Risk factors for early recurrence after radical gastrectomy followed by adjuvant chemotherapy for stage II or III gastric cancer: a multicenter, retrospective study

BACKGROUND

Radical gastrectomy followed by adjuvant chemotherapy is the standard treatment for stage II or III gastric cancer in Asian countries. Early recurrence during or after adjuvant chemotherapy is associated with poor prognosis; however, risk factors for early recurrence remain unclear.

METHODS

In this multicenter, retrospective cohort study including six institutions, we evaluated the clinicopathological factors of 553 patients with gastric cancer undergoing gastrectomy followed by adjuvant chemotherapy between 2012 and 2016. Patients were divided into the following groups: early recurrence (recurrence during adjuvant chemotherapy or within 6 months after adjuvant chemotherapy completion) and non-early recurrence, which was further divided into late recurrence and no recurrence. Early-recurrence risk factors were investigated using multivariate Cox proportional hazard model. The chronological changes in the recurrence hazard were also examined for each factor.

RESULTS

Early recurrence and late recurrence occurred in 83 (15.0%) and 73 (13.2%) patients, respectively. Based on the Cox proportional hazards model, a postoperative serum carcinoembryonic antigen level of ≥5 ng/mL (hazard ratio: 2.220, 95% confidence interval: 1.089-4.526) and a neutrophil-to-lymphocyte ratio of >1.8 (hazard ratio: 2.408, 95% confidence interval: 1.479-3.92) were identified as independent risk factors of early recurrence, but not late recurrence. The recurrence hazard ratios for neutrophil-to-lymphocyte ratio significantly decreased over time (P < 0.001) and carcinoembryonic antigen also had the same tendency (P = 0.08).

CONCLUSIONS

A carcinoembryonic antigen level of ≥5 ng/mL and a neutrophil-to-lymphocyte ratio of >1.8 are predictors of early recurrence after radical gastrectomy and adjuvant chemotherapy for stage II or III gastric cancer.

Clinical impact of pleural fluid carcinoembryonic antigen on therapeutic strategy and efficacy in lung adenocarcinoma patients with malignant pleural effusion

BACKGROUND/AIMS

Epidermal growth factor receptor (EGFR) mutation is important in determining the treatment strategy for advanced lung cancer patients with malignant pleural effusion (MPE). Contrary to serum carcinoembryonic antigen (S-CEA) levels, the associations between pleural fluid CEA (PF-CEA) levels and EGFR mutation status as well as between PF-CEA levels and treatment efficacy have rarely been investigated in lung adenocarcinoma patients with MPE.

METHODS

This retrospective study enrolled lung adenocarcinoma patients with MPE and available PF-CEA levels and EGFR mutation results. The patients were categorized based on PF-CEA levels: < 10 ng/mL, 10-100 ng/mL, 100-500 ng/mL, and ≥ 500 ng/mL. The association between PF-CEA levels and EGFR mutation status as well as their therapeutic impact on overall survival was compared among the four groups.

RESULTS

This study included 188 patients. PF-CEA level was found to be an independent predictor of EGFR mutation but not S-CEA level. The EGFR mutation rates were higher as the PF-CEA levels increased, regardless of cytology results or sample types. Among EGFR-mutant lung adenocarcinoma patients receiving EGFR-tyrosine kinase inhibitor (TKI) treatment, those with high PF-CEA levels had significantly better survival outcomes than those with low PF-CEA levels.

CONCLUSION

High PF-CEA levels were associated with high EGFR mutation rate and may lead to a favorable clinical outcome of EGFR-TKI treatment in EGFR-mutant lung adenocarcinoma patients with MPE. These findings highlight the importance of actively investigating EGFR mutation detection in patients with suspected MPE and elevated PF-CEA levels despite negative cytology results.

[A Case of Long-Term Survival with Metachronous Hepatic and Pulmonary Metastases from Transverse Colon Cancer by Multidisciplinary Treatment]

A 64-year-old woman underwent right hemicolectomy for transverse colon cancer. Histopathological findings revealed T, type 2, 24×22 mm, tub2, pT2N1a(1/23)M0, and pStage Ⅲa. Postoperative adjuvant chemotherapy was not administered at the patient's request. One year after surgery, carcinoembryonic antigen(CEA)level was elevated, and Gd-EOB-DTPA- enhanced MRI revealed a nodule in segment 2 and 4/8 of the liver. Based on the diagnosis of hepatic metastasis, laparoscopic partial hepatectomy was performed. Three years after hepatectomy, CEA level was found to be elevated again, and chest CT showed a solitary pulmonary nodule in segment 7 of the right lung. With a diagnosis as pulmonary metastasis, FOLFIRI plus bevacizumab was performed. After 41 courses of FOLFIRI plus bevacizumab, the pulmonary nodule decreased in size, and no new lesions appeared. The chemotherapy was terminated at the patient's request. Six months later, the pulmonary nodule increased in size, and thoracoscopic partial pulmonary resection was performed. Hepatic and pulmonary resection specimens were histopathologically consistent as metastasis of colorectal cancer. The patient has been alive without recurrence for about 4 years after final surgery(pulmonary resection)without postoperative adjuvant chemotherapy. We report a case of long-term survival with metachronous hepatic and pulmonary metastases from transverse colon cancer by multidisciplinary treatment.

Effect of bevacizumab administered prior to transarterial chemoembolization on the therapeutic effects of lenvatinib given post-TACE in primary liver cancer patients

OBJECTIVE

To determine the therapeutic effects of lenvatinib combined with bevacizumab following transarterial chemoembolization (TACE) in patients with primary liver cancer.

MATERIALS AND METHODS

100 patients with primary liver cancer were recruited in the period from January 2020 to January 2021 and allocated with randomization into a control group (n = 50) and a test (bevacizumab) group (n = 50). The patients in the control group received lenvatinib for 4 weeks following TACE, whereas those in the test group received bevacizumab for 6 weeks prior to TACE and subsequent therapy with lenvatinib for 4 weeks. The serum concentration of interferon-γ (INF-γ), interleukin-10 (IL-10), soluble interleukin-2 receptor (sIL-2R), interleukin-12 (IL-12), superoxide dismutase (SOD), total antioxidant capacity (TAOC), glutathione (GSH), malondialdehyde (MDA), total bilirubin (TBil), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), carbohydrate antigen 242 (CA242), CA724, α-fetoprotein (AFP) and carcinoembryonic antigen (CEA) were determined in both groups at the commencement of treatment in January 2020 and 12 months later and compared with the observed therapeutic effects.

RESULTS

The concentrations of CA242, CEA, CA724, and AFP in the bevacizumab group were lower than those in the control group (p < 0.05). The concentration of IL-12 and INF-γ in the bevacizumab group were higher, but the levels of IL-10 and sIL-2R lower than in the control group (p < 0.05). In the bevacizumab group, the level of MDA was lower, whereas the levels of TAOC, SOD, and GSH were higher than those in the control group (p < 0.05). The bevacizumab group also had lower levels of ALT, TBil, and AST and a higher level of ALP than control group (p < 0.05). The response rate based on tumor status (size, progression) in the bevacizumab group was higher than in the control group (p < 0.05).

CONCLUSION

The therapeutic effects of lenvatinib following TACE in primary liver cancer are significantly greater when combined with bevacizumab administered for 6 weeks prior to TACE.

Incidence, clinicopathological features, and clinical outcomes of low HER2 expressed, inoperable, advanced, or recurrent gastric/gastroesophageal junction adenocarcinoma

BACKGROUND

According to the DESTINY-Breast04 trial, treating patients with breast cancer and low human epidermal growth factor receptor 2 expressions (HER2-low) varies from that of those with no HER2 expression. However, it is interesting to know if HER2-low indicates for anti-HER2 therapy in the gastric or gastroesophageal junction (G/GEJ) adenocarcinoma. Hence we conducted this study to assess the incidence, clinicopathological features, and treatment outcomes of patients with HER2-low G/GEJ adenocarcinoma.

PATIENTS AND METHODS

This was a single-center, retrospective observational study. Patients with previously untreated G/GEJ adenocarcinoma were classified based on their HER2 status using immunohistochemistry (IHC) with or without in situ hybridization (ISH) as follows: HER2 negative (IHC 0), HER2-low (IHC 1+ or 2+/ISH-), and HER2-positive (IHC2+/ISH+ or 3+).

RESULTS

In total, 734 patients with G/GEJ adenocarcinoma were divided into three groups (HER2-negative, n = 410; HER2-low, n = 154, and HER2-positive, n = 170). The intestinal-type histology, peritoneal metastasis, and higher serum carcinoembryonic antigen (CEA) levels differed significantly among patients with negative, low, and positive HER2 statuses: intestinal-type histology (21.0%, 44.2%, and 59.8%, respectively), peritoneal metastasis (56.3%, 44.8%, and 21.8%, respectively), and higher serum CEA level (32.2%, 41.6%, and 56.5%, respectively). Improved survival was observed in the HER2-positive group than in the HER2-negative G/GEJ adenocarcinoma group [hazard ratio (HR) = 0.73, 95% confidence interval (CI) 0.59-0.89; P = 0.002]. However, the prognoses of the HER2-low and HER2-negative groups were similar (HR = 1.01, 95% CI 0.82-1.23; P = 0.843).

CONCLUSIONS

Patients with HER2-low G/GEJ adenocarcinoma exhibited intermediate and distinct characteristics than those in the HER2-negative group. Similarly, the HER2-low group's prognosis was worse than that of the HER2-positive group. Therefore developing novel therapeutic strategies targeting HER2-low G/GEJ adenocarcinoma is required.

Carcinoembryonic antigen-related cell adhesion molecule 1: a key regulatory protein involved in leiomyoma growth

OBJECTIVE

To assess and characterize the role of carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) in the development of uterine leiomyoma.

DESIGN

Laboratory study.

SETTING

Academic research center.

PATIENT(S)

Not applicable.

INTERVENTION(S)

Laboratory investigation. In vitro assessment of human leiomyoma and myometrial tissue specimens as well as immortalized leiomyoma and myometrial cell lines.

MAIN OUTCOME MEASURE(S)

Western blotting and immunohistochemical analyses were performed to assess differences in CEACAM1 content between leiomyoma and myometrial samples. Small interfering RNA silencing experiments and transient transfection experiments were performed to characterize the regulatory role of CEACAM1 on downstream signaling cascades.

RESULT(S)

Analysis of RNA sequencing data revealed decreased CEACAM1 expression in human uterine leiomyoma specimens compared with that in myometrial samples. This translated to a significant down-regulation in CEACAM1 protein content in human leiomyoma compared with patient-matched myometrial tissue samples (0.236 ± 0.05-fold). A similar decrease in CEACAM1 protein content was observed in matched immortalized leiomyoma cell (ILC) and immortalized myometrial cell lines (0.21 ± 0.07). Immunohistochemical analysis revealed decreased staining intensity in leiomyoma surgical specimens compared with the matched myometrium of placebo patients. Lower CEACAM1 levels in leiomyoma were associated with increased activation of both the mitogen-activated protein kinase (MAPK) and the phosphoinositide 3-kinase/protein kinase B pathways compared with that in myometrial cells. This is significant because activation of these pathways plays an important role in leiomyoma growth. Treatment of myometrial cells with CEACAM1 small interfering RNA resulted in a significant down-regulation of CEACAM1 at the protein level (0.272 ± 0.06-fold) and was associated with increased activation of the MAPK (1.62 ± 0.21-fold) and phosphoinositide 3-kinase/protein kinase B (1.79 ± 0.35-fold) pathways, as well as increased collagen production (2.1 ± 0.49-fold). Rescue of CEACAM1 expression in leiomyoma cells by transient transfection restored regulatory control and resulted in lower activation of the MAPK pathway (0.58 ± 0.37-fold).

CONCLUSION(S)

CEACAM1 is an important protein involved in regulating many signal transduction pathways. Decreased CEACAM1 expression in leiomyoma allows permissive uncontrolled overactivation and up-regulation of downstream pathways that may contribute to leiomyoma growth.

Carcinoembryonic antigen interacts with TGF-{beta} receptor and inhibits TGF-{beta} signaling in colorectal cancers

As a tumor marker for colorectal cancers, carcinoembryonic antigen (CEA) enhances the metastatic potential of cancer cells. CEA functions as an intercellular adhesion molecule and is upregulated in a wide variety of human cancers. However, the molecular mechanisms by which CEA mediates metastasis remain to be understood. Transforming growth factor-β (TGF-β) signaling regulates both tumor suppression and metastasis, and also contributes to the stimulation of CEA transcription and secretion in colorectal cancer cells. However, it remains unknown whether CEA, in turn, influences TGF-β functions and if a regulatory cross-talk exists between CEA and the TGF-β signaling pathway. Here, we report that CEA directly interacts with TGF-β receptor and inhibits TGF-β signaling. Targeting CEA with either CEA-specific antibody or siRNA rescues TGF-β response in colorectal cancer cell lines with elevated CEA, thereby restoring the inhibitory effects of TGF-β signaling on proliferation. CEA also enhances the survival of colorectal cancer cells in both local colonization and liver metastasis in animal study. Our study provides novel insights into the interaction between CEA and TGF-β signaling pathway and establishes a negative feedback loop in amplifying the progression of colon cancer cells to more invasive phenotypes. These findings offer new therapeutic opportunities to inhibit colorectal cancer cell proliferation by cotargeting CEA in promoting tumor-inhibitory action of the TGF-β pathway.

Benefits of gene transduction of granulocyte macrophage colony-stimulating factor in cancer vaccine using genetically modified dendritic cells

Granulocyte macrophage colony-stimulating factor (GM-CSF) is a key cytokine for the generation and stimulation of dendritic cells (DCs), and it may also play a pivotal role in promoting the survival of DCs. In this study, the feasibility of creating a cancer vaccine using DCs adenovirally transduced with the carcinoembryonic antigen (CEA) gene and the GM-CSF gene was examined. In addition, the effect of the co-transduction of GM-CSF gene on the lifespan of these genetically modified DCs was determined. A cytotoxic assay using peripheral blood mononuclear cell (PBMC)-derived cytotoxic T lymphocytes (CTLs) was performed in a 4-h 51Cr release assay. The apoptosis of DCs was examined by TdT-mediated dUTP-FITC nick end labeling (TUNEL) assay. CEA-specific CTLs were generated from PBMCs stimulated with genetically modified DCs expressing CEA. The cytotoxicity of these CTLs was augmented by co-transduction of DCs with the GM-CSF gene. Co-transduction of the GM-CSF gene into DCs inhibited apoptosis of these DCs themselves via up-regulation of Bcl-x(L) expression, leading to the extension of the lifespan of these DCs. Furthermore, the transduction of the GM-CSF gene into DCs also suppressed the incidence of apoptosis of DCs induced by transforming growth factor-beta1 (TGFbeta-1). Immunotherapy using these genetically modified DCs may therefore be useful with several advantages as follows: i) adenoviral toxicity to DCs can be reduced; ii) the lifespan of vaccinated DCs can be prolonged; and iii) GM-CSF may protect DCs from apoptosis induced by tumor-derived TGFbeta-1 in the regional lymph nodes.

DNA and Adenoviral Vectors Encoding Carcinoembryonic Antigen Fused to Immunoenhancing Sequences Augment Antigen-Specific Immune Response and Confer Tumor Protection

A panel of vectors was constructed to encode carcinoembryonic antigen (CEA) fused at its C-terminal end to various polypeptides, so as to compare their immunogenicity by plasmid DNA immunization and adenovirus injection in wild-type and CEA transgenic (CEA.tg) mice. Fusions between CEA and the minimized domain of tetanus toxin fragment C (CEA-DOM) or the Fc portion of IgG1 (CEA-FcIgG) were identified as highly immunogenic and elicited significant CEA-specific antibody and CD8+ T cell responses. CEA.tg mice were protected from tumor growth on challenge with MC38-CEA tumor cells only when immunized with repeated injections of plasmid pV1J/CEA-DOM followed by Ad/CEA-DOM. Depletion of T-regulatory cells resulted in an increased immune response and antitumor effect with DNA plus adenovirus immunization. In addition, this protective effect was abrogated if the NK, CD4+, or CD8+ cell population from immunized mice was depleted before tumor challenge. Passive transfer studies demonstrated that CD4+ and CD8+ T cells and antibodies contributed to the antitumor effect, thus suggesting that a genetic vaccine based on the use of plasmid DNA and adenoviral vectors encoding CEA fused to immunoenhancing sequences augments CEA-specific immune responses and effectively protects from tumor development.

Phase II trial of carcinoembryonic antigen radioimmunotherapy with 131I-labetuzumab after salvage resection of colorectal metastases in the liver: five-year safety and efficacy results

PURPOSE

Although complete resection (R0) of liver metastases (LM) remains the treatment of choice for colorectal cancer (CRC) patients amenable to curative therapy, only approximately one third survive for 5 years. The objective of this phase II study was to evaluate the safety and efficacy of radioimmunotherapy (RAIT) after salvage resection of LM.

PATIENTS AND METHODS

Twenty-three patients who underwent surgery for LM of CRC received a dose of 40 to 60 mCi/m2 of 131I-labetuzumab, which is a humanized monoclonal antibody against carcinoembryonic antigen. Safety (n = 23), disease-free survival (DFS; n = 19), and overall survival (OS; n = 19) were determined.

RESULTS

With a median follow-up of 64 months, the median OS time from the first liver resection for RAIT patients was 68.0 months (95% CI, 46.0 months to infinity), and the median DFS time was 18.0 months (95% CI, 11.0 to 31.0 months). The 5-year survival rate was 51.3%. RAIT benefited patients independently of bilobar involvement, size and number of LM, and resection margins. The major adverse effect was transient myelosuppression, resulting mostly in grade < or = 3 neutropenia and/or thrombocytopenia.

CONCLUSION

Because both the median OS and 5-year survival rates seem to be improved with adjuvant RAIT after complete LM resection in CRC, compared with historical and contemporaneous controls not receiving RAIT, these results justify further evaluation of this modality in a multicenter, randomized trial.

Immune-reconstituted influenza virosome containing CD40L gene enhances the immunological and protective activity of a carcinoembryonic antigen anticancer vaccine

The correct interaction of a costimulatory molecule such as CD40L with its contrareceptor CD40 expressed on the membrane of professional APCs, provides transmembrane signaling that leads to APC activation. This process can be exploited to significantly improve the efficacy of cancer vaccines and the outcome of a possible cancer vaccine-induced, Ag-specific CTL response. Therefore, we investigated whether a novel intranasal delivery of immune-reconstituted influenza virosomes (IRIV), assembled with the CD40L gene (CD40L/IRIV), could be used to improve protective immunity and the Ag-specific CTL response against carcinoembryonic Ag (CEA) generated with a novel vaccine constituted of IRIV assembled with the CEA gene (CEA/IRIV). Our results suggest that CD40L/IRIV was able to augment CEA-specific CTL activity and CEA-specific protective immunity induced by CEA/IRIV most likely through the induction of a CTL response associated with a Th1 phenotype. In conclusion, we provide evidence that CD40L/IRIV, by acting through the CD40L/CD40 signaling pathway, acts as an immune-adjuvant that could increase the efficacy of a CEA-specific cancer vaccine, which could provide an efficacious new strategy for cancer therapy.

Improved pretargeted delivery of radiolabelled hapten to human tumour xenograft in mice by avidin chase of circulating bispecific antibody

PURPOSE

Pretargeted therapy with radiolabelled bivalent haptens and bispecific antibodies has shown promising results, but blood clearance of the activity-carrying haptens under conditions designed for radioimmunotherapy is relatively slow. Thus, the chase of excess circulating bispecific antibody by biotinylation of the bispecific antibody and injection of avidin before hapten administration was tested with a view to increasing tumour-to-blood activity ratios.

METHODS

The anti-carcinoembryonic antigen (CEA) x anti-diethylene triamine penta-acetic acid-indium (di-DTPA-indium) bispecific antibody (hMN-14x734) was derivatised with NHS-LC-biotin and injected into LS-174T tumour-bearing nude mice at a dose of 3.5 nmol, followed by avidin and finally by the 125I-labelled di-DTPA-indium hapten (1 nmol). Blood samples were collected, animals sacrificed and tumours and normal tissues counted.

RESULTS

Avidin chased up to 72% of the circulating antibody in the liver and the spleen within 30 min. When the labelled hapten was injected 3 h after avidin, tumour to blood ratios measured 3 and 24 h after hapten injection were significantly improved by the chase (3.5-fold), whereas tumour uptake was not significantly reduced. Uptake in normal tissues was unchanged (liver, kidney) or decreased (muscle), with the exception of spleen, in which uptake of both antibody and hapten was increased by the avidin chase.

CONCLUSION

The chase strategy reduces hapten concentration in blood and thus should reduce bone marrow exposure. The use of two different recognition systems limits possible interference between the chase and targeting steps.

Technology evaluation: cT84.66, City of Hope

Chimeric T84.66 (cT84.66) is a high affinity anti-carcinoembryonic antigen (CEA) immunoglobulin G1, that is being developed by City of Hope for the potential treatment of CEA-expressing malignancies.

Immunotherapy with autologous, human dendritic cells transfected with carcinoembryonic antigen mRNA

Immunizations with dendritic cells (DC) transfected with RNA encoding tumor antigens induce potent tumor antigen-specific immune responses in vitro and in murine models. We performed a phase I study of patients with advanced carcinoembryonic antigen (CEA)-expressing malignancies followed by a phase II study of patients with resected hepatic metastases of colon cancer to assess safety and feasibility of administering autologous DC loaded with CEA mRNA. The immunizations were well tolerated. Of the 24 evaluable patients in the dose-escalation phase, there was 1 complete response (by tumor marker), 2 minor responses, 3 with stable disease, and 18 with progressive disease. In the phase II study, 9 of 13 patients have relapsed at a median of 122 days. Evidence of an immunologic response was demonstrated in biopsies of DC injection sites and peripheral blood of selected patients. We conclude that it is feasible and safe to administer mRNA-loaded DC to patients with advanced malignancies.

A dual-function DNA vaccine encoding carcinoembryonic antigen and CD40 ligand trimer induces T cell-mediated protective immunity against colon cancer in carcinoembryonic antigen-transgenic mice

A carcinoembryonic Ag (CEA)-based DNA vaccine encoding both CEA and CD40 ligand trimer achieved effective tumor-protective immunity against murine colon carcinoma in CEA-transgenic mice by activating both naive T cells and dendritic cells. Peripheral T cell tolerance to CEA was broken in a prophylactic model by this novel, dual-function DNA vaccine, whose efficacy was further enhanced by boosts with a recombinant Ab-IL-2 fusion protein (huKS1/4-IL-2). These conclusions are supported by four lines of evidence. First, a lethal challenge of MC38-CEA-KS Ag murine colon carcinoma cells was for the first time completely rejected in 100% of experimental animals treated by oral gavage of this DNA vaccine carried by attenuated Salmonella typhimurium, followed by five boosts with huKS1/4-IL-2. Second, specific activation of dendritic cells was indicated by their marked up-regulation in expression of costimulatory molecules B7.1 (CD80), B7.2 (CD86), and ICAM-1. Third, a decisive increase over control values was observed in both MHC class I Ag-restricted cytotoxicity of CTLs from successfully vaccinated mice and secretion of proinflammatory cytokines IFN-gamma and IL-12. Fourth, activation of CTLs was augmented, as indicated by up-regulation of activity markers LFA-1, CD25, CD28, and CD69. Taken together, these results suggest that a dual-function DNA vaccine encoding CEA and CD40 ligand trimer combined with tumor-targeted IL-2 may be a promising strategy for the rational development of DNA-based cancer vaccines for future clinical applications.

Enhancement of the therapeutic outcome of radio-immunotherapy by combination with whole-body mild hyperthermia

To enhance the effect of radio-immunotherapy for solid cancers, whole-body mild hyperthermia was added, and its effects on the pharmacokinetics of radiolabelled antibody, outcome of radio-immunotherapy, and radiosensitivity of the tumour were investigated. Nude mice bearing human colon cancer xenografts were heated to 40 degrees C for 3 or 6 h. After heating, mice received intravenous (i.v.) injections of [131I]-labelled anti-carcinoembryonic antigen (CEA) monoclonal antibody. Although 6-h heating did not alter the biodistribution of the radiolabelled antibody, and alone did not show any therapeutic effect on tumour growth, when combined with radio-immunotherapy, the therapeutic effect on tumour growth was significantly enhanced. Three-hour heating also significantly enhanced the effect of radio-immunotherapy. Colony formation assay showed that the radiosensitivity of the tumour was significantly enhanced after heating, which was achieved by a reduction of the hypoxic fraction of the tumour. In conclusion, the addition of whole-body mild hyperthermia significantly enhanced the therapeutic effect of radio-immunotherapy by increasing the radiosensitivity of the tumour.

Vaccination with a mixed vaccine of autogenous and allogeneic breast cancer cells and tumor associated antigens CA15-3, CEA and CA125--results in immune and clinical responses in breast cancer patients

In breast cancer there is often overexpression of the breast cancer antigen CA15-3, the carcinoembryonic antigen (CEA) and the ovarian cancer antigen CA125, which makes them potential target antigens for immunotherapy. In this study, we used a multi-antigen vaccine, which included the following antigens: autologous breast cancer cells (AUTOC), allogeneic breast cancer MCF-7 cells (ALLOC), and the tumor associated antigens CA15-3, CEA and CA125, plus low doses of granulocyte/macrophage-colony-stimulating factor (GM-CSF) and interleukin 2 (IL-2). Forty-two breast cancer patients received weekly subcutaneous vaccination at the 1st, 2nd, 3rd, 7th, 11th and 15th weeks. Their lymphocyte proliferative responses to AUTOC, ALLOC, CA15-3, CEA and CA125 were tested in lymphocyte blastogenesis assays (LBA) before and after vaccination. The disease stage and serum CA15-3, CEA and CA125 concentrations were also determined pre- and post-vaccination. We found that the vaccine was safe, and the only major side effects were swelling at the site of injection, muscle pain, and weakness or fatigue. The vaccine induced a significant increase in post-vaccination lymphocyte proliferative responses to AUTOC, CA15-3, CEA and CA125 but not ALLOC, compared to pre-vaccination (p < 0.05, p < 0.01, p < 0.05, p < 0.01 and p > 0.05, respectively, a paired t Test). Computed tomography (CT), ultrasound or bone scan showed evidence of disease improvement in 2 (12%) patients after vaccination. Hepatic metastases were reduced in size and number and some actually disappeared one patient. Metastatic disease in the L5 vertebra and the skull decreased in size and some osteolytic sites completely healed in a second patient. In addition, 7 patients (44%) had stable disease and 7 patients (44%) had disease progression. We did not find vaccination significantly reduced serum tumor markers CA15-3, CEA and CA125 of these breast cancer patients. These results suggest that the vaccine mixture of autologous and allogeneic breast cancer cells and tumor associated antigens plus GM-CSF and IL-2 can be administered safely to breast cancer patients and there is evidence for improved immunity and clinical efficacy.

Clinical and immune responses in resected colon cancer patients treated with anti-idiotype monoclonal antibody vaccine that mimics the carcinoembryonic antigen

PURPOSE

We generated an anti-idiotype antibody, designated CeaVac, that is an internal image of the carcinoembryonic antigen (CEA). We previously demonstrated that the majority of patients with advanced colorectal cancer generate specific anti-CEA responses. The purpose of the current study was to treat patients with surgically resected colon cancer with CeaVac to determine the immune response and clinical outcome to treatment with vaccine. We also compared the immune responses between patients treated with fluorouracil (5-FU) chemotherapy regimens plus vaccine versus vaccine alone.

PATIENTS AND METHODS

Thirty-two patients with resected Dukes' B, C, and D, and incompletely resected Dukes' D disease were treated with 2 mg of CeaVac every other week for four injections and then monthly until tumor recurrence or progression. Fourteen patients were treated concurrently with 5-FU chemotherapy regimens.

RESULTS

All 32 patients entered onto this trial generated high-titer immunoglobulin G and T-cell proliferative immune responses against CEA. The 5-FU regimens did not have a qualitative or quantitative effect on the immune response. Three of 15 patients with Dukes' B and C disease progressed at 19, 24, and 35 months. Seven of eight patients with completely resected Dukes' D disease remained on study from 12 to 33 months; one patient with resected Dukes' D disease relapsed at 9 months. One patient with incompletely resected Dukes' D disease remained on study at 14 months without evidence of progression; eight experienced disease progression at 6 to 31 months.

CONCLUSION

CeaVac consistently generated a potent anti-CEA humoral and cellular immune response in all 32 patients entered onto this trial. A number of very high-risk patients continue on study. 5-FU regimens, which are the standard of care for patients with Dukes' C disease, did not affect the immune response. These data warrant a phase III trial for patients with resected colon cancer.

Radioimmunotherapy of metastatic colorectal tumours with iodine-131-labelled antibody to carcinoembryonic antigen: phase I/II study with comparative biodistribution of intact and F(ab')2 antibodies

Studies in animal tumour models of colorectal cancer suggest that F(ab')2 antibody fragments to carcinoembryonic antigen (CEA) labelled with iodine-131 give superior therapy compared with intact anti-CEA antibody. The purpose of this study was to investigate this hypothesis in patients. Ten patients received intact A5B7 IgG1 mouse monoclonal antibody (MAb) to CEA and nine patients received the F(ab')2 fragment of the same antibody. The biodistribution for each molecule was compared using quantitative single-photon emission computerised tomographic (SPECT) gamma-camera imaging. Tumour responses were seen in both groups and myelosuppression was the limiting toxicity. F(ab')2 localised more rapidly than intact antibody in tumour, giving a mean percentage injected activity per kg at 4.25 h after injection of 8.2% for F(ab')2 compared with 4.4% for intact antibody (P < 0.05). No significant difference in antibody clearance from, or cumulative dose per unit administered activity (cGy MBq-1) to, tumour was seen. Distribution in blood was similar for both the intact and fragment antibody. These findings are consistent with more rapid penetration of the smaller F(ab')2 into tumour masses. More efficient early uptake will give higher maximum dose rates to the tumour which is valuable for radioimmunotherapy (RIT) when low dose rates may limit effectiveness of treatment. F(ab')2 fragments may provide a substantially enhanced method of delivering RIT.

Targeting of cancer with radiolabeled antibodies. Prospects for imaging and therapy

This article reviews the current status, including problems and some proposed solutions, of the targeting of cancer with radioactive antibodies for use in antibody imaging (radioimmunodetection) and radioimmunotherapy. The problems and results are similar for purified polyclonal and murine monoclonal antibodies. Foremost among the problems are the low accretion of antibody (0.01% to 0.001% of injected dose per gram) in tumor and the nonspecific deposition of radiometals that are more ideal for imaging or therapy after antibody conjugation. Despite these limitations, radioimmunodetection appears to be a safe and useful method, even at this early stage of development. Sensitivity, specificity, and accuracy rates of 80% to 90% have been achieved in some studies involving radioiodine labels and polyclonal or monoclonal antibodies, whereas lower percentages have been achieved with indium 111 or technetium Tc 99m radioconjugates. Even at a usual tumor resolution of 1.5 to 2.0 cm, occult cancers have been disclosed by radioimmunodetection when missed by traditional detection measures, including computed tomography and magnetic resonance imaging. Radioimmunotherapy is somewhat less developed as a treatment modality, but encouraging remissions have been observed, thus stimulating further active pursuit of this technology. These targeting results have been achieved with antibodies that are not truly cancer specific, but only exploit quantitative differences in antigen expression between tumor and adjacent normal tissues. Circulating target tumor antigens do not appear to prevent successful tumor targeting of the radioactive antibodies.