41P Switch from cetuximab (CET) to panitumumab (PANI) during encorafenib (ENCO)-based therapy in BRAF V600E mutated metastatic colorectal cancer (mCRC): An international multicenter analysis from the AGEO group

Cetuximab, known to be the principal active derivative of the key chemotherapeutic drug, exhibits significantly improved efficacy in the treatment of triple-negative breast cancer (TNBC). However, issues such as restricted bioavailability, insufficient water solubility, low stability, and nonspecific cancer cell targeting impede its clinical implementation. This study involved the fabrication of Cetuximab (CX)-loaded liposomes enveloped in macrophage membranes (CX@Lipo-MM) to evaluate their therapeutic efficacy and safety in treating TNBC. CX@Lipo-MM was developed using the incubation extrusion method, integrating a liposome with the macrophage membrane (Lipo). It was defined by diameter, polydispersity index, transmission electron microscopy analysis, and zeta potential. Characterization studies indicated that CX@Lipo-MM has a spherical structure with a uniform size (130.45 ± 7.14 nm) and a drug loading efficacy of 5.63 ± 0.71%. EdU, CCK-8, and staining experiments were conducted to assess the viability and apoptotic rates of MDA-MB-231 and MDA-MB-436 cells treated with CX@Lipo-MM. CX inhibited proliferation and induced apoptosis in MDA-MB-231 and MDA-MB-436 cell lines. The apoptosis was confirmed by various biochemical staining assays. The efficacy of CX was enhanced when administered through CX@Lipo and CX@Lipo-MM. An in vitro cellular uptake experiment was performed to assess the internalization of CX@Lipo-MM. CX@Lipo-MM demonstrated significant and specific anticancer efficacy in TNBC. Therefore, CX@Lipo-MM emerges as a promising liposome formulation that may enhance the anticancer efficacy of Cetuximab.

3563 Background: This CAPCET randomized phase II trial was designed to assess the efficacy and safety of modified capecitabine and oxaliplatin (mCapOX) plus cetuximab (CET) and modified fluorouracil, leucovorin, and oxaliplatin (mFOLFOX6) plus cetuximab (CET) for the first-line treatment of left-side unresectable RAS/BRAF wild-type (wt) metastatic colorectal cancer (mCRC). Methods: CAPCET was an open-label, multicenter, randomized, non-comparative phase II trial. Patients with unresectable RAS/BRAF wt mCRC were randomly assigned (1:1) to receive up to 12 cycles biweekly mCapOX (capecitabine 1000mg/m 2 orally twice daily on Day 1-7 and oxaliplatin 85 mg/m 2 iv on Day 1) plus CET (500mg/m 2 iv on day 1) (arm A) or biweekly mFOLFOX6 (oxaliplatin 85 mg/m 2 iv on day 1, leucovorin 400 mg/m 2 iv on day 1, fluorouracil 400mg/m 2 iv bolus on day 1, then fluorouracil 2400 mg/m 2 continuous infusion over 46-48h) plus CET (500mg/m 2 iv on day 1)(arm B) followed by maintenance(either capecitabine plus CET or capecitabine alone at the discretion of the investigators) or treatment-free intervals until progression on treatment, toxicity, or death. The primary endpoint was progression-free survival (PFS) rate at 9 months from randomization. Results: Between September 2021 and April 2024, 168 patients (84 in arm A and 84 in arm B) were enrolled in 20 China centres. Baseline characteristics were well balanced between arms. After a median follow-up of 21.0 months (IQR,19.5-22.5), the 9 months-PFS rates were 70.9% (95% CI 61.1%-82.3%) in arm A and 66.8% (95% CI 56.7%-78.6%; HR = 1.11, P = 0.558) in arm B, and the primary endpoint was met. The median PFS (arm A/B) was 12.7 months (95% CI 10.8–15.2)/12.0 months (95% CI 9.7–14.1). The overall response rate (ORR) and disease control rate (DCR) in arm A were higher than those in arm B with 69.2% versus 60.3% and 96.2% versus 89.7%, respectively. The 2-year overall survival (OS) rate (arm A/B) was 66.8% (95% CI 54.2%–82.3%)/65.6% (95% CI 52.5%–82.0%), and the median OS not reached. Grade≥3 adverse events (AEs) occurred in 28.8% of safety population set (n = 156), with 7.7% in arm A and 21.2% in arm B. The most commonly Grade≥3 AEs was neutropenia, rash, leukopenia and there were no grade 5 AEs reported. Conclusions: The CAPCET study met its first endpoint of 9-month PFS rate in patients with RAS/BRAF wt mCRC. Biweekly mCapOX plus CET had higher ORR and DCR than mFOLFOX6 plus CET, with signally reduced toxicity. Longer follows-up and a multicenter, open-label, randomized, controlled Phase CAPCET- III study (NCT06616259) will be further validate this innovative regimen. Clinical trial information: NCT05022030 .

Anti-HIV-1 HSPC-based gene therapy with safety kill switch to defend against and attack HIV-1 infection

Colorectal cancer (CRC) is one of the most prevalent cancers worldwide, with KRAS mutations playing a significant role in its tumorigenesis. Among the KRAS variants, the G13D mutation is associated with poor prognosis and distinctive biological behaviors. This study focuses on the role of HER2, a critical prognostic and predictive biomarker, in modulating the unique characteristics of KRASG13D-mutated CRCs. We identified a novel transcriptional regulatory network involving HER2, ELF3, and KRAS, with ELF3 acting as a key transcription factor (TF) that regulates KRAS expression under conditions of HER2 overexpression. Our findings reveal that this HER2-ELF3-KRAS axis is exclusively activated in KRASG13D, driving aggressive oncogenic features and conferring resistance to cetuximab (CTX) therapy. Through comprehensive analysis of gene expression profiles, we demonstrated that HER2 is a crucial therapeutic target specifically for KRASG13D CRCs. To explore this further, we introduced YK1, a small molecule inhibitor designed to disrupt the ELF3-MED23 interaction, leading to the transcriptional downregulation of HER2 and KRAS. This intervention significantly attenuated the HER2-ELF3-KRAS axis, sensitizing KRASG13D CRCs to CTX and reducing their tumorigenic potential by inhibiting the epithelial-to-mesenchymal transition process. Our study underscores the importance of HER2 as a key determinant in the unique biological characteristics of KRASG13D CRCs and highlights the therapeutic potential of targeting the HER2-ELF3-KRAS axis. By presenting YK1 as a novel pharmacological approach, we provide a promising strategy for developing tailored interventions for KRASG13D CRCs, contributing to the ongoing efforts in precision medicine for CRCs.Graphical

Triple-negative breastcancer (TNBC) is a highly aggressive andtreatment-resistant malignancy characterized by the lack of targetedtherapies and poor clinical outcomes. Here, we present a dual-targetingstrategy combining the anti-EGFR monoclonal antibody cetuximab (CTX)with H-ferritin (HFn), a nanoparticle targeting transferrin receptor1 (TfR1), for potential immunotherapy in CTX-resistant tumors. TheHFn–CTX nanoconjugate exhibited favorable biophysical propertiesand good tumor accumulation and significantly enhanced antibody-dependentcellular cytotoxicity (ADCC) in TNBC spheroids compared to CTX alone.Conversely, glioblastoma spheroids did not exhibit comparable reactivity.This effect correlated with elevated cell-surface EGFR expressionand plasma-membrane lingering of the nanoconjugate in TNBC cells,facilitating robust immune activation. Biodistribution studies showedselective accumulation of the HFn–CTX nanoconjugate in TNBCtumors in vivo. These findings highlight the potential of HFn–CTXnanoconjugates to repurpose CTX for refractory cancers that expressEGFR at high levels, such as TNBC, leveraging dual-receptor targetingto amplify immune-mediated cytotoxicity and overcome resistance.

Colorectal cancer (CRC) is the second-leading cause of cancer-associated deaths in the United States with a need for improved therapies. Antibody-drug conjugates (ADCs) are a rapidly expanding class of anticancer drugs that utilize monoclonal antibody (mAb) specificity to hone cytotoxic payloads to cancer cells. We generated ADCs targeting leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5), a cancer stem cell biomarker that is highly overexpressed in CRC. LGR5 ADCs demonstrated high specificity and efficacy in CRC cells and xenograft models without notable toxicity, although tumors eventually relapsed following treatment cessation. Interestingly, FDA-approved therapies targeting epidermal growth factor receptor (EGFR) have been shown to increase LGR5 expression in patient-derived models of CRC. This study therefore aims to determine the mechanisms of EGFR-mediated regulation of LGR5 expression and evaluate the therapeutic efficacy of EGFR-targeted therapies in combination with LGR5 ADCs for the improved treatment of CRC. We have demonstrated that cetuximab (CTX), an EGFR-targeting mAb approved for KRASWT metastatic CRC (mCRC), increases LGR5 protein levels independent of KRAS/PIK3CA mutational status in CRC cell lines, tumor organoids, and cell line-derived xenografts. Additionally, we identified a novel EGFR-LGR5 interaction that is enhanced by CTX treatment. Furthermore, we have generated a camptothecin-based LGR5 ADC (8E11-CPT2) utilizing site-specific conjugation technology that demonstrates target- and dose-dependent cytotoxicity in CRC cells and was well-tolerated. Importantly, combination treatment of 8E11-CPT2 with CTX in RASmut CRC patient-derived xenograft models significantly reduced tumor burden with notable regression in some mice and extended survival compared to LGR5 ADC and CTX monotherapies. These results demonstrate that combination treatments of LGR5 ADCs with CTX may prove more effective than ADC monotherapies in treating CRC and implicate expanded clinical utility for CTX to treat mCRCs with KRAS and/or PIK3CA mutations. Citation Format: Peyton High, Zhengdong Liang, Cara Guernsey-Biddle, Adela Aldana, Yukimatsu Toh, Qingyun Liu, Kendra S. Carmon. Cetuximab increases LGR5 expression and enhances efficacy of LGR5 antibody-drug conjugates in patient-derived models of colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2883.

Objective The controlled release method improves the stability of cetuximab (CTX), which is typically impacted by the environmental variables present in regular formulations. Significant It is possible to preserve the effectiveness of CTX by encapsulating it in a chitosan hydrogel to reach the target site via direct injection easily. Method CTX was loaded into the thermosensitive polymer-based hydrogel, namely chitosan (CH) with the aid of a crosslinking β-glycerophosphate (β-GP) alone or in combination with Pluronic F127 ( Pl F 127 ). The formulated hydrogels were subjected to different types of characterizations, such as stability and rheological studies. Furthermore, they were tested for their antiproliferative activities against HEPG2 (hepatic cancer cell lines). Results Hydrogels had a homogeneous preparation, were transparent, and showed no signs of aggregation. Moreover, CH/β-GP gel type recorded a lower viscosity in comparison to the other hydrogel type CH / β ‐ GP / Pl F 127 system of (110.3 ± 5.2, and 148.4 ± 4.4 Cp, respectively). The conducted pharmacokinetic studies demonstrated a continued increase in rabbits’ plasma throughout the first four days (T max) with C max of 3.663 μg/mL which also showed a decline below the detected limit after 15 days. Nevertheless, the formulated CH-based hydrogel showed a sustained release with a longer value of MRT of more than 9 days with an estimated AUC0-t of 41.917 μg/L/day. Conclusion The medicated CH/β-GP hydrogel formula demonstrated superior targeting-controlled efficiency compared to free CTX.

Abstract The incidence of HPV-associated (HPV+) head and neck squamous cell carcinoma (HNSCC) has been increasing in recent decades. The EGFR inhibitor cetuximab (CTX) is less active in HPV+ than HPV- HNSCC. HPV oncoproteins E6 and E7 induce HER3 overexpression, and EGFR-HER3 heterodimer-driven survival signaling via PIK3, AKT and ERK1-2 contributes to resistance to cetuximab and the EGFR inhibitor erlotinib. We demonstrate that although panHER inhibitors afatinib and dacomitinib more effectively inhibit growth of HPV+ HNSCC cells than do erlotinib or cetuximab, adaptive signaling through the AURKA/PLK1 axis mediates resistance to panHER inhibitors. We hypothesized that combined panHER and AURKA inhibition would synergize to overcome persistence of HPV+ HNSCC. We find that HPV+ HSNCC cells UM-SCC47 and UPCI:SCC154 express both EGFR and HER3. Indeed, cell viability experiments and clonogenic survival assays demonstrate strong synergy between panHER and AURKA inhibitors, confirmed in xenografted tumor models treated with the second generation AURKA inhibitor VIC-1911 and dacomitinib. We then performed RNAseq and shotgun proteomics to understand the cellular mechanisms behind our combination. Dacomitinib had expected effects downregulating Hallmark G2M and EGFR phosphorylation targets, upregulating EMT markers and cell death markers. In contrast, addition of AURKA inhibition upregulated PLK1 and pPLK1 and cell death markers. These findings indicate that combination therapy with AURKA inhibition will mitigate the adaptability to EGFR and panHER inhibitors previously described for HPV+ HNSCC. Citation Format: Sebastian Cruz-Gomez,Jong Woo Lee,Julian Barrantes,Richard Ivey,Sara Savage,Pratima Chaurasia,Gunner Dickson,Dickson Adah,Bing Zhang,Amanda Paulovich,Barbara Burtness. Aurora kinase A inhibition overcomes tolerance to panHER inhibitors in HPV positive HNSCC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 816.

Background/Objectives: Triple-negative breast cancer (TNBC) is a subtype of breast cancer that accounts for 15-20% of all breast cancer cases. TNBC is very difficult to treat with conventional treatment modalities such as chemotherapy, radiotherapy, and surgery; Methods: In this study, we developed a dual-loaded targeted nanotherapeutics against TNBC to solve the challenging problems associated with TNBC treatment: lack of efficacy, toxicity, and poor site-specific drug delivery; PEGylated methacrylate-polylactide copolymer containing cisplatin was synthesized and characterized; Results: The copolymer was used to fabricate nanoparticles (NPs) in the presence of paclitaxel with 1.33% drug loading. The nanoparticles were homogenous, with an average particle size of 198 nm and a negative zeta potential (-41.3 mV). Cetuximab (CTX), a monoclonal antibody that binds to the epidermal growth factor receptor (EGFR), was attached to the NP's surface to enhance the targetability to TNBC. In vitro studies including cell uptake and cytotoxicity in MDA-MB-231 cells confirmed that CTX-targeted NPs have the potential for treating TNBC. The IC50 of CTX-NPs after 96 h of incubation was 0.1 μM, which was significantly lower than those of p-NPs (0.49 μM) and free drugs (PTX + cPt: 0.57 μM); Conclusions: In summary, this research shows that CTX-targeted polymeric NPs containing cisplatin and paclitaxel are effective in treating TNBC in vivo investigations are ongoing.

This study aimed to synthesize cetuximab (CTX) conjugated hydroxyapatite zirconium (HApZr-CTX) as a nanocarrier for active delivery of photosensitizer and therapeutic radionuclide. The system enabled targeted radioenhancer in X-ray dynamic therapy and radioimmunotherapy for lung cancer. The results showed that HApZr-CTX had the main characteristics of hydroxyapatite crystal in X-ray powder diffraction (XRD), with particle size twice bigger, according to DLS-PSA and TEM measurements. Cellular ROS generation was elevated almost three times in A549 cells after being treated using 125 µg/mL HApZr-CTX and irradiated with 5 Gy of X-ray photon compared to untreated cells. The viability of the treated lung cancer cell line decreased after exposure to external radiation. Moreover, as a radioimmunotherapy candidate, 177Lu was successfully loaded into HApZr-CTX nanocarrier and internalized in A549 more than half of the given dose after 0.5 h incubation. [177Lu]Lu-HApZr-CTX was primarily accumulated in the lung organs of healthy mice one-hour post-injection. In conclusion, HApZr-CTX nanoparticles have the potential to be used as a radioenhancer in X-ray dynamic therapy and radioimmunotherapy for lung cancer therapy.

NF-kB oscillation profiles decode response to anti-EGFR monoclonal antibodies.

95P: Adagrasib (ADA) plus cetuximab (CETUX) in patients (pts) with advanced KRASG12C-mutated non-small cell lung cancer (NSCLC) from KRYSTAL-1

BackgroundPhagocytic clearance by macrophages represents a critical immune surveillance mechanism in cancer liver metastasis. Neutrophils, the most abundant immune cells encountered by cancer cells in circulation, play key roles in...

Hematopoietic stem/progenitor cell (HSPC)-based anti-HIV-1 gene therapy holds promise to provide life-long remission following a single treatment. Here we report a multi-pronged anti-HIV-1 HSPC-based gene therapy designed to defend against and attack HIV-1 infection. We developed a lentiviral vector capable of co-expressing three anti-HIV-1 genes. Two are designed to prevent infection, including a short-hairpin RNA (CCR5sh1005) to knock down HIV-1 co-receptor CCR5 and a membrane anchored HIV-1 fusion inhibitor (C46). The third gene is a CD4-based chimeric antigen receptor (CAR) designed to attack HIV-1 infected cells. Our vector also includes a non-signaling truncated human epidermal growth factor receptor (huEGFRt) which acts as a negative selection-based safety kill switch against transduced cells. Anti-HIV-1 vector-transduced human CD34+ HSPC efficiently reconstituted multi-lineage human hematopoietic cells in humanized bone marrow/liver/thymus (huBLT) mice. HIV-1 viral load was significantly reduced (1-log fold reduction, p <0.001) in transplanted huBLT mice. Anti-huEGFR monoclonal antibody Cetuximab (CTX) administration significantly reduced huEGFRt+ vector-modified cells (>4-fold reduction, p <0.01) in huBLT mice. These results demonstrate that our strategy is highly effective for HIV-1 inhibition, and that CTX-mediated negative selection can deplete anti-HIV-1 vector-modified cells in the event of unwanted adverse effects in huBLT mice.

Background: Non-small cell lung cancer (NSCLC) is a leading cause of cancer deaths globally. The most extensive treatment is Tyrosine Kinase Inhibitors (TKIs) that target epidermal growth factor receptor (EGFR) overexpression. Osimertinib, a third-generation TKI is approved to target EGFR exon 19 deletions or exon 21 L858R mutations. However, resistance is inevitable due to emergence of triple mutations (sensitizing mutations, T790M and C797S). To overcome this challenge, a combinatorial approach was used wherein Osimertinib liposomes were conjugated with cetuximab (CTX), an anti-EGFR monoclonal antibody, to improve drug efficacy and delivery. Additionally, pulmonary administration was employed to minimize systemic toxicity and achieve high lung concentrations. Methods: Osimertinib liposomes (OB-LPs) were prepared using thin film hydration method and immunoliposomes (CTX-OB-LPs) were prepared by conjugating the OB-LPs surface with CTX. Liposomes were characterized for particle size, zeta-potential, drug loading, antibody conjugation efficiency, in vitro drug release, and aerosolization performance. Further, the in vitro efficacy of immunoliposomes was evaluated in H1975 cell line. Results: Immunoliposomes exhibited a particle size of 150 nm, high antibody conjugation efficiency (87%), efficient drug release, and excellent aerosolization properties with an aerodynamic diameter of 3 μm and fine particle fraction of 88%. Furthermore, in vitro studies in H1975 cells showed enhanced cytotoxicity with CTX-OB-LPs displaying 1.7-fold reduction and 1.2-fold reduction in IC50 compared to Osimertinib and OB-LPs, respectively. The CTX-OB-LPs also significantly reduced tumor cell migration and colonization compared to Osimertinib and OB-LPs. Conclusions: These successful results for EGFR-targeting inhalable immunoliposomes exhibited potential for contributing to greater anti-tumor efficacy for the treatment of non-small cell lung cancer.

Magnetic lipid-poly(lactic-co-glycolic acid) nanoparticles conjugated with epidermal growth factor receptor antibody for dual-targeted delivery of CPT-11

ABSTRACT Despite advances in targeted therapies, primary and acquired resistance make the treatment of colorectal cancer (CRC) a pressing issue to be resolved. According to reports, the development of CRC is linked to miRNA dysregulation. Multiple studies have demonstrated that miR-135b-5p has an aberrant expression level between CRC tissues and adjacent tissues. However, it is unclear whether there is a correlation between miR-135b-5p and cetuximab (CTx) resistance in CRC. Use the GEO database to measure miR-135b-5p expression in CRC. Additionally, RT-qPCR was applied to ascertain the production level of miR-135b-5p in three human CRC cells and NCM460 cells. The capacity of cells to migrate and invade was examined utilizing the wound-healing and transwell assays, while the CCK-8 assay served for evaluating cell viability, as well as colony formation assays for proliferation. The expected target protein of miR-135b-5p in CRC cell cetuximab resistance has been investigated using western blot. Suppression of miR-135b-5p could increase the CTx sensitivity of CTx-resistant CRC cells, as manifested by the attenuation of proliferation, migration, and invasion ability. Mechanistic studies revealed miR-135b-5p regulates the epithelial-to-mesenchymal transition (EMT) process and Wnt/β-catenin signaling pathway through downgulating FOXN3. In short, knockdowning miR-135b-5p could increase FOXN3 expression in CRC cells, promote the EMT process, and simultaneously activate the Wnt/β-catenin signaling pathway to elevate CTx resistance in CRC cells.

BACKGROUND Although chemotherapy is effective for treating advanced gastric carcinoma (aGC), it may lead to an adverse prognosis. Establishing a highly effective and low-toxicity chemotherapy regimen is necessary for improving efficacy and outcomes in aGC patients. AIM To determine the efficacy and safety of cetuximab (CET) combined with the FOLFOX4 regimen (infusional fluorouracil, folinic acid, and oxaliplatin) as first-line therapy for patients with aGC, who received evidence-based care (EBC). METHODS A total of 117 aGC patients who received EBC from March 2019 to March 2022 were enrolled. Of these, 60 in the research group (RG) received CET + FOLFOX4 as first-line therapy, whereas 57 in the control group (CG) received FOLFOX4. The efficacy [clinical response rate (RR) and disease control rate (DCR)], safety (liver and kidney dysfunction, leukopenia, thrombocytopenia, rash, and diarrhea), serum tumor marker expression [STMs; carbohydrate antigen (CA) 19-9, CA72-4, and carcinoembryonic antigen (CEA)], inflammatory indicators [interleukin (IL)-2 and IL-10], and quality of life (QOL) of the two groups were compared. RESULTS A markedly higher RR and DCR were observed in the RG compared with the CG, with an equivalent safety profile between the two groups. RG exhibited notably reduced CA19-9, CA72-4, CEA, and IL-2 levels following treatment, which were lower than the pre-treatment levels and those in the CG. Post-treatment IL-10 was statistically increased in RG, higher than the pre-treatment level and the CG. Moreover, a significantly improved QOL was evident in the RG. CONCLUSION The CET + FOLFOX4 regimen is highly effective as first-line treatment for aGC patients receiving EBC. It facilitates the suppression of STMs, ameliorates the serum inflammatory microenvironment, and enhances QOL, without increased adverse drug effects.

Strengthened binding affinity of bispecific antibody nanoplatforms improved the anti-tumor efficacy