# Using Radioactive Antibodies to Treat B-Cell Lymphoma > A method for treating B-cell lymphoma by using radioactive antibodies to target cancer cells without destroying the patient's bone marrow. - **Patent:** US 5595721 - **Original title:** Radioimmunotherapy of lymphoma using anti-CD20 - **Owner:** Coulter Pharmaceutical Inc - **Granted:** 1997 - **Status:** Public domain (expired) - **Times cited:** 232 - **Field:** biotech, pharmaceutical ## What it does This patent describes a three-step process to treat B-cell lymphoma using antibodies that target the CD20 protein on cancer cells. First, a small amount of radioactive antibody is injected to image the patient and see where the drug goes. Second, a dose of unlabeled antibody is given to block non-tumor binding sites, ensuring the radioactive dose hits the cancer rather than healthy tissue. Finally, a therapeutic dose of radioactive antibody is administered at a level high enough to kill cancer cells but low enough to avoid damaging the bone marrow, which eliminates the need for a stem cell transplant. ## What it does NOT cover - Does not cover treatments that require hematopoietic stem cell replacement. - Does not cover antibodies that do not target the CD20 antigen. - Does not cover non-radioactive immunotherapy methods. - Does not cover the manufacturing process of the antibodies themselves. ## The clever bit The innovation is the pre-treatment step using unlabeled antibodies to saturate non-specific binding sites, which allows for a more precise and safer delivery of the radioactive payload to the tumor. ## Real-world examples 1. Bexxar (tositumomab and iodine I-131 tositumomab) ## Why it matters This patent provided the foundation for Bexxar, a landmark radioimmunotherapy drug. By allowing for effective treatment without the harsh side effects of bone marrow destruction, it changed how doctors approached non-Hodgkin's lymphoma, moving toward more targeted, less toxic therapies. ## Frequently asked questions ### What does Using Radioactive Antibodies to Treat B-Cell Lymphoma cover? A method for treating B-cell lymphoma by using radioactive antibodies to target cancer cells without destroying the patient's bone marrow. ### Who owns patent US 5595721? Coulter Pharmaceutical Inc owns this patent, granted in 1997. ### When does this patent expire? This patent has expired and is now in the public domain — anyone can use the invention freely. ### What is patent US 5595721 cited by? This patent has been cited by 232 later patents that build on its ideas. ### What problem does this patent solve? This patent provided the foundation for Bexxar, a landmark radioimmunotherapy drug. By allowing for effective treatment without the harsh side effects of bone marrow destruction, it changed how doctors approached non-Hodgkin's lymphoma, moving toward more targeted, less toxic therapies. ### What does this patent NOT cover? Does not cover treatments that require hematopoietic stem cell replacement. **Full plain-English explainer:** https://patentbrief.org/patent/us/5595721/pcr-thermal-cycler **Original patent:** https://patents.google.com/patent/US5595721 --- _Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._ ## Related patents Semantically similar inventions in the PatentBrief corpus: - [Using Radioactive Antibodies to Find Tumors Inside the Body](https://patentbrief.org/patent/us/3927193/ivermectin) — A 1973 method for finding cancer tumors by injecting patients with radioactive antibodies that attach to tumor-specific proteins, allowing doctors to scan for their location. - [How Genentech's Antibody Targets Cancerous B Cells](https://patentbrief.org/patent/us/9845355/tecentriq-atezolizumab) — This patent describes a specific humanized antibody designed to bind to a protein called CD79b, which is found on the surface of certain cancer cells. - [How to Build Smaller, Synthetic Antibody-Like Molecules for Medicine](https://patentbrief.org/patent/us/5455030/immunotheraphy-using-single-chain-polypeptide-binding-molecules) — This patent describes a way to create small, single-chain proteins that mimic the binding power of full-sized antibodies to deliver medicine more effectively. - [Using Antibodies to Target Tissue Factor Without Stopping Blood Clotting](https://patentbrief.org/patent/us/7993644/stelara-ustekinumab) — A patent describing specific antibodies that attach to a protein called tissue factor without interfering with the body's natural blood-clotting process. - [How Genetically Modified T-Cells Fight CD19 Cancers](https://patentbrief.org/patent/us/9481728/compositions-and-methods-for-treatment-of-cancer) — This patent describes how to create and use genetically modified human T cells that target and kill cancer cells expressing the CD19 protein, offering a new way to treat blood cancers.