HER2-positive Colorectal Cancer Research Articles

PRESSING Need of Precision Care in HER2-Positive Colorectal Cancer: The ELEPHANT in the Room.

Although dual HER2 inhibition has shown promising clinical activity in patients with RAS wild-type HER2-positive metastatic colorectal cancer, predictive biomarkers of response/resistance are less well characterized. Activating HER2/RTK/MAPK genomic alterations appears to blunt the clinical benefit of dual anti-HER2 therapy and may hold a potential albeit partial role in patient selection. See related article by Randon et al., p. 436.

A study to learn how well tucatinib plus trastuzumab works for treating participants with metastatic colorectal cancer, and how safe it is: a plain language summary of the MOUNTAINEER study.

This is a summary of an article describing an ongoing study called MOUNTAINEER. This article was published in The Lancet Oncology in 2023. The study included 117 adults with metastatic HER2-positive colorectal cancer. The researchers wanted to know whether a combination of 2 drugs called tucatinib and trastuzumab could shrink the participants' cancer. The researchers also wanted to know whether receiving tucatinib alone could also shrink the participants' cancer. In this study, researchers found that 32 out of 84 participants had their tumors respond to treatment with tucatinib with trastuzumab. This was about 4 in 10 participants. This means that the tumors shrank by at least 30% or disappeared. Participants whose tumors responded to tucatinib with trastuzumab responded for a median of 12.4months. 60 out of 84 participants had their tumors respond or remain about the same size after treatment with tucatinib with trastuzumab. This was about 7 in 10 participants. For those who received tucatinib with trastuzumab the median length of time participants lived during the study was 24.1months and the median length of time participants lived during the study without their cancer growing or spreading was 8.2months. 1 out of 30 participants had their tumors respond to treatment with tucatinib alone within 12weeks. 19 out of 86 participants who received tucatinib with trastuzumab had serious medical problems, also called serious adverse events. This was about 2 in 10 participants. Not all of these serious adverse events were related to tucatinib with trastuzumab. 3 out of 30 participants who received tucatinib alone who had serious adverse events. This was 1 in 10 participants. Not all of these serious adverse events were related to tucatinib alone. Tucatinib with trastuzumab could be a good treatment option for people with HER2-positive colorectal cancer that has spread to other parts of the body. On January 19, the Food and Drug Administration (FDA) granted accelerated approval to the combination of two targeted drugs, tucatinib (Tukysa) and trastuzumab (Herceptin) for people with HER2-positive colorectal cancer that is metastatic or that cannot be treated with surgery. The FDA can grant accelerated approval for new treatments that fill unmet needs for patients with serious medical conditions. Clinical Trial Registration: NCT03043313 (MOUNTAINEER study) (ClinicalTrials.gov).

Molecular Basis of HER2-Targeted Therapy for HER2-Positive Colorectal Cancer.

Human epidermal growth factor receptor 2 (HER2) amplification has emerged as a biomarker in colorectal cancer (CRC), occurring in 1-4% of metastatic CRC (mCRC). In addition to conventional methods, such as immunohistochemistry and fluorescence in situ hybridization, next-generation sequencing-based tissue or circulating tumor DNA analysis has recently been used to identify HER2 amplification and assess HER2 overexpression. Prospective clinical trials have demonstrated the efficacy of HER2-targeted therapies in HER2-positive mCRC. The TRIUMPH study, a phase II study of dual HER2 antibodies, i.e., pertuzumab plus trastuzumab, demonstrated promising efficacy for patients with HER2-positive mCRC confirmed by tissue-and/or blood-based techniques, which led to the regulatory approval of this combination therapy in Japan. The mechanisms associated with efficacy and resistance have also been explored in translational studies that incorporate liquid biopsy in prospective trials. In particular, HER2 copy number and co-alterations have repeatedly been reported as biomarkers related to efficacy. To improve the therapeutic efficacy of the current strategy, many clinical trials with various HER2-targeted agents are ongoing. This review discusses the molecular basis of HER2-targeted therapeutic strategies for patients with HER2-positive mCRC.

HER2 status is positively associated with vessel invasion of colorectal cancer: a retrospective large cohort study

PurposeHER2-positive colorectal cancer was drawn increasing attention in recent years. Accumulating evidence showed HER2-positive metastatic colorectal cancer could benefit from HER2-targeted therapy. While HER2 expression and the relationship between HER2 status and clinicopathological characteristics of overall colorectal cancer remains largely unknown. The aim of this study was to evaluate HER2 expression in colorectal cancer and compare the clinicopathological features between HER2-positive and HER2-negative colorectal cancer.MethodsWe retrospectively analyzed 3910 primary colorectal cancer patients treated in our institution from January 2016 to December 2019. Medical records and pathology reports after surgery were collected to provide information about HER2 status and other clinicopathological characteristics.ResultsWe identified 3347 HER2-negative and 79 HER2-positive colorectal cancer patients in our cohort. The chi-square test showed that vessel invasion was significantly more common in HER2-positive colorectal cancer patients. Crude analysis showed HER2 positive was associated with vessel invasion in colorectal cancer [OR and 95% CI 0.534 (0.341, 0.835), p = 0.006]. After adjusting for N stage, a significant association was still observed between HER2 status and vessel invasion in colorectal cancer [OR and 95% CI 0.550 (0.322, 0.941), p = 0.029]. Survival analysis showed that there was no significant difference in 3-year overall survival rate between HER2 positive and HER2 negative group (p = 0.603).ConclusionOur findings indicate that the rate of HER2 positivity in colorectal cancer was relatively low, and HER2 status was strongly associated with vessel invasion while having no significant influence on the 3-year overall survival rate in colorectal cancer patients.

Dual HER2 Targeted Therapy With Pyrotinib and Trastuzumab in Refractory HER2 Positive Metastatic Colorectal Cancer: A Result From HER2-FUSCC-G Study

BackgroundDual-HER2 targeted therapy has led to a promising antitumor effect in HER2 positive cancers including gastrointestinal cancer. The present data focus on patients with HER2 positive colorectal cancer who received pyrotinib and trastuzumab after failure to standard second-line treatment. MethodsPatients diagnosed of HER2 positive refractory or metastatic colorectal cancer were enrolled to receive trastuzumab in combination with pyrotinib as third-line and beyond therapy. Trastuzumab was given as a loading dose at 8 mg/kg followed by 6mg/kg once every 3 weeks, and oral pyrotinib as 400 mg per day until progression. ORR was set as the primary endpoint. PFS and OS were set as a secondary endpoints. This trial is registered with Clinical Trial.gov, NCT04960943, and is ongoing. ResultsBetween February 2020 to December 2021, 16 patients including 14 with RAS wild-type status were enrolled in this cohort. ORR was 50.0% in the overall population, and 57.1% in RAS wild-type patients. At a median follow-up of 11.2 months, median PFS and OS were 7.53 and 16.8 months, respectively. The RAS/BRAF wild-type patients had prolonged survival (PFS: 7.53 vs. 1.63 months, P = .02; OS: NR vs.4.13 months, P = .001) compared with RAS/BRAF mutant patients. The most common treatment-emergent adverse event (TEAE) reported is diarrhea. Five (31.3%) patients reported grade 3 TEAEs, and no death was reported. ConclusionsTrastuzumab in combination with pyrotinib demonstrated encouraging antitumor activity that translated to prolonged survival benefit in HER2 positive refractory or mCRC patients who are RAS wild-type with acceptable tolerance.

Anti-HER2 therapy with pyrotinib and trastuzumab in refractory HER2-positive metastatic colorectal cancer: A preliminary report from HER2-FUSCC-G study.

97 Background: Dual-targeted HER2 therapy has led to a promising antitumor effect in HER2 positive metastatic colorectal cancer. The current study was aimed to evaluate the therapeutic efficacy of pyrotinib and trastuzumab in patients with HER2 positive colorectal cancer. Methods: HER2-FUSCC-G is an ongoing, open-label, non-randomised, phase 2a study. Patients in this subset were diagnosed as HER2 positive metastatic colorectal cancer refractory to standard chemotherapies. All the enrolled patients were treated with a loading dose of trastuzumab at 8 mg/kg followed by 6mg/kg once every three weeks, and oral pyrotinib at 400 mg per day until progression. ORR was set as the primary endpoint. Estimates of PFS (progression free survival) and OS (overall survival) were obtained with the Kaplan-Meier method and compared with log-rank test. Results: Between January 2020 to June 2021, 11 patients were enrolled in this study. The ORR was 45.5% in whole population, and 55.6% in RAS wild-type patients. At a median follow-up of 17.73 months, median PFS and OS were 7.80 and 14.97 months, respectively. The KRAS wild-type group of patients had prolonged survival (PFS: 9.97 vs. 7.73 months, P = 0.19; OS: 20.67 vs. 12.43 months, P = 0.021) compared with KRAS mutant group. Nine of 11 (81.8%) patients reported≥1 grade treatment-emergent adverse events (TATEs), while 4 (36.4%) patients reported grade 3/4 TATEs. Conclusions: The combination of trastuzumab and pyrotinib showed a promising anti-tumor response and prolonged long-term survival benefit in RAS wild-type and HER2 positive mCRC with acceptable tolerance. Clinical trial information: NCT04960943.

HER2-/HER3-Targeting Antibody-Drug Conjugates for Treating Lung and Colorectal Cancers Resistant to EGFR Inhibitors.

Simple SummaryEpidermal growth factor receptor (EGFR) is one of the anticancer drug targets for certain malignancies including nonsmall cell lung cancer (NSCLC), colorectal cancer (CRC), and head and neck squamous cell carcinoma. However, the grave issue of drug resistance through diverse mechanisms persists. Since the discovery of aberrantly activated human epidermal growth factor receptor-2 (HER2) and HER3 mediating resistance to EGFR-inhibitors, intensive investigations on HER2- and HER3-targeting treatments have revealed their advantages and limitations. An innovative antibody-drug conjugate (ADC) technology, with a new linker-payload system, has provided a solution to overcome this resistance. HER2-targeting ADC trastuzumab deruxtecan or HER3-targeting ADC patritumab deruxtecan, using the same cleavable linker-payload system, demonstrated promising responsiveness in patients with HER2-positive CRC or EGFR-mutated NSCLC, respectively. The current manuscript presents an overview of the accumulated evidence on HER2- and HER3-targeting therapy and discussion on remaining issues for further improvement of treatments for cancers resistant to EGFR-inhibitors.Epidermal growth factor receptor (EGFR) is one of the anticancer drug targets for certain malignancies, including nonsmall cell lung cancer (NSCLC), colorectal cancer (CRC), and head and neck squamous cell carcinoma. However, the grave issue of drug resistance through diverse mechanisms persists, including secondary EGFR-mutation and its downstream RAS/RAF mutation. Since the discovery of the role of human epidermal growth factor receptor 2 (HER2) and HER3 in drug resistance, HER2- or HER3-targeting treatment strategies using monoclonal antibodies have been intensively examined and have demonstrated impressive responsiveness and limitations. Finally, an innovative targeted therapy called antibody drug conjugates (ADC) has provided a solution to overcome this resistance. Specifically, a new cleavable linker-payload system enables stable drug delivery to cancer cells, causing selective destruction. HER2-targeting ADC trastuzumab deruxtecan demonstrated promising responsiveness in patients with HER2-positive CRC, in a phase 2 clinical trial (objective response rate = 45.3%). Furthermore, HER3-targeting patritumab deruxtecan, another ADC, exhibited impressive tumor shrinkage in pretreated patients with EGFR-mutated NSCLC, in a phase 1 clinical trial. This manuscript presents an overview of the accumulated evidence on HER2- and HER3-targeting therapy, especially ADCs, and discussion of remaining issues for further improving these treatments in cancers resistant to EGFR inhibitors.

A Study of Pyrotinib Combined With Capecitabine for Metastatic HER-2 Positive Colorectal Cancer

A Study of Pyrotinib Combined With Capecitabine for Metastatic HER-2 Positive Colorectal Cancer

Comprehensive assessment of HER2 alteration in a colorectal cancer cohort: from next-generation sequencing to clinical significance.

PurposeHuman epidermal growth factor receptor 2 (HER2) is an emerging therapeutic target in colorectal cancer (CRC). Currently, immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) have been used to determine HER2-positive CRCs; however, the clinical utility of next-generation sequencing (NGS)-based techniques for determining HER2 status in CRC has been limited. Here, we detail our experience regarding the assessment of HER2 alterations in a CRC cohort.Materials and methodsWe prospectively enrolled 73 CRC patients who underwent surgery and received adjuvant oxaliplatin treatment. We then examined HER2 alterations using the Oncomine Comprehensive Assay version 1, as well as clinical outcomes, in this cohort.ResultsUsing the NGS-based assay, HER2 copy number gains in 12 of 73 CRCs were determined to range from 2.74 to 92.62. Of these 12 tumors, 6 had HER2 high-level copy number gain (92.6, 57.9, 57.0, 52.0, 35.2, and 8.42) and were all defined as HER2-positive CRC using HERACLES Diagnostic Criteria. Nevertheless, other 6 patients with low-level copy number gain (ranging from 2.74 to 3.04) and the remaining 61 patients without increase in HER2 copy number were all HER2-negative. Among the 6 HER2-positive CRCs, KRAS and PIK3CA mutations were detected in 1 (17%; G13D) and 2 (33.3%; 1 Q546R and 1 H1047R) patients, respectively. Moreover, 2 of the 6 (33.3%) HER2-positive patients had recurrent disease, while one patient had a partial response after anti-HER2 therapy.ConclusionNGS-based tools could assist in the simultaneous detection of HER2 and other genomic alterations in patients with CRC. Only CRCs with HER2 high-level copy number gain were HER2-postive by current diagnostic criteria.

Human epidermal growth factor receptor 2-positive digestive tumors.

This manuscript aims at providing an update and overview on the role of Human epidermal growth factor receptor 2 (HER2) testing and HER2-directed therapies in digestive tumors. Phase 3 trial data demonstrating a survival benefit of HER2-targeting treatments are limited to gastric cancer. However, HER2 positivity is also found in 5-6% of colorectal, 7% of pancreatic, and 16% of extrahepatic biliary cancers. Although phase 2 trial data support the use of the combination of trastuzumab and lapatinib with chemotherapy in HER2-positive colorectal cancer, the patient's benefit from targeted treatment of HER2-positive biliary or pancreatic neoplasms is currently unclear, and further clinical trials are necessary. With the exception of gastric cancer, there are currently no defined guidelines for HER2 testing in other digestive tumors. Various HER2-targeting therapies, which are standard of care in HER2-positive breast cancer, failed in HER2-positive gastric cancers. Thus, the predictive value of HER2 overexpression depends on the tumor type, and results of breast cancer trials cannot a priori be extrapolated to digestive cancers. Next-generation sequencing panel diagnostics may furthermore identify targetable activating mutations in gastric, extrahepatic biliary, and colorectal cancer, particularly if traditional testing (immunohistochemistry/in-situ hybridization) is negative. However, their clinical relevance needs to be determined.

Utility of comprehensive genomic sequencing for detecting HER2-positive colorectal cancer

HER2-targeted therapy is considered effective for KRAS codon 12/13 wild-type, HER2-positive metastatic colorectal cancer (CRC). In general, HER2 status is determined by the use of immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). Comprehensive genomic sequencing (CGS) enables the detection of gene mutations and copy number alterations including KRAS mutation and HER2 amplification; however, little is known about the utility of CGS for detecting HER2-positive CRC. To assess its utility, we retrospectively investigated 201 patients with stage I-IV CRC. The HER2 status of the primary site was assessed using IHC and FISH, and HER2 amplification of the primary site was also assessed using CGS, and the findings of these approaches were compared in each patient. CGS successfully detected alterations in 415 genes including KRAS codon 12/13 mutation and HER2 amplification. Fifty-nine (29%) patients had a KRAS codon 12/13 mutation. Ten (5%) patients were diagnosed as HER2 positive because of HER2 IHC 3+, and the same 10 (5%) patients had HER2 amplification evaluated using CGS. The results of HER2 status and HER2 amplification were completely identical in all 201 patients (P < .001). Nine of the 10 HER2-positive patients were KRAS 12/13 wild-type and were considered possible candidates for HER2-targeted therapy. CGS has the same utility as IHC and FISH for detecting HER2-positive patients who are candidates for HER2-targeted therapy, and facilitates precision medicine and tailor-made treatment.

Abstract CT082: Pertuzumab and trastuzumab-emtansine in HER2-positive colorectal cancer: the HERACLES B trial

Abstract Rationale: The HERACLES A trial showed that a clinical sizeable subset of 3% of metastatic colorectal cancers (mCRC), identifiable by the amplification of the HER2 gene, can be targeted for effective, durable and safe anti-HER2 treatment with a combination of the small molecule kinase inhibitor lapatinib (L) and the monoclonal antibody trastuzumab (T) [Siena et al. J Clin Oncol 33, 2015.(suppl; abs 3508)]. As with any other targeted therapy, however, the L+T combination was not active in all patients, and even in responders its efficacy was limited in time by the engagement of growth-promoting cues that compensate for inhibition of the targeted kinase, eventually leading to disease progression. In both primary and secondary resistant HERACLES A patients the amplification of the HER2 gene was nevertheless present in more than 50% of the tumor cells. We reasoned that this finding could be exploited by adding to the anti HER2 strategy a ‘precision chemotherapy’ component, embodied by the HER2 antibody-drug conjugate trastuzumab-emtansine (T1). To this end, we conducted a preclinical trial in CRC0186, the only patient-derived xenograft (PDX) of our HER2+ mCRC PDX collection (N = 7), showing tumor inhibition rather than tumor shrinkage after L+T treatment. Six mice per arm were randomized to either control, pertuzumab (P), T1 or P+T1. Optimal tumor shrinkage, mirroring clinical complete response, was only observed in the T1 and the P+T1 arms, and persisted after treatment stop only in the latter arm (Bertotti, unpublished data). Notably, this post treatment response was not observed in comparable experiments testing the L+T or P+T combinations in more sensitive HER2+ PDXs (Bertotti et al., Cancer discovery 2011; Leto et al., Clin Cancer Res 2015). In light of the above results we designed the HERACLES B trial. Trial design: HERACLES B is an independent phase II trial of P+T (accrual starting March 2016). Response rate is the primary endpoint, progression free survival the secondary. Sample size was calculated according to the Fleming &amp; A’Hern one stage design under the following assumptions: H0 = RR 10%, H1 = RR 30%. With a = 0.05 and β = 85%, we need to accrue 27 patient and observe ? 6 responses to declare the study positive. The clonal evolution of each patient tumor's is monitored via fortnightly liquid biopsies. Eligibility criteria: mCRC patients HER2+ according to HERACLES criteria (Valtorta E. et al, Modern Pathology, 2015) and wild type for KRAS, NRAS and BRAF; prior treatment with fluoropirimidines, oxaliplatin, and irinotecan containing regimens, ± anti EGFR or antiangiogenic treatment; measurable disease (RECIST v1.1), ECOG PS ?1, and adequate organ function. Treatment: Pertuzumab (840 mg/kg iv load followed by 420mg/kg IV) in combination with TDM1 (3,6 mg/kg) both q3wks. EudraCT number: 2012-002128-33; Funded by AIRC Grant # 9970. Citation Format: Livio Trusolino, Andrea Bertotti, Sara Lonardi, Andrea Sartore-Bianchi, Cosimo Martino, Francesca Cottino, Valentina Vurchio, Emanuele Valtorta, Calogero Lauricella, Daniele Regge, Angelo Vanzulli, Vittorina Zagonel, Francesco Leone, Patrizia Racca, Fortunato Ciardiello, Andrea Ardizzoni, Silvia Marsoni, Salvatore Siena. Pertuzumab and trastuzumab-emtansine in HER2-positive colorectal cancer: the HERACLES B trial. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr CT082.

Dual-targeted therapy with trastuzumab and lapatinib in treatment-refractory, KRAS codon 12/13 wild-type, HER2-positive metastatic colorectal cancer (HERACLES): a proof-of-concept, multicentre, open-label, phase 2 trial

We previously found that dual HER2 blockade with trastuzumab and lapatinib led to inhibition of tumour growth in patient-derived xenografts of HER2-amplified metastatic colorectal cancer. In this study, we aimed to assess the antitumour activity of trastuzumab and lapatinib in patients with HER2-positive colorectal cancer. HERACLES was a proof-of-concept, multicentre, open-label, phase 2 trial done at four Italian academic cancer centres. We enrolled adult patients with KRAS exon 2 (codons 12 and 13) wild-type and HER2-positive metastatic colorectal cancer refractory to standard of care (including cetuximab or panitumumab), an Eastern Cooperative Oncology Group performance status of 0 or 1, and at least one measurable lesion. We defined HER2 positivity in tumour samples by use of immunohistochemistry and fluorescence in-situ hybridisation in accordance with our previously validated colorectal cancer-specific diagnostic criteria. Eligible patients received intravenous trastuzumab at 4 mg/kg loading dose followed by 2 mg/kg once per week, and oral lapatinib at 1000 mg per day until evidence of disease progression. The primary endpoint was the proportion of patients achieving an objective response (defined as complete response or partial response), which was assessed by independent central review in the intention-to-treat population. This trial is registered with EudraCT, number 2012-002128-33. Between Aug 27, 2012, and May 15, 2015, we screened 914 patients with KRAS exon 2 (codons 12 and 13) wild-type metastatic colorectal cancer and identified 48 (5%) patients with HER2-positive tumours, although two died before enrolment. Of these patients, 27 were eligible for the trial. All were evaluable for response. At the time of data cutoff on Oct 15, 2015, with a median follow-up of 94 weeks (IQR 51-127), eight (30%, 95% CI 14-50) of 27 patients had achieved an objective response, with one patient (4%, 95% CI -3 to 11) achieving a complete response, and seven (26%, 95% CI 9-43) achieving partial responses; 12 (44%, 95% CI 25-63) patients had stable disease. Six (22%) of 27 patients had grade 3 adverse events, which consisted of fatigue in four patients, skin rash in one patient, and increased bilirubin concentration in one patient. No grade 4 or 5 adverse events were reported. We detected no drug-related serious adverse events. The combination of trastuzumab and lapatinib is active and well tolerated in treatment-refractory patients with HER2-positive metastatic colorectal cancer. Associazione Italiana Ricerca Cancro (AIRC), Fondazione Oncologia Niguarda Onlus, and Roche.

Targeted therapy for gastrointestinaI (GI) tumors based on molecular profiles: Early results from MyPathway, an open-label phase IIa basket study in patients with advanced solid tumors.

653 Background: Next-generation sequencing often reveals potentially actionable molecular alterations; however, data on approved targeted therapies in non-indicated tumors are limited. MyPathway (NCT02091141) evaluates agents targeting the HER2, EGFR, BRAF, or Hedgehog (Hh) pathways in tumors for which these therapies are not currently indicated. Here, we present early response data for patients with GI tumors. Methods: Eligible patients had metastatic tumors with potentially actionable genomic alterations, identified by a CLIA-certified lab, and progression on standard therapy. Based on the identified alteration, patients received standard doses of trastuzumab + pertuzumab (HER2), erlotinib (EGFR), vemurafenib (BRAF), or vismodegib (Hh). Response was evaluated by the investigator using RECIST v1.1. Results: As of Aug 21, 2015, 96 patients had enrolled, 36 of whom (38%) had GI tumors with the following alterations: HER2 (n=28 [22 amplifications, 5 activating mutations, 1 both]), BRAF (n=4), Hh (n=2 [2 PTCH-1 mutations]), and EGFR (n=2). Patients had a median of 4 (range, 1–8) prior lines of therapy. Tumor types and interim best response data are shown below. Among all evaluable patients with GI tumors (n=26), 5 have had a PR to targeted therapy (duration 3–10+ months). Conclusions: Targetable molecular alterations were found in a variety of GI tumors, resulting in clinical benefit from targeted treatments that would not have otherwise been realized. These early results support this molecular testing strategy. Accrual to the trial continues; based on activity observed, the HER2-positive colorectal cancer cohort will be expanded to ≥30 patients. Additional data will be presented at the meeting. Clinical trial information: NCT02091141. [Table: see text]

Bispecific anti-CD3 x anti-HER2 antibody mediates T cell cytolytic activity to HER2-positive colorectal cancer in vitro and in vivo.

Targeting HER2 overexpressed breast cancer cells with anti‑HER2 monoclonal antibodies inhibits tumor growth. Here we investigated whether HER2 can serve as a target for T cell-mediated immunotherapy of human colorectal carcinoma. Specific cytolytic activity of activated T cells (ATCs) armed with anti‑CD3 x anti‑HER2 bispecific antibody (HER2Bi-Ab) against HER2+ tumor cells was evaluated by bioluminescent signal generated by luciferase reporter on tumor cells in vitro and in vivo. In contrast to unarmed ATCs, increased cytotoxic activity of HER2Bi-armed ATCs against HER2+ tumor cells was observed. Moreover, HER2Bi-armed ATCs expressed higher level of activation marker CD69 and secreted significantly higher levels of IFN-γ than the unarmed ATC counterpart. In addition, compared with anti‑HER2 mAb (Herceptin®) or unarmed ATC, HER2Bi-armed ATCs showed significant suppression against colorectal carcinoma cells. In colorectal tumor cell xenograft mice, infusion of HER2Bi-armed ATCs successfully inhibited the growth of Colo205-luc cells. The HER2Bi-armed ATCs with anti-tumor effects may provide a promising immunotherapy for colorectal carcinoma in the future.

Molecular profiling of HER2-positive colorectal cancer for identification of multiple potential drug targets.

e14508 Background: Colorectal adenocarcinoma (CRC) is a clinically and genetically heterogeneous disease driven by multiple pathways including the HER2 receptor tyrosine kinase pathway. This study ...

298 Development of anti-EGFR immunoliposomes for specific delivery and enhanced efficacy in EGFR-overexpressing tumors

Amplification of the HER2 gene is an indicator of poor prognosis for several kinds of malignancies such as breast and gastric cancer, and anti-HER2 targeting therapies provide clinical benefits in these patients. In 2011, HER2 was identified as a resistance molecule for de novo and secondary anti-epidermal growth factor receptor (EGFR) antibody therapy. HER2 activation provides a bypass signaling pathway after anti-EGFR antibody treatment of colorectal cancer. Cell line-based screening revealed that HER2 genomic amplification induces resistance to the anti-EGFR antibody cetuximab in colorectal cancer. Recently, HER2 itself has been recognized as a target for oncotherapy in colorectal cancer. The first part of this review provides an update on the present state of knowledge about the role of HER2 in colorectal cancer, including its prognostic relevance and role in resistance to anti-EGFR antibody treatment. In the second part of the review, we discuss the results of preclinical and clinical studies that examined the potential utility of anti-HER2 targeted therapy in colorectal cancer. Although it acts as a barrier for other molecular targeting agents such as cetuximab, HER2 itself is a promising target for oncotherapy. Current research indicates that anti-HER2 drugs will be developed further and introduced into clinical practice for the treatment of patients with HER2-positive colorectal cancer.