Yttrium-90-labeled anti-CD20 monoclonal antibody therapy of recurrent B-cell lymphoma

A Phase I/II dose escalation study of 90Y-murine anti-CD20 monoclonal antibody (mAb) in patients with recurrent B-cell lymphoma was performed. The primary objectives of the study were: (a) to determine the effect of the preinfusion of unlabeled anti-CD20 mAb on the biodistribution of 111In-anti-CD20 mAb; (b) to determine the maximal tolerated dose of 90Y-anti-CD20 mAb that does not require bone marrow transplantation; and (c) to evaluate the safety and antitumor effect of 90Y-anti-CD20 mAb in patients with recurrent B-cell lymphoma. Eighteen patients with relapsed low- or intermediate-grade non-Hodgkin's lymphoma were treated. Biodistribution studies with 111In-anti-CD20 mAb were performed prior to therapy. Groups of three or four patients were treated at dose levels of approximately 13.5, 20, 30, 40, and 50 mCi 90Y-anti-CD20 mAb. Three patients were retreated at the 40-mCi dose level. The use of unlabeled antibody affected the biodistribution favorably. Nonhematological toxicity was minimal. The only significant toxicity was myelosuppression. The overall response rate following a single dose of 90Y-anti-CD20 mAb therapy was 72%, with six complete responses and seven partial responses and freedom from progression of 3-29+ months following treatment. Radioimmunotherapy with </=50 mCi 90Y-anti-CD20 mAb resulted in minimal nonhematological toxicity and durable clinical responses in patients with recurrent B-cell lymphoma. Doses of </=40 mCi 90Y-anti-CD20 mAb were not myeloablative.

Experimental hepatic tumor necrosis. Comparison of spin-echo and pulsed magnetization transfer contrast magnetic resonance imaging

RATIONALE AND OBJECTIVES

We compared the effectiveness of pulsed magnetization transfer contrast (MTC) magnetic resonance imaging (MRI) and spin-echo MRI in detecting tumor necrosis.

METHODS

Adenocarcinoma cells were transplanted in the livers of 12 syngenic BDIX rats. To induce various degrees of tumor necrosis, the rats were randomly assigned to the following groups: 1) control; 2) localized hyperthermia; 3) intralesional cisplatin; and 4) hyperthermia plus intralesional cisplatin. At day 7 after treatment, the rats were imaged using a 1.5-T imager with 1) multiplanar gradient-recalled echo sequence (MPGR) 500/8/20 degrees with and without magnetization transfer contrast (MTC); 2) spin-echo 2500/20,80, and 3) spin-echo 300/20 pulse sequences. The rats were then sacrificed and pathologic specimens were prepared using MR images as guidance. T2 and ratios of signal intensity after saturation to signal intensity before saturation (Ms/Mo ratios) of the necrotic and granulation tissues and viable tumors were determined in 10 rats.

RESULTS

Compared with standard MPGR images, MPGR images with MTC provided better contrast between the pathologic tissues and normal liver. However, T2 values were more useful than Ms/Mo ratios in distinguishing necrotic areas from viable tumor. The T2 values of coagulative necrosis and granulation tissue were significantly different from that of viable tumor. No significant difference between the Ms/Mo ratios of the different pathologic tissues and normal liver was found.

CONCLUSION

Pulsed magnetization transfer contrast MRI was inferior to spin-echo MRI in distinguishing necrotic from viable tumors in rat livers using the pulse sequences described, and none of the sequences studied was thought to be reliable enough for this purpose.

Combination therapy: lonidamine, hyperthermia, and chemotherapy against the RIF-1 tumor in vivo

Lonidamine enhances the cytotoxicity in vitro of several conventional antitumor drugs as well as that of hyperthermia (HT). We have investigated the possibility that such enhancement can also be demonstrated in vivo against the RIF-1 tumor system. Two assays were used to examine antitumor activity: tumor growth delay and clonogenicity of cells obtained from tumors from treated animals. We used drug (and HT) doses that by themselves did not achieve significant cell killing. The drugs whose interaction with lonidamine was tested were: cis-diamminedichloroplatinum (CDDP), mitomycin C (MMC), bleomycin, 5-fluorouracil, and nitrosourea. Of these only CDDP and MMC yielded positive data. Both assays gave essentially the same results, showing that antitumor activity reflected direct cell killing. CDDP and MCC activity was also enhanced by HT. When we combined all three modalities, however, the results of the trimodality therapies were no better than that of individual bimodality treatments. These last results suggest that lonidamine and HT have similar mechanisms, most likely inhibition of repair of DNA damage. Our data do suggest that lonidamine may have a role in multidrug therapies that include either CDDP or MMC as a component of the treatments.

Cytotoxicity of lonidamine alone and in combination with other drugs against murine RIF-1 and human HT1080 cells in vitro

Lonidamine is an agent that is reported to inhibit recovery from potentially lethal damage. By itself, it has only mild anticancer activity. We have examined the ability of lonidamine to enhance the cytotoxicity of several drugs against a mouse and a human fibrosarcoma cell line in vitro. By itself, lonidamine showed only a limited cytotoxic effect with drug exposure up to 100 micrograms/ml and 24-h duration. Lower concentrations and shorter term exposures were not toxic to either of these tumor cell lines. When tested against the mouse line, the cytotoxicity of 5-fluorouracil, methotrexate, and etoposide was enhanced by lonidamine if the latter drug was given either before or after the exposure of the cells to the cytotoxic agents. For cisplatinum, bleomycin, mitomycin C, doxorubicin, and Actinomycin D, cytotoxicity was also enhanced, but only if lonidamine followed the other agents. In contrast, potentiation of 1,3-bis(2-chloroethyl)-1-nitrosourea toxicity was maximum when lonidamine preceded the nitrosourea. The human cells were more resistant to lonidamine and to the combination treatments than were the mouse cells. Nevertheless, substantial enhancement was seen particularly for cisplatin and mitomycin C. We examined in more detail the enhancement of cisplatin. Maximum interaction was obtained when lonidamine was given immediately following (or in conjunction with) the platinum agent. Our results suggest that lonidamine enhances the effects of several other agents in a time- and concentration-dependent manner and indicate a potential usefulness for lonidamine in multidrug therapy.

A comparison of thermal responses of human and rodent cells

A comparison of heat responses of cells from human and rodent tumors indicates the following: (1) human cells appear to be appreciably more heat-resistant than are rodent cells in the range 41-45 degrees C; (2) while rodent cells show a marked increase in sensitivity as the temperature is increased from 42 and 43 degrees C, this change occurs at approximately 44 degrees C or higher for the human lines examined; (3) rodent cells are unable to acquire thermotolerance during exposure to 43 degrees C; the human cells do so readily; (4) decay of tolerance tends to be complete in 72 h in rodent cells; in human cells it may take twice that time. These results may have important implications for the clinical use of hyperthermia.

[Kinetics of the thermotolerance of human tongue squamous cell carcinoma cells (Tca 8113) in vitro]

This paper reports an observation on kinetics of induction and resolution of the thermotolerance expressed by Tca8113 in vitro in form of colony-forming rate, synchronization and laser flow cytometry after the cells being exposed to continuous and fractionized heat treatment of 41.5-45.5 degrees C for 4 hours. The process of thermotolerance kinetics could be divided into three phases: triggering, development and decay. The triggering phase lasted about 8 hours. The duration of development and decay phases was related to the temperature of initial heating. The higher the temperature, the shorter the duration. Generally, thermotolerance gradually disappeared 96 hours after the initial heating treatment. The thermotolerance of the synchronized cells in various phases was G1 greater than G2 greater than M greater than S. Hyperthermia simultaneously combined with pingyangmycin both produces a greater synergetic cytotoxic effect and reduces the degree of thermotolerance.