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Breakthrough metastatic breast cancer treatment hits snag

Breast Cancer Treatment ErSO
Posted at 12:09 PM, Dec 02, 2021

CHICAGO — A stunning breakthrough in treating metastatic breast cancer caught the attention of patients around the world. Early findings showed a new compound killed 95 to 100 percent of cancer cells in animals. But the promising new drug may have hit a snag on its road to human trials.

“It was hard to imagine that we had a drug that would take cancers and cause them to just disappear in a matter of days,” said biochemistry professor David Shapiro. That was his reaction when imaging came back showing that the drug ‘ErSO’ successfully targeted and killed metastatic breast cancer tumors in mice.

“All the tumors have been eradicated, they've been destroyed and they're no longer detectable,” he told us back in August.

The compound developed by a team at the University of Illinois Urbana-Champaign worked in just days, without reoccurrence of cancerous tumors or any noticeable side-effects.

“We have been making these kinds of drugs for over a decade and none of them ever did anything remotely like that,” said Shapiro.

It was so promising that pharmaceutical giant Bayer bought the exclusive licensing rights to develop ErSO as a cancer therapy in partnership with Arizona-based Systems Oncology a year before the Illinois study was even published. It was a deal originally worth up to $370 million.

For metastatic breast cancer patients around the world, it was astounding.

“That is an amazing promise that they made in their study. That is unheard of. That has never happened in oncology history. Never,” said Anja Mullins, a metastatic breast cancer patient and ErSO activist.

Hundreds of people like Mullins formed an advocacy group on Facebook to follow the ErSO progress.

“I had heard of ERSO and was kind of like, ‘Wow, this sounds amazing,’” said Jeanine Dolan who also has metastatic breast cancer and is a member of the ErSO Activism for Breast Cancer group.

But in recent weeks, the partnership between Systems Oncology and Bayer suddenly dissolved.

“The fact that it was taken up by Bayer, that seemed promising. And then after 12 months to think, well, we’re at the end of the line, it was disappointing. Really disappointing,” said cancer patient and ErSO Activism administrator Danny Goss.

In a statement Bayer wrote in part: “Following a thorough assessment of ERSO in preclinical studies, Bayer has decided to discontinue development activities of this program for scientific reasons… we must take prudent steps to ensure the compounds have the potential to provide the therapeutic benefits we are striving to achieve for patients with cancer.”

For hopeful cancer patients around the world— like Racheal Williams, a mother who found out her breast cancer had metastasized early this year—the hope has turned to frustration.

“We deserve research. We deserve funding. We deserve to know what happened to ErSO. What happened to it? And if it is a viable option, bring it to clinical trials,” said Williams.

Systems oncology has not responded to our repeated requests for comment.

Meanwhile, an online petition pressing for clinical trials of ErSO has gotten more than 20,000 signatures.

“What scientific reasons do you have for stopping a study on something that was 95-100% effective within three days? And nobody can. No one tells us that,” said Dolan.

In the meantime, Professor Shapiro and his team continue to study ErSO. He says he hopes the development of this unique family of anti-cancer drugs will eventually result in a clinical trial. For now, ErSO’s next steps remain uncertain.