Radiotherapy drugs need to be specially packaged in lead containers and liners and delivered quickly and accurately to the treatment site. Photo by Spanish newspaper La Nacional
Early one morning in late January 1896, in a light bulb factory in Chicago, Ms. Rose Lee did not realize that she was at the forefront of a pioneering medical practice. At the time, doctors placed an X-ray tube on a tumor in her left breast, using a stream of high-energy particles to penetrate the malignant tumor. This event marked the birth of X-ray therapy.
Since then, radiation therapy technology has made significant progress. With the discovery of radium and other radioactive elements, the medical community was able to apply higher doses of radiation to tumor sites deeper in the body. The introduction of proton therapy technology has further improved the accuracy of radiotherapy. With the development of medical physics, computer technology and imaging technology, the accuracy of this treatment has been greatly improved.
However, it was not until 2000 that the emergence of targeted radioactive drugs (also known as "nuclear drugs") led to molecular precision in radiotherapy. Such drugs are highly specific and can track cancer like programmed missiles, delivering radioactive material directly to tumors through the blood circulation system. Not only do they play an important role in the accurate diagnosis and treatment of major diseases, but they also provide valuable information for clinical decision-making with their unique ability to visualize live functions.
Currently, only a few targeted radioactive drugs are available for clinical use. But as the biopharmaceutical giant ramps up its investment in the field, more such drugs are expected in the future, giving patients new hope.
Clinical trials are still being explored.
Today, radioactive drugs have considerable heat. But if the treatment is to be extended to more types of cancer, new tumor killer particles will also need to be developed and more suitable targets found.
Radioactive iodine has been widely used for decades because of its ability to be absorbed by the thyroid gland and destroy cancer cells, but is largely limited to thyroid cancer. Other cancers don't have a similar affinity for radioactive elements, so researchers have developed drugs that identify and attach specific proteins to tumor cells and use them as targeted vectors to transport radioisotopes directly to diseased areas.
However, therapeutics that combine radioisotopes with cell-targeting molecules are not easy to establish in conventional cancer treatment. Quadramet, approved in 1997, is intended to relieve cancer bone pain rather than shrink tumors and has limited clinical use. At the beginning of the 21st century, two new drugs for lymphoma, although clinical trials were effective, were discontinued because they were not competitive with non-radioactive drugs.
These setbacks have led to stagnation in investment in radioactive drugs. But research continues, such as a trial of radioactively labeled antibodies to treat prostate cancer that began at Will Cornell Medical School in 2000. These efforts laid the foundation for the resurgence of radioactive drugs.
Lutetin drugs ignite hope
In Europe, clinicians have made progress in developing radioactively labeled drugs targeting somatostatin receptors. After experiments with different radioactive payloads, the researchers eventually focused on lutetium isotopes. It is a nuclein favored for its lower toxicity to the kidneys and longer half-life.
Meanwhile, lutathera, a lutetium-labeled drug introduced by the French company AAA, significantly slowed intestinal tumor progression and was quickly approved in Europe and the United States. Subsequently, a company acquired by Novartis, Endocyte, developed Pluvicto, a prostate-specific membrane antigen (PSMA) drug that extends disease progression time and lifespan in patients with advanced prostate cancer.
Pluvicto and Lutathera are built on specific peptides that bind specifically to target receptors on cancer cells. In prostate cancer treatment, Pluvicto targets the PSMA receptor, while Lutathera targets the somatostatin receptor. These drugs enter the bloodstream through an infusion and circulate throughout the body until they meet and adhere firmly to the surface of tumor cells.
Once the drug is anchored at the target site, the lutetium isotope in it releases beta particles and gamma rays that destroy DNA and cause cancer cells to die. Gamma-rays also allow healthcare workers to track the distribution of drugs in the body in real time.
alpha isotope into a new option
Current research directions and significant industry investments are gradually turning to alpha isotope-dependent drugs. Compared to beta particles, alpha particles are larger in mass and higher in energy, capable of tearing DNA and leading to highly localized cell destruction. This effect is figuratively likened to "the detonation of a shell in a cell."