Systemic administration of 3-bromopyruvate in treating disseminated aggressive lymphoma.

The Warburg hypothesis states that aggressive cancers obtain much of their adenosine triphosphate (ATP) by metabolizing glucose directly to lactic acid. As a result of its high tumor selectivity, 3-bromopyruvic acid (3-BrPA), a well-known inhibitor of energy metabolism, has been proposed as a specific anticancer agent. We investigated the effect of 3-BrPA in a mouse model of aggressive metastatic lymphoma. Epstein-Barr-virus-infected human Raji lymphoma cells with lentivirally transfected green fluorescent protein and luciferase were incubated with RPMI/fetal bovine serum, and various concentrations of 3-BrPA were used to determine the LD50 in vitro. In total, 18 severely combined immunodeficient mice were injected with 1 million human Raji lymphoma cells via the tail vein. Using bioluminescent imaging, tumor growth was measured daily for 12 days to determine the tumor burden. At day 0 (start of treatment), the mice were randomized. Six mice received 10 mg/kg 3-BrPA i.p. daily for 7 days, 6 mice received 1 treatment at day 0, and 6 mice received the control buffer. Tumor growth was assessed daily from day 0 until day 7 using bioluminescent imaging. All data were normalized to acquisition time (luminescence/second; L/s). Body weight was measured daily to determine the toxicity of 3-BrPA. The LD50 for Raji lymphoma cells exposed to 3-BrPA in vitro was 11 µM with an extremely steep dose response curve. At day 0, tumor activity medians in the group with daily treatment was 2131 L/s (244-12,725), with a 1-day dose of 3095 L/s (523-9650) and in the nontreated control group, 2997 L/s (1521-6911). In mice treated with a daily dose of 10 mg/kg 3-BrPa for 7 days, a significant reduction in tumor activity was found during the whole treatment period compared with the control mice (P = 0.0043 at day 7). In mice with a single treatment at day 0, growth delay was only evident at day 2 (P = 0.0152 at day 2) but not for the rest of the observation period. The only manifestation of toxicity of the daily administration of 10 mg/kg 3-BrPA was a reduction in body weight. Body weight at day 0 was 17.22 g ± 0.84 g in the treatment group and 17.58 g ± 0.86 g in the control group. Body weight at day +6 was 15.02 g ± 2.04 g in the treated group and 19.4 g ± 0.63 g in the control group. 3-BrPA demonstrated a significant positive tumor response both in vitro and in vivo. This, to our knowledge, is the first report of the use of 3-BrPA in a systemic tumor model. Based on these data, 3-BrPA holds promise for treatment of systemic metastatic cancers.

Radioimmunotherapy in non-Hodgkin lymphoma: opinions of nuclear medicine physicians and radiation oncologists.

UNLABELLED: Despite approval by the Food and Drug Administration and consistent reports of the efficacy and safety of (90)Y-ibritumomab tiuxetan and (131)I-tositumomab, these therapies are infrequently used. This study investigates the opinions and patterns of the use of radioimmunotherapy by nuclear physicians, affiliated researchers, nuclear medicine technologists, and radiation oncologists and aims to identify possible barriers to the use of this promising therapy. METHODS: An e-mail-based survey with 13 broad questions related to radioimmunotherapy was sent electronically to 13,221 Society of Nuclear Medicine members and radiation oncologists throughout the United States. RESULTS: Six hundred thirteen individuals (4.6%) responded to the electronic survey. Two hundred fifty-one responders (40.9%) had treated patients with non-Hodgkin lymphoma (NHL) with radioimmunotherapy in the last 24 mo. Of the responders, 29.5% used only (90)Y-ibritumomab tiuxetan, 7.6% used only (131)I-tositumomab, and 24.9% used both radiopharmaceuticals; 37.9% did not treat NHL with radioimmunotherapy. Most responders said their patients came from university hospitals (33.9%) or private offices (25.6%), and they mainly treated in a second-line (42.9%), third-line (35.6%), or consolidation (23.5%) setting. Major concerns were that referring oncologists and hematologists wanted to treat by themselves with nonradioactive compounds (mean ± SD, 3.418 ± 1.49) and that (90)Y-ibritumomab tiuxetan and (131)I-tositumomab were expensive (mean ± SD, 3.413 ± 1.35). Of the responders and involved physicians, 40.4% and 35.2%, respectively, did not know if their institution accepted Medicare patients for radioimmunotherapy. Almost 30% (29.6%) of the responders thought radioimmunotherapy would probably grow and 38.0% thought it would grow in importance in the future. Responders who did not administer radioimmunotherapy for NHL thought it took too much time to administer radioimmunotherapy (P < 0.01) and had concerns about the dosimetry procedure (P < 0.01) and radiation safety (P < 0.01). Individuals who perceived a negative future for radioimmunotherapy had significantly more concerns about the time-consuming administration process (P < 0.05) and the high cost of radioimmunotherapy (P < 0.05). Responders from academic centers had significantly fewer concerns about payment (P < 0.01), dosimetry (P < 0.01), and radiation safety (P < 0.01). CONCLUSION: Radioimmunotherapy was generally viewed positively by the surveyed population. However, limited referrals due to alternative nonradioactive therapies and logistic, educational, and economic concerns played an important role for subgroups in the perception of radioimmunotherapy for NHL.