An abortion drug for breast cancer is being blocked by moral and political interests

On December 1, 2006, the journal Science flagged up a promising development. “In the future, perhaps, drugs can be used to prevent breast cancer,” the article predicted. Almost 20 years later, that hasn’t happened. The ‘maybes’ in scientific journals should be written in capital letters. Science advances slowly and there are many obstacles in its path: lack of funding, errors, dead ends... But in this case, the research has also been impeded by moral prejudice and political bias.

The drug Science was talking about is called mifepristone and is used to induce abortions. And this is a problem. “It’s scary to investigate it and look pro-abortion,” Swedish researcher Kristina Gemzell Danielsson, from the Karolinska Institutet, explains. Danielsson is one of the signatories of a recent editorial published in The Lancet denouncing the situation. “We have very promising data, but no efforts are being made to continue with the research,” she explains. “Mifepristone is also extremely expensive to use for research and the regulatory hurdles are absurd, probably because it is associated with induced abortion.”

The editorial is based on three recent scientific studies and the conclusions of a multidisciplinary consensus workshop held in 2024 at the University of Innsbruck, Austria. Despite having a solid scientific basis, it says more about how research works than it does about how to prevent cancer. And its conclusions are not reassuring. “Research funding is usually politically driven,” Danielsson says. “Ideology can slow everything down.”

In addition to the regulatory, political, and legal barriers which have limited the research, there is minimal pharmaceutical investment, the editorial points out. And this is not only due to political interests, but also commercial ones. “Pharmaceutical companies want to make a profit. This is where the possibility of patenting comes into play,” says Danielsson. “Using an old drug for a new condition does not provide an immediate benefit.”

But not all of the medical community agrees with this view. “The barriers to carrying out this research identified by the editorial are coherent,” says Rodrigo Sánchez-Bayona, scientific secretary of the Spanish Society of Medical Oncology (SEOM) and medical oncologist at the Hospital 12 de Octubre in Madrid. “Like many other drugs, this drug has a potential for primary prevention of breast cancer, but lacks sufficient evidence to carry the research forward. The three studies you mention are preclinical. There are no prospective studies that have shown that taking mifepristone reduces the number of new breast cancer diagnoses in healthy women.”

Breast cancer is the cancer that kills the most women worldwide. More has been invested in improving detection and treatment than in primary prevention. The authors of the editorial advocate changing this approach, indicating the treatment of cervical cancer as an example. Vaccination against the human papillomavirus in young women has considerably reduced its prevalence. Some countries have reduced the incidence to less than four cases per 100,000 women, making something that until recently was unthinkable a reality: the elimination, for the first time in history, of a cancer.

In the case of breast cancer, the only prevention that exists is brutal and extreme, involving as it does the removal of the breasts. It is only recommended for women who carry a pathogenic variant in the BRCA1 or BRCA2 genes and who, therefore, have a very high risk of developing breast cancer. Approximately 70% will have done so before the age of 80. This gene is popularly known as the “Angelina Jolie gene” after the actress went public with her diagnosis and announced that she had removed her breasts to avoid developing the disease. It is an effective solution and reduces the risk of cancer by 90% but it is also undesirable, impacting the quality of life and self-esteem of patients. But mifepristone has been pointing for 20 years to another less aggressive solution. Although more research is needed, scientific evidence is growing and the mechanism by which it would protect against cancer is already known.

“Women with this genetic variant tend to have higher levels of the hormone progesterone during the second half of their menstrual cycle,” explains Martin Widschwendter, director of the European Translational Oncology Prevention & Screening Institute and also a participant in the Lancet editorial. “This hormone causes certain breast cells, known as luminal progenitor cells, to multiply. It is thought that these cells may develop into triple-negative breast cancers.” Mifepristone blocks the effects of progesterone. This causes fewer potentially cancerous cells to be produced. “We have conducted studies that show that intake of the drug reduces the number of these high-risk cells in the breast. We have also observed similar effects in mice, in which the drug significantly reduced the development of breast cancer,” Widschwendter says.

The compound also causes the breakdown of the uterine lining, leading to early termination of pregnancy. They are two different results, but the one has conditioned the other in a debate that is not so much medical as moral and political. “It is still a very politicized and polarizing issue in many countries,” Widschwendter says. “Researchers find it difficult to access the drug, pharmaceutical companies often avoid getting involved, and it is more difficult to get funding. It is frustrating to think that a drug with such a well-known biology and clear potential could help save lives, but it is not being thoroughly researched due to the social and political implications in another field of medicine.”

Researchers, academics, and health professionals hope to change this panorama with the Lancet editorial, which is not only aimed at the scientific community, but also at the pharmaceutical industry, policy makers, and society in general. It has been written at a time in which political bias in the scientific world is more apparent than ever. In the United States, the Secretary of Health, Robert F. Kennedy Jr. — a well-known spreader of conspiracy theories regarding vaccines — has just shot down an investment of $500 million into mRNA vaccine research. Faced with this concerning trend, many scientists are raising their voices and demanding that political ideology be left at the doors of the laboratory. “Research with mifepristone for breast cancer prevention must be done now if we are to reduce the risk of the most common cancer affecting women globally,” the editorial concludes.

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