Efficacy of panitumumab in older patients with metastatic colorectal cancer: a retrospective analysis using the database of the Hellenic Oncology Research Group (HORG)

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.

Targeted agents in older patients with gastrointestinal cancers - An overview

Targeted agents have been increasingly used in different malignancies and are associated with improved survival outcomes, including gastrointestinal cancers. Their use in the treatment of older patients is appealing given their favorable toxicity profile. In the last years, this subgroup of patients has been attracting increased interest given their representativeness and specific clinical needs. Nonetheless, the lack of data on efficacy and safety of standard treatments in older patients hinders proper evidence-based decision-making, leaving most therapeutic recommendations to be extrapolated from registration trials with low representation of older and frail patients. However, even if most decisions regarding the use of targeted agents in older patients with gastrointestinal cancer remain guided by subanalyses of large trials, data from recent older adult-specific trials are beginning to emerge, particularly in colorectal cancer. This review aims to summarize the existing evidence on treatment of older patients with gastrointestinal carcinomas (colon and rectum, stomach, esophagus, liver, and pancreas) with targeted agents (cetuximab, panitumumab, bevacizumab, ramucirumab, aflibercept, regorafenib, encorafenib, trastuzumab, sorafenib, lenvatinib, cabozantinib, erlotinib, olaparib), and place the evidence in a geriatric oncology perspective.

First-Line Biological Agents Plus Chemotherapy in Older Patients with Metastatic Colorectal Cancer: A Retrospective Pooled Analysis

BACKGROUND

Biologicals, in combination with chemotherapy, are recommended as first-line treatment of metastatic colorectal cancer (mCRC); however, evidence guiding the appropriate management of older patients with mCRC is limited.

OBJECTIVE

This study was undertaken to compare the efficacy and safety outcomes in older versus younger patients with mCRC who received first-line biological therapy.

METHODS

This retrospective analysis used pooled data from five trials undertaken by the Spanish Cooperative Group for the Treatment of Digestive Tumours. All were studies of adults with advanced CRC who received first-line treatment with chemotherapy plus bevacizumab, cetuximab or panitumumab, stratified by age (≥ 65 vs. < 65 years). Endpoints included progression-free survival (PFS), overall survival (OS), overall response rate (ORR) and safety.

RESULTS

In total, 999 patients from five studies were included in the analysis: 480 (48%) were aged ≥ 65 years, and 519 (52%) were aged < 65 years. Median PFS did not differ significantly between patients aged ≥ 65 and < 65 years (9.9 vs. 9.4 months; hazard ratio [HR] 1.01; 95% confidence interval [CI] 0.88-1.17). Median OS was significantly shorter in older than in younger patients (21.3 vs. 25.0 months; HR 1.21; 95% CI 1.04-1.41). There was no significant difference between older and younger patients in ORR (59 vs. 62%). Patients aged ≥ 65 years experienced significantly more treatment-related grade 3 or higher adverse events (61.67%) than did patients aged < 65 years (45.86%).

CONCLUSIONS

Biologicals plus chemotherapy is an effective first-line treatment option for selected patients aged ≥ 65 years with mCRC and has a manageable safety profile and efficacy comparable to that observed in younger patients.

Advanced Age Is a Risk Factor for Recurrence After Resection in Stage II Colorectal Cancer

BACKGROUND/AIM

The number of older patients with colorectal cancer (CRC) is increasing. Stage II CRC is a heterogeneous group of cancers with different prognoses. We aimed to examine older patients in relation to clinical outcome following curative resection in stage II CRC.

PATIENTS AND METHODS

We analyzed data for 329 consecutive patients with stage II CRC following curative resection. Recurrence-free survival (RFS) and overall survival (OS) were compared between older patients ≥75 years of age and those <75 years. Cox proportional hazards model was used to compute hazard ratios (HRs) controlling for potential confounders.

RESULTS

In the multivariable analyses, patients ≥75 years were independently associated with shorter RFS (multivariable HR=2.56, 95% confidence interval (CI)=1.55-4.31, p<0.001) and OS (multivariable HR=4.36, 95%CI=2.08-9.97, p<0.001) in stage II CRC.

CONCLUSION

Older patients were independently associated with shorter RFS and OS following curative resection in stage II CRC.

Treatment guidelines of metastatic colorectal cancer in older patients from the French Society of Geriatric Oncology (SoFOG)

BACKGROUND

Several guidelines dedicated to metastatic colorectal cancer (mCRC) are available. Since 2013 no recent guidelines are specifically dedicated to older patients and based on a systematic review.

MATERIALS AND METHODS

A multidisciplinary Task Force with digestive oncologists, geriatricians and methodologists from the SoFOG was formed in 2016 to update recommendations on medical treatment of mCRC based on a systematic review of publications from 2000 to 2018. Search strategy has followed a standardized protocol from the formulation of clinical questions and definition of a search algorithm to the selection of complete articles for recommendations.

RESULTS

The four selected key questions were: For which older patients with mCRC can we considered: (1) Any chemotherapy, (2) Mono or poly-chemotherapy, (3) Anti-angiogenic therapy, (4) Other targeted therapy. Main recommendations for older patients are: (1) Omission of chemotherapy should be discussed with a geriatrician for patients with severe comorbidities, advanced dementia, uncontrolled psychiatric disorder or severe loss of autonomy. (2) If tumor response is not the main aim, a mono-chemotherapy with 5-fluorouracil combined with bevacizumab is recommended as first-line. (3) For patients with symptoms related to metastases or with a planned metastasis ablation, a doublet chemotherapy combined with bevacizumab or anti-EGFR antibody in the context of a RAS wild type tumor is recommended as first-line. Preliminary data suggest that regorafenib may be used, in its registered indication, in patients under 80 with a performance status of 0 and no autonomy alterations and that trifluridine-tipiracil may be used with a tight supervising of hematological function.

EGFRvIII: An Oncogene with Ambiguous Role

Epidermal growth factor receptor variant III (EGFR^vIII) seems to constitute the perfect therapeutic target for glioblastoma (GB), as it is specifically present on up to 28–30% of GB cells. In case of other tumor types, expression and possible role of this oncogene still remain controversial. In spite of EGFR^vIII mechanism of action being crucial for the design of small active anticancer molecules and immunotherapies, i.e., CAR-T technology, it is yet to be precisely defined. EGFR^vIII is known to be resistant to degradation, but it is still unclear whether it heterodimerizes with EGF-activated wild-type EGFR (EGFR^WT) or homodimerizes (including covalent homodimerization). Constitutive kinase activity of this mutated receptor is relatively low, and some researchers even claim that a nuclear, but not a membrane function, is crucial for its activity. Based on the analyses of recurrent tumors that are often lacking EGFR^vIII expression despite its initial presence in corresponding primary foci, this oncogene is suggested to play a marginal role during later stages of carcinogenesis, while even in primary tumors EGFR^vIII expression is detected only in a small percentage of tumor cells, undermining the rationality of EGFR^vIII-targeting therapies. On the other hand, EGFR^vIII-positive cells are resistant to apoptosis, more invasive, and characterized with enhanced proliferation rate. Moreover, expression of this oncogenic receptor was also postulated to be a marker of cancer stem cells. Opinions regarding the role that EGFR^vIII plays in tumorigenesis and for tumor aggressiveness are clearly contradictory and, therefore, it is crucial not only to determine its mechanism of action, but also to unambiguously define its role at early and advanced cancer stages.

The impact of panitumumab treatment on survival and quality of life in patients with RAS wild-type metastatic colorectal cancer

Panitumumab is a fully human monoclonal antibody targeting the epidermal growth factor receptor (EGFR). It is currently approved for the treatment of RAS wild-type (WT) metastatic colorectal cancer (mCRC) in combination with chemotherapy in first- and second-line and as monotherapy in chemorefractory patients. This review will provide an overview of main efficacy data on panitumumab from its early development up to latest evidences, including novel perspectives on predictive biomarkers of anti-EGFRs efficacy and mechanisms of secondary resistance. Quality of life (QoL) related issues and panitumumab safety profile will be addressed as well.