SAPPHIRE: a randomised phase II study of planned discontinuation or continuous treatment of oxaliplatin after six cycles of modified FOLFOX6 plus panitumumab in patients with colorectal cancer

How to Balance Prognostic Factors in Controlled Phase II Trials: Stratified Permuted Block Randomization or Minimization? An Analysis of Clinical Trials in Digestive Oncology

In controlled phase II trials, major prognostic factors need to be well balanced between arms. The main procedures used are SPBR (Stratified Permuted Block Randomization) and minimization. First, we provide a systematic review of the treatment allocation procedure used in gastrointestinal oncology controlled phase II trials published in 2019. Second, we performed simulations using data from six phase II studies to measure the impacts of imbalances and bias on the efficacy estimations. From the 40 articles analyzed, all mentioned randomization in both the title and abstract, the median number of patients included was 109, and 77.5% were multicenter. Of the 27 studies that reported at least one stratification variable, 10 included the center as a stratification variable, 10 used minimization, 9 used SBR, and 8 were unspecified. In real data studies, the imbalance increased with the number of centers. The total and marginal imbalances were higher with SBR than with minimization, and the difference increased with the number of centers. The efficiency estimates per arm were close to the original trial estimate in both procedures. Minimization is often used in cases of numerous centers and guarantees better similarity between arms for stratification variables for total and marginal imbalances in phase II trials.

Fluorouracil, Leucovorin, and Irinotecan Plus Cetuximab Versus Cetuximab as Maintenance Therapy in First-Line Therapy for RAS and BRAF Wild-Type Metastatic Colorectal Cancer: Phase III ERMES Study

PURPOSE

The intensity of anti-EGFR-based first-line therapy for RAS/BRAF wild-type (wt) metastatic colorectal cancer (mCRC), once disease control is achieved, is controversial. A de-escalation strategy with anti-EGFR monotherapy represents a potential option to maintain efficacy while reducing cytotoxicity.

METHODS

In this multicenter, open-label, phase III trial, patients with untreated RAS/BRAF wt mCRC were randomly assigned to receive either fluorouracil, leucovorin, and irinotecan/cetuximab (FOLFIRI/Cet) until disease progression (arm A) or FOLFIRI/Cet for eight cycles followed by Cet alone (arm B). The coprimary end points were a noninferior progression-free survival (PFS) in the modified per-protocol (mPP) population (>eight cycles) and a lower incidence of grade (G) 3-4 adverse events (AEs) for arm B compared with arm A.

RESULTS

Overall, 606 patients were randomly assigned, with 300 assigned to arm A and 306 to arm B. The median follow-up was 22.3 months. In the mPP population, 291 events occurred with a PFS of 10 versus 12.2 months for arms B and A, respectively (P of noninferiority = .43). In the intention-to-treatment (ITT, ≥one cycle) population, 503 events occurred with a PFS of 9 versus 10.7 months (P = .39). The overall survival was 35.7 versus 30.7 months (P = .119) and 31.0 versus 25.2 months (P = .32) in the mPP and ITT population, respectively. Arm B had lower G3-4 AEs during the maintenance period than arm A (20.2% v 35.1%).

CONCLUSION

The ERMES study did not demonstrate noninferiority of maintenance with Cet alone. Despite a more favorable safety profile, maintenance with single-agent Cet after induction with FOLFIRI/Cet cannot be recommended for all patients but could represent an option in selected cases.

Efficacy of different maintenance strategies for RAS wild-type colorectal cancer: A network meta-analysis

INTRODUCTION

In metastatic RAS wild-type colorectal cancer (CRC), induction combination chemotherapy doublets (CT) with an anti-EGFR agent are considered the primary treatment. We performed a network meta-analysis (NMA) to compare the relative efficacy of different maintenance treatments for advanced RAS wild-type CRC.

MATERIALS AND METHODS

PubMed, EMBASE and Cochrane, from database inception until December 2021 were used. Randomized clinical trials enrolling adults with advanced RAS wild-type CRC and providing overall survival (OS) and/or progression-free survival (PFS) data PRISMA guidelines for NMA were followed. Between-group comparisons were estimated using hazard ratios (HRs) with 95% credible intervals (95% CrIs). Agents were ranked using surface under the cumulative ranking (SUCRA) probabilities.

RESULTS

A total of 7 randomized phase 2 trials were included (for a total of 1286 patients). Compared to depotentiation treatments, continuous CT + anti-EGFR was not significantly superior to other maintenance regimens for OS and was ranked as the best option for NMA (SUCRA p-score=0.69). Conversely, in the PFS analysis, single-agent fluoropyrimidines + anti-EGFR was ranked as the best treatment (SUCRA p-score=0.60).

CONCLUSIONS

Maintaining chemotherapy doublet + anti-EGFR until progression appears to be the best first-line strategy in terms of OS for advanced unresectable RAS wild-type mCRC treatment. However, fluoropyrimidines single-agent + cetuximab or panitumumab represent a reasonable choice regarding PFS.

Maintenance strategies after anti-EGFR-based induction in metastatic colorectal cancer: A systematic review and bayesian network meta-analysis

BACKGROUND

In RAS wild type (wt) metastatic colorectal cancer (mCRC) maintenance therapy after induction with fluoropyrimidine (FP)-based cytotoxic therapy (CT) plus anti-EGFR agents is controversial.

METHODS

Phase II-III randomized trials were included. Maintenance strategies considered were: observation, anti-EGFR or FP monotherapy, FP + anti-EGFR, doublet CT + anti-EGFR.

RESULTS

Maintenance with FP + anti-EGFR (HR 0.56, 95% CrI 0.36-0.89) showed the greatest PFS benefit compared to observation, ranking first on SUCRA analysis (96.4%). Considering OS, doublet CT+ anti-EGFR, FP + anti-EGFR and anti-EGFR monotherapy yielded similar results. For PFS, FP + anti-EGFR confirmed to be valuable in BRAF wt patients and left sided tumors. In left sided tumors, the OS benefit of adding CT was limited. FP plus anti-EGFR showed a favourable safety profile compared to doublet CT + anti-EGFR.

CONCLUSIONS

FP + anti-EGFR can be considered a valuable maintenance option in RAS wt mCRC. EGFR monotherapy can be considered, especially in left-sided tumors.

Maintenance Therapy With Cetuximab After FOLFIRI Plus Cetuximab for RAS Wild-Type Metastatic Colorectal Cancer: A Phase 2 Randomized Clinical Trial

Importance

The optimal maintenance strategy after induction chemotherapy with anti-epidermal growth factor receptor antibody for patients with RAS wild-type metastatic colorectal cancer (mCRC) remains to be debated.

Objective

To evaluate the efficacy and safety of maintenance therapy with single-agent cetuximab after FOLFIRI (leucovorin [folinic acid], fluorouracil, and irinotecan) plus cetuximab induction therapy.

Design, Setting, and Participants

The TIME (Treatment After Irinotecan-Based Frontline Therapy: Maintenance With Erbitux]) (PRODIGE 28 [Partenariat de Recherche en Oncologie Digestive]-UCGI 27 [UniCancer GastroIntestinal Group]) phase 2 noncomparative, multicenter randomized clinical trial was conducted from January 15, 2014, to November 23, 2018, among 139 patients with unresectable RAS wild-type mCRC. The cutoff date for analysis was July 21, 2022.

Interventions

After first-line induction therapy with 8 cycles of FOLFIRI plus cetuximab, patients without disease progression were randomized (1:1) to biweekly maintenance with cetuximab or observation. On disease progression, the same induction regimen was recommended for 16 weeks followed by further maintenance with cetuximab or observation until disease progression under the full induction regimen.

Main Outcomes and Measures

The primary end point was the 6-month progression-free rate from randomization. Analysis was performed on an intention-to-treat basis. An exploratory biomolecular analysis, using next-generation sequencing, investigated the putative prognostic value of the tumor mutation profile.

Results

Of 214 patients enrolled (141 men [65.9%]; median age, 67 years [range, 23-85 years]), 139 were randomized to receive cetuximab (n = 67; 45 men [67.2%]; median age, 64 years [range, 34-85 years]) or to be observed (n = 72; 50 men [69.4%]; median age, 68 years [23-85 years]). The 6-month progression-free rate was 38.8% ([26 of 67] 95% CI, 27.1%-51.5%) in the cetuximab group and 5.6% ([4 of 72] 95% CI, 1.5%-13.6%) in the observation group. At a median follow-up of 40.5 months (95% CI, 33.6-47.5 months), median progression-free survival (PFS) from randomization was 5.3 months (95% CI, 3.7-7.4 months) in the cetuximab group and 2.0 months (95% CI, 1.8-2.7 months) in the observation group. Median overall survival (OS) was 24.8 months (95% CI, 18.7-30.4 months) in the cetuximab group and 19.7 months (95% CI, 13.3-24.4 months) in the observation group. In an exploratory multivariate analysis, any tumor-activating mutation in the mitogen-activated protein kinase (MAPK) pathway genes was associated with shorter PFS from randomization regardless of treatment group (hazard ratio, 1.63 [95% CI, 1.01-2.62]; P = .04). The most frequent grade 3 or 4 treatment-related toxic effect in the cetuximab group during maintenance therapy was rash (8 of 67 [11.9%]).

Conclusion and Relevance

The randomized clinical trial did not meet its primary end point but suggests clinically meaningful PFS and OS benefits associated with cetuximab maintenance therapy. However, maintenance cetuximab or treatment breaks after first-line combination FOLFIRI-cetuximab therapy seems inappropriate for patients with MAPK-mutated independently of the side of primary tumor. A more complete assessment of MAPK pathway mutations warrants further investigation to the refine treatment strategy for patients with RAS wild-type mCRC.

Trial Registration

ClinicalTrials.gov Identifier: NCT02404935.

Optimal maintenance strategy following FOLFOX plus anti-EGFR induction therapy in patients with RAS wild type metastatic colorectal cancer: An individual patient data pooled analysis of randomised clinical trials

BACKGROUND

Anti-EGFR antibodies plus doublet chemotherapy is the standard of care in RAS/BRAF wild-type metastatic colorectal cancer (mCRC). No phase-3 level of evidence is available to guide treatment de-escalation after anti-EGFR-based first-line. Several randomised clinical trials investigated de-intensification strategies with 5-fluorouracil/leucovorin (5-FU/LV) and/or anti-EGFR.

METHODS

We performed an individual patient data pooled analysis of Valentino, Panama, MACRO-2, COIN-B trials including RAS wild-type mCRC patients who received first-line therapy with FOLFOX plus panitumumab or cetuximab followed by pre-specified maintenance strategy. Only patients who started maintenance according to the assigned arm were included. Patients were categorised by type of maintenance (i.e. 5-FU/LV, anti-EGFR or 5-FU/LV + anti-EGFR). Progression-free survival (PFS) and overall survival (OS) were calculated from the start of maintenance; toxicity was evaluated for the maintenance treatment period.

RESULTS

A total of 518 patients were included in the pooled analysis. Overall, 123, 185 and 210 patients received maintenance with 5-FU/LV, anti-EGFR, 5-FU/LV + anti-EGFR, respectively. Median PFS was 5.6, 6.0 and 9.0 (P = 0.009) and OS was 25.7, 24.0 and 28.0 months (P = 0.134) in 5-FU/LV, anti-EGFR and 5-FU/LV + anti-EGFR arms, respectively. Monotherapy maintenance (either 5-FU/LV or anti-EGFR) was inferior to combination in terms of PFS (hazard ratios [HR] 1.26, P = 0.016) and non-significantly trending also in OS (HR 1.20, P = 0.111). An increase of overall any grade and grade ≥ 3 AEs and selected AEs was reported in combination compared to either 5-FU/LV or anti-EGFR arms.

CONCLUSIONS

This pooled analysis including four randomised phase II supports the use of 5-FU/LV plus anti-EGFR as the preferred maintenance regimen. Data provide rational for a more individualised maintenance treatment approach based on tumour and patients features.

Progress of research on molecular targeted therapies for colorectal cancer

Colorectal cancer (CRC) is one of the most common malignancies, accounting for approximately 10% of global cancer incidence and mortality. Approximately 20% of patients with CRC present metastatic disease (mCRC) at the time of diagnosis. Moreover, up to 50% of patients with localized disease eventually metastasize. mCRC encompasses a complex cascade of reactions involving multiple factors and processes, leading to a diverse array of molecular mechanisms. Improved comprehension of the pathways underlying cancer cell development and proliferation, coupled with the accessibility of relevant targeted agents, has propelled advancements in CRC treatment, ultimately leading to enhanced survival rates. Mutations in various pathways and location of the primary tumor in CRC influences the efficacy of targeted agents. This review summarizes available targeted agents for different CRC pathways, with a focus on recent advances in anti-angiogenic and anti-epidermal growth factor receptor agents, BRAF mutations, and human epidermal growth factor receptor 2-associated targeted agents.

Consensus Molecular Subtypes as Biomarkers of Fluorouracil and Folinic Acid Maintenance Therapy With or Without Panitumumab in RAS Wild-Type Metastatic Colorectal Cancer (PanaMa, AIO KRK 0212)

PURPOSE

Consensus molecular subtypes (CMSs) were evaluated as prognostic and predictive biomarkers of patients with RAS wild-type metastatic colorectal cancer (mCRC) receiving fluorouracil and folinic acid (FU/FA) with or without panitumumab (Pmab) after Pmab + mFOLFOX6 induction within the randomized phase II PanaMa trial.

METHODS

CMSs were determined in the safety set (ie, patients that received induction) and full analysis set (FAS; ie, randomly assigned patients who received maintenance) and correlated with median progression-free survival (PFS) and overall survival (OS) since the start of induction or maintenance treatment and objective response rates (ORRs). Hazard ratios (HRs) and 95% CI were calculated by univariate/multivariate Cox regression analyses.

RESULTS

Of 377 patients of the safety set, 296 (78.5%) had available CMS data: CMS1/2/3/4: 29 (9.8%)/122 (41.2%)/33 (11.2%)/112 (37.8%) and unclassifiable: 17 (5.7%). The CMSs were prognostic biomarkers in terms of PFS (P < .0001), OS (P < .0001), and ORR (P = .02) since the start of induction treatment. In FAS patients (n = 196), with CMS2/4 tumors, the addition of Pmab to FU/FA maintenance therapy was associated with longer PFS (CMS2: HR, 0.58 [95% CI, 0.36 to 0.95], P = .03; CMS4: HR, 0.63 [95% CI, 0.38 to 1.03], P = .07) and OS (CMS2: HR, 0.88 [95% CI, 0.52 to 1.52], P = .66; CMS4: HR, 0.54 [95% CI, 0.30 to 0.96], P = .04). The CMS interacted significantly with treatment in terms of PFS (CMS2 v CMS1/3: P = .02; CMS4 v CMS1/3: P = .03) and OS (CMS2 v CMS1/3: P = .03; CMS4 v CMS1/3: P < .001).

CONCLUSION

The CMS had a prognostic impact on PFS, OS, and ORR in RAS wild-type mCRC. In PanaMa, Pmab + FU/FA maintenance was associated with beneficial outcomes in CMS2/4, whereas no benefit was observed in CMS1/3 tumors.

Current concepts of anti-EGFR targeting in metastatic colorectal cancer

Anti-EGFR targeting is one of the key strategies in the treatment of metastatic colorectal cancer (mCRC). For almost two decades oncologists have struggled to implement EGFR antibodies in the mCRC continuum of care. Both sidedness and RAS mutational status rank high among the predictive factors for the clinical efficacy of EGFR inhibitors. A prospective phase III trial has recently confirmed that anti-EGFR targeting confers an overall survival benefit only in left sided RAS-wildtype tumors when given in first line. It is a matter of discussion if more clinical benefit can be reached by considering putative primary resistance mechanisms (e.g., HER2, BRAF, PIK3CA, etc.) at this early stage of treatment. The value of this procedure in daily routine clinical utility has not yet been clearly delineated. Re-exposure to EGFR antibodies becomes increasingly crucial in the disease journey of mCRC. Yet re- induction or re-challenge strategies have been problematic as they relied on mathematical models that described the timely decay of EGFR antibody resistant clones. The advent of liquid biopsy and the implementation of more accurate next-generation sequencing (NGS) based high throughput methods allows for tracing of EGFR resistant clones in real time. These displays the spatiotemporal heterogeneity of metastatic disease compared to the former standard radiographic assessment and re-biopsy. These techniques may move EGFR inhibition in mCRC into the area of precision medicine in order to apply EGFR antibodies with the increase or decrease of EGFR resistant clones. This review critically discusses established concepts of tackling the EGFR pathway in mCRC and provides insight into the growing field of liquid biopsy guided personalized approaches of EGFR inhibition in mCRC.

The Validity of Surrogate Endpoints in Sub Groups of Metastatic Colorectal Cancer Patients Defined by Treatment Class and KRAS Status

Background and Aim: Findings from the literature suggest that the validity of surrogate endpoints in metastatic colorectal cancer (mCRC) may depend on a treatments' mechanism of action. We explore this and the impact of Kirsten rat sarcoma (KRAS) status on surrogacy patterns in mCRC. Methods: A systematic review was undertaken to identify randomized controlled trials (RCTs) for pharmacological therapies in mCRC. Bayesian meta-analytic methods for surrogate endpoint evaluation were used to evaluate surrogate relationships across all RCTs, by KRAS status and treatment class. Surrogate endpoints explored were progression free survival (PFS) as a surrogate endpoint for overall survival (OS), and tumour response (TR) as a surrogate for PFS and OS. Results: 66 RCTs were identified from the systematic review. PFS showed a strong surrogate relationship with OS across all data and in subgroups by KRAS status. The relationship appeared stronger within individual treatment classes compared to the overall analysis. The TR-PFS and TR-OS relationships were found to be weak overall but stronger within the Epidermal Growth Factor Receptor + Chemotherapy (EGFR + Chemo) treatment class; both overall and in the wild type (WT) patients for TR-PFS, but not in patients with the mutant (MT) KRAS status where data were limited. Conclusions: PFS appeared to be a good surrogate endpoint for OS. TR showed a moderate surrogate relationship with PFS and OS for the EGFR + Chemo treatment class. There was some evidence of impact of the mechanism of action on the strength of the surrogacy patterns in mCRC, but little evidence of the impact of KRAS status on the validity of surrogate endpoints.

The Role of Anti-EGFR Monoclonal Antibody in mCRC Maintenance Therapy

Background: Epidermal growth factor receptor (EGFR) monoclonal antibodies (mAbs) combined with chemotherapy in patients with RAS (rat sarcoma viral oncogene homolog) wild-type metastatic colorectal cancer (mCRC) can alleviate and stabilize the disease, effectively prolong the progression-free survival (PFS) and overall survival (OS), and improve the overall response rate (ORR), which is the first-line treatment standard scheme for RAS wild-type mCRC currently. However, whether anti-EGFR mAb can be used for the maintenance treatment after the first-line treatment of mCRC remains controversial. We reviewed the recent studies on anti-EGFR mAb. The contents include five parts, introduction, anti-EGFR mAb in mCRC and its status in first-line therapy, establishment of the maintenance treatment pattern after the standard first-line treatment for mCRC, research progress of anti-EGFR mAb in mCRC maintenance therapy, and conclusion. More studies support the maintenance treatment of anti-EGFR mAb, but some researchers raise the problems about high cost and drug resistance. Despite lack of the maintenance evidence of anti-EGFR mAb, especially lack of large-scale phase III prospective clinical trials, with the emergence of new evidence and more accurate screening of treatment-dominant groups, maintenance therapy with anti-EGFR mAb monotherapy or anti-EGFR mAb combined with fluorouracil-based schemes after first-line chemotherapy combined with anti-EGFR mAb therapy might strive for more treatment opportunities, optimize treatment strategies and prolong treatment continuity, and finally, lead to more survival benefit for suitable patients.

Reinduction of an Anti-EGFR-based First-line Regimen in Patients with RAS Wild-type Metastatic Colorectal Cancer Enrolled in the Valentino Study

Background

In patients with RAS/BRAF wild-type metastatic colorectal cancer (mCRC), growing evidence supports anti-epidermal growth factor receptor (EGFR) retreatment, whereas little is known on the outcomes of anti-EGFR-based reinduction therapy during the upfront strategy.

Methods

We included patients enrolled in the Valentino study who had disease progression and received at least one dose of post-progression therapy. The Kaplan–Meier method and Cox proportional hazards regression were used for the survival analysis. When comparing the outcomes of anti-EGFR-based reinduction versus any second line, a propensity score–based matching was used.

Results

Liver-limited/single site of disease (P &lt; .001 and P = .002), left-sidedness (P = .029), surgery of metastases (P = .003), early tumor shrinkage, and deeper responses (P = .018 and P = .036) were associated with the use of anti-EGFR-based reinduction versus any other second line. All patients treated with reinduction had an anti-EGFR-free interval of at least 3 months. In the propensity score–matched population, progression-free survival (PFS) was similar in the 2 treatment groups, the overall survival (OS) was significantly longer for patients treated with reinduction (P = .029), and the response rate was higher in patients treated with reinduction (P = .033). An oxaliplatin-free interval ≥12 months, left-sidedness, and molecular hyperselection beyond RAS/BRAF were associated with significantly better outcomes after anti-EGFR-based reinduction.

Conclusions

Reinduction strategies with anti-EGFR-based regimens are commonly used in clinical practice. Our data highlight the importance of clinical–molecular selection for re-treatments and the need for prospective strategy trials in selected populations.

Panitumumab Plus Fluorouracil and Folinic Acid Versus Fluorouracil and Folinic Acid Alone as Maintenance Therapy in RAS Wild-Type Metastatic Colorectal Cancer: The Randomized PANAMA Trial (AIO KRK 0212)

PURPOSE

The randomized PANAMA trial investigated the efficacy of panitumumab (Pmab) when added to maintenance therapy with fluorouracil and folinic acid (FU/FA) in patients with RAS wild-type metastatic colorectal cancer.

METHODS

Following first-line induction therapy with six cycles of FU/FA and oxaliplatin plus Pmab, responding patients (stable disease or partial or complete remission) were randomly assigned (1:1, open-label) to maintenance treatment with either FU/FA plus Pmab or FU/FA alone. The primary objective was to demonstrate superiority of progression-free survival (PFS, time from random assignment until progression or death) in favor of FU/FA plus Pmab with a hazard ratio (HR) of 0.75, a power of 80%, and a significance level of 10%. Secondary end points included overall survival, objective response rate of maintenance therapy, and toxicity. Survival end points were analyzed by the Kaplan-Meier method and compared by log-rank test and Cox regressions. Dichotomous variables were compared by Fisher's exact test; odds ratios were indicated when appropriate. The trial is registered with ClinicalTrials.gov (NCT01991873).

RESULTS

Overall, 248 patients were randomly assigned and received maintenance therapy with either FU/FA plus Pmab (125 patients) or FU/FA alone (123 patients). At data cutoff, with 218 events (of 218 needed), PFS of maintenance therapy was significantly improved with FU/FA plus Pmab (8.8 months v 5.7 months; HR, 0.72; 80% CI, 0.60 to 0.85; P = .014). Overall survival (event rate 54%) numerically favored the FU/FA plus Pmab arm (28.7 months v 25.7 months; HR, 0.84; 95% CI, 0.60 to 1.18; P = .32). Objective response rates were 40.8% in patients receiving FU/FA plus Pmab versus 26.0% in patients receiving FU/FA alone (odds ratio, 1.96; 95% CI, 1.14 to 3.36; P = .02). The most frequent Common Terminology Criteria for Adverse Event grade ≥ 3 event during maintenance therapy was skin rash (7.2%).

CONCLUSION

In RAS wild-type metastatic colorectal cancer, maintenance therapy with FU/FA plus Pmab induced a significantly superior PFS compared with FU/FA alone. If active maintenance therapy is aspired following induction therapy with FU/FA and oxaliplatin plus Pmab, FU/FA plus Pmab appears to be the most favorable option.

Impact of Value Frameworks on the Magnitude of Clinical Benefit: Evaluating a Decade of Randomized Trials for Systemic Therapy in Solid Malignancies

In the era of rapid development of new, expensive cancer therapies, value frameworks have been developed to quantify clinical benefit (CB). We assessed the evolution of CB since the 2015 introduction of The American Society of Clinical Oncology and The European Society of Medical Oncology value frameworks. Randomized clinical trials (RCTs) assessing systemic therapies for solid malignancies from 2010 to 2020 were evaluated and CB (Δ) in 2010–2014 (pre-value frameworks (PRE)) were compared to 2015–2020 (POST) for overall survival (OS), progression-free survival (PFS), response rate (RR), and quality of life (QoL). In the 485 studies analyzed (12% PRE and 88% POST), the most common primary endpoint was PFS (49%), followed by OS (20%), RR (12%), and QoL (6%), with a significant increase in OS and decrease in RR as primary endpoints in the POST era (p = 0.011). Multivariable analyses revealed significant improvement in ΔOS POST (OR 2.86, 95% CI 0.46 to 5.26, p = 0.02) while controlling for other variables. After the development of value frameworks, median ΔOS improved minimally. The impact of value frameworks has yet to be fully realized in RCTs. Efforts to include endpoints shown to impact value, such as QoL, into clinical trials are warranted.

Post-Induction Management in Patients With Left-Sided RAS and BRAF Wild-Type Metastatic Colorectal Cancer Treated With First-Line Anti-EGFR-Based Doublet Regimens: A Multicentre Study

Background

Few data regarding post-induction management following first-line anti-epidermal growth factor receptor (EGFR)-based doublet regimens in patients with left-sided RAS/BRAF wild-type metastatic colorectal cancer (mCRC) are available.

Methods

This multicenter, retrospective study aimed at evaluating clinicians’ attitude, and the safety and effectiveness of post-induction strategies in consecutive patients affected by left-sided RAS/BRAF wild-type mCRC treated with doublet chemotherapy plus anti-EGFR as first-line regimen, who did not experience disease progression within 6 months from induction initiation, at 21 Italian and 1 Spanish Institutions. The measured clinical outcomes were: progression-free survival (PFS), overall survival (OS), adverse events, and objective response rate (ORR).

Results

At the data cutoff, among 686 consecutive patients with left-sided RAS/BRAF wild-type mCRC treated with doublet plus anti-EGFR as first-line regimen from March 2012 to October 2020, 355 eligible patients have been included in the present analysis. Among these, 118 (33.2%), 66 (18.6%), and 11 (3.1%) received a maintenance with 5-fluorouracil/leucovorin (5FU/LV)+anti-EGFR, anti-EGFR, and 5FU/LV, respectively, while 160 (45.1%) patients continued induction treatment (non-maintenance) until disease progression, unacceptable toxicity, patient decision, or completion of planned treatment. The median period of follow-up for the overall population was 33.7 months (95%CI = 28.9–35.6). The median PFS values of the 5FU/LV+anti-EGFR, anti-EGFR, 5FU/LV, and non-maintenance cohorts were 16.0 (95%CI = 14.3–17.7, 86 events), 13.0 (95%CI = 11.4–14.5, 56 events), 14.0 (95%CI = 8.1–20.0, 8 events), and 10.1 months (95%CI = 9.0–11.2, 136 events), respectively (p < 0.001). The median OS values were 39.6 (95%CI = 31.5–47.7, 43 events), 36.1 (95%CI = 31.6–40.7, 36 events), 39.5 (95%CI = 28.2–50.8, 4 events), and 25.1 months (95%CI = 22.6–27.6, 99 events), respectively (p < 0.001). After adjusting for key covariates, a statistically significant improvement in PFS in favor of 5FU/LV+anti-EGFR (HR = 0.59, 95%CI = 0.44–0.77, p < 0.001) and anti-EGFR (HR = 0.71, 95%CI = 0.51–0.98, p = 0.039) compared to the non-maintenance cohort was found. Compared to the non-maintenance cohort, OS was improved by 5FU/LV+anti-EGFR (HR = 0.55, 95%CI = 0.38–0.81, p = 0.002) and, with marginal significance, by anti-EGFR (HR = 0.67, 95%CI = 0.51–0.98, p = 0.051). No difference was found in ORR. Any grade non-hematological and hematological events were generally higher in the non-maintenance compared to the maintenance cohorts.

Conclusion

Among the treatment strategies following an anti-EGFR-based doublet first-line induction regimen in patients affected by left-sided RAS/BRAF wild-type mCRC treated in a “real-life” setting, 5FU/LV+anti-EGFR resulted the most adopted, effective, and relatively safe regimen.

Impact of age and gender on the efficacy and safety of upfront therapy with panitumumab plus FOLFOX followed by panitumumab-based maintenance: a pre-specified subgroup analysis of the Valentino study

BACKGROUND

The safety and efficacy outcome of elderly metastatic colorectal cancer (mCRC) patients fit enough to receive combination chemotherapy plus biological agents is an issue of growing interest. Also, gender-specific differential toxicity and efficacy of anti-epidermal growth factor receptor (EGFR)-based upfront treatments need to be explored.

PATIENTS AND METHODS

Valentino was a multicenter, randomized, phase II trial, investigating two panitumumab-based maintenance strategies following first-line panitumumab plus FOLFOX in RAS wild-type mCRC patients. We carried out a subgroup analysis, aimed at assessing the differences in efficacy, safety and quality of life (QoL) according to age (<70 versus ≥70 years) and gender (male versus female). Efficacy endpoints were progression-free survival (PFS), overall survival (OS) and overall response rate (ORR); safety endpoints were rates of any grade and grade 3/4 adverse events (AEs).

RESULTS

No significant differences in terms of PFS, OS and ORR were observed between patients aged <70 or ≥70 years and the effect of the maintenance treatment arm on survival outcomes was similar in the two subgroups. The safety profile of both induction and maintenance treatment and the impact on QoL were similar in elderly and younger patients. No significant differences in PFS, OS, ORR or clinical benefit rate were observed according to gender. A significantly higher rate of overall grade 3/4 AEs (P = 0.008) and of grade 3/4 thrombocytopenia (P = 0.017), any grade and grade 3/4 neutropenia (P < 0.0001) and any grade conjunctivitis (P = 0.033) was reported in female as compared to male patients. Conversely, we reported a significantly higher incidence of any grade skin rash (P = 0.0007) and hypomagnesemia (P = 0.029) in male patients.

CONCLUSIONS

The upfront choice of an anti-EGFR-based doublet chemotherapy followed by a maintenance strategy represents a valuable option in RAS wild-type mCRC irrespective of gender and age, though a careful evaluation of patients to maximize the risk/benefit ratio is warranted.

First-Line Maintenance Treatment in Metastatic Colorectal Cancer (mCRC): Quality and Clinical Benefit Overview

Different strategies of maintenance therapy (sequential CT, intermittent CT, intermittent CT and MAbs, or de-escalation MAbs monotherapy) after first-line treatment are undertaken. Many randomized clinical trials (RCT), which evaluated these approaches, suffer from incorrect design, heterogenous primary endpoints, inadequate size, and other methodology flaws. Drawing any conclusions becomes challenging and recommendations are mainly vague. We evaluated those studies from another perspective, focusing on the design quality and the clinical benefit measure with a more objective and accurate methodology. These data allowed a clearer and more exact overview of the statement in maintenance treatment.

Controversies in the treatment of RAS wild-type metastatic colorectal cancer

Objective

To provide guidance for the management of RAS wild-type (wt) metastatic colorectal cancer (mCRC) in daily practice.

Methods

Nominal group and Delphi techniques were used. A steering committee of seven experts analyzed the current management of RAS wt mCRC, through which they identified controversies, critically analyzed the available evidence, and formulated several guiding statements for clinicians. Subsequently, a group of 30 experts (the expert panel) was selected to test agreement with the statements, through two Delphi rounds. The following response categories were established in both rounds: 1 = totally agree, 2 = basically agree, 3 = basically disagree, 4 = totally disagree. Agreement was defined if ≥ 75% of answers were in categories 1 and 2 (consensus with the agreement) or 3 and 4 (consensus with the disagreement).

Results

Overall, 71 statements were proposed, which incorporated the following areas: (1) overarching principles; (2) tumor location; (3) triplets; (4) maintenance; (5) second-line and beyond treatments; (6) Rechallenge and liquid biopsy. After the two Delphi rounds, only six statements maintained a lack of clear consensus.

Conclusions

This document aims to describe the expert’s attitude when dealing with several common clinical questions regarding patients with RAS wt mCRC.

Electronic supplementary material

The online version of this article (10.1007/s12094-020-02475-8) contains supplementary material, which is available to authorized users.

Maintenance treatment in metastatic colorectal cancer: in search of the best strategy

Over the last 2 decades, the standard fluoropyrimidine-based chemotherapy backbone for metastatic colorectal cancer has been complemented by the addition of novel biological agents, achieving impressive increases in 5-year survival rates. Nonetheless, these new combinations have also entailed increases in toxicity, leading to evaluation of de-escalated chemotherapy regimens and "drug holiday" periods in attempts to reduce side effects and optimise quality of life without impairing efficacy. Here, we review the current and emerging evidence for maintenance schedules with chemotherapy and targeted agents, versus continuous treatment after induction treatment, in metastatic colorectal cancer patients.