#Interviews
#Interviews
27.07.2026
Spider venom molecule eliminates leukemia cells in laboratory
Developed by researchers at the Butantan Institute and Einstein Hospital Israelita, the compound triggered programmed cell death even in chemotherapy-resistant leukemia cells
Thomaz Rocha e Silva, a professor of pharmacology and biochemistry at Einstein, led the study’s antitumor activity tests | Image: Einstein
Researchers at the Butantan Institute and Einstein Hospital Israelita have shown through in-vitro laboratory experiments that a polyamine molecule isolated from the venom of a tarantula native to the coast of São Paulo State can trigger programmed cell death (apoptosis) in leukemia cells.
Polyamines are a class of toxins commonly found in animal venoms. In this collaboration, the molecule was synthesized in the laboratory at the Butantan Institute, while purification—the removal of any contaminants—was carried out at Einstein.
The compound was created by chemically combining two known molecules, making it possible to produce without extracting venom from the spider and thereby streamlining the process.
A key advantage of this approach is that it induces apoptosis rather than necrosis. By undergoing programmed death, leukemia cells self-destruct in a controlled manner without triggering an inflammatory response—a contrast to the mechanism of many chemotherapy drugs currently in use.
Other strategies can also induce apoptosis in cancer cells, including monoclonal antibodies. However, these technologies require substantial investment and are time-consuming to develop and manufacture.
In an interview with Science Arena, Thomaz Rocha e Silva, a professor of pharmacology and biochemistry at Einstein who led the study’s antitumor activity tests, emphasized that the compound was able to eliminate even chemotherapy-resistant leukemia cells.
The research, which spanned nearly two decades and resulted in a patent, also paves the way for a new form of active immunotherapy (gene therapy) that, Rocha e Silva stresses, should not be confused with a therapeutic vaccine.
Science Arena – What took place during the two decades before the preclinical research began?
Thomaz Rocha e Silva – During that time, I completed my training and began my teaching career, which reduced the time available for the project. We also faced a lack of financial support. To date, the research has been funded exclusively through institutional resources, which also caused significant delays.
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What is innovative about the process of extracting the venom-derived compound from the Vitalius wacketi tarantula, and what roles did the Butantan Institute and Einstein play in its development and the resulting patent?
The innovation lies in a small molecule, small enough to be synthesized in the laboratory, that induces cell death through a noninflammatory process. At Butantan, researchers carried out the initial purification steps and synthesized the molecule. At Einstein, the synthetic compound was further purified and underwent biological testing.
What prompted you to investigate this molecule’s potential to control leukemia by inducing apoptosis? Which types of leukemia were tested?
Our premise was that venom must be toxic. We screened a panel of spider venoms, of which Vitalius wacketi proved to be the most promising. When we isolated the purified toxin, discovering that it induced cell death through apoptosis was a very positive surprise. The compound was tested in cells from chronic myeloid leukemia (CML) and acute lymphoblastic leukemia (ALL).
As the study develops, will there be tests on animal models, or is it ready to advance directly to clinical trials in humans?
We have made progress in our in vitro studies, particularly in demonstrating the molecule’s safety. Testing in animal models is a legitimate requirement of the Brazilian Health Regulatory Agency (ANVISA) before human clinical trials can begin.
In this sense, does the molecule remain an experimental promise, or has it become closer to reaching patients?
It is still an experimental promise, but we are finalizing an agreement with a startup. The goal is to establish a partnership with a company capable of producing the molecule at scale and funding animal studies—and, in the future, human trials, if it proves to be safe and effective.
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Does the molecule eliminate cancer cells without causing toxicity to healthy cells? In this regard, has it also acted against other types of cancer or revealed new therapeutic possibilities?
Yes. We tested it on healthy cells and observed no toxicity. It was also tested in solid tumor cell cultures, but its activity was lesser.
What are currently the main obstacles to beginning clinical trials in humans? Is there any timeline for this and other stages leading to the production of the molecule?
The main challenge is securing funding for the preclinical studies, which are estimated to cost around R$1 million. Large-scale production of the molecule, in turn, depends on partnerships to transform the discovery into a potential drug. We are awaiting the formalization of an agreement with a startup so that we can begin this stage.
If the drug successfully completes all preclinical and clinical research stages, will it be used as a standalone gene therapy, or will the approach be multimodal, including, for example, bone marrow transplantation and chemotherapy?
The expectation is that it will initially be used as an adjunct to traditional chemotherapy, since it would be unethical to test it in patients without the current standard treatment. If successful, the accumulation of evidence and clinical experience may lead to new indications for this molecule.
In addition to preventive and prophylactic vaccines, we have therapeutic vaccines for bladder and prostate cancer, with advanced-stage studies underway for diseases such as melanoma and pancreatic cancer. What has contributed to this promising scenario?
What is commonly referred to as a vaccine is, in fact, active immunotherapy or gene therapy. This promising landscape is certainly the result of advances in technology, which have made it possible to bring successful experimental approaches into clinical practice, combined with a deeper understanding of the unique molecular characteristics of each type of cancer.
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