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- Cederkrantz, Elin, et al.
(author)
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Absorbed Doses and Risk Estimates of (211)At-MX35 F(ab')2 in Intraperitoneal Therapy of Ovarian Cancer Patients.
- 2015
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In: International journal of radiation oncology, biology, physics. - : Elsevier BV. - 1879-355X .- 0360-3016. ; 93:3, s. 569-76
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Journal article (peer-reviewed)abstract
- Ovarian cancer is often diagnosed at an advanced stage with dissemination in the peritoneal cavity. Most patients achieve clinical remission after surgery and chemotherapy, but approximately 70% eventually experience recurrence, usually in the peritoneal cavity. To prevent recurrence, intraperitoneal (i.p.) targeted α therapy has been proposed as an adjuvant treatment for minimal residual disease after successful primary treatment. In the present study, we calculated absorbed and relative biological effect (RBE)-weighted (equivalent) doses in relevant normal tissues and estimated the effective dose associated with i.p. administration of (211)At-MX35F(ab')2.
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- Gustafsson-Lutz, Anna, 1981, et al.
(author)
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Therapeutic efficacy of alpha-radioimmunotherapy with different activity levels of the Bi-213-labeled monoclonal antibody MX35 in an ovarian cancer model
- 2017
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In: EJNMMI Research. - : Springer Science and Business Media LLC. - 2191-219X. ; 7
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Journal article (peer-reviewed)abstract
- Background: The aim of this study was to compare the therapeutic efficacy of two different activity levels of the Bi-213-labeled monoclonal antibody MX35 in an ovarian cancer model. Sixty female BALB/c (nu/nu) mice were inoculated intraperitoneally with human ovarian cancer cells (OVCAR-3). Two weeks later, 40 mice were injected intraperitoneal (i.p.) with 1 ml of Bi-213-MX35, 3 MBq/mL (n = 20), or 9 MBq/mL (n = 20). An additional 20 mice received unlabeled MX35. Incidence of tumors and ascites was investigated 8 weeks after therapy. Body weight and white blood cell counts were monitored after treatment for possible signs of toxicity. Results: The tumor-free fraction of the animals treated with 3 MBq/mL of Bi-213-MX35 was 0.55, whereas that of animals treated with 9 MBq/mL of Bi-213-MX35 was 0.78. The control group treated with unlabeled MX35 had a tumor-free fraction of 0.15. No significant reduction in white blood cell counts or weight loss was observed. Conclusions: Tumor growth after i.p. treatment with Bi-213-MX35 was significantly reduced compared to treatment with unlabeled MX35. Treatment with 9 MBq/mL of Bi-213-MX35 resulted in higher tumor-free fraction compared with 3 MBq/mL of Bi-213-MX35, but this difference was not statistically significant. No signs of toxicity were observed in the treated animals.
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4. |
- Hallqvist, Andreas, 1973, et al.
(author)
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Intraperitoneal alpha-Emitting Radioimmunotherapy with At-211 in Relapsed Ovarian Cancer: Long-Term Follow-up with Individual Absorbed Dose Estimations
- 2019
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In: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 2159-662X. ; 60:8, s. 1073-1079
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Journal article (peer-reviewed)abstract
- Eliminating microscopic residual disease with alpha-particle radiation is theoretically appealing. After extensive preclinical work with alpha-particle-emitting At-211, we performed a phase I trial with intraperitoneal alpha-particle therapy in epithelial ovarian cancer using At-211 conjugated to MX35, the antigen-binding fragments-F(ab')(2)-of a mouse monoclonal antibody. We now present clinical outcome data and toxicity in a long-term follow-up with individual absorbed dose estimations. Methods: Twelve patients with relapsed epithelial ovarian cancer, achieving a second complete or nearly complete response with chemotherapy, received intraperitoneal treatment with escalating (20-215 MBq/L) activity concentrations of At-211-MX35 F(ab')(2). Results: The activity concentration was escalated to 215 MBq/L without any dose-limiting toxicities. Most toxicities were low-grade and likely related to the treatment procedure, not clearly linked to the alpha-particle irradiation, with no observed hematologic toxicity. One grade 3 fatigue and 1 grade 4 intestinal perforation during catheter implantation were observed. Four patients had a survival of more than 6 y, one of whom did not relapse. At progression, chemotherapy was given without signs of reduced tolerability. Overall median survival was 35 mo, with a 1-, 2-, 5-, and 10-y survival of 100%, 83%, 50%, and 25%, respectively. Calculations of the absorbed doses showed that a lower specific activity is associated with a lower single-cell dose, whereas a high specific activity may result in a lower central dose in microtumors. Individual differences in absorbed dose to possible microtumors were due to variations in administered activity and the specific activity. Conclusion: No apparent signs of radiation-induced toxicity or decreased tolerance to relapse therapy were observed. The dosimetric calculations show that further optimization is advisable to increase the efficacy and reduce possible long-term toxicity.
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5. |
- Lindegren, Sture, 1960, et al.
(author)
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Binding Affinity, Specificity and Comparative Biodistribution of the Parental Murine Monoclonal Antibody MX35 (Anti-NaPi2b) and Its Humanized Version Rebmab200.
- 2015
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In: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 10:5
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Journal article (peer-reviewed)abstract
- The aim of this preclinical study was to evaluate the characteristics of the monoclonal antibody Rebmab200, which is a humanized version of the ovarian-specific murine antibody MX35. This investigation contributes to the foundation for future clinical α-radioimmunotherapy of minimal residual ovarian cancer with 211At-Rebmab200. Here, the biodistribution of 211At-Rebmab200 was evaluated, as was the utility of 99mTc-Rebmab200 for bioimaging. Rebmab200 was directly compared with its murine counterpart MX35 in terms of its in-vitro capacity for binding the immobilized NaPi2B epitope and live cells; we also assessed its biodistribution in nude mice carrying subcutaneous OVCAR-3 tumors. Tumor antigen and cell binding were similar between Rebmab200 and murine MX35, as was biodistribution, including normal tissue uptake and in-vivo tumor binding. We also demonstrated that 99mTc-Rebmab200 can be used for single-photon emission computed tomography of subcutaneous ovarian carcinomas in tumor-bearing mice. Taken together, our data support the further development of Rebmab200 for radioimmunotherapy and diagnostics.
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6. |
- Palm, Stig, 1964, et al.
(author)
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Biokinetic modeling and dosimetry for optimizing intraperitoneal radioimmunotherapy of ovarian cancer microtumors.
- 2016
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In: Journal of nuclear medicine : official publication, Society of Nuclear Medicine. - : Society of Nuclear Medicine. - 1535-5667. ; 57:4, s. 594-600
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Journal article (peer-reviewed)abstract
- A biokinetic model was constructed to evaluate and optimize various intraperitoneal (i.p.) radioimmunotherapies for micrometastatic tumors. The model was used to calculate the absorbed dose to both anticipated microtumors and critical healthy organs and demonstrates how i.p. targeted radiotherapy can be optimized to achieve a maximum ratio between them.
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8. |
- Palm, Stig, 1964, et al.
(author)
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Model of Intraperitoneal Targeted α-Particle Therapy Shows That Posttherapy Cold-Antibody Boost Enhances Microtumor Radiation Dose and Treatable Tumor Sizes.
- 2018
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In: Journal of nuclear medicine : official publication, Society of Nuclear Medicine. - : Society of Nuclear Medicine. - 1535-5667. ; 59:4, s. 646-651
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Journal article (peer-reviewed)abstract
- Intraperitoneally administered radiolabeled monoclonal antibodies (mAbs) have been tested in several clinical trials, often with promising results, but have never proven curative. Methods: We have previously presented simulations of clinically relevant amounts of intraperitoneal 90Y-mAbs for treatment of minimal disease and shown that such treatments are unlikely to eradicate microtumors. Our previous model simulated the kinetics of intraperitoneally infused radiolabeled mAbs in humans and showed the benefit of instead using α-emitters such as 211At. In the current work, we introduce penetration of mAbs into microtumors with radii of up to 400 μm. Calculations were performed using dynamic simulation software. To determine the radiation dose distribution in nonvascularized microtumors of various sizes after intraperitoneal 211At-radioimmunotherapy, we used an in-house-developed Monte Carlo program for microdosimetry. Our aim was to find methods that optimize the therapy for as wide a tumor size range as possible. Results: Our results show that high-specific-activity radiolabeled mAbs that are bound to a tumor surface will penetrate slowly compared with the half-lives of 211At and shorter-lived radionuclides. The inner-core cells of tumors with radii exceeding 100 μm may therefore not be sufficiently irradiated. For lower specific activities, the penetration rate and dose distribution will be more favorable for such tumors, but the dose to smaller microtumors and single cells will be low. Conclusion: Our calculations show that the addition of a boost with unlabeled mAb 1-5 h after therapy results in sufficient absorbed doses both to single cells and throughout microtumors up to approximately 300 μm in radius. This finding should also hold for other high-affinity mAbs and short-lived α-emitters.
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