563716), chemotherapy-naïve patients with locally advanced/metastatic NSCLC received either placebo + 1200 mg atezolizumab or 600 mg tiragolumab + 1200 mg atezolizumab q3w IV. We collected tumor pretreatment samples and serum samples (baseline and on-treatment) from patients enrolled in the trial, which were subject to bulk RNA-seq and proteomics, respectively. In the mouse tumor model, BALB/c mice were implanted with syngeneic CT26 tumors. After tumor establishment, mice were randomized by tumor volume and then treated with control IgG2a, anti-PD-L1, anti-TIGIT IgG2a-LALAPG (Fc-inactive) ± anti-PD-L1, anti-TIGIT IgG2b ± anti-PD-L1, or anti-TIGIT IgG2a ± anti-PD-L1. Three days after treatment, CD45+ immune cells were collected from the peripheral blood and tumor from selected treatment groups and underwent single cell RNA sequencing or flow cytometry profiling. Tumor growth was also monitored to determine efficacy.

Results: Here, we show that tiragolumab functions as both a conventional checkpoint inhibitor and, via Fc gamma receptor engagement, as a modulator of immunosuppressive myeloid cells and T regulatory (Treg) cells. Gene expression analysis of patient tumor samples revealed high levels of these cell subsets, were instead associated with treatment benefit in the tiragolumab + atezolizumab arm but not atezolizumab arm. Analysis of patient serum proteins suggested an association of myeloid cell activation with clinical benefit mediated by the combination therapy. In mouse tumor models, treatment with anti-PD-L1 + anti-TIGIT IgG2a (but not anti-TIGIT IgG2b or Fc-silent anti-TIGIT) led to effective tumor control in mice, suggesting a pivotal role for activating Fc receptors. Phenotypic profiling by single cell RNAseq and flow cytometry revealed that Fc-active anti-TIGIT remodels the tumor microenvironment, most prominently by inducing antigen presentation machinery in myeloid cells, counteracting of anti-PDL1-enforced CD8+ T cell exhaustion, and reducing Treg suppressive capacity.

Conclusions: These findings reveal that FcR engagement is one of several distinct mechanisms by which tiragolumab unleashes antitumor immune responses, and inform further clinical development of anti-TIGIT therapies.

Citation Format: Namrata S. Patil, Shyam Srivats, Yoonha Choi, Xiangnan Guan, Barzin Nabet, Lisa McGinnis, Eugene Chiang, Alexis Dunkle, Bill O’Gorman, Patrick S. Chang, Ruozhen Hu, John Silva, Joy Han, Amelia Au-Yeung, Chikara Takahashi, Nandini Molden, Pallavi Daggumati, Wendy Connolly, Melissa Johnson, Delvys Rodriguez Abreu, Byoung Chul Cho, Antoine Italiano, Ignacio Gil-Bazo, Enriqueta Felip, Ira Mellman, Raymond Meng, Sanjeev Mariathasan, Robert Johnston, David S. Shames. Anti-TIGIT antibody tiragolumab leverages myeloid cells and regulatory T cells to improve PD-L1 checkpoint blockade. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5712.

Isatuximab plus atezolizumab in patients with advanced solid tumors: results from a phase I/II, open-label, multicenter study

BACKGROUND

The anti-CD38 antibody isatuximab is approved for the treatment of relapsed/refractory multiple myeloma, but there are no data on its efficacy in solid tumors. This phase I/II study (NCT03637764) assessed the safety and activity of isatuximab plus atezolizumab (Isa + Atezo), an anti-programmed death-ligand 1 (PD-L1) antibody, in patients with immunotherapy-naive solid tumors: epithelial ovarian cancer (EOC), glioblastoma (GBM), hepatocellular carcinoma (HCC), and squamous cell carcinoma of the head and neck (SCCHN).

PATIENTS AND METHODS

Phase I assessed safety, tolerability, pharmacokinetics, pharmacodynamics, and the recommended phase II dose (RP2D) of isatuximab 10 mg/kg intravenously (i.v.) every week for 3 weeks followed by once every 3 weeks + atezolizumab 1200 mg i.v. every 3 weeks. Phase II used a Simon's two-stage design to assess the overall response rate or progression-free survival rate at 6 months (GBM cohort). Interim analysis was carried out at 6 months following first dose of the last enrolled patient in each cohort. Pharmacodynamic biomarkers were tested for CD38, PD-L1, tumor-infiltrating immune cells, and FOXP3+ regulatory T cells (Tregs) in the tumor microenvironment (TME).

RESULTS

Overall, 107 patients were treated (EOC, n = 18; GBM, n = 33; HCC, n = 27; SCCHN, n = 29). In phase I, Isa + Atezo showed an acceptable safety profile, no dose-limiting toxicities were observed, and RP2D was confirmed. Most patients experienced ≥1 treatment-emergent adverse event (TEAE), with ≤48.5% being grade ≥3. The most frequent TEAE was infusion reactions. The study did not continue to stage 2 based on prespecified targets. Tumor-infiltrating CD38+ immune cells were reduced and almost cleared after treatment. Isa + Atezo did not significantly modulate Tregs or PD-L1 expression in the TME.

CONCLUSIONS

Isa + Atezo had acceptable safety and tolerability. Clinical pharmacodynamic evaluation revealed efficient target engagement of isatuximab via treatment-mediated reduction of CD38+ immune cells in the TME. Based on clinical data, CD38 inhibition does not improve responsiveness to PD-L1 blockade in these patients.

SKYSCRAPER-02: Primary results of a phase III, randomized, double-blind, placebo-controlled study of atezolizumab (atezo) + carboplatin + etoposide (CE) with or without tiragolumab (tira) in patients (pts) with untreated extensive-stage small cell lung cancer (ES-SCLC)

LBA8507

Background: Atezo, in combination with CE, was the first cancer immunotherapy approved for 1L treatment of ES-SCLC. However, most pts eventually experience disease progression. TIGIT is a novel inhibitory immune checkpoint present on activated T cells and NK cells. Tira (anti-TIGIT) may synergise with other immunotherapies, such as PD-L1/PD-1 inhibitors, and further amplify the immune response to improve clinical outcomes. SKYSCRAPER-02 (NCT04256421) evaluates whether the antitumor effect and survival benefits of the combination of atezo + CE could be enhanced by adding tira in pts with ES-SCLC. Methods: Eligible pts with untreated ES-SCLC (asymptomatic treated or untreated brain metastases [BM] permitted) were randomized 1:1 to receive induction tira 600 mg IV or placebo (pbo) combined with atezo 1200 mg IV + CE for 4 x 21-day cycles followed by maintenance tira or placebo combined with atezo every 3 weeks until disease progression or loss of clinical benefit. Stratification factors include ECOG PS (0 vs 1); presence/history of BM (yes vs no); LDH (≤upper limit of normal [ULN] vs >ULN). Co-primary endpoints were investigator-assessed PFS and OS in all randomized pts without the history/presence of BM at baseline (primary analysis set [PAS]). Additional endpoints include PFS and OS in all randomized pts regardless of BM status (full analysis set [FAS]), objective response rate, duration of response, and safety. Results: A total of 490 patients were randomized (tira + atezo + CE, n=243; pbo + atezo + CE, n=247). As of 6 Feb 2022, median duration of follow-up was 13.9 months (mo); data represent final analysis for PFS and interim analysis for OS. In the PAS, no additional benefit was seen for tira + atezo + CE in PFS or OS compared with pbo + atezo + CE (Table). PFS and OS in the FAS were consistent with those observed in the PAS (Table). Grade 3/4 TRAEs occurred in 52.3% (tira + atezo + CE) and 55.7% (pbo + atezo + CE) and Grade 5 TRAEs occurred in 0.4% (tira + atezo + CE) and 2.0% (pbo + atezo + CE). TRAEs leading to any treatment discontinuation occurred in 5.0% and 5.3% with tira + atezo + CE and pbo + atezo + CE, respectively. Conclusions: The addition of tira to atezo + CE did not provide benefit over atezo + CE in pts with untreated ES-SCLC with or without BM. The combination was well tolerated, and no new safety signals were identified. The study will continue to planned final OS analysis. Clinical trial information: NCT04256421. [Table: see text]

5-aza-2'-deoxycytidine may regulate the inflammatory response of human odontoblast-like cells through the NF-κB pathway

AIM

To explore the role of DNA methylation in the innate immunity of the dental pulp, this study investigated the effect of 5-aza-2'-deoxycytidine (AZA) on lipoteichoic acid (LTA)-induced cytokine production and related intracellular signalling pathways in human odontoblast-like cells (hOBs).

METHODOLOGY

hOBs were cultured and differentiated from human dental pulp tissue, and the odontoblastic phenotype of the cells was detected using immunofluorescence, qRT-PCR and Western blotting. hOBs were pretreated with AZA and then stimulated with 10 μg mL^-1 LTA. The levels of 42 cytokines related to immunity and inflammation were examined using a cytokine antibody array and verified using qRT-PCR and ELISA. The effect of AZA on the LTA-induced NF-κB and MAPK signalling pathways was explored using Western blotting. The cells were treated with the specific NF-κB inhibitor PDTC and MAPK inhibitors (the ERK inhibitor U0126, the p38 inhibitor SB203580, and the JNK inhibitor SP600125) to further confirm the role of the signalling pathways in LTA-treated hOBs. DNA immunoprecipitation-PCR was used to examine the dynamic methylation status of the gene promoters of myeloid differentiation primary response 88 (MyD88) and tumour necrosis factor receptor-associated factor 6 (TRAF6) in the LTA-induced hOBs. Statistical analyses of the differences between two groups were performed using Student's t-test. One-way analysis of variance (anova) or repeated-measures anova with a post hoc Dunnett's test was used to assess the differences between multiple sets of data. P < 0.05 was considered to be statistically significant.

RESULTS

The odontoblastic markers were significantly higher in hOBs than those in human dental pulp cells (hDPCs) (P < 0.05). According to the cytokine antibody array results, hOBs pretreated with AZA had significantly increased production of several inflammatory cytokines (P < 0.05), in which the expression levels of IL-6 and IL-8 were the most dramatically increased upon LTA stimulation (P < 0.01). Furthermore, AZA resulted in the significant upregulation of p-IKKα/β, p-IκBα, p-p65, p-p38 and p-ERK in LTA-stimulated hOBs (P < 0.01). Treatment with the NF-κB pathway inhibitor suppressed both IL-6 and IL-8 expression (P < 0.05), whereas inhibitors of the MAPK pathway (SB203580 and SP600125) did not. In LTA-treated hOBs, AZA significantly increased the expression levels of TRAF6 and MyD88 (P < 0.05). AZA induced MyD88 promoter hypomethylation but did not affect TRAF6 methylation.

CONCLUSION

AZA regulated the LTA-induced inflammatory response through the NF-κB signal pathway in hOBs. This study highlights the important role of DNA methylation in the immunity defence of odontoblasts during the dental pulp immunity response to caries.

MiRNA-7b-5p attenuates the progression of osteoporosis by inhibiting adipose differentiation of hMSCs via regulating IRS2

OBJECTIVE

To elucidate whether microRNA-7b-5p (miRNA-7b-5p) could inhibit adipose differentiation of human bone marrow-derived mesenchymal stem cells (hMSCs) through regulating IRS2, thereby alleviating the progression of osteoporosis.

MATERIALS AND METHODS

Expression levels of miRNA-7b-5p and IRS2 in hMSCs at different stages of adipogenic differentiation and osteogenic differentiation were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) and Western blot. After transfection of miRNA-7b-5p mimic or pcDNA-IRS2 in hMSCs, lipid droplet formation in cells was observed by oil red O staining. Expressions of C/EBPα and PPARγ were detected by qRT-PCR and Western blot. The potential target gene of miRNA-7b-5p was predicted by bioinformatics and verified by dual-luciferase reporter gene assay. Finally, expressions of IRS2 in hMSCs transfected with miRNA-7b-5p-NC, miRNA-7b-5p mimic or co-transfected with miRNA-7b-5p mimic and pcDNA-IRS2 were examined.

RESULTS

Expressions of miRNA-7b-5p and IRS2 gradually decreased with the prolongation of adipogenic differentiation, but increased during osteogenic differentiation of hMSCs. Transfection of miRNA-7b-5p mimic reduced oil red O staining after adipogenic differentiation and downregulated mRNA and protein levels of C/EBPα and PPARγ. Transfection of pcDNA-IRS2 increased oil red O staining after osteogenic differentiation and upregulated mRNA and protein levels of C/EBPα and PPARγ. Dual-luciferase reporter gene results showed that miRNA-7b-5p could bind to IRS2. Overexpression of IRS2 reversed the downregulated mRNA and protein levels of adipogenic-related genes C/EBPα and PPARγ due to the overexpression of miRNA-7b-5p.

CONCLUSIONS

MiRNA-7b-5p inhibits the adipogenic differentiation of hMSCs through IRS2, thus alleviating the development of osteoporosis.

MicroRNA-330-5p promotes the development of osteosarcoma by regulating SPRY2

OBJECTIVE

MicroRNA is an endogenous, non-coding small RNA that has a significant role in regulating organisms and pathology. Previous studies have demonstrated that microRNA-330-5p was a cancer-promoting gene. However, the role of microRNA-330-5p in osteosarcoma (OS) has not been reported. The aim of this work was to explore the characteristics of microRNA-330-5p expression in OS, and to further study its expression in OS and its relationship with clinicopathological parameters and prognosis.

PATIENTS AND METHODS

Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was performed to investigate the expression of microRNA-330-5p in 48 pairs of OS tissues and paracancer tissues, and to analyze the relationship between the expression of microRNA-330-5p and OS clinical indicators and patient prognosis. Meanwhile, qRT-PCR was performed to verify the microRNA-330-5p expression in OS cells. In addition, the microRNA-330-5p knockdown expression model was constructed using lentivirus in OS cell lines U2OS and MG63. The effects of microRNA-330-5p on the biological function of OS cells were analyzed by Cell Counting Kit-8 (CCK-8) and transwell experiments. The potential mechanism was explored by Western blot.

RESULTS

In this paper, qRT-PCR results showed that the expression of microRNA-330-5p in OS was higher than that in paracancer tissues, and the difference was statistically significant. Compared with microRNA-330-5p low expression group, patients with high expression of microRNA -330-5p had a higher prevalence of distant metastasis and a lower overall survival rate. In vitro experiment showed that the proliferation, invasion and metastasis abilities of the cells in the microRNA-330-5p silencing group were markedly decreased compared with the negative control group (NC group). Western blot results demonstrated that microRNA-330-5p inhibitor can activate SPRY2 and regulate the expression of key proteins, such as p-Smad2, p-Smad3, TGF-β1, MMP9 and Vimentin in the TGF-β1/Smad signaling pathway. It was found that there was a mutual regulation between microRNA-330-5p and SPRY2, which promoted the malignant progression of OS.

CONCLUSIONS

The expression of microRNA-330-5p was markedly increased in OS, which was associated with distant metastasis and poor prognosis. Furthermore, we found that microRNA-330-5p may promote the vicious progression of OS by inter-modulating SPRY2 and the TGF-β1/Smad signaling pathways.

Abstract CT302: Phase Ia/Ib dose-escalation study of the anti-TIGIT antibody tiragolumab as a single agent and in combination with atezolizumab in patients with advanced solid tumors

Background: The immunomodulatory receptor TIGIT (T-cell Immunoreceptor with Ig and ITIM domains) is a novel inhibitory immune checkpoint present on activated T cells and NK cells in multiple cancers. In preclinical models, co-inhibition of the TIGIT and PD-L1/PD-1 pathways improved anti-tumor activity compared to either agent alone. Tiragolumab (tira or MTIG7192A) is a humanized IgG1/kappa monoclonal antibody (mAb) that binds TIGIT to prevent its interaction with its ligand PVR (CD155). In this first-in-human dose-escalation study, we report the preliminary safety and anti-tumor activity of tira as a single agent and in combination with atezolizumab (atezo) in patients with advanced solid tumors. Methods: Enrolled patients, ECOG PS 0-1, had advanced tumors for whom standard therapy did not exist or was ineffective. Patients received escalating doses of tira alone IV Q3W alone (Phase Ia) or in combination with atezo 1200 mg IV Q3W (Phase Ib) to determine the maximum tolerated dose (MTD) and continued until disease progression, intolerable toxicity, or patient/investigator decision. Study objectives included evaluation of safety and tolerability, pharmacokinetics (PK), pharmacodynamics, and anti-tumor activity of tira alone or tira + atezo. Data cut-off date was April 2019. Results: 73 patients with multiple tumor types were treated in dose-escalation (24 in Phase Ia, 49 in Ib with tira + atezo). In Phase Ia and Phase Ib, median age was 60 and 54 years, ECOG 0 for 29% and 27% of patients, and those who received ≥ 3 prior therapies were 67% and 57%, respectively. No DLTs were observed. Across doses, treatment-related AEs occurred in 67% in Phase Ia and 59% in Phase Ib (Grade ≥ 3: 4% and 4%, respectively), and most common AEs were fatigue (38%) in Phase Ia and anemia (31%) in Phase Ib. Exposure of tira increased with increasing dose, and saturation of nonlinear PK occurred at tira doses ≥ 100 mg Q3W. Complete and sustained occupancy of peripheral TIGIT receptors was observed at tira doses ≥ 30 mg Q3W. In Phase Ia, there were no objective responses, but SD of &gt; 4 months duration was observed (n=4). In Phase Ib, there were 3 responses, which all occurred in PD-L1 positive tumors (2 non-small cell lung cancer [NSCLC]: 1 CR, 1 PR; and 1 head/neck squamous cell carcinoma: PR) with two patients not receiving prior immunotherapy (CIT-naïve). Therefore, expansion cohorts were initiated in PD-L1-positive CIT-naïve indications in Phase Ib. In the metastatic NSCLC expansion cohort (n=14) ORR was 50%, with 1 CR and 6 PRs; DCR was 79%, and the safety profile was similar. Conclusions: Tira monotherapy or combined with atezo was well-tolerated and had an acceptable safety profile across all dose levels. Preliminary anti-tumor activity was observed in Phase Ib with tira + atezo in CIT-naïve PD-L1-positive tumors, including NSCLC, and enrollment is ongoing in these expansion cohorts.

Citation Format: Johanna C. Bendell, Philippe Bedard, Yung-Jue Bang, Patricia LoRusso, Stephen Hodi, Michael Gordon, Sandra D'Angelo, Sandra D'Angelo, Jayesh Desai, Elena Garralda, Antoine Italiano, Myung-Ju Ahn, Andres Cervantes, Zev Wainberg, Emiliano Calvo, Marta Gil-Martin, Maria Martinez-Garcia, Rastilav Bahleda, Philippe Cassier, Jean-Pierre Delord, Amy Prawira, Ignacio Melero, Leisha Emens, Emanuela Romano, Karen Miller, Robert W. Hsieh, Cloris Xue, Kari Morrissey, Patrick Twomey, Kelly Gash, Namrata S. Patil, Jane Grogan, Raymond Meng, Byoung Cho, Tae Won Kim. Phase Ia/Ib dose-escalation study of the anti-TIGIT antibody tiragolumab as a single agent and in combination with atezolizumab in patients with advanced solid tumors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT302.

Primary analysis of a randomized, double-blind, phase II study of the anti-TIGIT antibody tiragolumab (tira) plus atezolizumab (atezo) versus placebo plus atezo as first-line (1L) treatment in patients with PD-L1-selected NSCLC (CITYSCAPE)

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Background: The immunomodulatory receptor TIGIT is a novel inhibitory immune checkpoint present on activated T cells and NK cells in multiple cancers, including NSCLC. In a phase I study (GO30103), co-inhibition of TIGIT and PD-L1 signaling with tira plus atezo in CIT-naïve PD-L1 positive NSCLC potentially improved overall response rates (ORR) compared to historical ORR with PD-L1/PD-1 inhibitors. We conducted this phase II trial to confirm the efficacy and safety of tira plus atezo (TA) compared to placebo plus atezo (PA) in 1L NSCLC (GO40290, NCT NCT03563716). Methods: This prospective, randomized, double-blind, placebo-controlled trial enrolled patients (pts) with chemotherapy-naïve PD-L1+ (TPS ≥ 1% by 22C3 IHC pharmDx Dako assay) locally advanced or metastatic NSCLC with measurable disease, ECOG PS 0-1, and without EGFR or ALK alterations. Pts were randomized 1:1 to TA (tira 600 mg IV plus atezo 1200 mg IV) or PA (placebo plus atezo 1200 mg IV) on day 1 of every 3-week cycle. Stratification factors were PD-L1 status (TPS ≥ 50% vs TPS 1-49%), histology, and tobacco history. Co-primary endpoints were investigator assessed ORR and PFS, and additional endpoints were duration of response (DOR), OS, and safety. Exploratory endpoints were the effect of PD-L1 status on ORR and PFS. Results: 135 pts were randomized to PA (n = 68) or TA (n = 67). At primary analysis (30 Jun 2019), TA improved ORR and median PFS (mPFS) compared to PA, with median follow-up of 5.9 mo. In the safety population (68 in PA, 67 in TA), treatment-related AEs (TRAEs) occurred in 72% (PA) and 80.6% (TA); Grade ≥3 TRAEs occurred in 19.1% (PA) and 14.9% (TA). AEs leading to treatment withdrawal occurred in 10.3% (PA) and 7.5% (TA). Clinical trial information: NCT03563716 . With an additional six months of follow-up since the primary analysis (2 Dec 2019, median follow-up of 10.9 mo), improvement in ORR and mPFS was maintained in ITT for TA (37.3% [25.0, 49.6] and 5.6 mo [4.2, 10.4]) vs PA (20.6% [10.2, 30.9] and 3.9 mo [2.7, 4.5]). The safety profile remained tolerable. Conclusions: Treatment with TA compared to PA showed clinically meaningful improvement in ORR and PFS in ITT. The safety profile of TA was similar to PA. [Table: see text]