A survey of patient and physician acceptance of skin toxicities from anti-epidermal growth factor receptor therapies.

BACKGROUND: Inhibition of the epidermal growth factor receptor (EGFR) extends patient survival in multiple tumor types. Skin toxicities are the most common adverse event (AE) elicited by EGFR inhibitors. Here, we provide deeper insights into patients' and physicians' acceptance of the risk/benefit trade-offs of skin toxicities during cancer therapy, including comparison of their perceptions and experiences with dermatologic AEs. METHODS: A multinational survey of 195 patients and 120 physicians was conducted to gauge attitudes regarding skin toxicities as an AE during cancer therapy. RESULTS: Skin toxicities were identified by patients and physicians as the AE that is most discouraging to patients when undergoing cancer therapies. Skin toxicities were cited as causing pain, impairing quality of life, and proving difficult to manage. Despite these negative influences, the majority of patients (71%) indicated they were willing to accept skin toxicities as an AE of an effective therapy. Indeed, the majority of patients and physicians preferred a more effective therapy that induces more severe skin toxicities than a less efficacious therapy that induces less severe skin toxicities; interestingly, patients were willing to accept a higher likelihood of severe skin toxicities than physicians. CONCLUSION: In this examination of patients' perspectives, we found that patients were willing to accept skin toxicities if they were the anticipated byproduct of a more effective therapeutic regimen. Important differences were observed between patients' and physicians' attitudes regarding risk/benefit trade-offs during cancer therapy, suggesting that patient's considerations and shared decision-making are key to cancer care.

Rechallenge with anti-EGFR therapy to extend the continuum of care in patients with metastatic colorectal cancer.

In patients with RAS wild-type metastatic colorectal cancer (mCRC), an anti-epidermal growth factor receptor (EGFR) monoclonal antibody plus chemotherapy is a standard option for treatment in the first-line setting. Patients who progress while on treatment with anti-EGFR-based therapy can be resistant to further anti-EGFR treatment, but evidence suggests that the anti-EGFR-resistant clones decay, thereby opening the potential for rechallenge or reintroduction in later lines of treatment. Results from recent clinical studies have shown that some patients with mCRC who are rechallenged with anti-EGFR monoclonal antibodies exhibit durable responses. While other therapies have demonstrated improved overall survival in chemorefractory mCRC over the past decade, rechallenge with anti-EGFR monoclonal antibodies in later lines of treatment represents a new option that deserves further investigation in clinical trials. In this review, we summarize the molecular rationale for rechallenge or reintroduction in patients with mCRC who have progressed on earlier-line anti-EGFR treatment and examine the current evidence for using liquid biopsy as a method for selecting rechallenge as a therapeutic option. We also provide an overview of published trials and trials in progress in this field, and outline the potential role of rechallenge in the current clinical setting.

Real-world healthcare resource utilization and costs of weekly versus every-2-week cetuximab in metastatic colorectal cancer.

Aim: To compare healthcare resource utilization (HRU) and healthcare costs (HC) for every-2-week (Q2W) versus weekly (Q1W) cetuximab in metastatic colorectal cancer (mCRC). Patients & methods: Patients with mCRC receiving cetuximab plus chemotherapy in a line-agnostic setting. Cohort study of patients with mCRC treated with cetuximab and chemotherapy in IBM MarketScan. Analyses were weighted by inverse probability of treatment based on propensity score. Results: HRU was numerically lower with the Q2W versus Q1W regimen (weighted mean, 8.1 vs 9.5 encounters per-patient-per-month). The weighted average of HC was $17,653 and $16,469 per-patient-per-month for the Q2W and Q1W regimens, respectively; the difference between regimens decreased when restricting to CRC-related claims. Conclusion: HRU was lower and HC were similar between the Q2W and Q1W regimens.

Comparative effectiveness of weekly versus every-2-weeks cetuximab in metastatic colorectal cancer in a US-insured population.

Aim: To test the noninferiority of cetuximab administered every 2 weeks (Q2W) versus once weekly (Q1W) in treating metastatic colorectal cancer (mCRC) with regard to overall survival (OS). Patients: Patients receiving cetuximab plus chemotherapy for mCRC in a line-agnostic setting. Methods: This cohort study in IBM MarketScan followed patients from initiation of cetuximab for mCRC until the end of the data availability period, proxy-based death or loss of insurance coverage for >30 days. Results: The hazard ratio for OS was 0.94 (0.85-1.03), and the inferiority hypothesis was rejected at p < 0.001. No significant differences were noted in rates of safety events between Q2W and Q1W. Conclusion: Our real-world study confirmed the noninferiority of cetuximab administered Q2W versus Q1W for OS.

Cost-effectiveness of FOLFIRI + cetuximab vs FOLFIRI + bevacizumab in the first-line treatment of RAS wild-type metastatic colorectal cancer in Germany: data from the FIRE-3 (AIO KRK-0306) study.

Aims: This analysis evaluates the cost-effectiveness of first-line treatment with FOLFIRI + cetuximab vs FOLFIRI + bevacizumab for patients with RAS wild-type (wt) metastatic colorectal cancer (mCRC) in Germany based on the randomized phase 3 FIRE-3 trial. For patients with RAS wt mCRC, FOLFIRI + cetuximab yielded statistically significant median overall survival gains over FOLFIRI + bevacizumab.Materials and methods: A standard 3-state partitioned survival cost-utility model was developed to compare the health benefits and costs of treatment from a German social health insurance perspective using individual patient-level trial data. Health outcomes were reported in life-years (LYs) and quality-adjusted life-years (QALYs) gained. Survival was estimated based on Kaplan-Meier (KM) curves supplemented with best-fitting parametric survival model extrapolations. Subgroup analyses of patients with a left-sided primary tumor location or patients with metastases confined to the liver were performed.Results: In the modified intention-to-treat analysis, FOLFIRI + cetuximab, providing 0.68 additional LYs (0.53 QALYs), yielded incremental cost-effectiveness ratios (ICERs) of €36,360/LY and €47,250/QALY. In subgroup analyses, patients experienced improved survival gains without a corresponding increase in costs, resulting in lower ICERs. Our model was most sensitive to changes in treatment duration across all lines of therapy, utility of progressive disease, as well as patients' weight and body surface area.Limitations: This cost-effectiveness analysis was based on patient-level data from the FIRE-3 trial. Trial outcomes may not adequately reflect those in the real-world setting. Additionally, resource use and costs were obtained from tariff lists, which do not account for differences in treatment practice. These considerations limit generalizability of outcomes to other countries, or within the German healthcare setting.Conclusions: Based on our analyses, FOLFIRI + cetuximab is cost-effective compared with FOLFIRI + bevacizumab in patients with RAS wt mCRC, with ICERs well below willingness-to-pay thresholds for diseases with a high burden.

Distinguishing Features of Cetuximab and Panitumumab in Colorectal Cancer and Other Solid Tumors.

Cetuximab and panitumumab are two distinct monoclonal antibodies (mAbs) targeting the epidermal growth factor receptor (EGFR), and both are widely used in combination with chemotherapy or as monotherapy to treat patients with RAS wild-type metastatic colorectal cancer. Although often considered interchangeable, the two antibodies have different molecular structures and can behave differently in clinically relevant ways. More specifically, as an immunoglobulin (Ig) G1 isotype mAb, cetuximab can elicit immune functions such as antibody-dependent cell-mediated cytotoxicity involving natural killer cells, T-cell recruitment to the tumor, and T-cell priming via dendritic cell maturation. Panitumumab, an IgG2 isotype mAb, does not possess these immune functions. Furthermore, the two antibodies have different binding sites on the EGFR, as evidenced by mutations on the extracellular domain that can confer resistance to one of the two therapeutics or to both. We consider a comparison of the properties of these two antibodies to represent a gap in the literature. We therefore compiled a detailed, evidence-based educational review of the known molecular, clinical, and functional differences between the two antibodies and concluded that they are distinct therapeutic agents that should be considered individually during treatment planning. Available data for one agent can only partly be extrapolated to the other. Looking to the future, the known immune activity of cetuximab may provide a rationale for this antibody as a combination partner with investigational chemotherapy plus immunotherapy regimens for colorectal cancer.

Optimising the use of cetuximab in the continuum of care for patients with metastatic colorectal cancer.

The anti-epidermal growth factor receptor (EGFR) monoclonal antibody cetuximab in combination with chemotherapy is a standard of care in the first-line treatment of RAS wild-type (wt) metastatic colorectal cancer (mCRC) and has demonstrated efficacy in later lines. Progressive disease (PD) occurs when tumours develop resistance to a therapy, although controversy remains about whether PD on a combination of chemotherapy and targeted agents implies resistance to both components. Here, we propose that some patients may gain additional clinical benefit from the reuse of cetuximab after having PD on regimens including cetuximab in an earlier treatment line. We conducted a non-systematic literature search in PubMed and reviewed published and ongoing clinical trials, focusing on later-line cetuximab reuse in patients with mCRC. Evidence from multiple studies suggests that cetuximab can be an efficacious and tolerable treatment when continued or when fit patients with mCRC are retreated with it after a break from anti-EGFR therapy. Furthermore, on the basis of available preclinical and clinical evidence, we propose that longitudinal monitoring of RAS status may identify patients suitable for such a strategy. Patients who experience progression on cetuximab plus chemotherapy but have maintained RAS wt tumour status may benefit from continuation of cetuximab with a chemotherapy backbone switch because they have probably developed resistance to the chemotherapeutic agents rather than the biologic component of the regimen. Conversely, patients whose disease progresses on cetuximab-based therapy due to drug-selected clonal expansion of RAS-mutant tumour cells may regain sensitivity to cetuximab following a defined break from anti-EGFR therapy. Looking to the future, we propose that RAS status determination at disease progression by liquid, needle or excisional biopsy may identify patients eligible for cetuximab continuation and rechallenge. With this approach, treatment benefit can be extended, adding to established continuum-of-care strategies in patients with mCRC.

Blood-based detection of RAS mutations to guide anti-EGFR therapy in colorectal cancer patients: concordance of results from circulating tumor DNA and tissue-based RAS testing.

An accurate blood-based RAS mutation assay to determine eligibility of metastatic colorectal cancer (mCRC) patients for anti-EGFR therapy would benefit clinical practice by better informing decisions to administer treatment independent of tissue availability. The objective of this study was to determine the level of concordance between plasma and tissue RAS mutation status in patients with mCRC to gauge whether blood-based RAS mutation testing is a viable alternative to standard-of-care RAS tumor testing. RAS testing was performed on plasma samples from newly diagnosed metastatic patients, or from recurrent mCRC patients using the highly sensitive digital PCR technology, BEAMing (beads, emulsions, amplification, and magnetics), and compared with DNA sequencing data of respective FFPE (formalin-fixed paraffin-embedded) tumor samples. Discordant tissue RAS results were re-examined by BEAMing, if possible. The prevalence of RAS mutations detected in plasma (51%) vs. tumor (53%) was similar, in accord with the known prevalence of RAS mutations observed in mCRC patient populations. The positive agreement between plasma and tumor RAS results was 90.4% (47/52), the negative agreement was 93.5% (43/46), and the overall agreement (concordance) was 91.8% (90/98). The high concordance of plasma and tissue results demonstrates that blood-based RAS mutation testing is a viable alternative to tissue-based RAS testing.