Dosimetry and treatment planning for 90Y-labeled antiferritin in hepatoma

Radiation absorbed-dose estimates and treatment planning are reported for 11 patients with hepatoma who were administered 90Y-labeled polyclonal antiferritin IgG for therapy in a Phase 1-2 trial. Dosimetric studies included quantitation of the localization and clearance of 111In-labeled antiferritin IgG in tumor and normal tissues and computer-assisted tumor and normal liver volumetrics from X ray CT scans. For the group of patients studied, hepatoma volumes at the time of treatment ranged from 135 to 3442 cm3. Quantitative 111In antiferritin imaging prior to and following 600 or 900 cGy of external-beam irradiation of the primary tumor demonstrated that tumor uptake increased 1.1 to 5.8-fold (mean 2.8) following external beam. In contrast, changes in uptake of radiolabeled antiferritin in normal liver ranged from 0.35 to 2.1-fold (mean 0.93) after external irradiation. Administered activities of 90Y antiferritin ranged from 8 to 37 mCi and were dependent on tumor volume and tumor localization of radiolabeled antiferritin. Following external-beam irradiation, tumor dose rates achieved with 90Y antiferritin ranged from 10 to 20 cGy/hr and normal liver dose rates from 1.1 to 5.7 cGy/h. The corresponding absorbed dose in hepatomas ranged from 900 to 2150 cGy and in normal liver from 80 to 650 cGy. After external-beam irradiation, tumor and normal liver uptake of 90Y antiferritin was consistent with that of 131I antiferritin.

Radiation enhancement of radiolabelled antibody deposition in tumors

Recent clinical observations led to the use of external radiation to increase tumor targeting by radiolabelled 131-I antiferritin. Examination of increased uptake of 131-I labelled antiferritin following external radiation was carried out in syngeneic implanted hepatomas (H4IIE, 3924A, 7800, and 7777). Exposure to 10 Gy increased the tumor: liver uptake ratio from 1.55 to 1.86 for H4IIE; from 1.56 to 2.0 for 7800; from 1.34 to 1.97 for 7777; and from 1.05 to 1.19 for 3924A. The pattern of uptake varied among the different tumor types, reflecting their inherent differences in vascularity, tumor permeability, antigen density and growth rate, all of which influence antibody targeting of the tumors. When tumor and liver were irradiated, the tumor showed increased differential uptake of labelled antibody compared to normal liver. 51-Cr labelled erythrocytes were used to study the relative vascularity and blood pooling in H4IIE hepatoma and normal tissue. External radiation to the tumor did not increase the uptake of 51-Cr labelled erythrocytes in any site. These studies provide an insight into the role of external radiation as a modality that increases radiolabelled antibody targeting in hepatoma.

Conversion by new treatment modalities of nonresectable to resectable hepatocellular cancer

Eleven patients with hepatocellular cancer had nonresectable lesions, ten as determined by laparotomy and one by computed tomographic (CT) evidence of inferior vena caval invasion. These patients were treated with a variety of new modalities, particularly radiolabeled antiferritin antibodies. Following treatment, seven of the 11 patients were considered to have converted their lesions to possible resectability. Six patients had complete resections, and one patient was partially resected. All patients had the common features of either nodular massive or nodular multifocal hepatocellular cancer. Relative to the patient's initial status, the quality of life remains high, and a new approach in the treatment of the nodular form of nonresectable hepatoma has been demonstrated. The present rate of such conversion to resectability is unknown. However, with further advances in radiolabeled antibody therapy, these results offer a new opportunity in the management of hepatocellular cancer.

Multi-modality treatment of primary nonresectable intrahepatic cholangiocarcinoma with 131I anti-CEA--a Radiation Therapy Oncology Group Study

Thirty-seven patients with primary nonresectable intrahepatic cholangiocarcinoma (57% with prior treatment and/or metastasis) were prospectively treated with external radiation, chemotherapy, and 131I labelled anti-CEA. Therapy began in all trials with whole liver irradiation (21.0 Gy, 3.0 Gy/Fx, 4 days/week, 10 MV photons) with alternate treatment day chemotherapy (Adriamycin, 15 mg + 5-FU, 500 mg). One month after external beam therapy, chemotherapy was given (Adriamycin, 15 mg + 5-FU, 500 mg) followed the next day by the first administration of 131I anti-CEA. The treatment schedule used was 20 mCi day 0; 10 mCi day 5 as an outpatient. This schedule was derived from tumor dose estimates which indicated that 20 mCi (8-10 mCi/mg IgG) was sufficient to achieve tumor saturation with a tumor effective half-life of 3 to 5 days, depending upon the species of animal from which the antibody was obtained. The median tumor dose for the 20 mCi + 10 mCi regimen was 6.2 Gy. Antibody therapy was delivered in 2-month cycles using antibody generated in different species of animals; rabbit, pig, monkey, and bovine. Toxicity was limited to hematologic toxicity and was manifested as thrombocytopenia and leukocytopenia (3.2% Grade IV for each according to RTOG toxicity criteria). Tumor remission evaluated by CT scan digitized tumor volume analysis indicated a 26.6% partial response (PR). Tumor remission by physical examination indicated a 33.3% remission rate (25.9% PR and 7.4% complete remission (CR]. The median survival for patients who responded was 15.2 months. The actuarial median survival for the entire group of patients (metastases and previous treatment) was 6.5 months. The longest partial remission is presently more than 4 years.

Myocardial perfusion changes following 1 year of exercise training assessed by thallium-201 circumferential count profiles

The effect of exercise training on myocardial perfusion was assessed using initial and 1-year thallium-201 (Tl-201) exercise studies in 56 patients with stable coronary artery disease (CAD). Subjects had been randomized into a trained group participating in supervised exercise three times per week and a control group. Indices (non-dimensional units) based on computer-analyzed circumferential count profile from nine regions of the heart, assessed in three projections, were used to eliminate observer bias and more accurately quantitate Tl-201 distribution and 4-hour washout. There was serial improvement of the global distribution count profiles in 21 of 27 (77.8%) of the trained and in 9 of 29 (31.0%) of the control subjects (p less than 0.001). The mean interval change in global initial distribution over the year period was 5 +/- 13 (mean +/- SD) in the trained and -6 +/- 14 in the control groups (p less than 0.003). The mean initial distribution of the trained group had improvement in all nine regions (significant in three), while the control group showed mean improvement in only one of nine regions. Additionally, the trained group showed improvement in the mean washout in five of nine regions (significant in three), while no mean regional washout improvement occurred in the control group. Thus, in this group of patients with stable CAD, exercise training resulted in apparently improved cardiac perfusion evidenced by enhance Tl-201 uptake and washout.

Detection of specific anti-antibodies in patients treated with radiolabeled antibody

Over 100 patients have received cyclic treatment with polyclonal 131I labeled anti-ferritin and anti-carcinoembryonic antigen (CEA) antibodies from different animal species (rabbit, pig, cynomolgous monkey, bovine, and baboon). Because survival was prolonged from original cyclic treatment, retreatment with original antibodies (recycling) became a necessary consideration. An assay using autoradiography of Ouchterlony gels, with diffusion of patients' sera against the varied radiolabeled antibodies, was developed to detect anti-antibody precipitin bands. Anti-antibody could be detected with a sensitivity to the 60 ng level. Sera from 35 patients given from 1 to 7 separate cycles (2 injections/week, total antibody 6 mg/cycle) of radiolabeled foreign antibody were studied for the production of anti-antibodies. Anti-antibodies were detected in 11 of 22 primary hepatoma patients studied, 3 of 4 intrahepatic biliary cancer patients, and 0 of 9 Hodgkin's disease patients. In all but two of the patients, the anti-antibodies produced were specific for the species used in the treatment of the patient. Eight patients were reinjected (recycled) with previously used antibodies and the presence or absence of precipitin bands correlated with the ability of these antibodies to deposit in the tumor or to be rapidly degraded. The importance of this assay is its simplicity, sensitivity, and the rapid detection of anti-antibody activity for patients requiring treatment with radiolabeled antibodies.

Limitations of indium-111 leukocyte scanning in febrile renal transplant patients

Indium-111-labeled leukocyte scanning was evaluated as a technique for investigating possible abscess as the cause of fever in 10 renal allograft recipients under therapy for rejection, acute tubular necrosis, or urinary infection. The usefulness of the method in this setting was found to be limited by marked nonspecificity of renal, pulmonary, and other focal leukocyte accumulation. Although wound infections were correctly identified, false-positive scans resulted in multiple nonproductive consultations and radiologic procedures (some invasive) and contributed to the decision to perform one negative exploratory laparotomy. Such generalized nonspecificity in this patient population is in distinct contrast to the experience with this diagnostic test in nontransplant patients, and has not previously been reported. Possible explanations and implications of these findings are discussed. Consequently, great caution is recommended in the use of indium-111 leukocyte scans to diagnose infection in febrile renal transplant patients who present in a similar clinical setting.

90Yttrium antiferritin--a new therapeutic radiolabeled antibody

A new radiolabel 90Yttrium has been chelated to antiferritin antibodies for the treatment of hepatocellular cancer. The isotope 90Yttrium has the advantage of no significant external radiation to other individuals, that is, outpatient therapy and potentially more therapeutic power with an increase from 0.3 Mev 131I beta radiation to 0.9 Mev 90Yttrium pure beta radiation. Six patients treated in the Phase I study have had modest hematologic toxicity and two have had partial remissions of their primary tumors. One of these patients has had complete remission of a pulmonary metastasis. The use of external radiation (900 rad) to the primary tumor in advance of radiolabeled antibody administration has increased antibody uptake and increased tumor dose rate and total dose. An extensive study of 90Yttrium antiferritin is planned.

Ferritin concentration and 131I-antiferritin tumor localization in an experimental hepatoma

Polyclonal 131I-labeled rabbit anti-rat ferritin was shown to specifically localize in the H4IIe rat hepatoma model. Tumor targeting was shown to be maximal in primary tumors or metastatic lesions less than 1 gram. Radiolabeled antiferritin tumor targeting decreased with increasing tumor size. In this study, ferritin levels were measured in H4IIe tumors grown both in vitro and in vivo. In vitro tumor cells synthesized and secreted ferritin into the medium as measured by radioimmunoassay, and confirmed by the incorporation of 14C-leucine into ferritin synthesis. The concentration of ferritin in the tumor cells as measured by radioimmunoassay remained relatively constant over this same time period. In vivo tumor ferritin levels in whole tumor extracts were highest in small tumors (less than 1 gram) and decreased as the tumors became larger. Serum ferritin levels of tumor-bearing animals paralleled the level in the tumors themselves. The elevated serum ferritin levels in animals with small tumors did not inhibit tumor targeting with radiolabeled antiferritin antibody. These findings are a foundation for understanding the selective tumor targeting of tumor associated proteins by radiolabeled antibodies, which includes factors such as tumor size, vascularity, antigen content, and circulating antigen.

The role of steroid metabolic profiling as an aid in the diagnosis of familial precocious puberty, a subgroup of true precocious puberty

We report the results of a study of a rare form of true precocious puberty in a family with a history of the condition. Only the male members manifest the trait, whereas it appears to be carried by both males and females. Routine urinary steroid analysis rapidly eliminated most of the classical enzyme defects associated with premature sexual maturation. Further investigation of urinary steroid extracts using gas chromatography and gas chromatography-mass spectrometry revealed essentially normal prepubertal androgen values for the proband A at 4 years of age, and for his affected and carrier relatives when compared with healthy age-matched individuals. While his plasma gonadotropin levels were in the prepubertal range, his plasma testosterone value was significantly elevated with values just below the normal range for an adult male. This is the fourteenth reported family with a vertical pattern of familial sexual precocity, but the first to have a steroid profile. Analysis suggests sex-limited autosomal dominance with a greater than 90% penetrance. The elevated plasma testosterone concentration, prepubertal plasma gonadotropin concentration, minimal histopathologic evidence of gametogenesis and only moderate increase in testicular volume over the five-year course of follow-up support a diagnosis of the recently described condition of familial gonadotropin independent sexual precocity. The gas chromatography-mass spectrometry urinary profiling shows elevated cortisol output but otherwise normal adrenal function.

Iodine 131 antiferritin, a new treatment modality in hepatoma: a Radiation Therapy Oncology Group study

One hundred five patients with hepatoma were treated with iodine 131 antiferritin in three sequential protocols in phase 1-2 trials. Therapy began in all trials with external beam irradiation and chemotherapy. The dosimetric results with 131I antiferritin indicated that 30 mCi (8 to 10 mCi/mg immunoglobulin G [IgG]) was sufficient to saturate the tumor. Tumor-effective half-life of the radioactive antibody was 3 to 5 days and was dependent on the species of animal from which the antibody was derived. This led to a 30 mCi on day 0 and 20 mCi on day 5 treatment schedule. Toxicity was predominantly thrombocytopenia. Due to clinical remission, cyclic therapy was next developed with antibodies from different species of animals. Rabbit, pig, monkey, and bovine antibodies were determined to produce the longest tumor-effective half-life and therefore the highest dose of radiation. Integration of 15 mg doxorubicin and 500 mg 5-fluorouracil (5-FU) with 131I antiferritin was accomplished next. Remission to external beam radiation was evaluated by computed tomography (CT) scan tumor volume computations that indicated that 22% of the patients had a partial remission (PR) from initial presentation to 1 month following external irradiation and chemotherapy. From the time of radioactive antibody administration, 48% of the patients (7% complete response [CR] and 41% PR) achieved remission to 131I antiferritin. Of 79 patients evaluated by CT scan tumor volumetrics 50% of the patients (7% CR and 43% PR) remitted to the entire treatment regimen. Patients not previously treated and without metastasis who were alpha fetoprotein positive (AFP+) had a 5-month median survival compared with AFP- median survival of 10 1/2 months. There were four CRs with one being 3 years and 6 months. The longest PR was 5 years and 8 months. These studies have demonstrated the toxicity and therapeutic activity of 131I antiferritin and the emerging role of radiolabelled antibody in cancer therapy.

Gallium-67 uptake by hepatoma: studies in cell cultures, perfused livers, and intact rats

In this investigation, the effect of transferrin on 67Ga uptake by rat hepatoma was studied at three levels: at the level of individual tumor cells in culture; at the level of isolated, perfused livers with implanted intrahepatic tumors; and in intact animals bearing intrahepatic tumors. This approach was possible using H-4-II-E hepatoma cells which grew into discrete tumors when implanted intrahepatically. Transferrin at low concentrations (0.05-0.5 mg/ml) stimulated, while at a higher concentration (1.0 mg/ml) it inhibited 67Ga uptake by tumor cells in culture. In contrast, in isolated, perfused livers with intrahepatic tumors, transferrin at concentration levels of 0.05 and 0.1 mg/ml had no effect, while at 0.25-1.0 mg/ml transferrin inhibited 67Ga uptake by intact tumors. Administration of transferrin which markedly enhanced the serum unsaturated iron binding capacity, had no effect on 67Ga accumulation in the intrahepatic tumors in vivo. These results indicate that, although transferrin at low concentration promotes the uptake of 67Ga by individual tumor cells in culture, it does not do so in intact tumors in isolated rat liver preparations or in tumor bearing rats. We conclude that the mechanism of 67Ga uptake by intact tumors is different from that of tumor cells growing in culture.

Computed tomography assisted volumetric analysis of primary liver tumor as a measure of response to therapy

Serial computed tomography assisted volumetric analyses were made in 33 patients with hepatoma. Thirteen of 27 patients with tumor volumes less than 2,290 cc had a partial response to experimental therapy. However, only three of these patients also demonstrated a significant change in liver volume. Tumor volume determinations made by the method described are an accurate (+/- 10%) and reproducible way to measure response to therapy. In spite of small changes in total liver volume, there may be concomitantly substantial changes in tumor volume.

A model system that predicts effective half-life for radiolabeled antibody therapy

Radiolabeled antibodies to tumor associated proteins localize in both experimental and clinical cancers. In the therapeutic applications of radiolabeled antibody, tumor effective half-life (composite of biological and physical half-lives), along with the concentration of isotope deposited and energies of the isotope used, determine the tumor dose. Antibodies directed against the same antigenic specificity but derived from different species have varied tumor and whole body effective half-lives and as a result, achieve different tumor doses. In vitro testing does not evaluate the in vivo differences in effective half-life that affect tumor dose. We have developed an animal model to evaluate the effective half-life and biodistribution of radiolabeled immunoglobulin (IgG) from diverse species. To determine the relevance of such a model, the effective half-lives and tissue distributions of the different immunoglobulins in the model were compared to those obtained from the clinical program using the same radiolabeled antibody preparations. In both the experimental model and in the clinical trials, radiolabeled immunospecific and normal IgG derived from monkey, rabbit, and porcine sources had the longest effective half-lives, goat and sheep had intermediate effective half-lives, and chicken and turkey had the shortest effective half-lives. Prescreening of bovine and baboon normal IgG predict long half-lives and similar organ distributions. These species have been immunized for clinical use. Bovine IgG has a long clinical half-life and has been added to our other successful antibodies. Baboon IgG is now ready for clinical testing. The value of this model system is that it appears to be an effective in vivo preclinical screen for tumor effective half-life of antibodies and IgG from diverse species, thus guiding potential clinical use.

Factors that affect antiferritin localization in four rat hepatoma models

The effect of tumor size, vascularity, ferritin content and the amount of injected 131I-antiferritin on tumor localization was studied in four hepatoma models with varying growth rates, histology, vascularity, and ferritin content. Separate groups of 12 animals with the H-4-II-E, 7800, 7777, and 3924A rat hepatomas with less than 2 g or greater than 2 g tumors were injected with escalating doses of 131I-antiferritin or 131I nonspecific IgG (control). Tumor vascularity was measured by 51Cr-labeled erythrocyte injection, ferritin content of tumors by radioimmunoassay and immunoperoxidase staining, and the histological location of 131I-antiferritin by autoradiography. 131I-antiferritin specifically localized in the H-4-II-E and 7800 models and correlated with the tumor size, vascular content, and amount of injected antiferritin. No localization took place in the 7777 or 3924A tumors despite the presence of ferritin in these models. The only factor that correlated with localization in the models was vascularity. The vascularity of 3924A and 7777 tumors was significantly reduced in comparison to the H-4-II-E and 7800 tumors. The dependence of targeting on vascularity was demonstrated with autoradiography as well. These findings indicate the correlation of vascularity and tumor localization with 131I-antiferritin.

The effect of iron dextran on ferritin content and 131I-antiferritin localization in experimental hepatomas

Polyclonal 131I rabbit antirat ferritin localizes in certain hepatoma models. The effect of intraperitoneal iron dextran on tumor and sera ferritin content and tumor and normal tissue localization with 131I antiferritin was studied. Separate groups of 10-12 animals were injected with escalating doses of 131I-antiferritin IgG, or nonspecific IgG, one week after injection with iron dextran or normal saline. The results demonstrate that tumor, serum, and normal tissue ferritin content was increased after iron dextran administration but tumor localization increased after administration of 131I-antiferritin in the H4II-E and 7800 models. The 3924A and 7777 models showed no tumor localization with or without iron dextran but did show an increase in normal tissue localization after iron dextran. Immunoperoxidase staining of tissues with antiferritin revealed increased staining in the liver and spleen and only a slight increase in the tumors after iron dextran was administered. The results demonstrate that tumor localization is a complex phenomenon that depends on normal tissue, sera, and tumor-antigen distribution.

Distribution of and physiologic factors that affect 131I-antiferritin tumor localization in experimental hepatoma

Polyclonal 131I rabbit anti-rat ferritin localizes in the H-4-II-E hepatoma model. The effect of tumor size, vascularity, and ferritin content on tumor localization was examined. The extravascular and intravascular quantity and location of 131I non-specific IgG and 131I-antiferritin IgG in tumors were determined by gamma counter analysis of tissue samples and autoradiography. Separate groups of 8-10 tumor bearing rats with 0.6-1 g, 1-3 g, 4-8 g, 8-14 g, and greater than 14 g tumors were injected with 500 microCi (200 micrograms) of 131I non-specific IgG or 131I-antiferritin. Tumor targeting with antiferritin occurred maximally in primary or metastatic lesions less than 1 g in size. Decreased localization occurred with increasing tumor size and no localization took place in tumors greater than 8 g in size. This finding is independent of administered dose because increasing the amount of injected antiferritin from 2- to 10-fold did not increase the antiferritin/normal IgG targeting ratio in any group of tumors greater than 4 g. The quantity and physical characteristics of the tumor vasculature may in part explain selective tumor localization. Tumor vascularity per gram as measured by 51Cr labeled erythrocytes decreased as tumor size increased. Decreased localization was evident in the necrotic portions of large tumors. Autoradiography of tumor sections revealed that most of the 125I-IgG activity is deposited perivascularly with decreased deposition of antibody in necrotic areas of tumors and at increasing distance from the lumen of vessels. These findings have clinical importance since this non-homogeneous distribution of antibody could result in the delivery of low doses of radiation to large necrotic areas of tumors. These results help to demonstrate some of the complex physiologic factors that affect tumor localization and antibody distribution.

Variables affecting the tumor localization of 131I-antiferritin in experimental hepatoma

Ferritin is both a normal tissue- and tumor-associated protein. The in vivo localization of 131I-radiolabeled antitumor ferritin and normal IgG antibodies in the H-4-II-E rat hepatoma model was investigated in both tumor and normal tissues over a dose range of 0.67 micrograms to 5 mg of normal and antiferritin IgG and at labeling ratios (microCi 131I per micrograms IgG) of 15:1, 5:1, and 1:10. The total dose from nonpenetrating radiation in rads was calculated and demonstrated a maximum of 2.9 times greater dose deposition (rads) of antiferritin than normal IgG in hepatoma without specific increase in binding in normal tissues. The maximum tumor targeting achieved was dependent on the amount of injected IgG and not on the labeling ratio or procedure. The binding in tumor could be inhibited by unlabeled antiferritin but not by unlabeled normal rabbit IgG and demonstrated the requirement of specificity for tumor binding. Normal tissues did not target with antiferritin. Most normal tissues have a capacity to bind normal and antiferritin IgG nonspecifically that is linear in relationship to the amount of injected IgG. The results demonstrate that 131I-antiferritin selectively targets ferritin-secreting hepatoma over normal tissues and that the amount of targeting is dependent on the amount of antiferritin injected. The physiologic reasons for such selective localization is not known, but the term "biologic window" has been used to describe the differential availability of tumor ferritin for binding.

Comparative tumor dose from 131I-labeled polyclonal anti-ferritin, anti-AFP, and anti-CEA in primary liver cancers

Results of dosimetric studies are reported for 30 patients with hepatoma and 5 patients with primary hepatic cholangiocarcinoma who received treatment with 131I-labeled polyclonal antibodies. Studies included liver and tumor volume computations from X-ray CT scans, in vivo quantitation of the activity of radiolabeled antibodies in hepatic tumors and normal liver tissue, and effective half-life measurements. Twenty-two patients with hepatoma were administered 131I-labeled polyclonal anti-ferritin. Five hepatoma patients, who were AFP-positive, were administered anti-alpha-fetoprotein (AFP). Three patients with AFP-positive hepatomas received both 131I-labeled anti-ferritin and anti-AFP in a bolus. The five cholangiocarcinoma patients were treated with 131I-labeled anti-carcinoembryonic antigen (CEA). For administered activities of 30 mCi on day 0 and 20 mCi on day 5, mean values of the radiation dose to hepatomas were approximately 1100 rads for anti-ferritin, 350 rads for anti-AFP, and 960 rads for the combination of anti-ferritin and anti-AFP. Polyclonal anti-ferritin has, therefore, become the antibody of choice in the treatment of hepatoma. The radiation dose to cholangiocarcinomas from 131I-labeled anti-CEA and administered activities of 20 mCi on day 0 and 10 mCi on day 5 was approximately 620 rads. Total-body irradiation for these injection schedules ranged from 30 to 50 rads.

Selective tumor localization in experimental hepatoma by radiolabeled antiferritin antibody

The in vivo localization of 131I-radiolabeled antiferritin and normal IgG in the H-4-II-E rat hepatoma model was investigated by serial necropsy. Groups of 14 to 18 animals were injected with 500 microCi (200 micrograms) of normal and antiferritin IgG. The total dose from the nonpenetrating beta radiation was calculated for tumor and normal tissue, and expressed as a targeting ratio of antiferritin to normal IgG for each organ studied. The results demonstrate 2.9 times greater dose deposition in tumors of animals treated with 131I-antiferritin than with 131I-normal IgG. 131I-antiferritin deposited equivalently in primary tumors and metastatic lesions of similar size. The specific binding in tumors could be competitively inhibited by the addition of unlabeled antiferritin but not unlabeled normal IgG. Specific targeting with 131I-antiferritin comparison to 131I-normal IgG did not occur in any normal tissue. There was considerable variation in the dose deposition in different normal tissues.

Dosimetry of 131I-labeled antiferritin in hepatoma: specific activities in the tumor and liver

Dosimetric studies are reported for 22 patients with hepatoma who received treatment with 131I-labeled antiferritin IgG. Studies included liver and tumor volume computations based on computerized axial tomographic scan analysis, in-vivo quantitation of the activity deposited in hepatic tumors and normal liver tissue, and effective half-life measurements of the activity in the tumor, liver, and total body. Administered activities of polyclonal and affinity-column purified 131I-labeled antiferritin IgG ranged from 32 to 157 mCi. Tumor volumes at the time of radioimmunoglobulin infusion ranged from 220 to 3020 cm3 and total liver volumes ranged from 900 to 4620 cm3. For tumor volumes ranging from 220 to 1700 cm3, the maximum tumor activity was linearly proportional to tumor volume, but independent of antiferritin preparations and administered activities. In this range of tumor volumes, the mean value of tumor-to-liver ratios of specific activities was 4.8:1. Hepatomas ranging from 2290 to 3020 cm3 had reduced tumor uptake of radiolabeled antiferritin IgG and had a tumor-to-liver ratio of specific activities of 1.6:1. For all patients studied there was a linear relationship between the volume of normal liver tissue and the maximum activity deposited. These data, in conjunction with toxicity studies and tumor effective half-life measurements, led to the present treatment regimen of administering 30 mCi of polyclonal antiferritin IgG on Day 0 and 20 mCi on Day 5 following the first injection. This has resulted in the same range of absorbed dose to the tumor as was achieved with larger administered activities, but with a significant reduction of total-body irradiation to the patient.

Ip immunotherapy and chemotherapy in advanced epithelial ovarian cancer

Nine patients with advanced epithelial ovarian cancer, classified as either stage III with macrometastatic residual disease or stage IV, received combination chemotherapy in conjunction with ip rabbit-derived human ovarian antitumor serum (HOATS). The HOATS regimen consisted of the ip instillation of 100 ml of ovarian antitumor serum on Days 1 and 3 of the first chemotherapy cycle. Side effects attributable to HOATS were low-grade fever in three patients and diffuse skin rash in two. The 1-year cumulative survival was 87%, with a clinical response rate of 80%. No significant toxic reactions to HOATS have been observed. Continuation of the present study seems justified.

Multimodality treatment of patients with advanced ovarian carcinoma

A multimodality treatment program has been applied to ovarian carcinoma at the Johns Hopkins Hospital since August 1975. Forty-nine patients were subdivided into 23 patients with maximally resected Stage III micrometastatic, and 26 patients with significant retained disease, 20 with Stage III macrometastatic and 6 with Stage IV. After initial pilot studies, those patients with minimally retained disease entered a randomized prospective study. Antiovarian antiserum was used in one arm of the study; in both study arms colloidal P-32, delayed split whole abdominal irradiation, and maintenance melphalan were used. For the 23 patients with micrometastatic disease the cumulative survival and survival without evidence of disease at four years is 78 and 34% respectively. Twenty-six patients with macrometastatic disease were treated with or without intraperitoneal antiserum and multiagent chemotherapy; their cumulative one year survival is 50%. The lack of significant toxicity of intraperitoneal antiovarian antiserum and the results of multimodality therapy indicate the feasibility of this therapeutic approach to further improve ovarian cancer therapy.

Phase I-II study of isotopic immunoglobulin therapy for primary liver cancer

A phase I-II study of isotopic immunoglobulin therapy was performed in 18 patients with primary liver cancer; 14 were evaluable for toxicity. The patients received a dose of 37-157 millicuries of 131I-labeled antibody. The dose-limiting factor appears to be hematologic toxicity, especially thrombocytopenia. An objective antitumor effect was seen in six of nine patients who were evaluable for response. Present results suggest that further clinical studies with isotopic immunoglobulin are indicated.

The integration of new therapies and radiation in the management of ovarian cancer

New biologic information has led to a therapeutic program in Stage III ovarian cancer that considers the whole peritoneal cavity the tumor-bearing region and that uses intraperitoneal administration of ovarian cancer antiserum, intraperitoneal P-32, delayed split abdominal irradiation, and chemotherapy. The survival for those patients completing irradiation was 85%. Forty-nine patients with advanced (Stage III, IV, or recurrent) ovarian cancer have been treated with combinations of the present agents. Twenty-two patients have received intraperitoneal ovarian cancer antiserum without significant toxicity. Extensive staging has been a requirement for initial evaluation and includes maximal surgical resection, omentectomy, TAH and BSO, nodal biopsies, and peritoneal cytology. Nineteen patients had 5-mm nodules or less residual disease and were treated with colloidal P-32, abdominal irradiation, and chemotherapy; five of these patients received intraperitoneal antiserum before cytotoxic therapy. The four-year cumulative survival is 84%, and the disease-free survival 43%. A randomized prospective study is now examining the value of antiserum therapy. New experimental data from our laboratory indicate 1) the value of 2/3 biomarkers (alpha globulin and free secretory protein) in following patients for remission of disease and 2) the probability of the development of more effective antiserum with high specific titer. Studies of the radiosensitivity of ovarian cancer indicate the tumor was not different from other solid tumors. Our studies indicate the role of radiation therapy as a cytoreductive agent should be integrated in multimodality therapy and that the immune system offers new possibilities in amplifying therapeutic results.

Antiferritin IgG antibody for isotopic cancer therapy

Radiolabeled antiferritin IgG will target ferritin-bearing tumors such as hepatoma, lung cancer, and neuroblastoma. In hepatoma 4 of 5 patients have had clinical remission of malignancy following intravenous doses up to 150 mCi of radiolabeled antiferritin IgG. The dosimetry of radiolabeled 131I-antiferritin reveals a 3-day effective half-life, low dose rate isotopic implant of tumors 5 rad/h, 2,000-3,000 rad to the tumor, and a tumor half-life of 7.7 days. The possibilities of this new cancer agent are discussed in regard to isotopes, greater antibody specificity, and methods of evaluation.

Use of isotopic immunoglobulin in therapy

Antibodies raised in heterologous species against tumor-associated antigens such as ferritin and carcinoembryonic antigen may be utilized in diagnostic scanning and in cancer therapy. The radiolabeled (131I) antibodies have a mean effective half-life of 3 days. The tumor-bearing regions retain activity which was associated with objective evidence of remission in primary hepatic cancers. Major organ toxicity was not apparent in eight of nine patients treated with radioactive antibody. Objective evidence of clinical remission was documented by computer-assisted axial tomography scan remission in sequential studies that determine residual tumor in the same planar cuts. Future possible improvements in radioimmunoglobulin are discussed in light of the clinical findings.

Quantitation of secretory component levels in cyst fluids, ascitic fluids, and sera from ovarian adenocarcinoma patients

A secretory component (SC) was detected by radioimmunoassay in the cyst fluids, ascitic fluids, and sera from patients with ovarian adenocarcinomas. Serous cyst fluids and ascitic fluids showed lower levels (expressed as means +/- SE) of SC (1.37 +/- 0.37 and 1.24 +/- 0.24 microgram/ml, respectively) than mucinous cyst fluids (181.50 +/- 50.40 microgram/ml). SC levels in the sera of all patients with ovarian adenocarcinoma were high (12.67 +/- 1.43 microgram/ml) when compared to SC levels in the sera of normal individuals (2.34 +/- 0.41 microgram/ml). Sera from patients with ovarian cancers diagnosed as serous, mucinous, papillary, and poorly differentiated adenocarcinomas showed SC levels of 9.93 +/- 1.68, 22.44 +/- 3.24, 7.35 +/- 1.13, and 10.10 +/- 1.58 microgram/ml, respectively.

Quantitation of secretory protein levels by radioimmunoassay

A radioimmunoassay was designed for the detection of secretory protein, a component of secretory immunoglobulin A, in human serum. The assay uses free secretory protein isolated from human colostrum, and antisera raised in rabbits to the purified antigen. The mean level of secretory protein in the control group was 2.34 +/- 0.41 microgram/ml (mean +/- S.E.M.). The level in cord blood was slightly lower (0.74 +/- 0.26 microgram/ml), while the level in patients with ovarian carcinoma was significantly increased (12.67 +/- 1.43 microgram/ml). Pregnant women have increasing secretory protein levels with increasing length of gestation (5.86 +/- 2.02, 11.55 +/- 1.30 and 17.00 +/- 1.16 microgram/ml for the first, second and third trimesters, respectively.

Electron transport in the cni-1 mutant of Neurospora crassa

1. Mitochondria from the nuclear mutant cni-1 have no optically detectable cytochrome aa3 in early log phase growth. These mitochondria have a high level of respiration that is not inhibited by cyanide but is inhibited by salicylhydroxamic acid. They also show a substantial amount of cyanide-sensitive respiration. 2. As cultures of mutant cni-1 age, flux through the hydroxamate-sensitive pathway decreases markedly while flux through the cytochrome chain remains constant. 3. Growth studies with mutant cni-1 indicate that the cytochrome chain in this mutant is more important in supporting growth than the hydroxamate-sensitive pathway. 4. Measurements of the steady-state level of reduction of cytochrome c in mutant cni-1 indicate that the rate-limiting step in the cytochrome chain is at the position occupied by cytochrome oxidase. 5. Electron spin resonance studies with cni-1 mitochondria show normal cytochrome oxidase signals in the g approximately 6 region although there is little or no optically detectable cytochrome aa3.

Immunologic studies on the cystic effusions of ovarian epithelial neoplasms

Cystic effusions from 12 epithelial tumors of the ovary and pooled normal ovarian tissue were studied by immunodiffusion for the presence of immunoglobulins G (IgG), M (IgM), and A (IgA) and free secretory component (FSC). In pooled normal ovarian tissue, IgG was the only immunoglobulin detected. In the neoplastic samples studied, IgG was detected in each of the 12 samples (100%), IgM was found in 10 of the 12 samples (83%), and IgA was detected in 11 of the 12 samples (92%). There was no discernible correlation between the immunoglobulins detected and the composition of the effusions or the pathologic classification of the tumors. FSC was detected in all mucinous samples studied, malignant as well as benign. This substance was not detected in any of the nonmucinous samples or in pooled normal ovarian tissue. The data suggest a correlation between the presence of FSC and the mucinous composition of the tumor effusion. Possible use of FSC assays in the study of mucinous tumors of the ovary is discussed.

Regulation of mitochondrial membrane assembly in Neurospora crassa. Transient expression of a respiratory mutant phenotype

Cultures of mutant cni-1, a chromosomal mutant of Neurospora crassa, undergo a marked change in respiratory properties as the age of the culture increases. Early log phase cultures have a high level of respiration that is insensitive to inhibition by cyanide or antimycin A. Late log and stationary phase cultures have reduced rates of respiration. A high percentage of this respiration is inhibited by cyanide. Mitochondria from early log phase cni-1 have an excess of cytochrome c and little or no detectable cytochrome aa3. Mitochondria from late log and stationary phase cultures have levels of c-, b-, and a-type cytochromes that are not significantly different in concentration from those found in wild type cells. The cytochrome aa3 content and the cytochrome oxidase activity of cni-1 mitochondria increase 5- to 10-fold as the age of the culture increases. Mitochondria from early log phase cells of cni-1 synthesize only polypeptides of apparent molecular weights 7,000 to 10,000 and donot synthesize any of the mitochondrial components of cytochrome oxidase. Mitochondria from late log and stationary phase cells synthesize the normal complement of mitochondrial translation products including the mitochondrial components of cytochrome oxidase. The assembly of cytochrome oxidase is likely due to the availability of the mitochondrially synthesized components of the enzyme. The regulation of mitochondrial translation in the cni-1 mutant is independent of the nutrient content of the growth medium and is due to the accumulation or depletion of some component within the cell.