Phasehuman trials suggest breast cancer drug is safe, effective


Date:
August 27, 2020
Source:
University of Illinois at Chicago
Summary:
A new type of breast cancer drug can help halt progression of
disease and is not toxic, according to phase 1 clinical trials.



FULL STORY ==========================================================================
A new type of breast cancer drug developed by researchers at the
University of Illinois Chicago can help halt progression of disease and is
not toxic, according to phase 1 clinical trials. The drug is specifically designed for women whose cancer has stopped responding to hormone therapy.


==========================================================================
The results are published in the journal Breast Cancer Research and
Treatment.

Breast cancer affects one in eight women in the United States, and while
there are many types of breast cancer, around 80% are categorized as
estrogen receptor-positive, or ER-positive. This means the cancer cells
have receptors - - molecules that can receive signals from chemicals in
the body -- that are sensitive to and react to the hormone estrogen.

In the case of ER-positive breast cancer, this means that estrogen fuels
cancer growth. To treat this type of breast cancer, doctors prescribe medication to block hormone production in the body or interfere with the
effect hormones have on cancer cells. This type of treatment is called
hormone therapy. However, nearly half of women treated with hormone
therapy become resistant, leaving traditional chemotherapy and its side
effects as the only option for treatment.

"While there are many treatments for breast cancer, about half of women
with ER-positive cancers become resistant to hormone therapy, leaving
them with few treatments other than chemotherapy, with its well-known
toxic side effects," said Debra Tonetti, professor of pharmacology at
the UIC College of Pharmacy and an author on the paper.

Tonetti, together with Gregory Thatcher, the Hans W. Vahlteich Chair
of medicinal chemistry at UIC and co-author on the paper, developed
the new drug, called TTC-352. Preclinical studies showed that TTC-352,
which is a selective human estrogen receptor partial agonist, causes
complete tumor regression, but unlike tamoxifen, may pose a reduced risk
of uterine cancer development.

In the phase 1 clinical trial, 15 women who had metastatic breast cancer
and previously were treated with several rounds of hormone therapy
and, in some cases, chemotherapy including a CDK4/6 inhibitor, were
enrolled. The researchers found that there were no toxic side effects,
even at the highest doses.

In total, six patients experienced stable disease with a lack of disease progression: two for 6 months and four for 3 months.

"This is very encouraging because these participants were at an advanced
stage of their disease, and we saw that their cancers stopped growing
for a significant amount of time," said Tonetti, who is also a member
of the University of Illinois Cancer Center.

The doses given to participants were in line with what the researchers
believe are therapeutic levels -- in other words, participants received
doses equivalent with what patients would be given to treat their disease.

"The results of the phase 1 trial indicate that TTC-352 is a safe and
tolerable alternative to chemotherapy -- therefore, without the side
effects of chemotherapy -- for patients who have already been treated
with hormone therapy," Thatcher said.


========================================================================== Story Source: Materials provided by
University_of_Illinois_at_Chicago. Note: Content may be edited for style
and length.


========================================================================== Journal Reference:
1. Arkadiusz Z. Dudek, Li C. Liu, James H. Fischer, Elizabeth L. Wiley,
Jasgit C. Sachdev, Jonathan Bleeker, Randolph W. Hurley, Debra A.

Tonetti, Gregory R. J. Thatcher, Robert P. Venuti, Ruth
M. O'Regan. Phase 1 study of TTC-352 in patients with metastatic
breast cancer progressing on endocrine and CDK4/6 inhibitor
therapy. Breast Cancer Research and Treatment, 2020; DOI:
10.1007/s10549-020-05787-z ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200827172050.htm

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