Safety and Efficacy of Lenvatinib in Very Old Patients with Unresectable Hepatocellular Carcinoma

BACKGROUND

Data concerning the use of lenvatinib in very old patients (≥ 80 years) are limited, although the incidence of hepatocellular carcinoma (HCC) in this patient population is constantly increasing.

OBJECTIVE

This analysis aimed to evaluate the efficacy and safety of lenvatinib in a large cohort of very old patients (≥ 80 years) with unresectable HCC.

PATIENTS AND METHODS

The study was conducted on a cohort of 1325 patients from 46 centers in four Western and Eastern countries (Italy, Germany, Japan, and the Republic of Korea) who were undergoing first-line treatment with lenvatinib between July 2010 and February 2022. Patients were stratified according to age as very old (≥ 80 years) and not very old (< 80 years).

RESULTS

The median overall survival (OS) was 15.7 months for patients < 80 years old and 18.4 months for patients ≥ 80 years old [hazard ratio (HR) = 1.02, 95% confidence interval (CI) 0.84-1.25, p = 0.8281]. Median progression free survival (PFS) was 6.3 months for patients < 80 years old and 6.5 months for patients ≥ 80 years old (HR = 1.07, 95% CI 0.91-1.25, p = 0.3954). No differences between the two study groups were found in terms of disease control rate (DCR; 80.8% versus 78.8%; p = 0.44) and response rate (RR; 38.2% versus 37.9%; p = 0.88). Patients < 80 years old experienced significantly more hand-foot skin reaction (HFSR) grade ≥ 2 and decreased appetite grade ≥ 2. Conversely, patients ≥ 80 years old experienced significantly more fatigue grade ≥ 2. In the very old group, parameters associated with prognosis were AFP, albumin-bilirubin (ALBI) grade, Barcelona Clinic Liver Cancer (BCLC), and Child-Pugh score. BCLC stage was the only independent predictor of overall survival (OS; HR = 1.59, 95% CI 1.11-2.29, p = 0.01115).

CONCLUSIONS

Our study highlights the same efficacy and safety of lenvatinib between very old and not very old patients.

Prevalence and type of MMR expression heterogeneity in colorectal adenocarcinoma: therapeutic implications and reporting

Mismatch repair (MMR) immunohistochemical (IHC) evaluation has entered pathology routine practice as the first-line screening method to identify patients with MMR deficient (MMRd)/microsatellite instability (MSI) colorectal cancer (CRC), and its misdiagnosis may significantly impact the personalization of CRC patient care. To determine the prevalence of MMR protein intratumor heterogeneity in real-world practice, we collected a series of 8282 CRCs tested for MMR proteins in the setting of Lynch syndrome universal screening. Four heterogenous cases were also investigated for tumor infiltrating lymphocytes count, MSI status, and consensus molecular subtypes by Nanostring nCounter® Platform. Overall, 1056 (12.8%) CRCs showed a MMR altered status, with 46 cases showing a heterogeneous MMR profile (0.56% of the total, and 4.36% of all MMRd cases). To conclude, the authors make some critical remarks regarding the approach to MMR heterogeneity in clinical practice and routine diagnostics.

Pembrolizumab plus trastuzumab and chemotherapy for HER2-positive gastric or gastro-oesophageal junction adenocarcinoma: interim analyses from the phase 3 KEYNOTE-811 randomised placebo-controlled trial

BACKGROUND

Evidence for the efficacy of combined PD-1 and HER2 blockade with chemotherapy on progression-free and overall survival in HER2-positive gastro-oesophageal cancer is scarce. The first interim analysis of the randomised, phase 3 KEYNOTE-811 study showed a superior objective response with pembrolizumab compared with placebo when added to trastuzumab plus fluoropyrimidine and platinum-based chemotherapy. Here, we report results from protocol-specified subsequent interim analyses of KEYNOTE-811.

METHODS

The randomised, phase 3 KEYNOTE-811 trial involved 168 medical centres in 20 countries worldwide. Patients aged 18 years or older with locally advanced or metastatic HER2-positive gastro-oesophageal junction adenocarcinoma, without previous first-line treatment, were randomly assigned (1:1) by an integrated interactive voice-response and web-response system to intravenous pembrolizumab 200 mg or placebo, both to be combined with standard chemotherapy (fluoropyrimidine and platinum-based therapy) plus trastuzumab every 3 weeks for up to 35 cycles or until disease progression, unacceptable toxic effects, or investigator or participant-initiated withdrawal. Randomisation used a block size of four and was stratified by region, PD-L1 status, and chemotherapy. Dual primary endpoints were progression-free and overall survival, analysed by intention to treat. Safety was assessed in all randomly assigned patients who received at least one dose of study treatment according to the treatment received. KEYNOTE-811 is registered with ClinicalTrials.gov (NCT03615326) and is active but not recruiting.

FINDINGS

Between Oct 5, 2018, and Aug 6, 2021, 698 patients were assigned to pembrolizumab (n=350) or placebo (n=348). 564 (81%) were male and 134 (19%) were female. At the third interim analysis, 286 (82%) of 350 patients in the pembrolizumab group and 304 (88%) of 346 in the placebo group who received treatment had discontinued treatment, mostly due to disease progression. At the second interim analysis (median follow-up 28·3 months [IQR 19·4-34·3] in the pembrolizumab group and 28·5 months [20·1-34·3] in the placebo group), median progression-free survival was 10·0 months (95% CI 8·6-11·7) in the pembrolizumab group versus 8·1 months (7·0-8·5) in the placebo group (hazard ratio [HR] 0·72, 95% CI 0·60-0·87; p=0·0002). Median overall survival was 20·0 months (17·8-23·2) versus 16·9 months (15·0-19·8; HR 0·87 [0·72-1·06]; p=0·084). At the third interim analysis (median follow-up 38·4 months [IQR 29·5-44·4] in the pembrolizumab group and 38·6 months [30·2-44·4] in the placebo group), median progression-free survival was 10·0 months (8·6-12·2) versus 8·1 months (7·1-8·6; HR 0·73 [0·61-0·87]), and median overall survival was 20·0 months (17·8-22·1) versus 16·8 months (15·0-18·7; HR 0·84 [0·70-1·01]), but did not meet prespecified criteria for significance and will continue to final analysis. Grade 3 or worse treatment-related adverse events occurred in 204 (58%) of 350 patients in the pembrolizumab group versus 176 (51%) of 346 patients in the placebo group. Treatment-related adverse events that led to death occurred in four (1%) patients in the pembrolizumab group and three (1%) in the placebo group. The most common treatment-related adverse events of any grade were diarrhoea (165 [47%] in the pembrolizumab group vs 145 [42%] in the placebo group), nausea (154 [44%] vs 152 [44%]), and anaemia (109 [31%] vs 113 [33%]).

INTERPRETATION

Compared with placebo, pembrolizumab significantly improved progression-free survival when combined with first-line trastuzumab and chemotherapy for metastatic HER2-positive gastro-oesophageal cancer, specifically in patients with tumours with a PD-L1 combined positive score of 1 or more. Overall survival follow-up is ongoing and will be reported at the final analysis.

FUNDING

Merck Sharp & Dohme.

Comparative Genomic Analysis and Clinical Outcomes of BRAF-mutated Advanced Biliary Tract Cancers

PURPOSE

BRAF mutations are rare in biliary tract cancers (BTC), but are of interest given the recent developments in targeted therapy for BTC. We investigated the clinical outcomes in a cohort of BRAF-mutant advanced BTC treated with first-line chemotherapy. Furthermore, we investigated the genomic landscape of BRAF class I, II, and III mutations in the intrahepatic cholangiocarcinoma (iCCA) subgroup of BTC.

EXPERIMENTAL DESIGN

We analyzed two nonoverlapping cohorts. We examined the genomic landscape of BRAF-mutated iCCA in a "genomic cohort" [187 class I, 82 class II, 113 class III BRAF mutants and 8,026 wildtype (WT)]. We also analyzed median progression-free survival (PFS) and overall survival (OS) on first-line chemotherapy in a separate multi-institutional "clinical cohort" of patients with BTC (including iCCA and extrahepatic cholangiocarcinoma (eCCA) and gallbladder cancer; 41 class I, 32 class II+III BRAF mutants and 1,042 WT).

RESULTS

In the entire BTC clinical cohort, the median PFS was shorter for class I [HR, 2.11 (P < 0.001)] and class II+III [HR, 1.72 (P = 0.007)] as compared with BRAF WT. OS was also shorter in class I [HR, 2.04 (P = 0.011)] and class II+III [HR, 1.86 (P = 0.002)] as compared with BRAF WT. In the iCCA subgroup, class I alterations were mutually exclusive with FGFR2, IDH1/2, ERBB2, and KRAS mutations. Class II+III mutations appear to be mutually exclusive with FGFR2 and KRAS.

CONCLUSIONS

In BTC, all classes of BRAF mutations are associated with a worse prognosis. BRAF mutations occur in 5% of iCCA subgroup and may be mutually exclusive with other targetable mutations.

Negative hyperselection of elderly patients with RAS and BRAF wild-type metastatic colorectal cancer receiving initial panitumumab plus FOLFOX or 5-FU/LV

BACKGROUND

Upfront anti-EGFR therapy represents the standard of care for patients with left-sided, MSS/pMMR, RAS and BRAF wild-type mCRC. Molecular 'hyperselection' may optimize EGFR inhibition by detecting additional resistance alterations.

MATERIALS AND METHODS

We used comprehensive genomic profiling on archival samples of elderly patients enrolled in the PANDA trial to detect: HER2 amplification/mutations; MET amplification; NTRK/ROS1/ALK/RET rearrangements; PIK3CA exon 20 mutations; PTEN alterations; AKT1 mutations; MAP2K1 mutations. We defined 'Gene Altered' (GA) patients whose tumour harboured at least one alteration, and 'Hyperselected' (HS) those without. Survival and tumour response outcomes were correlated to hyperselection status alone or combined with primary tumour sidedness or treatment arm.

RESULTS

Genomic alterations were detected in 41/147 patients (27.9%). PFS, OS and ORR were inferior in GA versus HS (median PFS: 7.6 versus 12.8 months, HR = 2.08, 95% CI: 1.43-3.03, p < 0.001; median OS: 20.0 versus 29.5 months, HR = 1.82, 95% CI:1.23-2.69, p = 0.002; ORR: 51% versus 71%; OR = 0.43, 95% CI: 0.21-0.91, p = 0.02). In the multivariable models, the impact of hyperselection on PFS and OS was confirmed. Lower ORR was observed with 5-FU/LV/panitumumab in GA (40% versus 62%), but not in HS (70% versus 72%). GA was associated with worse survival and response regardless of primary tumour sidedness, whereas in the HS subgroup, right-and left sided tumours had similar outcomes.

CONCLUSIONS

Molecular hyperselection and comprehensive genomic profiling have a potential usefulness in elderly patients with RAS/BRAF wild-type, pMMR/MSS mCRC, eligible for upfront EGFR inhibition.

KEYSTEP-008: phase II trial of pembrolizumab-based combination in MSI-H/dMMR metastatic colorectal cancer

Robust clinical activity has been observed with the immune checkpoint inhibitor pembrolizumab in patients with microsatellite instability-high/mismatch repair-deficient (MSI-H/dMMR) metastatic colorectal cancer (mCRC). However, given the response rate of 45% and a median progression-free survival of 16.5 months with first-line pembrolizumab demonstrated in KEYNOTE-177, there is room for improvement. Targeting a second immune receptor, such as CTLA-4, LAG-3, TIGIT, or ILT-4 may improve efficacy of PD-1 inhibition. Here we describe the design and rationale for the open-label, randomized, phase II KEYSTEP-008 trial, which will evaluate the efficacy and safety of pembrolizumab-based combination therapy compared with pembrolizumab monotherapy in chemotherapy-refractory (cohort A) or previously untreated (cohort B) MSI-H/dMMR mCRC. Clinical Trial Registration: NCT04895722 (ClinicalTrials.gov).

Initial Panitumumab Plus Fluorouracil, Leucovorin, and Oxaliplatin or Plus Fluorouracil and Leucovorin in Elderly Patients With RAS and BRAF Wild-Type Metastatic Colorectal Cancer: The PANDA Trial by the GONO Foundation

PURPOSE

To verify whether both doublet chemotherapy with a modified schedule of fluorouracil, leucovorin, and oxaliplatin (mFOLFOX) and monochemotherapy with fluorouracil plus leucovorin (5-FU + LV) achieve satisfactory efficacy when both regimens are combined with panitumumab (PAN) as initial treatment of elderly patients with RAS/BRAF wild-type metastatic colorectal cancer (mCRC).

PATIENTS AND METHODS

PANDA (ClinicalTrials.gov identifier: NCT02904031) was an open-label, randomized phase II noncomparative trial in previously untreated patients age 70 years and older with unresectable RAS/BRAF wild-type mCRC. Patients were randomly assigned 1:1 to mFOLFOX + PAN (arm A) or 5-FU + LV + PAN (arm B) for up to 12 cycles, followed by PAN maintenance. The primary end point was progression-free survival (PFS). In each arm, assuming a null hypothesis of median PFS time ≤6 months and target PFS ≥9.65, 90 patients per arm were needed to achieve 90% power and 5% type I error (one-sided Brookmeyer-Crowley test).

RESULTS

Between July 2016 and April 2019, 91 patients were randomly assigned to arm A and 92 to arm B. At a median follow-up of 50.0 months (IQR, 45.6-56.4), median PFS was 9.6 and 9.0 months for arm A and B, respectively (P < .001 in each arm). Overall response rate was 69% and 52%, whereas median overall survival was 23.5 and 22.0 months in arm A and B, respectively. The overall rate of grade >2 chemotherapy-related adverse events was 60% and 37%, respectively. Baseline G8 and Chemotherapy Risk Assessment Scale for High-Age Patients scores were prognostic, but they were not associated with efficacy and safety of the two arms.

CONCLUSION

Both mFOLFOX and 5-FU + LV + PAN are reasonable options as initial therapy of elderly patients with RAS/BRAF wild-type mCRC. 5-FU + LV + PAN is associated with a better safety profile.

Different prognostic values of KRAS exon 2 submutations and BRAF V600E mutation in microsatellite stable (MSS) and unstable (MSI) stage III colon cancer: an ACCENT/IDEA pooled analysis of seven trials

BACKGROUND

The prognostic value of KRAS and BRAFV600E mutations in stage III colon cancer (CC) remains controversial and has never been clearly analyzed in patients with microsatellite instability-high (MSI-H) tumors due to sample size limitations. Data are also lacking for KRAS submutations and prognosis.

PATIENTS AND METHODS

We examined clinicopathological variables and prognosis in patients with surgically resected stage III CC who participated in seven clinical trials from the ACCENT/IDEA databases. Associations between KRAS exon 2 and BRAFV600E mutations and time to recurrence (TTR), overall survival (OS), and survival after recurrence (SAR) were assessed using a Cox model. We also analyzed the prognostic value of KRAS exon 2 submutations.

RESULTS

Among 8460 patients, 11.4% had MSI-H status. In the MSI-H group, BRAFV600E, KRAS exon 2 mutants, and double-wild-type statuses were detected in 40.6%, 18.1%, and 41.3%, respectively, whereas and in the microsatellite stable (MSS) group, these were detected in 7.7%, 38.6%, and 53.8%, respectively. In the MSS group, 5-year TTR rates of 61.8%, 66.3%, and 72.9% were observed among patients with BRAFV600E, KRAS exon 2 mutants, and those who were DWT, respectively [adjusted hazard ratio (HR) = 1.58 and 1.31, both P < 0.001]. In the MSI-H group, 5-year TTR rates did not differ significantly among the mutated subgroups. Similar results were found for OS. However, survival after relapse was significantly shorter in the KRAS exon 2- and BRAFV600E-mutated patients in both MSS (adjusted HR = 2.06 and 1.15; both P < 0.05) and MSI-H (adjusted HR = 1.99 and 1.81; both P < 0.05) groups. In the MSS group, KRAS exon 2 mutations were associated with TTR, but only p.G12C, p.G12D, and p.G13D were associated with poor outcomes after disease recurrence.

CONCLUSIONS

Testing for both KRAS and BRAFV600E mutations in stage III patients should be considered as they can better define individual patient prognosis, and may also enable patient selection for (neo)adjuvant trials dedicated to specific molecular subtypes with poor prognosis.

Time to recurrence and its relation to survival after recurrence in patients resected for stage III colon cancer

BACKGROUND

It is intuitively thought that early relapse is associated with poor survival after recurrence (SAR) in resected colon cancer (CC) patients, but this has never been formally studied.

METHODS

We pooled data from stage III patients treated with oxaliplatin-based adjuvant therapy in two phase III trials, to analyse time to recurrence (TTR) and its relationship with SAR. TTR and SAR were also studied according to molecular status (mismatch repair (MMR), RAS, and BRAFV600E). Early relapsing patients were defined as patients having a TTR event within 12 months after starting adjuvant chemotherapy.

RESULTS

4548 stage III CC patients were included in the present analysis. Deficient MMR (dMMR) CC patients experienced fewer recurrences than proficient (p)MMR CC patients (18.8% versus 27.6%) but had a significantly shorter median TTR (mTTR; 0.74 versus 1.40 years, p < 0.0001). In pMMR patients, BRAF and RAS mutations were also associated with earlier mTTR as compared to double wild-type (WT) patients (0.99 versus 1.38 versus 1.54 years, respectively, p < 0.0001). Early recurrence occurred in 397 patients and was associated with a median SAR (2.2 versus 3.3 years, p = 0.0007). However, this association was mainly due to pMMR/RAS and BRAFV600E mutated tumours and was not confirmed in dMMR and pMMR/double WT subgroups.

CONCLUSION

In resected stage III CC treated with standard oxaliplatin-based adjuvant therapy, TTR varies between dMMR, pMMR/RAS, or BRAFV600E mutated and pMMR/double WT tumours. In addition, early relapse is associated with poor survival, mainly due to patients resected for a pMMR/RAS or BRAFV600E mutated tumour.

Concordance of microsatellite instability and mismatch repair status in paired biopsies and surgical specimens of resectable gastroesophageal adenocarcinoma: time for a call to action

BACKGROUND

Reliability of mismatch repair proteins and microsatellite instability assessment is essential in order to define treatment strategy and identify candidates to immune checkpoint inhibitors in locally advanced gastroesophageal carcinoma. We evaluated the concordance of deficient mismatch repair (dMMR) and microsatellite instability-high (MSI-H) status between endoscopic biopsies and surgical specimens.

METHODS

Consecutive patients with resectable gastric or gastroesophageal junction adenocarcinoma classified as MSI-H/dMMR by polymerase chain reaction (PCR) or immunohistochemistry (IHC) and operated at three referral Institutions were included. The primary endpoint was the rate of concordance between biopsy and surgical samples. If needed, central revision by IHC/PCR was performed by specialized pathologists from coordinating Institutions.

RESULTS

Thirteen (19.7%) out of 66 patients showed discordant MSI-H/dMMR results in the original pathology reports. In most cases (11, 16.7%) this was due to the diagnosis of proficient mismatch repair status on biopsies. Among the ten cases available for central review, four were due to sample issues, four were reclassified as dMMR, one case showed dMMR status but was classified as microsatellite stable by PCR, one was linked to misdiagnosis of endoscopic biopsy by the local pathologist. Heterogeneity of mismatch repair proteins staining was observed in two cases.

CONCLUSIONS

Available methods can lead to conflicting results in MSI-H/dMMR evaluation between endoscopic biopsies and surgical samples of gastroesophageal adenocarcinoma. Strategies aiming to improve the reliability of assessment should be primarily focused on the optimization of tissue collection and management during endoscopy and adequate training of dedicated gastrointestinal pathologists within the multidisciplinary team.

ILUSTRO: Phase II Multicohort Trial of Zolbetuximab in Patients with Advanced or Metastatic Claudin 18.2-Positive Gastric or Gastroesophageal Junction Adenocarcinoma

PURPOSE

Zolbetuximab, an IgG1 monoclonal antibody, binds to claudin 18.2 (CLDN18.2) and mediates tumor cell death through antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity. We sought to examine zolbetuximab combinations in CLDN18.2-positive HER2-negative gastric/gastroesophageal junction (G/GEJ) adenocarcinoma.

PATIENTS AND METHODS

This phase II study assessed efficacy and safety of zolbetuximab, alone or with modified FOLFOX6 (mFOLFOX6) or pembrolizumab, in CLDN18.2-positive advanced/metastatic G/GEJ adenocarcinoma. Patients received zolbetuximab as monotherapy in third/later-line (Cohort 1A, n = 30), with mFOLFOX6 in first-line (Cohort 2, n = 21), or with pembrolizumab in third/later-line (Cohort 3A, n = 3) treatment. The primary endpoint for Cohort 1A was objective response rate (ORR). Key secondary endpoints were ORR (Cohorts 2 and 3A), overall survival (OS; Cohort 1A), and progression-free survival (PFS) and safety (all cohorts).

RESULTS

ORR was 0% in Cohorts 1A and 3A, and 71.4% [95% confidence interval (CI), 47.82-88.72] in Cohort 2. Median PFS was 1.54 months (95% CI, 1.31-2.56) in Cohort 1A, 2.96 months (95% CI, 1.48-4.44) in Cohort 3A, and 17.8 months (95% CI, 8.05-25.69) in Cohort 2. Median OS in Cohort 1A was 5.62 months (95% CI, 2.27-11.53). Gastrointestinal adverse events occurred across cohorts [nausea, 63%-90% (grade ≥ 3, 4.8%-6.7%) and vomiting, 33%-67% (grade ≥ 3, 6.7%-9.5%)].

CONCLUSIONS

Zolbetuximab plus mFOLFOX6 demonstrated promising efficacy in previously untreated patients with CLDN18.2-positive G/GEJ adenocarcinoma. These data support the first-line development of zolbetuximab in patients whose tumors are CLDN18.2-positive. Across cohorts, zolbetuximab treatment was tolerable with no new safety signals.

The prognostic Value of Thyroid Hormone Levels in Immunotherapy-Treated Patients With Metastatic Urothelial Carcinoma

INTRODUCTION

A low fT3/fT4 ratio has been associated with a poorer prognosis in patients treated for different solid malignancies. However, the prognostic role of baseline thyroid function in patients with metastatic urothelial carcinoma (mUC) has not yet been established.

PATIENTS AND METHODS

We analyzed 72 consecutive immunotherapy-treated patients with mUC from a single institution. We recorded clinical data, baseline blood test results, and oncological outcomes. We stratified patients into three groups according to the fT3/fT4 ratio value and analyzed differences in progression-free survival (PFS), overall survival (OS), and radiological response in the three groups. We also conducted univariate and multivariate analyses to identify prognostic factors for PFS and OS.

RESULTS

The median PFS in the low, intermediate, and high fT3/fT4 ratio groups was 2.2, 4.1, and 8.2 months, respectively (P < 0.01). The median OS in the low, intermediate, and high fT3/fT4 groups was 3.6, 10.3, and 19.1 months, respectively (P < .01). The low fT3/fT4 ratio maintained its prognostic role independently of other prognostic factors. Patients with a high fT3/fT4 ratio had an increased radiological response.

CONCLUSION

Thyroid hormone impairment, as measured by the fT3/fT4 ratio, is a strong prognostic factor in patients treated with immunotherapy for urothelial carcinoma.

Transcriptomic Signatures of MSI-High Metastatic Colorectal Cancer Predict Efficacy of Immune Checkpoint Inhibitors

PURPOSE

Microsatellite instability (MSI) is currently the only predictive biomarker of efficacy of immune checkpoint inhibitors (ICI) in metastatic colorectal cancers (mCRC). However, 10% to 40% of patients with MSI mCRC will experience a primary resistance to ICI.

EXPERIMENTAL DESIGN

In two cohorts of patients with MSI mCRC treated with ICI (exploratory, N = 103; validation, N = 35), 3' RNA sequencing was performed from primary tumors. Previously described single-cell transcriptomic signatures of tumor microenvironment (TME) were analyzed.

RESULTS

In the exploratory cohort, the unsupervised clustering allowed the identification of three clusters of tumors with distinct transcriptional profiles: cluster A ("stromalHIGH-proliferationLOW"), cluster B ("stromalHIGH-proliferationMED"), and cluster C ("stromalLOW-proliferationHIGH"), with an enrichment of patients progressing at first disease assessment under ICI in cluster A (30% vs. 12% in cluster B and 8.1% in cluster C; P = 0.074). Progression-free survival (PFS) was also significantly shorter in patients belonging to cluster A, compared with clusters B or C (P < 0.001) with 2-year PFS rates of 33.5%, 80.5%, and 78.3%, respectively. In multivariate analysis, PFS was still significantly longer in patients belonging to cluster B [HR, 0.19; 95% confidence interval (CI), 0.08-0.45; P < 0.001] and cluster C (HR, 0.25; 95% CI, 0.10-0.59; P = 0.02), compared with patients belonging to cluster A. The association of this clustering with PFS under ICI was confirmed in the validation cohort. PFS related to non-ICI-based regimens was not significantly different according to cluster.

CONCLUSIONS

This unsupervised transcriptomic classification identified three groups of MSI mCRCs with different compositions of TME cells and proliferative capacities of TME/tumor cells. The "stromalHIGH-proliferationLOW" cluster is associated with a poorer prognosis with ICI treatment.

BRAF V600E/RAS Mutations and Lynch Syndrome in Patients With MSI-H/dMMR Metastatic Colorectal Cancer Treated With Immune Checkpoint Inhibitors

BACKGROUND

We pooled data from 2 cohorts of immune checkpoint inhibitors-treated microsatellite instability-high/mismatch repair-deficient (MSI/dMMR) metastatic colorectal cancer patients to evaluate the prognostic value of RAS/BRAFV600E mutations and Lynch syndrome (LS).

PATIENTS AND METHODS

Patients were defined as LS-linked if germline mutation was detected and as sporadic if loss of MLH1/PMS2 expression with BRAFV600E mutation and/or MLH1 promoter hypermethylation, or biallelic somatic MMR genes mutations were found. Progression-free survival (PFS) and overall survival (OS) were adjusted on prognostic modifiers selected on unadjusted analysis (P < .2) if limited number of events.

RESULTS

Of 466 included patients, 305 (65.4%) and 161 (34.5%) received, respectively, anti-PD1 alone and anti-PD1+anti-CTLA4 in the total population, 111 (24.0%) were treated in first-line; 129 (28.8%) were BRAFV600E-mutated and 153 (32.8%) RAS-mutated. Median follow-up was 20.9 months. In adjusted analysis of the whole population (PFS/OS events = 186/133), no associations with PFS and OS were observed for BRAFV600E-mutated (PFS HR= 1.20, P = .372; OS HR = 1.06, P = .811) and RAS-mutated patients (PFS HR = 0.93, P = .712, OS HR = 0.75, P = .202). In adjusted analysis in the Lynch/sporadic status-assigned population (n = 242; PFS/OS events = 80/54), LS-liked patients had an improved PFS compared to sporadic cases (HR = 0.49, P = .036). The adjusted HR for OS was 0.56 with no significance (P = .143). No adjustment on BRAFV600E mutation was done due to collinearity.

CONCLUSION

In this cohort, RAS/BRAFV600E mutations were not associated with survival while LS conferred an improved PFS.

Demystifying BRAF Mutation Status in Colorectal Liver Metastases : A Multi-institutional, Collaborative Approach to 6 Open Clinical Questions

OBJECTIVE

To investigate the clinical implications of BRAF -mutated (mut BRAF ) colorectal liver metastases (CRLMs).

BACKGROUND

The clinical implications of mut BRAF status in CRLMs are largely unknown.

METHODS

Patients undergoing resection for mut BRAF CRLM were identified from prospectively maintained registries of the collaborating institutions. Overall survival (OS) and recurrence-free survival (RFS) were compared among patients with V600E versus non-V600E mutations, KRAS/BRAF comutation versus mut BRAF alone, microsatellite stability status (Microsatellite Stable (MSS) vs instable (MSI-high)), upfront resectable versus converted tumors, extrahepatic versus liver-limited disease, and intrahepatic recurrence treated with repeat hepatectomy versus nonoperative management.

RESULTS

A total of 240 patients harboring BRAF -mutated tumors were included. BRAF V600E mutation was associated with shorter OS (30.6 vs 144 mo, P =0.004), but not RFS compared with non-V600E mutations. KRAS/BRAF comutation did not affect outcomes. MSS tumors were associated with shorter RFS (9.1 vs 26 mo, P <0.001) but not OS (33.5 vs 41 mo, P =0.3) compared with MSI-high tumors, whereas patients with resected converted disease had slightly worse RFS (8 vs 11 mo, P =0.01) and similar OS (30 vs 40 mo, P =0.4) compared with those with upfront resectable disease. Patients with extrahepatic disease had worse OS compared with those with liver-limited disease (8.8 vs 40 mo, P <0.001). Repeat hepatectomy after intrahepatic recurrence was associated with improved OS compared with nonoperative management (41 vs 18.7 mo, P =0.004). All results continued to hold true in the multivariable OS analysis.

CONCLUSIONS

Although surgery may be futile in patients with BRAF -mutated CRLM and concurrent extrahepatic disease, resection of converted disease resulted in encouraging survival in the absence of extrahepatic spread. Importantly, second hepatectomy in select patients with recurrence was associated with improved outcomes. Finally, MSI-high status identifies a better prognostic group, with regard to RFS while patients with non-V600E mutations have excellent prognosis.

Clinical and Genomic Characterization of Pancreatic Ductal Adenocarcinoma with Signet-Ring/Poorly Cohesive Cells

Signet-ring cell (SRC)/poorly cohesive cell carcinoma is an aggressive variant of pancreatic ductal adenocarcinoma (PDAC). This study aimed to clarify its clinicopathologic and molecular profiles based on a multi-institutional cohort of 20 cases. The molecular profiles were investigated using DNA and RNA sequencing. The clinicopathologic parameters and molecular alterations were analyzed based on survival indices and using a validation/comparative cohort of 480 conventional PDAC patients. The primary findings were as follows: (1) clinicopathologic features: SRC carcinomas are highly aggressive neoplasms with poor prognosis, and the lungs are elective metastatic sites; (2) survival analysis: a higher SRC component was indicative of poorer prognosis. In particular, the most clinically significant threshold of SRC was 80%, showing statistically significant differences in both disease-specific and disease-free survival; (3) genomic profiles: SRC carcinomas are similar to conventional PDAC with the most common alterations affecting the classic PDAC drivers KRAS (70% of cases), TP53 (55%), SMAD4 (25%), and CDKN2A (20%). EGFR alterations, RET::CCDC6 fusion gene, and microsatellite instability (3 different cases, 1 alteration per case) represent novel targets for precision oncology. The occurrence of SMAD4 mutations was associated with poorer prognosis; (4) pancreatic SRC carcinomas are genetically different from gastric SRC carcinomas: CDH1, the classic driver gene of gastric SRC carcinoma, is not altered in pancreatic SRC carcinoma; (5) transcriptome analysis: the cases clustered into 2 groups, one classical/exocrine-like, and the other squamous-like; and (6) SRC carcinoma-derived organoids can be successfully generated, and their cultures preserve the histologic and molecular features of parental SRC carcinoma. Although pancreatic SRC carcinoma shares similarities with conventional PDAC regarding the most important genetic drivers, it also exhibits important differences. A personalized approach for patients with this tumor type should consider the clinical relevance of histologic determination of the SRC component and the presence of potentially actionable molecular targets.

Predictive Impact of RNF43 Mutations in Patients With Proficient Mismatch Repair/Microsatellite Stable BRAFV600E-Mutated Metastatic Colorectal Cancer Treated With Target Therapy or Chemotherapy

PURPOSE

Target therapy (TT) with encorafenib plus cetuximab is a standard option in patients with BRAFV600E-mutated (mut) pretreated metastatic colorectal cancer (mCRC). Recently, mutations in RNF43, encoding a negative regulator of the WNT pathway, were associated with longer progression-free survival (PFS) and overall survival (OS) in patients with proficient mismatch repair/microsatellite stable (pMMR/MSS) BRAFV600E-mut mCRC treated with TT. Here, we explored the effect of RNF43 mutations on the efficacy of second-line TT versus standard chemotherapy (CT).

METHODS

A retrospective cohort of patients with pMMR/MSS BRAFV600E-mut tumors, available RNF43 mutational status, and treated with second-line TT or oxaliplatin- and/or irinotecan-based CT was analyzed.

RESULTS

One hundred thirty-two patients with pMMR/MSS BRAFV600E-mut mCRC were included. RNF43 was found mut in 34 (26%) cases. Among RNF43 mutants, TT was associated with longer PFS (7.7 v 3.0 months; P = .002) and higher overall response rate (ORR; 45% v 0%; P = .009) compared with CT. Conversely, among RNF43 wild-type (wt) patients, only a trend for longer PFS (4.5 v 3.7 months; P = .064) favoring TT, with no differences in ORR (P = .14), was observed. After excluding 36 patients receiving TT in third line or beyond, a longer OS (19.4 v 10.1 months; P = .022) and a numerically OS advantage (10.6 v 6.6 months; P = .068) were reported for TT both in the RNF43-mut and in the RNF43 wt groups. However, no interaction effect was reported between RNF43 mutational status and treatment in ORR (Pinteraction = .96), PFS (Pinteraction = .13), and OS (Pinteraction = .44).

CONCLUSION

Patients with pMMR/MSS BRAFV600E-mut mCRC achieve benefit from TT versus CT independently of RNF43 mutational status, although a higher magnitude of benefit from TT is observed in RNF43-mut tumors. These findings deserve confirmation in concluded and ongoing randomized trials.

Adverse events during first-line treatments for mCRC: The Toxicity over Time (ToxT) analysis of three randomised trials

BACKGROUND

In clinical trials, the assessment of safety is traditionally focused on the overall rate of high-grade and serious adverse events (AEs). A new approach to AEs evaluation, taking into account chronic low-grade AEs, single patient's perspective, and time-related information, such as ToxT analysis, should be considered especially for less intense but potentially long-lasting treatments, such as maintenance strategies in metastatic colorectal cancer (mCRC).

PATIENTS AND METHODS

We applied ToxT (Toxicity over Time) evaluation to a large cohort of mCRC patients enroled in randomised TRIBE, TRIBE2, and VALENTINO studies, in order to longitudinally describe AEs throughout the whole treatment duration and to compare AEs evolution over cycles between induction and maintenance strategies, providing numerical and graphical results overall and per single patient. After 4-6 months of combination therapy, 5-fluorouracil/leucovorin (5-FU/LV) + bevacizumab or panitumumab was recommended in all studies except for the 50% of patients in the VALENTINO trial who received panitumumab alone.

RESULTS

Out of 1400 patients included, 42% received FOLFOXIRI (5-FU/LV, oxaliplatin, and irinotecan)/bevacizumab, 18% FOLFIRI/bevacizumab, 24% FOLFOX/bevacizumab, 16% FOLFOX/panitumumab. Mean grade of general and haematological AEs was higher in the first cycles, then progressively decreasing after the end of induction (p < 0.001), and always remaining at the highest levels with FOLFOXIRI/bevacizumab (p < 0.001). Neurotoxicity became more frequent over the cycles with late high-grade episodes (p < 0.001), while the incidence but not the grade of hand-and-foot syndrome gradually increased (p = 0.91). Anti-VEGF-related AEs were more severe in the first cycles, then setting over at low levels (p = 0.03), while anti-EGFR-related AEs still affected patients during maintenance.

CONCLUSIONS

Most of chemotherapy-related AEs (except for HFS and neuropathy) reach the highest level in the first cycles, then decrease, probably due to their active clinical management. Transition to maintenance allows relief from most AEs, especially with bevacizumab-based regimens, while anti-EGFR-related AEs may persist.

Durvalumab plus gemcitabine and cisplatin in advanced biliary tract cancer: An early exploratory analysis of real-world data

BACKGROUND

The TOPAZ-1 phase III trial reported a survival benefit with the anti-programmed death cell ligand 1 (anti-PD-L1) durvalumab in combination with gemcitabine and cisplatin in patients with advanced biliary tract cancer. The present study investigated the efficacy and safety of this new standard treatment in a real-world setting.

METHODS

The analysed population included patients with unresectable, locally advanced or metastatic adenocarcinoma of the biliary tract treated with durvalumab in combination with gemcitabine and cisplatin at 17 Italian centres. The primary endpoint of the study was progression-free survival (PFS), whereas secondary endpoints included overall survival (OS), overall response rate (ORR) and safety. Unadjusted and adjusted hazard ratios (HRs) by baseline characteristics were calculated using the Cox proportional hazards model.

RESULTS

From February 2022 to November 2022, 145 patients were enrolled. After a median follow-up of 8.5 months (95% CI: 7.9-13.6), the median PFS was 8.9 months (95% CI: 7.4-11.7). Median OS was 12.9 months (95% CI: 10.9-12.9). The investigator-assessed confirmed ORR was 34.5%, and the disease control rate was 87.6%. Any grade adverse events (AEs) occurred in 137 patients (94.5%). Grades 3-4 AEs occurred in 51 patients (35.2%). The rate of immune-mediated AEs (imAEs) was 22.7%. Grades 3-4 imAEs occurred in 2.1% of the patients. In univariate analysis, non-viral aetiology, ECOG PS >0 and NLR ≥3 correlated with shorter PFS.

CONCLUSION

The results reported in this first real-world analysis mostly confirmed the results achieved in the TOPAZ-1 trial in terms of PFS, ORR and safety.

Sequential therapies after atezolizumab plus bevacizumab or lenvatinib first-line treatments in hepatocellular carcinoma patients

INTRODUCTION

The aim of this retrospective proof-of-concept study was to compare different second-line treatments for patients with hepatocellular carcinoma and progressive disease (PD) after first-line lenvatinib or atezolizumab plus bevacizumab.

MATERIALS AND METHODS

A total of 1381 patients had PD at first-line therapy. 917 patients received lenvatinib as first-line treatment, and 464 patients atezolizumab plus bevacizumab as first-line.

RESULTS

49.6% of PD patients received a second-line therapy without any statistical difference in overall survival (OS) between lenvatinib (20.6months) and atezolizumab plus bevacizumab first-line (15.7months; p = 0.12; hazard ratio [HR]= 0.80). After lenvatinib first-line, there wasn't any statistical difference between second-line therapy subgroups (p = 0.27; sorafenib HR: 1; immunotherapy HR: 0.69; other therapies HR: 0.85). Patients who underwent trans-arterial chemo-embolization (TACE) had a significative longer OS than patients who received sorafenib (24.7 versus 15.8months, p < 0.01; HR=0.64). After atezolizumab plus bevacizumab first-line, there was a statistical difference between second-line therapy subgroups (p < 0.01; sorafenib HR: 1; lenvatinib HR: 0.50; cabozantinib HR: 1.29; other therapies HR: 0.54). Patients who received lenvatinib (17.0months) and those who underwent TACE (15.9months) had a significative longer OS than patients treated with sorafenib (14.2months; respectively, p = 0.01; HR=0.45, and p < 0.05; HR=0.46).

CONCLUSION

Approximately half of patients receiving first-line lenvatinib or atezolizumab plus bevacizumab access second-line treatment. Our data suggest that in patients progressed to atezolizumab plus bevacizumab, the systemic therapy able to achieve the longest survival is lenvatinib, while in patients progressed to lenvatinib, the systemic therapy able to achieve the longest survival is immunotherapy.

Clinical outcomes with atezolizumab plus bevacizumab or lenvatinib in patients with hepatocellular carcinoma: a multicenter real-world study

PURPOSE

The purpose of this study is to compare response rates of lenvatinib and atezolizumab plus bevacizumab, in first-line real-world setting.

METHODS

Overall cohort included Western and Eastern hepatocellular carcinoma (HCC) patient populations from 46 centres in 4 countries (Italy, Germany, Japan, and Republic of Korea).

RESULTS

1312 patients were treated with lenvatinib, and 823 patients were treated with atezolizumab plus bevacizumab. Objective response rate (ORR) was 38.6% for patients receiving lenvatinib, and 27.3% for patients receiving atezolizumab plus bevacizumab (p < 0.01; odds ratio 0.60). For patients who achieved complete response (CR), overall survival (OS) was not reached in both arms, but the result from univariate Cox regression model showed 62% reduction of death risk for patients treated with atezolizumab plus bevacizumab (p = 0.05). In all multivariate analyses, treatment arm was not found to be an independent factor conditioning OS. Comparing ORR achieved in the two arms, there was a statistically significant difference in favor of lenvatinib compared to atezolizumab plus bevacizumab in all subgroups except for Eastern patients, Child-Pugh B patients, presence of portal vein thrombosis, α-feto-protein ≥ 400 ng/mL, presence of extrahepatic disease, albumin-bilirubin (ALBI) grade 2, and no previous locoregional procedures.

CONCLUSION

Lenvatinib achieves higher ORR in all patient subgroups. Patients who achieve CR with atezolizumab plus bevacizumab can achieve OS so far never recorded in HCC patients. This study did not highlight any factors that could identify patient subgroups capable of obtaining CR.

Survival outcomes from atezolizumab plus bevacizumab versus Lenvatinib in Child Pugh B unresectable hepatocellular carcinoma patients

INTRODUCTION

The best first-line treatment for patients with advanced hepatocellular carcinoma (HCC) and Child-Pugh (CP) class B remains unknown. The aim of the present study was to perform a real-world analysis on a large sample of patients with unresectable HCC with CP B treated with atezolizumab plus bevacizumab Vs Lenvatinib.

METHODS

The study population included patients affected by advanced (BCLC-C) or intermediate (BCLC-B) HCC patients not suitable for locoregional therapies from both the Western and Eastern world (Italy, Germany, Republic of Korea and Japan), who received atezolizumab plus bevacizumab or Lenvatinib as first-line treatment. All the study population presented a CP class of B. The primary endpoint of the study was the overall survival (OS) of CP B patients treated with Lenvatinib compared to atezolizumab plus bevacizumab. Survival curves were estimated using the product-limit method of Kaplan-Meier. The role of stratification factors was analyzed with log-rank tests. Finally, an interaction test was performed for the main baseline clinical characteristics.

RESULTS

217 CP B HCC patients were enrolled in the study: 65 (30%) received atezolizumab plus bevacizumab, and 152 (70%) received lenvatinib. The mOS for patients receiving Lenvatinib was 13.8 months (95% CI: 11.6-16.0), compared to 8.2 months (95% CI 6.3-10.2) for patients receiving atezolizumab plus bevacizumab as first-line treatment (atezolizumab plus bevacizumab Vs Lenvatinib: HR 1.9, 95% CI 1.2-3.0, p = 0.0050). No statistically significant differences were highlighted in terms of mPFS. The multivariate analysis confirmed that patients receiving Lenvatinib as first-line treatment have a significantly longer OS compared to patients receiving atezolizumab plus bevacizumab (HR 2.01; 95% CI 1.29-3.25, p = 0.0023). By evaluating the cohort of patients who received atezolizumab plus bevacizumab, we found that Child B patients with ECOG PS 0, or BCLC B stage or ALBI grade 1 were those who had benefited from the treatment thus showing survival outcomes no significantly different compared to those receiving Lenvatinib.

CONCLUSION

The present study suggests for the first time a major benefit from Lenvatinib compared to atezolizumab plus bevacizumab in a large cohort of patients with CP B class HCC.

Trastuzumab deruxtecan in patients in the USA and Europe with HER2-positive advanced gastric or gastroesophageal junction cancer with disease progression on or after a trastuzumab-containing regimen (DESTINY-Gastric02): primary and updated analyses from a single-arm, phase 2 study

BACKGROUND

Approximately 15-20% of advanced gastric and gastro-oesophageal junction cancers overexpress HER2. In DESTINY-Gastric01, the HER2-targeted antibody-drug conjugate trastuzumab deruxtecan improved response and overall survival versus chemotherapy in patients from Japan and South Korea with locally advanced or metastatic HER2-positive gastric or gastro-oesophageal junction cancer whose disease progressed after two lines of previous therapy including trastuzumab. Here, we report primary and updated analyses of the single-arm, phase 2 DESTINY-Gastric02 trial, which aimed to examine trastuzumab deruxtecan in patients living in the USA and Europe.

METHODS

DESTINY-Gastric02 is a single-arm, phase 2 study in adult patients from 24 study sites in the USA and Europe (Belgium, Spain, Italy, and the UK). Eligible patients were aged at least 18 years and had an Eastern Cooperative Oncology Group performance status of 0 or 1, pathologically documented unresectable or metastatic gastric or gastro-oesophageal junction cancer, progressive disease on or after first-line therapy with a trastuzumab-containing regimen, with at least one measurable lesion per Response Evaluation Criteria in Solid Tumours (version 1.1), and centrally confirmed HER2-positive disease on a postprogression biopsy. Patients were given 6·4 mg/kg of trastuzumab deruxtecan intravenously every 3 weeks until disease progression, withdrawal by patient, physician decision, or death. The primary endpoint was confirmed objective response rate by independent central review. The primary endpoint and safety were assessed in the full analysis set (ie, participants who received at least one dose of study drug). Here, we report the primary analysis of this study, with a data cutoff of April 9, 2021, and an updated analysis, with a data cutoff of Nov 8, 2021. This trial is registered with ClinicalTrials.gov, NCT04014075, and is ongoing.

FINDINGS

Between Nov 26, 2019, and Dec 2, 2020, 89 patients were screened and 79 were enrolled and subsequently treated with trastuzumab deruxtecan (median age 60·7 years [IQR 52·0-68·3], 57 [72%] of 79 were male, 22 [28%] were female, 69 [87%] were White, four [5%] were Asian, one [1%] was Black or African American, one [1%] was Native Hawaiian or Pacific Islander, one had missing race, and three [4%] were other races). At the primary analysis (median follow-up 5·9 months [IQR 4·6-8·6 months]), confirmed objective response was reported in 30 (38% [95% CI 27·3-49·6]) of 79 patients, including three (4%) complete responses and 27 (34%) partial responses, as assessed by independent central review. As of data cutoff for the updated analysis (median follow-up 10·2 months [IQR 5·6-12·9]), a confirmed objective response was reported in 33 (42% [95% CI 30·8-53·4]) of 79 patients, including four (5%) complete responses and 29 (37%) partial responses, as assessed by independent central review. The most common grade 3 or worse treatment-emergent adverse events were anaemia (11 [14%]), nausea (six [8%]), decreased neutrophil count (six [8%]), and decreased white blood cell count (five [6%]). Drug-related serious treatment-emergent adverse events occurred in ten patients (13%). Deaths determined to be associated with study treatment occurred in two patients (3%) and were due to interstitial lung disease or pneumonitis.

INTERPRETATION

These clinically meaningful results support the use of trastuzumab deruxtecan as second-line therapy in patients with HER2-positive advanced gastric or gastro-oesophageal junction cancer.

FUNDING

Daiichi Sankyo and AstraZeneca.

Efficacy of immune checkpoint inhibitors in microsatellite unstable/mismatch repair-deficient advanced pancreatic adenocarcinoma: an AGEO European Cohort

BACKGROUND

Immune checkpoint inhibitors (ICIs) improve oncological outcomes in patients with microsatellite instability-high (MSI) or mismatch repair-deficient (dMMR) advanced solid tumours. Nevertheless, based on limited published data, the outcome of patients with MSI/dMMR pancreatic ductal adenocarcinoma (PDAC) seems poorer when compared to other malignancies. This multi-institutional analysis sought to assess the efficacy and tolerability of ICIs in a large real-world cohort of patients with MSI/dMMR PDAC.

METHODS

We retrospectively collected data from patients with MSI/dMMR advanced PDAC treated with ICIs in 16 centers. Progression-free survival and overall survival were calculated from the start of treatment, and we report objective response and disease control rates according to RECIST V1.1.

RESULTS

Thirty-one MSI/dMMR advanced PDAC patients were identified. Twenty-five patients received single-agent anti-PD-1 antibodies, three patients received the combination of nivolumab and ipilimumab and three patients received immunotherapy in combination with chemotherapy. Among 31 evaluable patients, 15 (48.4%) had an objective response (three complete responses and 12 partial responses), and six (19.4%) had stable disease. With a median follow-up of 18 months, the median progression-free survival (PFS) was 26.7 months and the median overall survival (OS) was not reached. Disease control rates (DCRs) among patients with only one line of prior therapy (N = 17) was 76.5%. Grade 3-4 treatment-related adverse events were not observed.

CONCLUSION

This retrospective analysis suggests that ICIs are effective and well tolerated in patients with MSI/dMMR advanced PDAC. Hence, our work supports the use of PD-1 inhibition in this group of patients with high unmet medical need.

Tumour mutational burden as a biomarker in patients with mismatch repair deficient/microsatellite instability-high metastatic colorectal cancer treated with immune checkpoint inhibitors

BACKGROUND

Immune checkpoint inhibitors (ICIs) are the standard treatment in patients with mismatch repair deficient (dMMR)/microsatellite instability-high (MSI-H) metastatic colorectal cancer (mCRC). Tumour mutational burden (TMB) is a promising biomarker for the prediction of treatment outcomes.

PATIENTS AND METHODS

We screened 203 patients with dMMR/MSI-H mCRC treated with an anti-PD-(L)1 (anti-Programmed-Death-(Ligand)1) plus or minus an anti-Cytotoxic T-Lymphocyte Antigen 4 (anti-CTLA-4) agent at three Italian Academic Centers. TMB was tested by Foundation One Next Generation Sequencing assay and correlated with clinical outcomes, in the overall population and according to ICI regimen.

RESULTS

We included 110 patients with dMMR/MSI-H mCRC. Eighty patients received anti-PD-(L)1 monotherapy and 30 received anti-CTLA-4 combinations. Median TMB was 49 mut/Mb (range: 8-251 mut/Mb). The optimal prognostic cut-off for progression-free survival (PFS) stratification was 23 mut/Mb. Patients with TMB ≤23 mut/Mb had significantly worse PFS (adjusted Hazard Ratio [aHR] = 4.26, 95% confidence interval [CI]:1.85-9.82, p = 0.001) and overall survival (OS) (aHR = 5.14, 95% CI: 1.76-14.98, p = 0.003). Using a cut-off optimised for predicting treatment outcome, anti-CTLA-4 combination was associated with a significant PFS/OS benefit versus anti-PD-(L)1 monotherapy in patients with TMB>40 mut/Mb (2-year PFS: 100.0% versus 70.7%, p = 0.002; 2-year OS: 100.0% versus 76.0%, p = 0.025), but not in those with TMB ≤40 mut/Mb (2-year PFS: 59.7% versus 68.6%, p = 0.888; 2-year OS: 80.0% versus 81.0%, p = 0.949).

CONCLUSION

Patients with dMMR/MSI-H mCRC and relatively lower TMB value displayed early disease progression when receiving ICIs, whereas patients with the highest TMB values may obtain the maximal benefit from intensified anti-CTLA-4/PD-1 combination.