Endocytosis Inhibition in Humans to Improve Responses to ADCC-Mediating Antibodies.

A safe and controlled manipulation of endocytosis in vivo may have disruptive therapeutic potential. Here, we demonstrate that the anti-emetic/anti-psychotic prochlorperazine can be repurposed to reversibly inhibit the in vivo endocytosis of membrane proteins targeted by therapeutic monoclonal antibodies, as directly demonstrated by our human tumor ex vivo assay. Temporary endocytosis inhibition results in enhanced target availability and improved efficiency of natural killer cell-mediated antibody-dependent cellular cytotoxicity (ADCC), a mediator of clinical responses induced by IgG1 antibodies, demonstrated here for cetuximab, trastuzumab, and avelumab. Extensive analysis of downstream signaling pathways ruled out on-target toxicities. By overcoming the heterogeneity of drug target availability that frequently characterizes poorly responsive or resistant tumors, clinical application of reversible endocytosis inhibition may considerably improve the clinical benefit of ADCC-mediating therapeutic antibodies.

An epidermal growth factor receptor-targeting immunotoxin based on IgG shows potent antitumor activity against head and neck cancer.

The epidermal growth factor receptor (EGFR) is an important target for cancer therapies. Many head and neck cancer (HNC) cells have been reported to overexpress EGFR; therefore, anti-EGFR therapies have been attempted in patients with HNC. However, its clinical efficacy is limited owing to the development of drug resistance. In this study, we developed an EGFR-targeting immunotoxin consisting of a clinically proven anti-EGFR IgG (cetuximab; CTX) and a toxin fragment (LR-LO10) derived from Pseudomonas exotoxin A (PE) using a novel site-specific conjugation technology (peptide-directed photo-crosslinking reaction), as an alternative option. The immunotoxin (CTX-LR-LO10) showed specific binding to EGFR and properties of a typical IgG, such as stability, interactions with receptors of immune cells, and pharmacokinetics, and inhibited protein synthesis via modification of elongation factor-2. Treatment of EGFR-positive HNC cells with the immunotoxin resulted in apoptotic cell death and the inhibition of cell migration and invasion. The efficacy of CTX-LR-LO10 was evaluated in xenograft mouse models, and the immunotoxin exhibited much stronger tumor suppression than CTX or LR-LO10. Transcriptome analyses revealed that the immunotoxins elicited immune responses and altered the expression of genes related to its mechanisms of action. These results support the notion that CTX-LR-LO10 may serve as a new therapeutic agent targeting EGFR-positive cancers.

Nuclear miR-451a activates KDM7A and leads to cetuximab resistance in head and neck squamous cell carcinoma.

Cetuximab resistance has been a major challenge for head and neck squamous cell carcinoma (HNSCC) patients receiving targeted therapy. However, the mechanism that causes cetuximab resistance, especially microRNA (miRNA) regulation, remains unclear. Growing evidence suggests that miRNAs may act as "nuclear activating miRNAs" for targeting promoter regions or enhancers related to target genes. This study elucidates a novel mechanism underlying cetuximab resistance in HNSCC involving the nuclear activation of KDM7A transcription via miR-451a. Herein, small RNA sequencing, quantitative real-time polymerase chain reaction (qRT‒PCR) and fluorescence in situ hybridization (FISH) results provided compelling evidence of miR-451a nuclear enrichment in response to cetuximab treatment. Chromatin isolation via RNA purification, microarray analysis, and bioinformatic analysis revealed that miR-451a interacts with an enhancer region in KDM7A, activating its expression and further facilitating cetuximab resistance. It has also been demonstrated that the activation of KDM7A by nuclear miR-451a is induced by cetuximab treatment and is AGO2 dependent. Logistic regression analyses of 87 HNSCC samples indicated the significance of miR-451a and KDM7A in the development of cetuximab resistance. These discoveries support the potential of miR-451a and KDM7A as valuable biomarkers for cetuximab resistance and emphasize the function of nuclear-activating miRNAs.

Inhibition of autocrine HGF maturation overcomes cetuximab resistance in colorectal cancer.

Although amplifications and mutations in receptor tyrosine kinases (RTKs) act as bona fide oncogenes, in most cancers, RTKs maintain moderate expression and remain wild-type. Consequently, cognate ligands control many facets of tumorigenesis, including resistance to anti-RTK therapies. Herein, we show that the ligands for the RTKs MET and RON, HGF and HGFL, respectively, are synthesized as inactive precursors that are activated by cellular proteases. Our newly generated HGF/HGFL protease inhibitors could overcome both de novo and acquired cetuximab resistance in colorectal cancer (CRC). Conversely, HGF overexpression was necessary and sufficient to induce cetuximab resistance and loss of polarity. Moreover, HGF-induced cetuximab resistance could be overcome by the downstream MET inhibitor, crizotinib, and upstream protease inhibitors. Additionally, HAI-1, an endogenous inhibitor of HGF proteases, (i) was downregulated in CRC, (ii) exhibited increased genomic methylation that correlated with poor prognosis, (iii) HAI-1 expression correlated with cetuximab response in a panel of cancer cell lines, and (iv) exogenous addition of recombinant HAI-1 overcame cetuximab resistance in CC-HGF cells. Thus, we describe a targetable, autocrine HAI-1/Protease/HGF/MET axis in cetuximab resistance in CRC.

A phase 2 trial combining afatinib with cetuximab in patients with EGFR exon 20 insertion-positive non-small cell lung cancer.

BACKGROUND: Epidermal growth factor receptor (EGFR) exon 20 insertion (ex20ins) mutations are the third most common EGFR mutations in patients with non-small cell lung cancer (NSCLC) and are associated with primary resistance to EGFR tyrosine kinase inhibitors (TKIs). There is evidence of activity of combining EGFR TKIs with monoclonal antibodies. This study reports on the efficacy and safety of afatinib in combination with cetuximab. METHODS: In this single-arm phase 2 trial, patients with advanced NSCLC harboring an EGFR ex20ins mutation were treated with afatinib 40 mg once daily in combination with cetuximab 500 mg/m2 every 2 weeks. The primary end point was disease control rate (DCR) at 18 weeks of treatment. RESULTS: Thirty-seven patients started treatment, with a median age of 65 years (range, 40-80 years), 78% female, and 95% White. The study achieved its primary end point with a DCR of 54% at 18 weeks, an overall response rate (ORR) of 43%, and a 32% confirmed ORR. Best responses were partial (n = 16), stable (n = 16), progressive disease (n = 2), or not evaluable (n = 3). Median progression-free survival was 5.5 months (95% CI, 3.7-8.3 months) and median overall survival was 16.8 months (95% CI, 10.7-25.8 months). The most common treatment-related adverse events (TRAEs) were diarrhea (70%), rash (65%), dry skin (59%), paronychia (54%), and erythema (43%). Grade 3 TRAEs were reported in 54% of all patients. CONCLUSIONS: Combination treatment with afatinib and cetuximab demonstrated antitumor activity with a DCR of 54% at 18 weeks and a 32% confirmed ORR. Toxicity was significant, although manageable, after dose reduction.

Targeted delivery of FAK siRNA by engineered exosomes to reverse cetuximab resistance via activating paraptosis in colon cancer.

BACKGROUND: Cetuximab is extensively used in the treatment of metastatic colorectal cancer (mCRC). However, resistance poses a significant challenge to successful therapy. Recently, paraptosis, a non-classical programmed cell death, has garnered increased attention for its potential application value in antitumor treatments. We aimed to identify the essential pathways and signaling molecules involved in paraptosis inhibition and select them as therapeutic targets in cetuximab resistance. Additionally, engineered exosome technology is used as a drug delivery system with both targeted and effector properties. RESULTS: By comparing the differential expression of paraptosis-related genes between drug-resistant colon cancer cells and sensitive cells, it was observed that the paraptosis level induced by cetuximab was significantly downregulated in drug-resistant cells. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis identified the focal adhesion kinase (FAK) signaling pathway as a key pathway involved in the suppression of paraptosis. The biological function of FAK in cetuximab-resistant cells was investigated through cell morphology observation, CCK-8 assay, colony formation assay, RT-qPCR, Western Blot, and loss-of-function experiments. The results showed that the FAK signaling pathway was significantly upregulated in cetuximab-resistant colon cancer cells, and siRNA interference targeting FAK could notably inhibit cell proliferation while upregulating the paraptosis level. Based on this, engineered colon cancer cells targeted and FAK siRNA loaded exosomes (CT-Exo-siFAK1) were constructed. In vitro experiments, CT-Exo-siFAK1 could effectively activate paraptosis and inhibit the proliferation of drug-resistant colon cancer cells. In vivo experiments also confirmed that CT-Exo-siFAK1 significantly suppressed tumor growth and metastasis while upregulating the paraptosis level. CONCLUSION: This study suggests that FAK signaling pathway-mediated inhibition of paraptosis levels is crucial in the sensitivity of cetuximab targeted therapy in colon cancer, and the use of engineered exosomes to deliver FAK siRNA may be an effective strategy to reverse cetuximab resistance.

Direct Functionalization of Polysaccharide-Based Xylan Phenyl Carbonate Nanoparticles with Tumor Cell Specific Antibodies.

An efficient and easy-to-use approach is presented for obtaining biocompatible polysaccharide-based nanoparticles (NP) that can act as tumor-specific drug delivery agents. Two antibodies are directly immobilized onto reactive xylan phenyl carbonate (XPC) NP; namely Cetuximab (CTX) that binds to human epidermal growth factor receptor (EGFR) and Atezolizumab (ATZ) that binds to programmed death-ligand 1 (PD-L1). High coupling efficiency (up to 100 %) are achieved without any pre-activation and no aggregation occurs during antibody immobilization. By quartz crystal microbalance experiments with dissipation monitoring (QCM-D), flow cytometry assays, and confocal laser scanning microscopy imaging it is demonstrated that the functionalized XPC-NP specifically bind to cells carrying the corresponding antigens. Moreover, the NP retain the antibody specific bioactivities (growth inhibition for CTX and induction of T-cell cytotoxicity for ATZ).

Evaluation of a new score associated with acute kidney injury in patients treated with cisplatin based EXTREME regimen.

BACKGROUND: This study evaluates the association of diuresis and hydration through a new monitoring indicator called U sen and the risk of acute kidney injury in patients treated with cisplatin based-EXTREME regimen. METHODS: We retrospectively reviewed all the cycles of patients with recurrent and/or metastatic head and neck cancer who received cisplatin based-EXTREME regimen from June 2008 to July 2022. Hydration regimen, urine output and concomitant treatments data were collected on the day of cisplatin infusion and the following day of each course received. RESULTS: Of the 110 courses received by 46 patients, 38 (34.5%) results in AKI. No patient characteristics showed a significant difference between AKI (70%) and non-AKI (30%) group. In univariate analysis, dose reduction of cisplatin (odds ratio = 0.166 [0.04; 0.75], p = 0.01)) and U sen >8 (odds ratio = 0.316 [0.133; 0.755], p = 0.015) and cardiac treatments (odds ratio = 3.24 [1.26; 8.52], p = 0.02) were significantly associated with AKI risk. In multivariate analysis, cisplatin dose reduction (odds ratio = 0.129 [0.0241; 0.687], p = 0.016) and U sen >8 (odds ratio = 0.184 [0.0648; 0.523], p = 0.0015) were associated with a risk reduction of cisplatin-related AKI. Concomitant administration of cardiac treatments (odds ratio = 3.18 [1.1; 9.22], p = 0.033) showed an increased risk of cisplatin-related AKI. CONCLUSION: The combination of diuresis and i.v. hydration through the U sen composite score was shown to be associated with cisplatin-induced AKI risk in patients treated with cisplatin based EXTREME regimen. It could be used as a practical indicator to trigger specific clinical management to limit the risk of cisplatin induced AKI.

Intraocular cetuximab: Safety and effect on axial elongation in young Guinea pigs with lens-induced myopization.

This study aimed to examine the intraocular tolerability of the epidermal growth factor receptor antibody cetuximab, when applied intravitreally, and its effect on axial elongation. Guinea pigs aged 2-3 weeks were subjected to bilateral plano glasses and bilateral lens-induced myopization (LIM) as a single procedure for group I (n = 8) and group II (n = 8), respectively. In the animals of group III (n = 8), group IV (n = 8), and group V (n = 8), the right eyes of the animals, in addition to LIM, received four weekly intravitreal injections of cetuximab (Erbitux®) in doses of 6.25 µg, 12.5 µg, and 25 µg, respectively. As controls, the left eyes, in addition to LIM, received corresponding intraocular injections of phosphate-buffered saline. The animals underwent regular ophthalmoscopic examinations and biometry for axial length measurements. With increasing doses of cetuximab, the inter-eye difference in axial elongation (at study end, left eyes minus right eyes) were significantly the smallest in group I (0.00 ± 0.02 mm) and group II (-0.01 ± 0.02 mm), they were larger in group III (0.04 ± 0.04 mm) and group IV (0.10 ± 0.03 mm), and they were the largest in group V (0.11 ± 0.01 mm). The inter-eye difference in axial elongation enlarged (P < 0.001) with the number of injections applied. Retinal thickness at the posterior pole (right eyes) was significantly thicker in group V than in group II (P < 0.01). The density of apoptotic cells (visualized by TUNEL-staining) did not vary significantly between any of the groups (all P > 0.05). The results suggest that intravitreal injections of cetuximab in young guinea pigs with LIM resulted in a reduction in axial elongation in a dose-dependent and number of treatment-dependent manner. Intraocular toxic effects, such as intraocular inflammation, retinal thinning, or an increased density of apoptotic cells in the retina, were not observed in association with the intravitreally applied cetuximab.

Increasing the Dye Payload of Cetuximab-IRDye800CW Enables Photodynamic Therapy.

Cetuximab (Cet)-IRDye800CW, among other antibody-IRDye800CW conjugates, is a potentially effective tool for delineating tumor margins during fluorescence image-guided surgery (IGS). However, residual disease often leads to recurrence. Photodynamic therapy (PDT) following IGS is proposed as an approach to eliminate residual disease but suffers from a lack of molecular specificity for cancer cells. Antibody-targeted PDT offers a potential solution for this specificity problem. In this study, we show, for the first time, that Cet-IRDye800CW is capable of antibody-targeted PDT in vitro when the payload of dye molecules is increased from 2 (clinical version) to 11 per antibody. Cet-IRDye800CW (1:11) produces singlet oxygen, hydroxyl radicals, and peroxynitrite upon activation with 810 nm light. In vitro assays on FaDu head and neck cancer cells confirm that Cet-IRDye800CW (1:11) maintains cancer cell binding specificity and is capable of inducing up to ∼90% phototoxicity in FaDu cancer cells. The phototoxicity of Cet-IRDye800CW conjugates using 810 nm light follows a dye payload-dependent trend. Cet-IRDye800CW (1:11) is also found to be more phototoxic to FaDu cancer cells and less toxic in the dark than the approved chromophore indocyanine green, which can also act as a PDT agent. We propose that antibody-targeted PDT using high-payload Cet-IRDye800CW (1:11) could hold potential for eliminating residual disease postoperatively when using sustained illumination devices, such as fiber optic patches and implantable surgical bed balloon applicators. This approach could also potentially be applicable to a wide variety of resectable cancers that are amenable to IGS-PDT, using their respective approved full-length antibodies as a template for high-payload IRDye800CW conjugation.

Fluorescence-guided surgery using cetuximab-800CW in patients with penile carcinoma.

OBJECTIVE: To investigate the feasibility of fluorescence molecular imaging (FMI), using cetuximab-800CW, as an intraoperative tool to determine surgical margins in penile squamous cell carcinoma (PSCC). PATIENTS AND METHODS: A total of 11 patients with PSCC received 75 mg cetuximab followed by 15 mg cetuximab-800CW 2 days before surgery. FMI of the whole excision specimen and tissue slices was performed. Fluorescence visualisation was correlated to histopathology. Based on tumour and healthy tissue regions of interest, mean fluorescence intensity was calculated for each individual patient. RESULTS: Significant differences between tumour and healthy mean fluorescence intensity were found with tumour-to-background ratios of a median (IQR) of 1.51 (0.99) and a mean (SD) of 1.51 (0.32) in the excision specimen and tissue slices, respectively. One patient showed a high relative fluorescence intensity with a signal-to-background ratio of 1.79, corresponding to a tumour-positive margin on fresh frozen sectioning. CONCLUSION: In this Phase I study we showed that cetuximab-800CW seems suitable to discriminate PSCC from background tissue. The tracer was well tolerated, and no false positive spots were seen.

AGCM-22, a novel cetuximab-based EGFR-targeting antibody-drug-conjugate with highly selective anti-glioblastoma efficacy.

The epidermal growth factor receptor (EGFR) has received significant attention as a potential target for glioblastoma (GBM) therapeutics in the past two decades. However, although cetuximab, an antibody that specifically targets EGFR, exhibits a high affinity for EGFR, it has not yet been applied in the treatment of GBM. Antibody-drug conjugates (ADCs) utilize tumor-targeting antibodies for the selective delivery of cytotoxic drugs, resulting in improved efficacy compared to conventional chemotherapy drugs. However, the effectiveness of cetuximab as a targeted antibody for ADCs in the treatment of GBM remains uncertain. In this study, we synthesized AGCM-22, an EGFR-targeted ADC derived from cetuximab, by conjugating it with the tubulin inhibitor monomethyl auristatin E (MMAE) using our Valine-Alanine Cathepsin B cleavable linker. In vitro experiments demonstrated that AGCM-22 effectively inhibited GBM cell proliferation through increased levels of apoptosis and autophagy-related cell death, whereas cetuximab alone had no anti-GBM effects. Additionally, both mouse and human orthotopic tumor models exhibited the selective tumor-targeting efficacy of AGCM-22, along with favorable metabolic properties and superior anti-GBM activity compared to temozolomide (TMZ). In summary, this study presents a novel ADC for GBM therapy that utilizes cetuximab as the tumor-targeting antibody, resulting in effective delivery of the cytotoxic drug payload.

Palbociclib inhibits the progression of head and neck cancer and improves the Cetuximab response under specific condition in vitro and in vivo.

BACKGROUND: In head and neck squamous cell carcinoma (HNSCC) with human papillomavirus (HPV)-negative, deregulation of cell cycle is partly due to inactivation of p16INK4 and overexpression of cyclin D1. Here we investigated the in vitro and in vivo effects of the CDK4/6 inhibitor Palbociclib alone or combined with EGFR inhibitor Cetuximab in HNSCC. METHODS AND RESULTS: CCK-8, soft agar assay, colony formation assay, wound healing assay and transwell assay, ß-galactosidase assay, western blotting, and cell-derived xenografts were used to investigated the in vitro and in vivo activity of drugs. Cell viability and colony formation decreased in a dose-dependent manner in Tu686, AMC-HN8, and Fadu cells under Palbociclib treatment. Palbociclib remarkably inhibited migration, invasion and the expression MMP-9 in HNSCC cells. Palbociclib also induced senescence. Palbociclib caused the dephosphorylation of RB but increased the cyclin D1 level in a dose-dependent manner. Moreover, combination with Cetuximab could significantly prevent the induction of cyclin D1 and activation of EGFR signals from Palbociclib treatment. Nevertheless, only within the range of certain concentrations, a synergistic inhibitory effect on cell growth was observed when combined with Palbociclib and Cetuximab. Although the synergistic effect in Palbociclib/Cetuximab combined therapy was comparable to that in traditional chemotherapeutic regimens (cisplatin/Cetuximab) in Fadu tumor xenograft, the combination therapy was less active than Cetuximab monotherapy in Tu686 tumor xenograft. CONCLUSION: In HPV-negative HNSCC, CDK4/6 inhibitor shows promising anti-tumor effects, which exhibits a synergistic effect when combined with EGFR inhibitor only in specific drug concentration and mouse model.

Cetuximab every 2 weeks versus standard weekly dosing administration schedule.

Cetuximab every 2 weeks (Q2W) dosing schedule is approved by the US FDA and by the Japanese Pharmaceuticals and Medical Devices Agency in patients with metastatic colorectal cancer and squamous cell carcinoma of the head and neck. Phase II trials have found comparable efficacy and safety for the weekly (Q1W) and Q2W schedules, and real-world studies have shown noninferiority of the Q2W compared with the Q1W schedule. Several guidelines recommend cetuximab Q2W administration as an alternative to the Q1W dosing schedule. Cetuximab Q2W can be administered with a Q2W dose of chemotherapy, making it a more convenient option to the Q1W schedule, potentially resulting in reduced costs for administration, increased flexibility for clinical staff and improved patient adherence.

Cetuximab is a drug for patients with colorectal cancer or cancer of the head and neck. It is usually administered once a week. However, studies have shown that cetuximab given once every 2 weeks instead has similar clinical benefits and side effects. Based on this evidence, the every 2 weeks dosing schedule has been approved for use in USA and Japan. The every 2 weeks dosing schedule is a convenient alternative to the weekly schedule. It may result in fewer hospital visits, improved patient quality of life, reduced healthcare costs and more flexibility for medical staff. This review summarizes the current evidence and benefits for the every 2 weeks dosing schedule.

SEAMARK: phase II study of first-line encorafenib and cetuximab plus pembrolizumab for MSI-H/dMMR BRAFV600E-mutant mCRC.

Patients with both BRAF V600E mutations and microsatellite instability-high (MSI-H)/mismatch repair-deficient (dMMR) metastatic colorectal cancer (mCRC) have poor prognosis. Currently, there are no specifically targeted first-line treatment options indicated for patients with mCRC whose tumors harbor both molecular aberrations. Pembrolizumab is a checkpoint inhibitor approved for the treatment of MSI-H/dMMR mCRC, and the BRAF inhibitor encorafenib, in combination with cetuximab, is approved for previously treated BRAF V600E-mutant mCRC. Combination of pembrolizumab with encorafenib and cetuximab may synergistically enhance antitumor activity in patients with BRAF V600E-mutant, MSI-H/dMMR mCRC. SEAMARK is a randomized phase II study comparing the efficacy of the combination of pembrolizumab with encorafenib and cetuximab versus pembrolizumab alone in patients with previously untreated BRAF V600E-mutant, MSI-H/dMMR mCRC.

Colorectal cancer (CRC) occurs when there is an abnormal growth of cells (known as a tumor) in the colon or rectum. Some people with CRC have changes in their tumor genes (known as gene mutations). A gene is a piece of DNA that tells the cell to make specific molecules, such as proteins. Mutations in a gene called BRAF can turn on signals that help the cancer cells grow. Gene mutations that impair DNA repair mechanisms can also make the cancer cells grow more quickly and allow the immune system to detect the cancer cells as being foreign to the body. Targeted therapy is a type of cancer treatment that turns off specific genes and proteins involved in cancer cell survival and growth. BRAF and EGFR inhibitors are targeted therapies that work well together in treating people with BRAF-mutant CRC. BRAF proteins can help cancer cells grow, and BRAF inhibitors block these proteins to prevent, slow, or stop the growth of the cancer cells. Immunotherapy is a type of cancer treatment that helps a person's immune system fight cancer. Immunotherapy is effective for treating CRC that has mutations in the DNA repair mechanisms. By combining targeted therapy and immunotherapy, patients may be able to live longer without their disease getting worse. In the SEAMARK study, we will use a treatment combination including a BRAF inhibitor (encorafenib), an EGFR inhibitor (cetuximab) and an immunotherapy (pembrolizumab) in patients with CRC who have a BRAF mutation and deficiencies in the DNA repair mechanism. Clinical Trial Registration: NCT05217446 (ClinicalTrials.gov), 2021-003715-26 (EudraCT).

Steroid Premedication and Monoclonal Antibody Therapy: Should We Reconsider?

OPINION STATEMENT: Monoclonal antibody (mAb) therapy is now considered a main component of cancer therapy in Australia. Although traditionally thought of as pure signalling inhibitors, a large proponent of these medications function through antibody-dependent cell-mediated cytotoxicity (ADCC). Currently, most protocols and institutional guidelines for ADCC-mediated mAbs promote the use of corticosteroids as premedication: this is implemented to reduce infusion-related reactions (IRRs) and antiemesis prophylaxis and combat concurrently administered chemotherapy-related syndromes. Concerningly, the inhibitory effects of ADCC by corticosteroids are well documented; henceforth, it is possible the current standard of care is misaligned to the literature surrounding ADCC. Subsequently, clinicians' decisions to act in contrast to this literature may be reducing the efficacy of mAbs. The literature suggests that the redundant use of corticosteroids should be cautioned against when used in conjunction with ADCC-mediated mAbs-this is due to the consequent reduction in anti-tumour activity. Owing to the fact IRRs typically occur upon initial infusion, the authors advocate for individual clinicians and institutional protocols to considering augmenting their practice to corticosteroid premedication at the first dose only, unless clinically indicated. Additionally, product information (PI) and consumer medicine information (CMI) documents distributed by Australian and international regulatory agencies should consider disclosing the risk of concurrent steroids with these medications. Moreover, the authors suggest considering alternative medications for the management of side effects.

Risk Factors of Cetuximab-Induced Hypomagnesemia and the Effect of Magnesium Prophylaxis in Patients with Head and Neck Cancer: A Retrospective Study.

Hypomagnesemia is a characteristic adverse event of cetuximab in patients with head and neck cancer (HNC). However, there is limited information about its prevalence, risk factors, and preventive strategies. This study aimed to investigate the risk factors of hypomagnesemia and examine the preventive effects of prophylactic magnesium (Mg) administration. We initially investigated HNC patients treated with cetuximab between 2013 and 2019. Our institute started prophylactic Mg treatment (20-mEq Mg sulfate administration before cetuximab) in practice during this period. We retrospectively assess the preventive efficacy by comparing patients before and after its implementation. In total, 109 patients were included. In 60 patients without prophylaxis, all-grade and grade ≥2 hypomagnesemia at 3 months occurred in 61.7 and 15.0% of patients. The incidence of hypomagnesemia was not affected by regimens and concomitant medications. In 49 patients treated with prophylactic Mg treatment, there was no significant decrease in the cumulative incidence of hypomagnesemia. However, the preventive Mg treatment eliminated the need for additional Mg repletion to maintain Mg levels in patients treated with paclitaxel + cetuximab. A risk factor in patients without prophylaxis was a low Mg level at pre-treatment (≤2.0 mg/dL) (odds ratio: 6.03, 95% confidence interval: 1.78-20.4, p = 0.004), whereas that in patients with prophylaxis was the number of cetuximab doses (≥10) (odds ratio: 5.50, 95% confidence interval: 1.52-19.87, p = 0.009). In conclusion, a low pre-treatment Mg level was the only risk factor that could be avoided by prophylactic Mg administration. This preventive intervention is recommended for managing cetuximab-induced hypomagnesemia.

Safety and efficacy of neoadjuvant chemotherapy with paclitaxel, carboplatin, and cetuximab for locally advanced head and neck squamous cell carcinoma.

BACKGROUND: As a substantial waiting time is usually required for radical surgery, safe and effective preoperative neoadjuvant chemotherapy (NAC) is desired for the treatment of locally advanced head and neck squamous cell carcinoma (HNSCC). However, the significance of NAC in advanced HNSCC is still unclear. This study aimed to assess the safety and efficacy of NAC using the paclitaxel, carboplatin, and cetuximab (PCE) regimen. METHODS: We retrospectively evaluated the background characteristics, incidence of adverse events, overall response rate (ORR), pathological response, recurrence-free survival (RFS), and overall survival (OS) in 26 patients. Patients receiving the PCE regimen were further divided into two groups based on the number of chemotherapy cycles (one cycle or more) and eligibility for cisplatin. Patients aged ≥ 75 years and those with an estimated glomerular filtration rate (eGFR) < 60 mL/min were classified as ineligible for cisplatin. RESULTS: The median age was 70 (27-81) years. The median eGFR at treatment initiation was 63.2 (41.1-89.7) mL/min. Fourteen (53.8%) patients were ineligible for cisplatin. Grade 3 or higher neutropenia was observed in 11 of 25 (42.3%) patients. No delay in or withdrawal from surgery was observed. The ORR was 65.4%. The 2-year RFS and OS were 61.5% and 76.7%, respectively. No significant differences in safety and efficacy between the number of chemotherapy cycles and cisplatin eligibility were observed. CONCLUSION: NAC using the PCE regimen for patients with locally advanced HNSCC, including cisplatin-ineligible patients, has acceptable toxicity and favorable efficacy.

Extended physicochemical stability of cetuximab in opened vials and infusion bags when stored at 4°C and 25°C.

INTRODUCTION: This study aimed to determine the stability of cetuximab: (1) under "in-use" conditions after dilution to 1 mg/mL in 0.9% sodium chloride in polyolefin bags and (2) as an undiluted solution (5 mg/mL) repackaged in polypropylene bags or kept in the vial after opening. METHODS: Ready-to-use 500 mg/100 mL vials of cetuximab solution were diluted to 1 mg/mL in 100 mL bags of 0.9% sodium chloride or repackaged as a 5 mg/mL solution into empty 100 mL bags. Bags and vials were stored at 4°C for 90 days and 25°C for 3 days. A syringe sample of 7 mL was taken from each bag for the initial determinations. The sampled bags were weighed to determine their initial weight and placed under the planned storage conditions. The physicochemical stability of cetuximab was estimated using validated methods. RESULTS: No changes in turbidity, no protein loss, and no changes in cetuximab tertiary structure were observed after 30 days of storage or when subjected to a temperature excursion of 3 days at 25°C and when stored at 4°C for up to 90 days, regardless of the concentrations and batches. The colligative parameters did not change under any of the tested conditions. No evidence of microbial growth was found in bags after 90 days of storage at 4°C. CONCLUSION: These results support the extended in-use shelf-life of cetuximab vials and bags, which can be cost-effective for healthcare providers.

Premedication strategy in cetuximab rechallenge after Grade 2 hypersensitivity reactions.

INTRODUCTION: Cetuximab, an IgG1 monoclonal antibody, is utilized in the treatment of metastatic colorectal cancer and squamous cell head and neck cancers. Due to the risk of hypersensitivity reactions, standard premedication with a histamine-1 (H-1) antagonist is recommended prior to administration, however, there is less guidance for premedication strategies to assist with rechallenge after infusion reactions. Here, we describe two cases of successful cetuximab treatment after Grade 2 reactions, in addition to risk factors and proposed premedication strategies for successful rechallenge. CASE REPORT: Two patients who experienced Grade 2 hypersensitivity reactions were both successfully rechallenged with increased premedications 1-2 weeks after initial infusions. The first patient was a 56-year-old male diagnosed with metastatic colorectal cancer receiving cetuximab as part of a clinical trial. The second patient was a 73-year-old male diagnosed with head and neck cancer receiving cetuximab as part of standard of care concurrent with radiation. MANAGEMENT AND OUTCOME: Each patient was rechallenged with an increased premedication strategy including dexamethasone, famotidine, diphenhydramine, and acetaminophen in addition to reducing the infusion rate. Both patients either continued treatment or successfully completed therapy, without any additional infusion-related reactions. DISCUSSION: We aimed to review risk factors related to cetuximab infusion reactions and propose a premedication strategy for rechallenge postreaction. Known risk factors include male sex and the accumulation of cetuximab-specific IgE. These may be mitigated by the addition of increased premedication with dexamethasone and famotidine with concurrent reduced infusion rate.