Jan-Erik Frödin

Durable Carcinoembryonic Antigen (CEA)-Specific Humoral and Cellular Immune Responses in Colorectal Carcinoma Patients Vaccinated with Recombinant CEA and Granulocyte/Macrophage Colony-Stimulating Factor

Purpose: Previous studies have indicated that carcinoembryonic antigen (CEA) might be a suitable immunotherapeutic target in colorectal carcinoma (CRC). The aim of the present study was to analyze the immunological and clinical effects of vaccination with CEA together with the adjuvant granulocyte/macrophage colony-stimulating factor (GM-CSF). Experimental Design: Twenty-four resected CRC patients without macroscopic disease were immunized seven times with recombinant CEA at four different dose levels over a 12-month period. Half of the patients received GM-CSF (80 μg/day for 4 consecutive days) at each immunization. Patients were monitored immunologically for 36 months and clinically for 76 months. T-cell response was evaluated by a [3H]thymidine incorporation assay, and IgG response was determined by ELISA. Results: Minor local side effects were common. All 12 patients (100%) in the GM-CSF group developed a CEA-specific T-cell as well as an IgG response. The corresponding figures in the CEA alone group were 9 of 12 (75%) and 8 of 12 (66%), respectively. GM-CSF significantly augmented the amplitude of the T-cell response and the IgG titers. No dose–response relationship was noted. The immune responses at 12 months persisted 24 months after the last vaccination. Anti-CEA IgG titers were associated with increased survival (P < 0.05), whereas standard prognostic factors had no relationship, with the exception of serum CEA value. Conclusions: Vaccination with recombinant CEA and GM-CSF appears to be a nontoxic regimen inducing potent and durable antigen-specific IgG and T-cell response. The results of this study justify more extensive trials with recombinant CEA protein for immunotherapy of CRC.

Multiple Primary Malignant Tumors in a National Cancer Registry: Reliability of Reporting

During the years 1958-1988, 808,522 individuals were registered in the Swedish national population-based cancer register with a total of 933,900 primary malignant tumors. Roughly 11% of the tumors reported to the Swedish Cancer Registry in 1988 were found in persons earlier registered for another primary malignancy. One hundred of the individuals registered with multiple primary malignant tumors were randomly selected for a study of the reliability of reporting of multiple malignancies. Medical records and when necessary histopathological slides and other relevant diagnostic material for each malignancy were collected and the diagnoses reevaluated. Three persons had to be excluded; thus 97 cases with 209 reported malignancies were analysed. Of these, 94% of the first, 98% of the second and 79% of the third malignancy were accepted. Twelve of the reported tumors were not accepted as malignant, five were benign or cancer in situ, five were incorrectly reported as new primaries and two were a second incorrect registration of a previously registered malignancy. All 97 persons had at least one malignant tumor, in 90% of the persons all reported diagnoses were accepted and 93% had multiple primary malignancies. The results of this quality control study indicate that suitable data are available in the Swedish Cancer Registry for investigations related to the occurrence of multiple primary malignancies in a large unselected population. The Swedish Cancer Registry, to which all newly diagnosed malignancies by law have to be reported, comprise today close to one million individuals with registered malignancies.

Immunohistochemical monitoring of metastatic colorectal carcinoma in patients treated with monoclonal antibodies (MAb 17-1A)*

SummaryA therapeutic trial using repeated doses of a mouse monoclonal antibody against the tumor-associated antigen (TAA) CO17-1A in metastatic colorectal carcinomas was carried out. Metastatic lesions sampled by repeated thick needle (1.2 mm) biopsies during therapy were examined immunohistochemically for the presence of various TAAs, mouse IgG, complement, and infiltrating leukocytes. The CO17-1A was consistently expressed in all cases along the basement membrane of tumor glands and could only be demonstrated on cryostat sections whereas the TAAs GICA19-9, GA73-3, and Br55-2 were also visualized in B5-fixed paraffin-embedded biopsies. The CO17-1A and GA73-3 were predominantly present at the basal region in contrast to the GICA 19-9 and Br55-2 which were predominant at the luminal and the apical region of the tumor glands. Antigenic modulation was not seen either after 24–72 h or during prolonged treatment. In all cases the infused mouse IgG was detected, from 24 h after infusion up to 6–8 weeks, mainly along the basal region of tumor glands. In 13/14 posttreatment biopsies, complement factor C3 was found at the same sites as mouse IgG. In 6 out of 9 posttreatment biopsies an increase in mononuclear cells (monocytes, natural killer (NK) cells and/or T cells) was observed. Monocytes were close to the tumor cells whereas NK cells and T cells were predominantly scattered in the stroma.

Humoral anti-idiotypic and anti-anti-idiotypic immune response in cancer patients treated with monoclonal antibody 17-1A

Abstract A group of 96 patients with advanced colorectal carcinoma were treated with the mouse (m) or chimeric (c) (mouse variable regions × human IgG1 constant regions) monoclonal antibody (mAb) 17-1A recognizing the tumour-associated antigen GA733-2. Eighty-two of the 83 patients treated with mmAb17-1A and 69% of the patients given cmAb17-1A (n = 13) developed anti-idiotypic antibodies (ab2). Auto-antibodies binding to tumour cells expressing GA733-2 were found in 7% of the patients. In a further 38 patients (40%) antitumour-cell antibodies, i.e. anti-anti-idiotypic antibodies (ab3), were induced by the mAb17-1A therapy. Patients with detectable ab3 after treatment had significantly higher ab2 levels than those not developing ab3. Addition of granulocyte/macrophage-colony-stimulating factor (GM-CSF) to mmAb17-1A significantly enhanced the induction of ab2 as well as induction of anti-anti-idiotypic antibodies (ab3), compared to mmAb17-1A alone. Patients with a high increase in antitumour-cell antibodies (ab3) induced by the therapy lived significantly longer than patients with no or a low level of induction of ab3 (P = 0.016). The results indicate that induction of an idiotypic network response might be an important effector mechanism in mAb therapy.

Augmentation of the immune response with granulocyte-macrophage colony-stimulating factor and other hematopoietic growth factors.

Granulocyte-macrophage colony-stimulating factor is by far the most widely used hematopoietic growth factor to augment immune responses. At present, the best secured effect is as an adjuvant cytokine for vaccination. Granulocyte-macrophage colony-stimulating factor can be delivered as gene-transduced tumor cells, as plasmid DNA, or as the soluble free granulocyte-macrophage colony-stimulating factor protein. Granulocyte-macrophage colony-stimulating factor must be present at the same site as the vaccine component. Granulocyte-macrophage colony-stimulating factor may also augment the effect of therapeutic monoclonal antibodies by enhancing various effector functions such as antibody-dependent cellular cytotoxicity and amplifying an idiotypic network response (i.e., antitumor immunity). It may also be advantageous to combine granulocyte colony-stimulating factor with monoclonal antibodies (neutrophil and monocyte antibody-dependent cellular cytotoxicity) for tumor therapy. However, these growth factors might also induce immune suppression, which may hamper the contemplated effect of the growth factor. It is urgently warranted to better understand these dual effects on the immune system so that we can find optimal uses for the growth factors in various clinical settings.

Natural killer (NK) cell function is a strong prognostic factor in colorectal carcinoma patients treated with the monoclonal antibody 17-1A.

Tumor cells might be susceptible to different effector functions of the immune system. This cytotoxic capacity has been utilized to analyze the prognostic significance of peripheral blood mononuclear cells (PBMC) in patients with metastatic colorectal carcinoma (CRC) treated with the monoclonal antibody (MAb)17‐1A. Such analysis might form the basis for future patient selection and may lead to improvements in therapeutic strategies. Between 1986 and 1998, 73 patients were treated with regimens containing MAb17‐1A. Prior to therapy, the lytic capability of PBMC was assayed against: K562 (4 hr assay), the CRC cell line SW948 (4 hr and 18 hr assays) and antibody‐dependent cellular cytotoxicity (ADCC, 18 hr assay). Since the study was performed over 13 years, the assays were checked for time‐related bias. Reproducibility over time was satisfactory. Patients exhibited a significantly higher cytotoxic capability in all 4 assays compared to healthy control donors. No correlation to clinical outcome was noted for 18 hr ADCC and 18 hr spontaneous cytotoxicity. Pretreatment natural killer (NK) cell cytotoxicity (K562) was significantly related to overall survival (OS), progression‐free survival (PFS), and response rate. OS for patients with high and low NK cell cytotoxicity was 71 vs. 30 weeks, respectively (p = 0.007). NK cell cytotoxicity (K562) was an independent prognostic factor for OS (p = 0.016). Pretreatment NK cell activity is a strong prognostic factor for patients with metastatic CRC receiving MAb17‐1A therapy and is a predictor for OS, PFS and response. These results should be considered when designing antibody‐based therapeutic protocols.

Vaccination with Ep-CAM Protein or Anti-Idiotypic Antibody Induces Th1-Biased Response against MHC Class I- and II-Restricted Ep-CAM Epitopes in Colorectal Carcinoma Patients

Purpose: The tumor-associated antigen Ep-CAM (epithelial cell adhesion molecule) is overexpressed in colorectal carcinoma (CRC). The aim of the present study was to evaluate and compare the safety and immunogenicity of a recombinant Ep-CAM protein and a human anti-idiotypic antibody (anti-Id) mimicking Ep-CAM. Experimental Design: Patients with resected American Joint Committee on Cancer stages II–IV CRC without remaining macroscopic disease received intradermal/subcutaneous injections of Ep-CAM (400 μg/dose; n = 7) or anti-Id (500 μg/dose; n = 6) at weeks 0, 2, and 6 in combination with granulocyte macrophage colony-stimulating factor (75 μg/day, for 4 consecutive days). Results: Adverse reactions were mild (grade I–II). All patients immunized with the Ep-CAM protein produced Ep-CAM–specific IgG antibodies, predominantly IgG1 and IgG3 subclasses, whereas no humoral response was induced by the anti-Id vaccine. All patients, with one exception in each group, mounted an Ep-CAM–specific proliferative T-cell response. The immune response was more rapid, potent, and protracted after Ep-CAM in comparison with anti-Id vaccination. Interferon-γ-secreting cells (ELISPOT) were detected in both immunization groups against the Ep-CAM protein as well as various Ep-CAM–derived MHC class I- and II-restricted peptides. Flow cytometry analysis showed that Ep-CAM–specific interferon-γ- and perforin-producing cells predominantly resided within CD8+CD56− and CD8dimCD56+ T cells. Conclusions: Ep-CAM protein in combination with granulocyte macrophage colony-stimulating factor induced a long-lasting, Th1-biased humoral and cellular immune response compared with anti-Id. Ep-CAM–specific T cells and natural killer-like T cells responding in a MHC class I- and II-restricted manner were also induced. Vaccination with Ep-CAM protein may warrant further investigation as a novel therapeutic approach to CRC.

Clinical Phase I study with an Insulin-like Growth Factor-1 receptor inhibitor: experiences in patients with squamous non-small cell lung carcinoma.

Abstract Background. Inhibition of the Insulin-like Growth Factor-1 receptor (IGF-1R) has resulted in extensive anti-tumor effects. Picropdophyllin (PPP, AXL1717) is a small-molecule inhibitor of the IGF-1R without inhibition of closely related receptors including the insulin receptor and has shown extensive effects against a wide range of tumors in animals. PPP is currently tested as an orally administrated single agent treatment in an open-label combined Phase I/II clinical study in advanced cancer patients with solid tumors which progress in spite of several lines of treatment. Patients and methods. The first part (Phase IA) consisted of single day BID dosing every three weeks with consecutive dose escalations. The second part (Phase IB) consists of seven days or longer BID dosing every three weeks, dosing range being 520–700 mg BID. Non-progressing patients could continue treatment within a compassionate use setting. Results and discussion. The present report describes our experience with the four patients with progressive squamous non-small cell lung cancer (NSCLC) that have received treatment with PPP. Despite more than seven months of PPP treatment as third or fourth line treatment, the reported patients did not develop any additional metastases. Furthermore, CT scans as well as 18FDG-Positron Emission Tomography (PET) scans of the patients demonstrated large central necrotic areas, which may suggest tumor response. At the same time, the study drug is so far well tolerated. The phenomenon of necrosis in the tumors suggestive of tumor response has not been reported before in anti-IGF-1R treatment and will be subject to further studies in the present clinical trial.

The clinical significance of HAMA in patients treated with mouse monoclonal antibodies

Twenty-four patients were analyzed for the development of HAMA (human antimouse antibodies) after being treated with repeated doses (200–500 mg) of the mouse monoclonal antibody (MAb) 17-1A. All patients developed anti-17-1A IgG antibodies, and most of them also developed IgM antibodies. In only two patients could immune complexes be demonstrated. Allergic reactions were rare (1.9%). In an extended study, a further 19 patient were analyzed for an idiotypic response. Forty-one out of 43 patients developed antiidiotypic antibodies (ab2), and 20 of these also antianti-idiotypic antibodies (ab3). Ab3+ patients responded significantly better (p=0.01) and survived longer (p<0.001) compared to ab3− patients. In this study, we showed that MAb 17-1A could be repeatedly given on a safe basis. The development of high titers of HAMA did not cause significant clinical problems when further repeated infusions of MAb 17-1A were given. The development of an idiotypic response also indicate that the induction of HAMA might be beneficial and not harmful to the patient.

Granulocyte/macrophage-colony-stimulating factor augments the induction of antibodies, especially anti-idiotypic antibodies, to therapeutic monoclonal antibodies

A group of 86 patients with advanced colorectal carcinoma were treated with the mouse (m) (IgG2A) or chimeric (c) monoclonal antibody (mAb) 17-1A. Prior to therapy, no patient had detectable levels of antibodies to mAb17-1A. All mmAb17-1A-treated patients (n=76) developed antibodies against both idiotypic and isotypic determinants. Addition of granulocyte/macrophage-colony-stimulating factor (GM-CSF) to mmAb17-1A significantly enhanced the induction of anti-idiotypic (ab2) as well as anti-isotypic antibodies. Of the mmAb17-1A-treated patients, 16 developed type I allergic reactions. These patients had significantly higher concentrations of anti-(mouse Ig) antibodies than patients without type I reactions. Of these 16 patients, 5 had received mmAb17-1A alone; they constituted 9% of this group (5/56). The remaining 11 patients had been given mmAb17-1A together with GM-CSF, and represented 55% of this treatment group (11/20). The difference was statistically significant (P<0.001). Of 10 patients, 9 (90%) treated with cmAb17-1A and GM-CSF developed ab2. The ab2 concentration in this patient group was significantly lower compared to those treated with mmAb-17A. Anti-(mouse Ig) antibodies caused clinical symptoms requiring therapeutic intervention in fewer than 10% of the patients treated with mmAb17-1A alone. With the addition of GM-CSF, the antibody concentration as well as the frequency of allergic side-effects calling for medical action increased significantly. Significantly more patients with a high ab2 concentration (at least 15μg/ml) 1 month after completion of mAb therapy responded to mAb treatment as compared to those with a low ab2 concentration (P<0.05). Moreover, patients with a high ab2 concentration (at least 15 μg/ml) had a median survival time of 15 months while those with a lower concentration survived for a median time of 9 months (P=0.01).