Tumor-intrinsic expression of the autophagy gene Atg16l1 suppresses anti-tumor immunity in colorectal cancer

Microsatellite-stable colorectal cancer (MSS-CRC) is highly refractory to immunotherapy. Understanding tumor-intrinsic determinants of immunotherapy resistance is critical to improve MSS-CRC patient outcomes. Here, we demonstrate that high tumor expression of the core autophagy gene ATG16L1 is associated with poor clinical response to anti-PD-L1 therapy in KRAS-mutant tumors from IMblaze370 (NCT02788279), a large phase III clinical trial of atezolizumab (anti-PD-L1) in advanced metastatic MSS-CRC. Deletion of Atg16l1 in engineered murine colon cancer organoids inhibits tumor growth in primary (colon) and metastatic (liver and lung) niches in syngeneic female hosts, primarily due to increased sensitivity to IFN-γ-mediated immune pressure. ATG16L1 deficiency enhances programmed cell death of colon cancer organoids induced by IFN-γ and TNF, thus increasing their sensitivity to host immunity. In parallel, ATG16L1 deficiency reduces tumor stem-like populations in vivo independently of adaptive immune pressure. This work reveals autophagy as a clinically relevant mechanism of immune evasion and tumor fitness in MSS-CRC and provides a rationale for autophagy inhibition to boost immunotherapy responses in the clinic.

PD-1 Blockade in Mismatch Repair-Deficient, Locally Advanced Rectal Cancer

BACKGROUND

Neoadjuvant chemotherapy and radiation followed by surgical resection of the rectum is a standard treatment for locally advanced rectal cancer. A subset of rectal cancer is caused by a deficiency in mismatch repair. Because mismatch repair-deficient colorectal cancer is responsive to programmed death 1 (PD-1) blockade in the context of metastatic disease, it was hypothesized that checkpoint blockade could be effective in patients with mismatch repair-deficient, locally advanced rectal cancer.

METHODS

We initiated a prospective phase 2 study in which single-agent dostarlimab, an anti-PD-1 monoclonal antibody, was administered every 3 weeks for 6 months in patients with mismatch repair-deficient stage II or III rectal adenocarcinoma. This treatment was to be followed by standard chemoradiotherapy and surgery. Patients who had a clinical complete response after completion of dostarlimab therapy would proceed without chemoradiotherapy and surgery. The primary end points are sustained clinical complete response 12 months after completion of dostarlimab therapy or pathological complete response after completion of dostarlimab therapy with or without chemoradiotherapy and overall response to neoadjuvant dostarlimab therapy with or without chemoradiotherapy.

RESULTS

A total of 12 patients have completed treatment with dostarlimab and have undergone at least 6 months of follow-up. All 12 patients (100%; 95% confidence interval, 74 to 100) had a clinical complete response, with no evidence of tumor on magnetic resonance imaging, 18F-fluorodeoxyglucose-positron-emission tomography, endoscopic evaluation, digital rectal examination, or biopsy. At the time of this report, no patients had received chemoradiotherapy or undergone surgery, and no cases of progression or recurrence had been reported during follow-up (range, 6 to 25 months). No adverse events of grade 3 or higher have been reported.

CONCLUSIONS

Mismatch repair-deficient, locally advanced rectal cancer was highly sensitive to single-agent PD-1 blockade. Longer follow-up is needed to assess the duration of response. (Funded by the Simon and Eve Colin Foundation and others; ClinicalTrials.gov number, NCT04165772.).

Abstract CT021: PD-1 blockade in solid tumors with defects in polymerase epsilon

Context: Polymerase epsilon (POLE) gene missense hotspot mutations can generate pathogenic (p) proofreading defects resulting in hypermutated genomic profiles.

Aim: Determine the prevalence, genomic consequences and immunotherapy sensitivity of advanced POLE mutated tumors according to mutation site, primary tumor and tumor mutational burden (TMB).

Results: Pan-Cancer TCGA & MSKCC databases genomic analyses found a prevalence of non-pathogenic POLE mutations (POLEnp) of 3.4% with median TMB of 11 mutations/Megabase (mt/Mb, IQR 3-34). Pathogenic POLE mutations (POLEp) prevalence was 0.4% with median TMB of 215 mt/Mb (IQR 107-324), predominantly in colorectal and endometrial cancers. Prevalence dropped to 0.1% in metastatic cancers. We assessed prospectively the efficacy of PD-1 blockade in mismatch repair proficient advanced solid tumors harboring POLE missense mutations (phase II ASCe Nivolumab trial; NCT03012581). Variants were categorized prospectively by a molecular board as POLEp, POLEnp or Variants with Unknown significance (VUS). The primary endpoint was the Overall Response Rate (ORR) at 12 weeks according to RECIST 1.1, and secondary endpoints included survival analyses according to POLE variants pathogenicity. Among 61 screened patients, 21 were eligible and 20 received Nivolumab and 19 were assessable for response (table 1). The 12-week ORR was 37% for patients harboring POLEp and VUS and resulted in major survival improvement compared to POLEnp patients (HR=0.1 ; CI95% 0.02-0.7); see results in Table 1. Among patients POLEp tumors, while higher TMB was not predictive of response, higher proportion of POLE-related mutational signature correlated with improved benefit. In silico exonucleasic POLE domain analyses confirmed that all POLEp and 2 VUS clustered in the DNA binding or the Catalytic site. Recategorizing the VUS according to the location within the exonucleasic domain improved the prediction of survival outcomes.

Impact: This study gives new insights on how DNA repair defects, mutational burden and signatures sensitize to PD-1 blockade and may offer emerging tumor agnostic biomarkers for benefit to checkpoint blockade.

POLE variant pathogenicity All(N=21) POLEnp(N=5) VUS(N=4) POLEp(N=12) Age, years ± SD 57 ± 16 64 ± 10 56 ± 16 54 ± 17 Sex, Male (%) 12 (57) 5 (100) 2 (50) 5 (42) PS (ECOG)=1 (%) 16 (75) 4 (80) 2 (50) 10 (83) Primary tumor Colorectal 9 (43) 2 (40) 2 (50) 5 (42) Endometrial 6 (29) 0 (0) 0 (0) 6 (50) Gastric 2 (9) 2 (40) 0 (0) 0 (0) Glial 1 (5) 0 (0) 0 (0) 1 (8) Biliary tract 1 (5) 0 (0) 1 (25) 0 (0) Pancreas 2 (9) 1 (20) 1 (25) 0 (0) Number of previous treatments 2.4 ± 2 5 ± 2 1.8 ± 1 1.5 ± 1 TMB (mt/Mb, Min-Max)(N=16) 36.2 (2-385) 5 (4-9) 3 (2-4) 114 (25-385) ORR at 12 weeks (CR+PR) 37%(N=7/19) 0%(N=0/5) 50%(N=2/4) 46%(5/10) DCR at 12 weeks (CR+PR+SD) 58%(N=11/19) 0%(N=0/5) 75%(N=3/4) 80%(8/10) Median Progresssion-Free survival (months) 5.6 2.3 10.3vs POLEnp: HR=0.2 IC95% 0.1-0.7 Median Overall Survival (months) 9.1 5.0 Not Reachedvs POLEnp:HR=0.1 IC95% 0.02-0.7

Citation Format: Benoît Rousseau, Ivan Bieche, Eric Pasmant, Nadim Hamzaoui, Nicolas Leulliot, Lucas Michon, Aurelien de Reynies, Mike Foote, Julien Masliah-Planchon, Magali Svrcek, Romain Cohen, Victor Simmet, Paule Augereau, David Malka, Antoine Hollebecque, Damien Pouessel, Carlos Gomez-Roca, Rosine Guimbaud, Amandine Bruyas, Marielle Guillet, Muriel Duluc, Sophie Cousin, Christelle de la Fourchardiere, Frederic Rolland, Sandrine Hiret, Esma Saada-Bouzid, Olivier Bouche, Thierry Andre, Diane Pannier, Farid El Hajbi, Stephane Oudard, Christophe Tournigand, Jean-Charles Soria, Drew Gerber, Dennis Stephens, Michelle Lamandola-Essel, Steven B Maron, Bill Diplas, Guillem Argiles, Asha Krishnan, Neil Segal, Andrea Cercek, Nathalie Hoog-Labouret, Frederic Legrand, Clotide Simon, Assia Lamrani-Ghaouti, Luis A. Diaz, Pierre Saintigny, Sylvie Chevret, Aurelien Marabelle. PD-1 blockade in solid tumors with defects in polymerase epsilon [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 CT021.

PD-1 Blockade in Solid Tumors with Defects in Polymerase Epsilon

Missense mutations in the polymerase epsilon (POLE) gene have been reported to generate proofreading defects resulting in an ultramutated genome and to sensitize tumors to checkpoint blockade immunotherapy. However, many POLE-mutated tumors do not respond to such treatment. To better understand the link between POLE mutation variants and response to immunotherapy, we prospectively assessed the efficacy of nivolumab in a multicenter clinical trial in patients bearing advanced mismatch repair-proficient POLE-mutated solid tumors. We found that only tumors harboring selective POLE pathogenic mutations in the DNA binding or catalytic site of the exonuclease domain presented high mutational burden with a specific single-base substitution signature, high T-cell infiltrates, and a high response rate to anti-PD-1 monotherapy. This study illustrates how specific DNA repair defects sensitize to immunotherapy. POLE proofreading deficiency represents a novel agnostic biomarker for response to PD-1 checkpoint blockade therapy.

SIGNIFICANCE

POLE proofreading deficiency leads to high tumor mutational burden with high tumor-infiltrating lymphocytes and predicts anti-PD-1 efficacy in mismatch repair-proficient tumors. Conversely, tumors harboring POLE mutations not affecting proofreading derived no benefit from PD-1 blockade. POLE proofreading deficiency is a new tissue-agnostic biomarker for cancer immunotherapy. This article is highlighted in the In This Issue feature, p. 1397.

Effect of trifluridine/tipiracil in patients treated in RECOURSE by prognostic factors at baseline: an exploratory analysis

Background

The choice of treatment in patients with metastatic colorectal cancer (mCRC) is generally influenced by tumour and patient characteristics, treatment efficacy and tolerability, and quality of life. Better patient selection might lead to improved outcomes.

Methods

This post hoc exploratory analysis examined the effect of prognostic factors on outcomes in the Randomized, Double-blind, Phase 3 Study of trifluridine tipiracil (FTD/TPI) plus Best Supportive Care (BSC) versus Placebo plus BSC in Patients with mCRC Refractory to Standard Chemotherapies (RECOURSE) trial. Patients were redivided by prognosis into two subgroups: those with <3 metastatic sites at randomisation (low tumour burden) and ≥18 months from diagnosis of metastatic disease to randomisation (indolent disease) were included in the good prognostic characteristics (GPC) subgroup; the remaining patients were considered to have poor prognostic characteristics (PPC).

Results

GPC patients (n=386) had improved outcome versus PPC patients (n=414) in both the trifluridine/tipiracil and placebo arms. GPC patients receiving trifluridine/tipiracil (n=261) had an improved median overall survival (9.3 vs 5.3 months; HR (95% CI) 0.46 (0.37 to 0.57), p<0.0001) and progression-free survival (3.3 vs 1.9 months; HR (95% CI) 0.56 (0.46 to 0.67), p<0.0001) than PPC patients receiving trifluridine/tipiracil (n=273). Improvements in survival were irrespective of age, Eastern Cooperative Oncology Group Performance Status (ECOG PS), KRAS mutational status, and site of metastases at randomisation. In the trifluridine/tipiracil arm, time to deterioration of ECOG PS to ≥2 and proportion of patients with PS=0–1 discontinuing treatment were longer for GPC than for PPC patients (7.8 vs 4.2 months and 89.1% vs 78.4%, respectively).

Conclusion

Low tumour burden and indolent disease were factors of good prognosis in late-line mCRC, with patients experiencing longer progression-free survival and greater overall survival.

Early clinical experience with trifluridine/tipiracil for refractory metastatic colorectal cancer: The ROS study

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Background: Trifluridine/tipiracil is currently approved for metastatic colorectal cancer (mCRC) refractory to available therapies. However, there is no consensus on factors that predict treatment outcomes in daily practice. We assessed the early clinical experience with trifluridine/tipiracil in Spain and potential survival markers. Methods: This was a retrospective cohort study of mCRC patients who participated in the trifluridine/tipiracil early clinical experience program in Spain. The primary outcome was overall survival (OS). Associations between OS and patient characteristics were assessed using multivariate Cox regression analyses. Results: A total of 379 patients were included in the study. Trifluridine/tipiracil was administered for a median of 3.0 cycles and discontinued mainly due to disease progression (79.2%). The median OS was 7.9 months, with a 12-month OS rate of 30.5%. Cox analyses revealed that the following variables independently favoured OS: ≤2 metastases, no liver metastasis, alkaline phosphatase < 300 IU, trifluridine/tipiracil dose reductions, and neutrophil/lymphocyte ratio < 5. Grade ≥3 toxicities were reported in 141 (37.2%) patients, including mainly afebrile neutropenia (23.2%), anaemia (12.1%), and thrombocytopenia (5.3%). Conclusions: This study supports the real-life efficacy and safety of trifluridine/tipiracil for refractory mCRC and identifies tumour burden, liver metastasis, alkaline phosphatase, dose reductions, and neutrophil/lymphocyte ratio as survival markers.

Phase II study evaluating trifluridine/tipiracil + bevacizumab and capecitabine + bevacizumab in first-line unresectable metastatic colorectal cancer (mCRC) patients who are noneligible for intensive therapy (TASCO1): Results of the final analysis on the overall survival

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Background: Our phase II randomized study was conducted in patients with previously untreated unresectable mCRC not eligible to receive standard oxaliplatin- or irinotecan- based chemotherapy regimens. The results of the primary study analysis were reported earlier and demonstrated a promising efficacy in terms of progression-free survival (PFS) and an acceptable safety profile for the combination of trifluridine/tipiracil + bevacizumab (E. Van Cutsem et al. Ann. Oncol. 2020). Here we present the final end-of-study analysis on the overall survival (OS). Methods: Eligible patients were randomized in 1:1 ratio to receive either trifluridine/tipiracil administered orally at 35 mg/m²/dose bid from days 1-5 and days 8-12, and bevacizumab at 5 mg/kg on days 1 and 15 of a 28-day treatment cycle (TT-B), or capecitabine administered orally at 1250 or 1000 mg/m²/dose bid (according to the patient’s status) from days 1-14 and bevacizumab at 7.5 mg/kg on day 1 of a 21-day treatment cycle (C-B). Cycles were repeated until documented disease progression, unacceptable toxicity, or investigator’s/patient’s decision. Following the treatment discontinuation, all patients were followed for OS until the end-of-study, which was defined as the date of the withdrawal visit for the last patient. In the absence of death confirmation or for patients alive as of the end-of-study date, survival time was censored at the date of their last study follow-up. For the OS analysis the HR and the corresponding 2-sided 80% and 2-sided 95% CIs for TT-B versus C-B were estimated using a Cox proportional hazard model adjusting for the stratification factors based on IWRS data. OS was summarized using Kaplan-Meier curves and further characterized in terms of the median and survival probabilities at 6, 12, 18, and 24 months along with the corresponding 2-sided 80% and 2-sided 95% CI (Brookmeyer and Crowley CI for median and Kalbfleisch and Prentice CI for survival probabilities). Results: From April 2016 to March 2017, 153 patients were randomized and followed until end-of-study on September 1, 2020. Twenty-one patients, 11 from TT-B and 10 from C-B, were alive and censored for the analysis. Median OS was 22.31 months in TT-B and 17.67 months in C-B with HR 0.78 (95% CI, 0.55, 1.10). Survival probability at 18 months in TT-B was 0.62 (95% CI, 0.50, 0.72), and 0.47 (95% CI, 0.35, 0.57) in C-B. Conclusions: Our study demonstrated earlier a median PFS of 9.2 months for TT-B and 7.8 months for C-B when administered to patients with previously untreated unresectable mCRC ineligible for standard combination chemotherapy. The final study analysis performed on OS, the main secondary endpoint, provided further evidence for TT-B as a noteworthy valuable regimen in this population settings. Clinical trial information: NCT02743221.

Phase I dose-escalation study of MCLA-158, a first-in-class bispecific antibody targeting EGFR and LGR5, in metastatic colorectal cancer (CRC)

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Background: The WNT and EGFR signaling pathways are oncogenic and mitogenic drivers in CRC and other cancers. MCLA-158 is an ADCC enhanced human IgG1 cLC bispecific antibody identified from functional screening of CRC patient (pt)-derived organoids (PDO). MCLA-158 exposure leads to EGFR degradation in LGR5+ cancer and exhibits potent growth inhibition of RASmut and wt CRC PDOs, while minimal inhibition is observed in non-tumoral PDOs. Blockade of metastasis initiation was seen in preclinical in vivo models. MCLA-158 also demonstrated tumor regression or stasis in esophageal squamous (6/6) and gastric adenocarcinoma (6/8) PDX models selected for LGR5 and EGFR expression. Methods: Metastatic CRC pts progressing after oxaliplatin, irinotecan and fluoropyrimidines, and EGFR monoclonal antibodies if RASwt, received MCLA-158 IV every 2 weeks (q2w; 4-week cycle) in a phase I study. Safety, efficacy (per RECIST 1.1), PK and ADA were assessed. WNT and EGFR pathway components were evaluated in tumor tissue. EGFR pathway mutations (ctDNA) and soluble EGFR (sEGFR) were assessed in blood. PDOs were derived from baseline biopsies and assessed for MCLA-158 responsiveness. Results: As of 7 September 2020, 33 pts were treated over 11 dose levels (5 to 1500 mg, flat dose). At enrollment, median age was 58 years (range 35-76), ECOG PS 0/1:22/11, and 15 pts were RASmut. Pts had a median of 3 metastatic sites (range 1-12) with a median of 4 prior lines of therapy (range 1-10). A median of 2 MCLA-158 cycles (range 1-6) were administered. No dose limiting toxicity occurred. Infusion-related reactions were the most common AEs (67% of pts), occurred mostly in cycle 1 (21/22 pts), and were manageable. Other common related AEs included rash acneiform (36%), diarrhea (15%), pyrexia (9%) and asthenia/fatigue (9%). Related AEs were mostly mild or moderate; G3 related AEs were IRRs (4 pts; 12%), diarrhea and hypophosphatemia (1 pt each). The RP2D (1500 mg) was selected based on safety, PK and receptor occupancy prediction. MCLA-158 exhibited target-mediated clearance with proportional PK from 750 mg (t1/2 ~80 h at 1500 mg). Low ADA titers were seen in 3/23 pts, with no effect on PK. Target saturation is predicted at steady state serum trough levels. No clinical responses were observed during dose escalation. No/low baseline tumor EGFR expression (0-1+ IHC) was observed in 17/30 pts and non-elevated sEGFR levels ( < 4 ng/mL) in 18/22 pts. More than 1 activating mutation in EGFR signaling pathway genes were identified in ctDNA from 10/20 pts. 1/4 PDOs had > 30% growth inhibition with MCLA-158 ex vivo. MCLA-158 activity on PDOs correlated negatively with the presence of EGFR pathway resistance-mutations. Conclusions: Dual EGFR/LRG5 blockade with MCLA-158 was well tolerated, and the RP2D was 1500 mg IV q2w. Enrollment of pts with gastric and other non-CRC cancers at the RP2D continues in the expansion phase. Clinical trial information: NCT03526835.

Association of Consensus Molecular Subtypes and Molecular Markers With Clinical Outcomes in Patients With Metastatic Colorectal Cancer: Biomarker Analyses From LUME-Colon 1

INTRODUCTION

LUME-Colon 1 (NCT02149108) was a global, placebo-controlled phase III study of nintedanib in advanced colorectal cancer (CRC). Pre-specified biomarker analyses investigated the association of CRC consensus molecular subtypes (CMS) and tumor genomic and circulating biomarkers with clinical outcomes.

MATERIALS AND METHODS

Archival tumor tissue, cell-free DNA (cfDNA), and plasma samples were collected for genomic, transcriptomic, and proteomic analyses to investigate potential associations between CRC CMS and other biomarkers with nintedanib response and clinical outcomes.

RESULTS

Of the 765 treated patients, 735, 245, and 192 patient samples were analyzed in the circulating protein, tumor tissue, and cfDNA datasets, respectively. Patients were classified as CMS1 (1.7%), CMS2 (27.7%), CMS3 (0.9%), CMS4 (51.5%), or unclassified (18.2%). Unclassified/mixed CMS was associated with longer overall survival (OS) with nintedanib vs. CMS2 or CMS4 (interaction P-value = .0086); no association was observed for CMS4. Gene expression-based pathway analysis revealed an association between vascular endothelial growth factor-related signaling and OS for nintedanib (P = .0498). The most frequently detected somatic mutations were APC (72.0% [tumor tissue] vs. 56.8% [cfDNA]), TP53 (47.1% vs. 34.9%), KRAS (40.8% vs. 28.6%), and PIK3CA (16.6% vs. 11.5%); concordance rates were > 80%. Median OS differences were observed for APC and TP53 mutations vs. wild-type in cfDNA, indicating a potential prognostic value. Circulating ANG-2, CA-9, CEACAM1, collagen-IV, IGFBP-1, ICAM-1, IL-8, and uPAR were potentially prognostic for both OS and progression-free survival.

CONCLUSION

We demonstrated the feasibility of large-scale biomarker analyses and CMS classification within a global clinical trial, and identified signals suggesting a potential for greater nintedanib treatment response in the unclassified/mixed CMS subgroup, despite these tumors showing heterogeneous patterns of CMS mixtures. Our results revealed a high degree of concordance in somatic mutations between tumor tissue and cfDNA. Associations with prognosis for cfDNA somatic mutations, as well as several protein-based biomarkers, may warrant further investigation in future trials.

AXL is a predictor of poor survival and of resistance to anti-EGFR therapy in RAS wild-type metastatic colorectal cancer

BACKGROUND

RAS mutations are the only validated biomarkers in metastatic colorectal cancer (mCRC) for anti-epidermal growth factor receptor (EGFR) therapy. Limited clinical information is available on AXL expression, marker of epithelial to mesenchymal transition, in mCRC.

METHODS

AXL was retrospectively assessed by immunohistochemistry in 307 patients. RAS wild-type (WT) patients (N = 136) received first-line anti-EGFR-based therapy; RAS mutant patients (N = 171) received anti-angiogenic-based regimens. Preclinical experiments were performed using human RAS WT CRC cell lines and xenograft models. AXL RNA levels were assessed in a cohort of patients with available samples at baseline and at progression to anti-EGFR treatment and in the GSE5851 dataset.

RESULTS

AXL was expressed in 55/307 tumour tissues, correlating with worse survival in the overall population (AXL-positive, 23.7 months; AXL-negative, 30.8 months; HR, 1.455, P = 0.032) and in RAS WT patients (AXL-positive, 23.0 months; AXL-negative, 35.8 months; HR,1.780, P = 0.032). Progression-free survival (PFS) in the RAS WT cohort was shorter in the AXL-positive cohort (6.2 months versus 12.1 months; HR, 1.796, P = 0.013). Three-dimensional cultures obtained from a patient following anti-EGFR therapy resulted AXL-positive, showing resistance to anti-EGFR drugs and sensitivity to AXL inhibition. AXL transfection in CRC cell lines induced AXL overexpression and resistance to the EGFR blockade. At progression to cetuximab, 2/10 SW48-tumour xenograft mice showed AXL expression. Consistently, AXL RNA levels increased in 5/7 patients following anti-EGFR therapy. Moreover, in the GSE5851 dataset higher AXL RNA levels correlated with worse PFS with cetuximab in KRAS-exon2 WT chemorefractory patients.

CONCLUSIONS

AXL is a marker of poor prognosis in mCRC with consistent clinical and preclinical evidences of involvement in primary and acquired resistance to anti-EGFR drugs in RAS WT patients.

Abstract CT034: Phase I study of WNT974 + spartalizumab in patients (pts) with advanced solid tumors

Background: WNT974, a Porcupine inhibitor, has shown evidence of Wnt pathway inhibition in clinical trials. Dysregulated Wnt signaling has been linked to immunotherapy resistance, suggesting WNT974 may act synergistically with checkpoint inhibitors. Spartalizumab is an αPD-1 mAb with demonstrated clinical activity in solid tumors. Methods: In this Phase I, open-label trial (NCT01351103) adult pts received WNT974 ± spartalizumab; here we report on the dose escalation of the combination. Eligible pts had melanoma (including uveal), lung SCC, HNSCC, esophageal SCC, cervical SCC, or TNBC. Pts with melanoma, lung SCC, or HNSCC must have had a best response of progressive disease (primary refractory) to prior αPD-1 therapy; other pts were naïve or primary refractory to prior αPD-1. WNT974 was dosed orally QD in 28-day cycles (2.5-10 mg, Days 1-8 or 1-15 of Cycles 1 or 1-4); spartalizumab was dosed IV at 400 mg Q4W. Objectives were to determine the maximum tolerated dose (MTD)/recommended dose for expansion (RDE), safety, pharmacokinetics (PK), pharmacodynamics, and activity of WNT974 + spartalizumab. Pre- and on-treatment pt samples were collected: skin samples for RT-PCR analysis of AXIN2, a marker of Wnt pathway activity; tumor samples for RNAseq of AXIN2 and immune cell markers. Results: As of Sept 2, 2019, 27 pts were enrolled: 24 discontinued (18 due to disease progression; 67%), 3 were ongoing. Most common tumor types were non-uveal melanoma (n=8), TNBC (n=7), and uveal melanoma (n=5); 63% had received prior αPD-1. PK parameters for WNT974 + spartalizumab were consistent with prior single agent data. Dose-limiting toxicities were reported in 2 pts: Grade (G) 2 spinal compression fracture that occurred in the setting of trauma and G3 arthralgia. 78% of pts experienced a treatment-related AE, the most common being hypothyroidism (19%); 4 pts (15%) had 7 suspected-related G3/4 AEs (arthralgia, atrial fibrillation, diabetes mellitus, diabetic ketoacidosis, hyperglycemia, hyponatremia, and maculopapular rash). One pt (4%) with TNBC had a partial response, 11 pts (41%) had stable disease (SD), 13 pts (48%) had progressive disease; response was unknown in 2 pts. SD was reported in 9/17 pts (53%) who were primary refractory to prior αPD-1; 4 remained on study &gt;24 wks. All pts with uveal melanoma (n=5) had SD. Evidence of Porcupine inhibition, assessed by skin AXIN2 suppression, was detected at all dose levels studied. Pts with the largest reductions in tumor size had on-treatment increases in immune marker mRNA in tumor samples, including a pt with αPD-1 primary refractory melanoma with high baseline AXIN2 expression and 42% reduction in the sum of target lesion diameters; this pt remained on study at 48 wks at the cutoff date. Conclusions: WNT974 + spartalizumab was well tolerated; MTD/RDE have not been determined. Preliminary data suggest blocking Wnt signaling may enable response to checkpoint inhibition in some pts.

Citation Format: Filip Janku, Filip de Vos, Maria de Miguel, Patrick Forde, Antoni Ribas, Misako Nagasaka, Guillem Argiles, Ana Maria Arance, Aitano Calvo, Marios Giannakis, Maritza Melendez, Jiachang Gong, Sebastian Szpakowski, Rebecca Kan, Susan E. Moody, Maja De Jonge. Phase I study of WNT974 + spartalizumab in patients (pts) 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 CT034.

Colorectal cancer residual disease at maximal response to EGFR blockade displays a druggable Paneth cell-like phenotype

Blockade of epidermal growth factor receptor (EGFR) causes tumor regression in some patients with metastatic colorectal cancer (mCRC). However, residual disease reservoirs typically remain even after maximal response to therapy, leading to relapse. Using patient-derived xenografts (PDXs), we observed that mCRC cells surviving EGFR inhibition exhibited gene expression patterns similar to those of a quiescent subpopulation of normal intestinal secretory precursors with Paneth cell characteristics. Compared with untreated tumors, these pseudodifferentiated tumor remnants had reduced expression of genes encoding EGFR-activating ligands, enhanced activity of human epidermal growth factor receptor 2 (HER2) and HER3, and persistent signaling along the phosphatidylinositol 3-kinase (PI3K) pathway. Clinically, properties of residual disease cells from the PDX models were detected in lingering tumors of responsive patients and in tumors of individuals who had experienced early recurrence. Mechanistically, residual tumor reprogramming after EGFR neutralization was mediated by inactivation of Yes-associated protein (YAP), a master regulator of intestinal epithelium recovery from injury. In preclinical trials, Pan-HER antibodies minimized residual disease, blunted PI3K signaling, and induced long-term tumor control after treatment discontinuation. We found that tolerance to EGFR inhibition is characterized by inactivation of an intrinsic lineage program that drives both regenerative signaling during intestinal repair and EGFR-dependent tumorigenesis. Thus, our results shed light on CRC lineage plasticity as an adaptive escape mechanism from EGFR-targeted therapy and suggest opportunities to preemptively target residual disease.

Molecular subtypes and the evolution of treatment management in metastatic colorectal cancer

Colorectal cancer (CRC) is a heterogeneous disease representing a therapeutic challenge, which is further complicated by the common occurrence of several molecular alterations that confer resistance to standard chemotherapy and targeted agents. Mechanisms of resistance have been identified at multiple levels in the epidermal growth factor receptor (EGFR) pathway, including mutations in KRAS, NRAS, and BRAF V600E, and in the HER2 and MET receptors. These alterations represent oncogenic drivers that may co-exist in the same tumor with other primary and acquired alterations via a clonal selection process. Other molecular alterations include DNA damage repair mechanisms and rare kinase fusions, potentially offering a rationale for new therapeutic strategies. In recent years, genomic analysis has been expanded by a more complex study of epigenomic, transcriptomic, and microenvironment features. The Consensus Molecular Subtype (CMS) classification describes four CRC subtypes with distinct biological characteristics that show prognostic and potential predictive value in the clinical setting. Here, we review the panorama of actionable targets in CRC, and the developments in more recent molecular tests, such as liquid biopsy analysis, which are increasingly offering clinicians a means of ensuring optimal tailored treatments for patients with metastatic CRC according to their evolving molecular profile and treatment history.

Patient and tumor characteristics as determinants of overall survival (OS) in BRAF V600 mutant (mt) metastatic colorectal cancer (mCRC) treated with doublet or triplet targeted therapy

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Background: BRAF V600 mt mCRC is an aggressive disease with poor OS under standard chemotherapy. Treatment with doublet and triplet targeted combinations, such as BRAF inhibitor+ antiEGFR+/- MEK inhibitor, has been shown to improve outcomes. Prognostic factors in this targeted treated population remain to be studied. Methods: Prospective international cohort of patients who received doublet or triplet anti-BRAF combinations in clinical trials or as compassionate use. Univariate Cox models for OS were constructed and the strongest predictors in stepwise variable selection were used to develop a prognostic score. The final multivariate model with selected predictors was stratified by prior lines. Results: In total, 42 patients were enrolled. Median age 60.7 y (33-83), 61% female, 61% right-sided tumors, 26% received 2 or more prior chemotherapy lines. One patient (2.6%) achieved complete response and 36% had partial response with median follow-up of 14.3 months. Median progression-free survival was 5.5 months (CI95% 4.4-10.4) and median OS (mOS) was 10.7 months (CI95% 8.4-22.1). In univariate models, ECOG performance status (1 vs 0), CEA levels (high - > 3.5 ng/mL- vs low - < 3.5 ng/mL), CA 19.9 (high vs. low), LDH (high vs. low), number of metastatic sites and presence of liver metastasis were significant prognostic factors. On the other hand, MSI status and peritoneal or nodal metastasis did not associate with outcome. In multivariable model, strongest determinants of OS were ECOG and baseline CEA levels. If high-risk for both factors (ECOG 1 and CEA high, 46% of the patients), mOS was 5.6 months (CI95% 4.2-NA); if intermediate-risk (either ECOG 1 or CEA high, 33%), mOS was 13.5 months (CI95% 10.6-NA); if low-risk (ECOG 0 and CEA low, 21%), mOS not reached (CI95% 16.5-NA). Differences between intermediate- and high-risk prognostic groups compared to low-risk were significant (HR = 5.9, p = 0.03; and HR = 25.9, p < 0.001, respectively). Conclusions: Patients characteristics such as ECOG and surrogates of tumor burden like CEA levels remain important OS determinants in BRAF V600 mt mCRC treated with doublet or triplet targeted therapy. In fact, there are not prognostic scores regarding BRAF mt mCRC treated with targeted therapies. Our study suggests that these prognostic factors may be considered as stratification factors in future clinical trials.

The predictive role of plasma mutant allele fraction to antiangiogenic drugs in patients with mCRC: An expanded analysis of surrogate biomarkers of response to first-line treatment with bevacizumab

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Background: So far, no biomarkers of response to anti-angiogenic drugs are available in colorectal cancer (CRC) treatment. Liquid biopsy tracks dynamic mutational changes in CRC patients (pts). RAS mutant allele fraction in plasma (plMAF) is an independent prognostic marker in metastatic CRC (mCRC). We explored the predictive value of plMAF in RAS mutant pts treated in 1st line with chemotherapy +/- bevacizumab (bev). Methods: A multicentric prospective/retrospective analysis was conducted. We collected data from 226 mCRC pts and selected the subset not eligible for metastasis resection with basal plMAF sample evaluable for RAS mutant MAF quantification with digital PCR (BEAMing). Pts were stratified as high (≥ 5.8%) or low ( < 5.8%) plMAF. We investigated associations between clinicopathological variables and progression-free survival (PFS) stratified by plMAF RAS levels using Cox regression models and survival data were calculated by Kaplan-Meier method. Computational analysis of baseline CT scan data extracted 93 radiomics features of all the lesions per patient including 1) 1st class from density histogram distribution and texture analysis by 2) 2nd order and 3) higher order feature classes. The radiomic features distribution between pts with high and low pIMAF was assessed with Student’s t-test analysis. Results: From October 17 to May 19, 63 basal plasma samples were analysed with BEAMing. 42 pts (67.7%) were classified as high and 21 pts (32,3%) as low plMAF. In high plMAF subgroup, a statistically significant longer PFS favouring FOLFOX+bev was observed, compared to FOLFOX alone (10.7 vs 6.9 mts; HR: 0.30; p = 0.002). In low RAS plMAF subgroup, no differences in terms of PFS were observed in either arm (8.9 vs 8.7 mts; HR: 0.7; p = 0.6). Multivariate PFS model showed no association between RAS plMAF and clinicopathological variables, except for high RAS plMAF and treatment benefit with FOLFOX+bev. The CT-radiomics signature, that may translate tumor vascularization, differentiated patients with high vs low pIMAF (p = 0.002). 58 patients (92%) had similar radiomic score; 5 patients with high plMAF (8%) presented very heterogeneous radiomic score distribution. Conclusions: Tumor-borne RAS plMAFs may constitute a potential predictive biomarker of efficacy for anti-angiogenic drugs in mCRC. Next steps will include the identification of -histological, transcriptomic and radiomic- surrogate biomarkers of response that reflect tumor irrigational status.

Trifluridine/tipiracil in combination with oxaliplatin and either bevacizumab or nivolumab: Results of the expansion part of a phase I study in patients with metastatic colorectal cancer

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Background: Trifluridine/tipiracil (FTD/TPI) is approved for use in patients (pts) with pretreated mCRC. In vivo studies have shown an increase in anti-tumor activity when combining FTD/TPI, oxaliplatin or bevacizumab, and an increase in tumor immunogenicity after treatment with FTD/TPI and oxaliplatin (Ghiringhelli, 2018). The recommended dose for expansion had been defined as FTD/TPI 35 mg/m² bid, days 1–5 q14, together with oxaliplatin 85 mg/m² (day 1). Methods: In addition to FTD/TPI and oxaliplatin, eligible pts received bevacizumab 5 mg/kg (Cohort A) or nivolumab 3 mg/kg (Cohort B) on day 1. Eligibility criteria included measurable disease, performance status (PS) 0-1, normal organ function, progression after > 1 prior anti-tumor therapy (excluding oxaliplatin), and confirmed MSS status (Cohort B). A Bayesian design was used for futility and efficacy assessments. Efficacy endpoints of objective response rate (ORR), disease control rate (DCR), progression free survival (PFS) and adverse events (AEs) were assessed for each cohort; biomarkers of immune function including PD-L1 expression for Cohort B. Results: A total of 37 and 17 pts were enrolled in Cohorts A and B respectively; with a median age of 64 years (range 33 to 83 years), 61% and 39% had an PS of 0 and 1. At baseline, no pt showed PD-L1 expression on tumor cells, and only 1 pt on immune cells (5% threshold). At data cutoff, 32 and 12 pts were evaluable for response in Cohorts A and B. In Cohort A, ORR was 13% (1 CR; 3 PR), and DCR was 91%. The mPFS was 6.9 months (95% IC, 4.3-9.3). In Cohort B, ORR was 8% (1 PR), DCR was 67%. The mPFS was 6.5 months (95% IC, 1.8-8.6). Overall, the most common treatment-related AEs (≥20% of pts) included neutropenia, nausea, diarrhoea, and fatigue; only 1 pt reported grade 3 febrile neutropenia; 5 pts discontinued due to AEs and no treatment-related death were reported. Conclusions: In this study, bevacizumab in addition to FTD/TPI and oxaliplatin showed antitumor activity. The cohort of nivolumab was prematurely discontinued due to lack of efficacy. Both cohorts showed an acceptable safety profile in pretreated mCRC pts. Clinical trial information: NCT02848443.

Nintedanib for the treatment of patients with refractory metastatic colorectal cancer (LUME-Colon 1): a phase III, international, randomized, placebo-controlled study

Background

Angiogenesis is critical to colorectal cancer (CRC) growth and metastasis. Phase I/II studies have demonstrated the efficacy of nintedanib, a triple angiokinase inhibitor, in patients with metastatic CRC. This global, randomized, phase III study investigated the efficacy and safety of nintedanib in patients with refractory CRC after failure of standard therapies.

Patients and methods

Eligible patients (Eastern Cooperative Oncology Group performance status 0–1, with histologically/cytologically confirmed metastatic/locally advanced CRC adenocarcinoma unamenable to surgery and/or radiotherapy) were randomized 1 : 1 to receive nintedanib (200 mg twice daily) or placebo (twice daily), until disease progression or undue toxicity. Patients were stratified by previous regorafenib, time from onset of metastatic disease to randomization, and region. Co-primary end points were overall survival (OS) and progression-free survival (PFS) by central review. Secondary end points included objective tumor response and disease control by central review.

Results

From October 2014 to January 2016, 768 patients were randomized; 765 were treated (nintedanib n = 384; placebo n = 381). Median follow-up was 13.4 months (interquartile range 11.1–15.7). OS was not improved [median OS 6.4 months with nintedanib versus 6.0 months with placebo; hazard ratio (HR), 1.01; 95% confidence interval (CI), 0.86–1.19; P = 0.8659]. There was a significant but modest increase in PFS with nintedanib versus placebo (median PFS 1.5 versus 1.4 months, respectively; HR 0.58; 95% CI 0.49–0.69; P < 0.0001). There were no complete or partial responses. Adverse events (AEs) occurred in 97% of 384 nintedanib-treated patients and 93% of 381 placebo-treated patients. The most frequent grade ≥3 AEs were liver-related AEs (nintedanib 16%; placebo 8%) and fatigue (nintedanib 9%; placebo 6%).

Conclusions

The study failed to meet both co-primary end points. Nintedanib did not improve OS and was associated with a significant but modest increase in PFS versus placebo. Nintedanib was well tolerated.

ClinicalTrials.gov number

NCT02149108 (LUME-Colon 1).

Health-related Quality of Life in the Phase III LUME-Colon 1 Study: Comparison and Interpretation of Results From EORTC QLQ-C30 Analyses

INTRODUCTION

We used European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30) data from the LUME-Colon 1 study to illustrate different methods of statistical analysis for health-related quality of life (HRQoL), and compared the results.

PATIENTS AND METHODS

Patients were randomized 1:1 to receive nintedanib 200 mg twice daily plus best supportive care (n = 386) or matched placebo plus best supportive care (n = 382). Five methods (mean treatment difference averaged over time, using a mixed-effects growth curve model; mixed-effects models for repeated measurements (MMRM); time-to-deterioration (TTD); status change; and responder analysis) were used to analyze EORTC QLQ-C30 global health status (GHS)/QoL and scores from functional scales.

RESULTS

Overall, GHS/QoL and physical functioning deteriorated over time. Mean treatment difference slightly favored nintedanib over placebo for physical functioning (adjusted mean, 2.66; 95% confidence interval [CI], 0.97-4.34) and social functioning (adjusted mean, 2.62; 95% CI, 0.66-4.47). GHS/QoL was numerically better with nintedanib versus placebo (adjusted mean, 1.61; 95% CI, -0.004 to 3.27). MMRM analysis had similar results, with better physical functioning in the nintedanib group at all timepoints. There was no significant delay in GHS/QoL deterioration (10%) and physical functioning (16%) with nintedanib versus placebo (TTD analysis). Status change analysis showed a higher proportion of patients with markedly improved GHS/QoL and physical functioning in the nintedanib versus placebo groups. Responder analysis showed a similar, less pronounced pattern.

CONCLUSION

Analyses of EORTC QLQ-C30 data showed that HRQoL was not impaired by treatment with nintedanib versus placebo. Analysis and interpretation of HRQoL endpoints should consider symptom type and severity and course of disease.

Patient survival with immune checkpoint inhibitors and targeted agents in phase 1 trials: A propensity score weighted analysis

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Background: There have been important changes in early drug development units with an unprecedented increase of immune-oncology (IO) trials. Currently at the Vall d’Hebron Institute Oncology (VHIO) close to 50% of our Phase 1 trials (Ph1t) portfolio includes IO drugs, while from 2011 to 2015 more than 80% of our trials assessed targeted agents (TA). We wanted to investigate whether this swift had a positive impact on patient (pts) outcome. Methods: We performed a retrospective analysis of the pts treated with IO and TA at VHIO Ph1t Unit from Jun’11 to May’18. Only patients treated with IO in ≥ 2nd line were included (and without an approved IO therapy as per standard-of-care) and those with TA classified as tiers II-III-IV by the ESMO scale for clinical actionability of molecular targets ESCAT (which also represents unapproved indications). The aim of this study was to compare overall survival (OS) for the two cohorts. Given the non-randomized nature of the study a propensity score weighting (PSW) was used to control for selection bias in treatment effect estimation. Results: Out of 545 eligible pts, 281 (51.5%) received TA and 264 (48.5%) IO, with unadjusted median OS (mOS) of 7.7 months (m) and 9.2m, respectively. In univariate analysis, OS was associated with tumor type, number of previous treatment lines, regimen (monotherapy vs combination), and clinical-laboratory prognostic factors (Vioscore: albumin < 3.5 g/dl; LDH > upper limit of normal; neutrophil/[leukocytes minus neutrophils] ratio (dNLR) > 3; more than 2 sites of metastasis; and presence of liver metastasis) (p < 0.05). After adjusting for these factors in a PSW model, the IO group showed statistically significant longer OS with HR = 0.75 (CI95% 0.65 – 0.86, p < 0.0001). The In a stratified analysis by tumor type we found no significant heterogeneity in the relative benefit of IO over TA. Conclusions: In real world data from our Ph1t population, treatment with IO was associated with longer OS than treatment with TA, even after adjusting for known prognostic factors and treatment selection biases. These results suggest that the likelihood of patient benefit with IO therapies in Ph1t is increasing.

Maximising clinical benefit with adequate patient management beyond the second line in mCRC

New therapeutic options for refractory metastatic colorectal cancer (mCRC) include trifluridine/tipiracil (TAS-102) and regorafenib. However, the optimal chemotherapeutic regimen for use of each agent beyond the second line for patients with mCRC remains unclear and various factors may influence treatment decision. Available efficacy data suggest treatment with either trifluridine/tipiracil or regorafenib may be appropriate as both can extend patient survival. Thus, the safety profiles of each agent, along with patient performance status, are likely to determine treatment choice. The safety profiles of trifluridine/tipiracil and regorafenib are markedly different: higher levels of non-haematological adverse events such as fatigue, diarrhoea, hypertension and hand-foot skin reaction are reported with regorafenib, while haematological events such as neutropaenia are more common with trifluridine/tipiracil. In general, neutropaenia is a manageable treatment-related toxicity, while hand-foot skin reaction can be troublesome for patients, affecting their ability to carry out everyday activities and get on with their lives, while also affecting treatment adherence. Thus, the occurrence of any potential adverse effects and patient adherence should be closely monitored at each clinic visit. As quality of life is an important issue for patients with mCRC, it is important to balance extended survival and the likely quality of this extended life. Likewise, discussing possible side effects along with treatment expectations with patients can greatly facilitate adherence to therapy, and ultimately improve patients’ quality of life and eventual clinical outcomes.

Population pharmacokinetics (popPK) of Sym004 to evaluate the effect of intrinsic and extrinsic factors on exposure in metastatic colorectal cancer (mCRC)

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Background: Sym004 consists of two anti-EGFR monoclonal antibodies (futuximab and modotuximab) directed against non-overlapping epitopes in the EGFR domain III. Sym004 induces rapid and efficient removal of the EGFR from the cancer cell surface by triggering EGFR internalization and degradation and has shown promising efficacy in mCRC patients. Based upon a post-hoc analysis of a Phase 2 study, a Phase 3 trial in genomically selected mCRC patients is in preparation. Methods: The aim was to establish a popPK model for Sym004 in order to i) evaluate impact of covariates (intrinsic and extrinsic factors) on Sym004 exposure and ii) provide exposure metrics for a PK/PD analysis. Sym004 serum concentrations were obtained from 330 patients with mCRC (n = 247) or advanced solid tumors (studies Sym004-01, Sym004-02, Sym004-05 and Sym004-06). Sym004 (0.4-18 mg/kg) was dosed by i.v. infusion weekly or every 2nd week, or as a 9 mg/kg loading dose followed by 6 mg/kg weekly (9/6 mg/kg weekly). Non-linear mixed effects modelling was done in NONMEM v7.3.0. Covariates evaluated included body weight, age, sex, race, albumin, renal function, hepatic function, tumor type and size, ECOG and previous anti-EGFR treatments. Results: The base popPK model was a 2-compartment model with linear and non-linear Michaelis-Menten-type elimination and a priori inclusion of body weight on CL, Vmax, V1 and V2. The model captured the non-linear PK well. The final covariate model retained covariates whose point estimates were outside the range of 0.8 to 1.25 and whose 90% confidence intervals did not overlap with the null value and included only body weight and albumin. Inter-individual variability was estimated for CL, Vmax and V1 and was in the range of 18-30%. Simulations were used to assess the clinical relevance of the covariates as judged by the magnitude of the change in exposure of the Phase 3 dose regimen of 9/6 mg/kg weekly. Conclusions: The popPK model described the Sym004 PK data well. No covariates were present that changed the Sym004 exposure in a clinically significant manner which would necessitate a dose modification. The model is suitable for simulating the Sym004 PK for PK/PD analyses. Clinical trial information: NCT01117428,NCT01417936,NCT02083653,NCT01955473.

QoL from TASCO1: Health-related quality of life of trifluridine/tipiracil-bevacizumab and capecitabine-bevacizumab as first-line treatments in metastatic colorectal cancer patients not eligible for intensive chemotherapy—Results from the TASCO1 phase II study

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Background: TASCO1 is a phase II study which evaluated the safety and efficacy of trifluridine/tipiracil + bevacizumab (TT-B) and capecitabine + bevacizumab (C-B) in first-line unresectable mCRC patients non-eligible for intensive therapy. Promising activity was shown on progression-free survival with TT-B (9.2 months) and C-B (7.8 months). Here we present the Quality of Life (QoL) analysis of the two treatment arms. Methods: In TASCO1, patients were randomized 1:1 to receive TT-B (n = 76) on a four-week cycle or C-B (n = 77) on a three-week cycle. QoL was assessed in TASCO1 at baseline and at each 12 weeks thereafter, until discontinuation of study treatment, using the QLQ-C30 and QLQ-CR29 questionnaires. Responses were described separately in each arm using descriptive statistics. Results: For QLQ-C30, 121 patients completed baseline questionnaire. No clinically relevant difference was observed on treatment in mean change of score from baseline for the global health status, functioning scales, and for most of the symptom scales, except for nausea/vomiting and diarrhoea (worsening in the TT-B group and stable in the C-B group for both symptoms), fatigue (stable in the TT-B group and worsening in the C-B), loss appetite (worsening in the two groups) and insomnia (improvement in the two groups). For QLQ-CR29, 117 patients completed baseline questionnaire. No clinically relevant difference on treatment was observed in mean change of score from baseline for most of items except for the following: hair loss, trouble with taste (worsening for both symptoms in the TT-B group while stable for hair loss and improvement for trouble with taste in the C-B group), sore skin, dry mouth (stable in the TT-B group and worsening in the C-B group for both symptoms), and anxiety (stable in the TT-B group and improvement in the C-B group). Conclusions: The Global Health Scale was maintained in Trifluridine/tipiracil+bevacizumab arm as well as in the capecitabine+bevacizumab arm. No clinically relevant difference from baseline was observed over time in both groups except for few sub-scales. Clinical trial information: NCT02743221.

First-in-human phase I study of the microtubule inhibitor plocabulin in patients with advanced solid tumors

Background Plocabulin (PM060184) is a novel marine-derived microtubule inhibitor that acts as an antitumor agent. This first-in-human study evaluated dose-limiting toxicities (DLT) to define the maximum tolerated dose (MTD) and phase II recommended dose (RD) of plocabulin given as a 10-min infusion on Day (D) 1, D8 and D15 every four weeks. Patients and methods Forty-four patients with advanced solid tumors received plocabulin following an accelerated titration design. Results Plocabulin was escalated from 1.3 mg/m² to 14.5 mg/m², which was defined as the MTD. No RD was confirmed, because frequent dose delays and omissions resulted in low relative dose intensity (66%) at the 12.0 mg/m² expansion cohort. The main DLT was grade 3 peripheral sensory neuropathy (PSN); other DLTs were grade 4 tumor lysis syndrome, grade 4 cardiac failure and grade 3 myalgia. Toxicities were mainly mild to moderate, and included abdominal pain, myalgia, fatigue, nausea, and vomiting. Myelosuppression was transient and manageable. Plocabulin had a half-life of ~4 h and a wide diffusion to peripheral tissues. Antitumor response was observed in cervix carcinoma and heavily pretreated metastatic non-small cell lung cancer patients, and disease stabilization (≥3 months) in patients with colorectal, thymic, gastrointestinal stromal and breast tumors, among others. The clinical benefit rate was 33%. Conclusion The main DLT of plocabulin was PSN, as anticipated for a tubulin-binding agent. Since encouraging antitumor activity was observed, efforts to improve toxicity and to find the RD were planned in other trials evaluating D1&D8 and D1-D3 plus D15-D17 schedules.

Transcriptional subtyping and CD8 immunohistochemistry identifies poor prognosis stage II/III colorectal cancer patients who benefit from adjuvant chemotherapy

Purpose

Transcriptomic profiling of colorectal cancer (CRC) has led to the identification of four consensus molecular subtypes (CMS1 to 4) that have prognostic value in stage II and III disease. More recently, the Colorectal Cancer Intrinsic Subtypes (CRIS) classification system has helped to define the biology specific to the epithelial component of colorectal tumors; however, the clinical value of these classification systems in the prediction of response to standard-of-care adjuvant chemotherapy remains unknown.

Patients and Methods

Using samples from four European sites, we assembled a novel cohort of patients with stage II and III CRC (n = 156 samples) and performed transcriptomic profiling and targeted sequencing and generated a tissue microarray to enable integrated multiomics analyses. We also accessed data from two published cohorts of patients with stage II and III CRC: GSE39582 and GSE14333 (n = 479 and n = 185 samples, respectively).

Results

The epithelial-rich CMS2 subtype of CRC benefitted significantly from treatment with adjuvant chemotherapy in both stage II and III disease (P = .02 and P < .001, respectively), whereas the CMS3 subtype significantly benefitted in stage III only (P = .001). After CRIS substratification of CMS2, we observed that only the CRIS-C subtype significantly benefitted from treatment with adjuvant chemotherapy in stage II and III disease (P = .0081 and P < .001, respectively), whereas the CRIS-D subtype significantly benefitted in stage III only (P = .0034). We also observed that CRIS-C patients with low levels of CD8⁺ tumor-infiltrating lymphocytes were most at risk for relapse in both stage II and III disease (log-rank P = .0031; hazard ratio, 12.18 [95% CI, 1.51 to 98.58]).

Conclusion

Patient stratification using a combination of transcriptional subtyping and CD8 immunohistochemistry analyses is capable of identifying patients with poor prognostic stage II and III disease who benefit from adjuvant standard-of-care chemotherapy. These findings are particularly relevant for patients with stage II disease, where the overall benefit of adjuvant chemotherapy is marginal.

Initial experience with the bispecific anti-CEA anti-CD3 antibody and its expected impact on future treatment for patients with colorectal cancer

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Phase I multicenter, open-label study to establish the maximum tolerated dose (MTD) of trifluridine/tipiracil (TAS-102) and oxaliplatin combination in patients (pts) with metastatic colorectal cancer (mCRC)

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Background: Preclinical evidence suggests improved efficacy when combining trifluridine/tipiracil with oxaliplatin compared to each monotherapy (Nukatsuka, 2015). The primary objective was to determine the MTD and the safety profile of the doublet among mCRC pts who have progressed after at least one prior line of treatment. Methods: Using a 3+3 design, eligible pts received escalating trifluridine/tipiracil doses from 25, 30 to 35 mg/m² bid, days 1–5 q14, together with a fixed dose of oxaliplatin 85 mg/m² (day 1). An intermediate cohort with a lower dose of oxaliplatin (65 mg/m²) plus 35 mg/m² of trifluridine/tipiracil was also tested. Results: Fifteen of 17 enrolled pts were evaluable for DLTs. Median age was 61 years (range 32-74), 11 and 6 pts had an ECOG PS of 0 and 1, respectively; 76% received ≥2 lines including for 10 pts previous line with oxaliplatin. Pts received a median of four cycles (range 1–23). The MTD was defined at the maximal planned dose: trifluridine/tipiracil 35 mg/m² bid, oxaliplatin 85 mg/m². Combination was well tolerated and only one DLT was observed (grade 3 febrile neutropenia). The most common ( > 20%) non-hematologic adverse drug reactions (ADRs) included nausea, asthenia, vomiting, diarrhea and decreased appetite. Moderate-to-severe neutropenia occurred in 5 pts and thrombocytopenia in 4 pts (all grade 1); 1 pt experienced a grade 4 anemia at Cycle 4. Oxaliplatin-related neurotoxicity grade ≥2 was observed in 2 pts. ADRs were manageable with basic supportive care, with treatment delays or temporary interruptions. Best overall response includes partial response (n = 1, unconfirmed), stable disease (n = 7). Conclusions: At the MTD (trifluridine/tipiracil 35 mg/m² bid, oxaliplatin 85 mg/m²), incidence and severity of bone marrow suppression as well as gastrointestinal toxicities were similar to previously published data. A cohort of 6 additional pts will confirm the MTD. An expansion part combining the doublet with either nivolumab or bevacizumab evaluating the safety and preliminary antitumor activity of each triplet will start soon. Clinical trial information: NCT02848443.

Prognostic value of neutrophil-to-lymphocyte ratio (NLR) on overall survival (OS), progression free survival (PFS) and disease control rate (DCR) in patients with metastatic colorectal cancer (mCRC) from the RECOURSE study

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Background: Elevated neutrophil-to-lymphocyte (NLR) ratios may represent markers of a suboptimal host immune response to cancer and have been shown to correlate with prognosis in multiple tumor types. Trifluridine/tipiracil (FTD/TPI also known as TAS-102) compared with placebo significantly improved OS (median: 7.1 vs.5.3 months, hazard ratio (HR) = 0.68, 95% confidence interval (CI) [0.58;0.81], p < 0.0001), PFS, and DCR in the phase 3 RECOURSE study, conducted in patients with refractory mCRC. A post-hoc analysis was conducted to assess correlation between clinical outcomes and baseline NLR (in blood) in RECOURSE. Methods: A retrospective review on 782/800 patients, with available NLR, was performed on OS, PFS, and DCR in two subgroups of patients with low ( < 3) or high (≥ 3) NLR at baseline. Based on literature, the cutoff value of 3 was chosen as the number of patients was similar in each NLR subgroup. Between-group comparison was performed using a stratified Cox’s proportional hazard model for OS and PFS, and Fisher’s Exact test for DCR. Results: The median value of NLR at baseline was similar in each group, FTD/TPI (N = 519): 4.4 ± 6.3, placebo (N = 263): 4.7 ± 6.5. Almost 60% of patients in each group had high NLR. In the low NLR vs. high NLR subgroup, there were differences at baseline for ethnic origin (Asian: 45% vs.29%), ECOG PS 0 (69% vs. 49%), and number of metastatic sites ≥ 3 (32% vs. 46%). The median OS [95 % CI] was statistically significantly higher in the low vs. high NLR subgroup: 8.4 [7.8;9.5] vs. 5.3 [4.7;5.7] months, HR = 0.49, 95% CI [0.41;0.59], p < 0.0001. Irrespective of NLR, all patients benefited from FTD/TPI vs. placebo. The results of PFS and DCR were statistically significantly better in the low NLR vs. high NLR subgroup. The multivariate Cox analysis for OS with the interaction test between treatment groups and NLR showed that NLR is not a predictive factor (p = 0.15). Conclusions: In this retrospectively analyzed mCRC population, NLR was shown to be an independent prognostic factor. Further research is warranted to assess if NLR can be a stratification factor in mCRC clinical trials. Clinical trial information: NCT01607957.

BRAF mutant colorectal cancer: prognosis, treatment, and new perspectives

The MAPK cascade plays a crucial role in tumor cell proliferation and survival. Accumulating evidence suggests that mutations in the BRAF oncogene are not only associated with poor prognosis but also linked with less benefit when treated with anti-epidermal growth factor receptor antibodies in metastatic colorectal cancer (mCRC). Targeting this molecular aberration has thus become a matter of particular interest in mCRC drug development. In contrast to other malignances such as BRAF mutant melanoma, efficacy observed with BRAF inhibitors in monotherapy in mCRC is poor. Several mechanisms of resistance have been identified leading to the development of different treatment strategies that have shown promising activity in early clinical trials. Hence, rational combination of targeted therapies is expected to further increase the efficacy of selective BRAF inhibitors. Herein, we discuss the main clinical and molecular characteristics of BRAF mutant colorectal cancer and its translation into the clinic, with a focus on developmental therapeutics and combination strategies. In addition, we contextualize the available data with potential future approaches that include the extended access to next-generation sequencing platforms and gene expression strategies for molecular subtyping. These approaches will facilitate the identification of certain patient profiles providing more therapeutic possibilities.

Analysis of mutant allele fractions in driver genes in colorectal cancer - biological and clinical insights

Sequencing of tumors is now routine and guides personalized cancer therapy. Mutant allele fractions (MAFs, or the ‘mutation dose’) of a driver gene may reveal the genomic structure of tumors and influence response to targeted therapies. We performed a comprehensive analysis of MAFs of driver alterations in unpaired primary and metastatic colorectal cancer (CRC) at our institution from 2010 to 2015 and studied their potential clinical relevance. Of 763 CRC samples, 622 had detailed annotation on overall survival in the metastatic setting (OSmet) and 89 received targeted agents matched to KRAS (MEK inhibitors), BRAF (BRAF inhibitors), or PIK3CA mutations (PI3K pathway inhibitors). MAFs of each variant were normalized for tumor purity in the sample (adjMAFs). We found lower adjMAFs for BRAF^V600E and PIK3CA than for KRAS,NRAS, and BRAF non‐V600 variants. TP53 and BRAF^V600E adjMAFs were higher in metastases as compared to primary tumors, and high KRAS adjMAFs were found in CRC metastases of patients with KRAS wild‐type primary tumors previously exposed to EGFR antibodies. Patients with RAS‐ or BRAF^V600E‐mutated tumors, irrespective of adjMAFs, had worse OSmet. There was no significant association between adjMAFs and time to progression on targeted therapies matched to KRAS,BRAF, or PIK3CA mutations, potentially related to the limited antitumor activity of the employed drugs (overall response rate of 4.5%). In conclusion, the lower BRAF^V600E and PIK3CA adjMAFs in subsets of primary CRC tumors indicate subclonality of these driver genes. Differences in adjMAFs between metastases and primary tumors suggest that approved therapies may result in selection of BRAF^V600E‐ and KRAS‐resistant clones and an increase in genomic heterogeneity with acquired TP53 alterations. Despite significant differences in prognosis according to mutations in driver oncogenes, adjMAFs levels did not impact on survival and did not help predict benefit with matched targeted agents in the metastatic setting.

A phase I dose-escalation of trifluridine/tipiracil in combination with oxaliplatin in metastatic colorectal cancer

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Background: Trifluridine/tipiracil, also known as TAS‐102, is a combination of an antineoplastic thymidine‐based nucleoside analogue (trifluridine) and a thymidine phosphorylase inhibitor (tipiracil hydrochloride). The antitumor activity of combined trifluridine/tipiracil and oxaliplatin has been studied in gastrointestinal tumor xenografts, including a 5‐FU resistant subline, using a nude mouse model. This study demonstrated increased antitumor activity for the combination compared to trifluridine/tipiracil or oxaliplatin alone (p < 0.001) (Nukatsuka et al., Anticancer Res 2015). These data support the rationale for clinical use of the combination. We describe a phase 1, international, dose-escalation study of the combination in metastatic colorectal cancer (mCRC). Methods: This trial includes mCRC patients pretreated with at least one line of standard chemotherapy. The 14‐day administration schedule of trifluridine/tipiracil differs from current clinical practice to avoid overlapping toxicity, notably decreased neutrophils due to oxaliplatin or trifluridine/tipiracil. Trifluridine/tipiracil is administered orally (cohort 1: 25 mg/m² bid; cohort 2: 30 mg/m² bid; cohort 3: 35 mg/m² bid) from day 1 to 5; and oxaliplatin at 85 mg/m² (with a possibility to reduce to 65 mg/m²) on day 1. The primary objective is to determine the maximum tolerated dose (MTD) through a 3+3 design. Secondary objectives include safety, pharmacokinetics, and preliminary efficacy (overall survival, progression‐free survival, overall response rate and biomarkers). As of December 2016, no dose‐limiting toxicities had been reported in cohorts 1 or 2. The MTD has not yet been reached and dose‐escalation continues with enrollment in cohort 3 at full dose for both drugs (trifluridine/tipiracil 35 mg/m² bid and oxaliplatin 85 mg/m²). Once established, the MTD will be confirmed in 6 additional patients to define the recommended dose to be used in the expansion part of the study planned in the same patient population. The results of the dose‐escalation part are expected in 2017. (NCT02848443). Clinical trial information: NCT02848443.

Phase Ia and Ib studies of the novel carcinoembryonic antigen (CEA) T-cell bispecific (CEA CD3 TCB) antibody as a single agent and in combination with atezolizumab: Preliminary efficacy and safety in patients with metastatic colorectal cancer (mCRC)

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Background: CEA CD3 TCB (RG7802, RO6958688) is a novel T-cell bispecific antibody targeting CEA on tumor cells and CD3 on T cells. In preclinical models, CEA CD3 TCB displays potent anti-tumor activity, leads to increased intra-tumoral T cell infiltration and activation and upregulates PD-1/PD-L1. Methods: Intwo ongoing dose-escalation phase I studies, RO6958688 is given as monotherapy (S1) i.v. QW or in combination (QW) with atezolizumab 1200 mg Q3W (S2) in adult patients (pts) with advanced CEA+ solid tumors. In S1, 80 pts (mCRC: 68) were treated at dose levels from 0.05 mg to 600 mg; in S2, 38 pts (mCRC: 28) from 5 mg to 160 mg. In S1, a Bayesian logistic regression model with overdose control guided dose escalation. Data cutoff 25.01.17. Results: At doses ≥60mg (36 pts in S1; 10 in S2), CT scans revealed tumor inflammation within days of first dose, consistent with the mode of action of RO6958688. 2 (5%) pts in S1 (both microsatellite stable (MSS) and 2 (20%; 1 MSS) in S2 had a partial response (RECIST v1.1). Preliminary tumor size reduction ( > -10% and < -30% [stable disease]) was observed in 4 (11%) additional pts in S1 and 5 (50%) in S2. At week 4-6 FDG PET scan assessment, 10 (28%) pts with mCRC in S1 and 6 (60%) in S2 had a metabolic partial response (EORTC criteria). At all doses in S1, the most common related AEs were pyrexia (56.3%), infusion related reaction (IRR, 50%) and diarrhea (40%). The most common grade ≥ 3 (G3) related AEs were IRR (16.3%) and diarrhea (5%). 5 patients experienced DLTs: G3 dyspnea, G3 diarrhea, G3 hypoxia, G4 colitis and G5 respiratory failure (G4-5 at 600mg). DLT events were likely associated with tumor lesion inflammation. In S2, there was no evidence of new or additive toxicities, with 1 DLT at 160 mg (G3 transient increase of ALT in a patient with liver metastases). PK/PD data are reported separately. Conclusions: Evidence of antitumor activity was observed with RO6958688 monotherapy in ongoing dose escalation. Activity appeared to be enhanced with doses in combination with atezolizumab, with a manageable safety profile. Updated data will be presented. Clinical trial information: NCT02324257 and NCT02650713.

Compassionate use program with FDT-TPI (trifluridine-tipiracil) in pre-treated metastatic colorectal cancer patients: Spanish real world data

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Background: Trifluridine/tipiracil (FTD-TPI) is comprised of an antineoplastic nucleoside analog, trifluridine, and a thymidine phosphorylase inhibitor, tipiracil. Compassionate use programs (CUPs) provide a treatment option for patients with unmet medical needs and an early opportunity to obtain data on efficacy, safety and use in a real-world setting. Methods: Patients were registered and approved to receive 2 cycles of trifluridine/tipiracil treatment, which could be renewed as necessary, we analysed baseline characteristics, safety results and exposure to the treatment with trifluridine/tipiracil (FTD-TPI) in the Spanish CUP. Results: A total 636 were registered in Spain and 538 received treatment with trifluridine/tipiracil. Median age was 64 years, of which 25% were older than 70 years old and 60% were male, 67% of pts were ECOG PS 1. Oral trifluridine/tipiracil was initiated at 35 mg/m2 bid. Most pts had received 2, 3, or ≥4 lines of prior treatment for metastatic disease (27%, 28%, and 38%, respectively); and 4% unknown. 275 (47%) patients had KRAS mutated and 209 (36%) had KRAS wild type. 35% received adjuvant chemotherapy and 20% of the patients were treated with regorafenib in previous lines. The main reasons for not initiating treatment included cancellation of request due to worsening condition and progressive disease. Treatment was generally well tolerated. A total of 173 AEs were reported in the Spanish CUP, the majority were myelosuppressive AEs; febrile neutropenia (grade ≥3) was reported in 6 pts (1.3%), grade _ > 3 neutropenia was reported in 56 (33%), grade 4 neutropenia in 16 (9%). Grade 3 anemia was reported in 8 (15% of the total AEs reported).The majority of pts 306 (56%) were allocated 3-4 cycle of treatment, 95(17.3%) 5-6 cycles, and 30(5. 5%) between 7-8 cycles. Conclusions: Thisreal-world data analysis is consistent with those reported in phase 3 trials of trifluridine/tipiracil (FDT-TP)in pretreated mCRC. The efficacy analyses of this population is planned.

Pharmacokinetics (PK) and pharmacodynamics (PD) of a novel carcinoembryonic antigen (CEA) T-cell bispecific antibody (CEA CD3 TCB) for the treatment of CEA-expressing solid tumors

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Background: CEA CD3 TCB (RO6958688) targets CEA on tumor cells and is agonistic for CD3e on T cells. In mouse models, CEA CD3 TCB displays potent anti-tumor activity, leads to increased intra-tumoral T cell infiltration and activation and up-regulates the PD-1/PD-L1 pathway. Methods: Biodistribution was assessed in mice using SPECT/CT. Patient (pts) samples correspond to 2 dose-escalation studies in CEA+ solid tumors. Study 1 (S1): single agent weekly (qW) (0.052 to 600 mg, iv, n = 80), and Study 2 (S2): combination of RO6958688 qW (5 to 160 mg, iv) with 1200mg atezolizumab q3W (n = 38). Analytical methods: PK - population modeling approach; anti-drug antibodies (ADA) - ELISA; immunophenotyping in peripheral blood (PB) by flow cytometry (FCM), in pre- (BSL) and on-treatment (OT) biopsies by immunohistochemistry (IHC) and FCM; plasma cytokines - multiplex assays; PD-L1 - SP142 assay. Results: In mice, RO6958688 preferentially accumulated in CEA+ tumors. In pts with no ADAs tested thus far in both studies (S1 29; S2 21), RO6958688 showed near linear PK and exposure. In S1, OT biopsies demonstrated a statistically significant increase in density and activation profile of T cells (CD3: 2.6-fold, n = 21; CD3/CD8: 3.7 fold, n = 17; CD3/Ki67: 4-fold, n = 20; CD8/PD1: 1.7-fold, n = 15) without dose-dependence. In S2, preliminary data of T cell density (5-80mg) were similar to S1 (2-fold). In S1, a significant correlation was observed between treatment-induced tumor lesion reduction and increases of OT CD8/CD25 fluorescence intensity from BSL (p = 0.028). PD-L1 expression increased in OT biopsies in both studies. In S1, from week 4, a moderate expansion of activated CD8 T cells (HLA-DR/Ki67) but not of CD4, was detected in PB at doses > 60mg ( > 3.3 fold). Transient increases of several cytokines were seen in both studies with levels peaking within 24hrs. Conclusions: PK and PD results consistent with tumor inflammation and mechanism of action support that RO6958688 is the first tumor-targeted T cell bispecific to show intra-tumoral biological activity in pts with CEA+ solid tumors. Updated data will be presented. Clinical data are reported separately.

Randomized Phase II Trial of Parsatuzumab (Anti-EGFL7) or Placebo in Combination with FOLFOX and Bevacizumab for First-Line Metastatic Colorectal Cancer

Lessons Learned.

These negative phase II results for parsatuzumab highlight the challenges of developing an agent intended to enhance the efficacy of vascular endothelial growth factor inhibition without the benefit of validated pharmacodynamic biomarkers or strong predictive biomarker hypotheses.

Any further clinical development of anti‐EGFL7 is likely to require new mechanistic insights and biomarker development for antiangiogenic agents.

Background.

EGFL7 (epidermal growth factor‐like domain 7) is a tumor‐enriched vascular extracellular matrix protein that supports endothelial cell survival. This phase II trial evaluated the efficacy of parsatuzumab (also known as MEGF0444A), a humanized anti‐EGFL7 IgG₁ monoclonal antibody, in combination with modified FOLFOX6 (mFOLFOX6) (folinic acid, 5‐fluorouracil, and oxaliplatin) bevacizumab in patients with previously untreated metastatic colorectal cancer (mCRC).

Methods.

One‐hundred twenty‐seven patients were randomly assigned to parsatuzumab, 400 mg, or placebo, in combination with mFOLFOX6 plus bevacizumab, 5 mg/kg. Treatment cycles were repeated every 2 weeks until disease progression or unacceptable toxicity for a maximum of 24 months, with the exception of oxaliplatin, which was administered for up to 8 cycles.

Results.

The progression‐free survival (PFS) hazard ratio was 1.17 (95% confidence interval [CI], 0.71–1.93; p = .548). The median PFS was 12 months for the experimental arm versus 11.9 months for the control arm. The hazard ratio for overall survival was 0.97 (95% CI, 0.46–2.1; p = .943). The overall response rate was 59% in the parsatuzumab arm and 64% in the placebo arm. The adverse event profile was similar in both arms.

Conclusions.

There was no evidence of efficacy for the addition of parsatuzumab to the combination of bevacizumab and chemotherapy for first‐line mCRC.