Dr. Jose Luis Carreras gets excited when he talks about superposition, a powerful strategy that works like a precision missile against the cells of some cancers. Carreras, chief of the nuclear medicine department at Clinico San Carlos in Madrid, reports “amazing results” in some terminal patients. The doctor recalls the case of a 62-year-old German man who had extensive prostate cancer with bone metastases. After an experimental treatment with autopsy at the central clinic in Bad Berka (Germany), he appeared clean eight months later. He returned to work and exercise. Three and a half years later, she is still cancer-free, Carreras said in February at a scientific session at the Royal National Academy of Medicine in Madrid.
Teragnosis has been one of the champions of the largest annual conference dedicated to cancer in the world, and one of the American Society of Clinical Oncology (ASCO), online and expired on Tuesday. The term teragnosis is a combination of two words: treatment and diagnosis. Using the same molecule, disease can be diagnosed and treated. This strategy, used for decades against thyroid cancer, is now being used with promising results in other tumors, such as neuroendocrine carcinomas, especially prostate cancer, which is most common in men.
Michael Morris, MD, of Memorial Sloan Kettering Cancer Center in New York, presented at the ASCO Conference the latest diagnostic findings against advanced prostate cancer. The technique consists of using a molecule highly affinity for PSMA, a protein normally found in large amounts in prostate cancer cells. To make a diagnosis, this PSMA-related molecule joins a radioactive chemical element, gallium-68, which glows in a positron emission tomography (PET) scan. For treatment, the same molecule joins with another chemical element, lutetium-177, which emits local radiation that kills cancer cells. It’s like shooting an arrow first with a flashlight and then another arrow with a small explosive charge.
The Morris trial involved 831 patients with castration-resistant and metastatic prostate cancer, a type of tumor that is usually fatal. Patients who received treatment for ataxia lived 15.3 months, compared to 11.3 months for men who received standard treatment. Four months apart – 35% more – it may seem like a small thing, but they were practically desperate patients whose chemotherapy and hormone therapy had already failed.
Dr. Jose Luis Carreras stresses that the additional four months of survival is average. “There are cases where it does not respond, but there are some cases where the improvement is amazing,” he says. Beginning in September, his team at Clinico San Carlos will participate in two clinical trials of crosslinking against advanced prostate cancer. “This isn’t the future, it’s the present. It’s precise and personalized molecular radiotherapy. It’s not about killing flies with cannon fire like other technologies. It goes directly to the cancer cell, puts radiation in and destroys it.”n site without affecting the surrounding healthy tissue.
Carreras believes that in the coming years molecules “for all types of tumors,” such as the fibroblast activating protein inhibitor (FAPI), will arrive with affinity for cells from various malignancies. Almost all tumors have fibroblasts [um tipo de célula abundante nos tecidos fibrosos] mixed with cancer cells. With FAPI, it is possible to send radiation to fibroblasts, but because lutetium-177 has a radiation range of one or two millimeters, it also destroys cancer cells. The advantage of FAPI, Carreras says, is that it’s valid for any type of tumor. The doctor adds that there is still little evidence of the therapeutic efficacy of this strategy, due in part to the low radiation dose that is reached on the cancer cells.
A promising experimental treatment presented at the ASCO conference, called 177Lu-PSMA-617, was in development at the US biopharmaceutical company Endocyte. Swiss pharmaceutical giant Novartis announced in October 2018 that it was buying the company for 1.7 billion euros (10 billion R$). Some previous research, such as a study of 30 patients in 2016 at the University Hospital Heidelberg (Germany), has already demonstrated the potential of this strategy.
Oncologist Teresa Alonso, of the Ramón y Cajal Hospital in Madrid, believes that the benefit of the treatment would “certainly be much greater” if it was given to patients in advance. “The concept is old, but now it’s going to be very popular,” says Alonso, scientific secretary of the Spanish Society of Medical Oncology (SEOM). The researcher notes that it is a similar strategy to the one used decades ago against thyroid cancer, in this case with iodine-123 for diagnosis and iodine-131 for treatment. In recent years, this technique has also been adopted against neuroendocrine tumors, with an annual incidence of less than 10 cases per 100,000 population. “Teragnosis is a very beautiful concept and it is a very powerful prostate cancer treatment,” the oncologist applauds. The researcher, however, keeps her feet on the ground: “This is not a cure for prostate cancer, of course.”
ASCO Conference President, North American Oncologist Laurie Pierce, celebrated the results of advanced prostate cancer treatment against prostate cancer. “The success of this treatment demonstrates the importance of researching alternatives to conventional cancer treatments,” Pierce said in a statement. Michael Morris, chief of prostate cancer at Sloan Kettering, directly suggested that authorities study the possibility of converting 177Lu-PSMA-617 into a new standard treatment for these patients.
Dr. Jose Luis Carreras laments the “slowness” of drug regulators when approving new treatments. One of the problems is the high price. Carreras calculates that treating a neuroendocrine tumor costs 65,000 euros (400,000 riyals) per patient. “It has a longer survival time than other alternatives and the price is competitive. He argues that it’s no more expensive than the chemotherapy it replaces.”