When the anticancer drug Herceptin is delivered to mice via a
slow-release, nontoxic hydrogel (left), it localizes to tumors for a sustained
period of at least two weeks (right).
A nontoxic hydrogel developed by the A*STAR Institute of Bioengineering
and Nanotechnology and IBM Research offers a new way forward for breast cancer
therapeutics
Breast
cancer is the most common form of invasive cancer affecting women worldwide.
Treatment usually involves surgery followed by a course of either chemotherapy,
radiotherapy or hormone therapy designed to reduce the risk of the cancer’s
recurrence. In recent years, however, targeted drugs have increasingly become
an effective option to fight the disease.
One
such drug is Herceptin, also known as trastuzumab, a monoclonal antibody that
can slow or even halt tumor growth in patients with human epidermal growth
factor receptor 2 (HER2)-positive breast cancer — a particularly fast-growing
form of the disease that affects one in four patients. Typically, the drug is
administered at a clinic through an intravenous drip, a process that can take
up to 90 minutes. A major drawback of this method of delivery is that without
frequent follow-up doses, Herceptin loses its effectiveness. Therefore,
patients are commonly required to visit the clinic on a weekly basis.
Now, a
team of researchers from the A*STAR Institute of Bioengineering and
Nanotechnology (IBN) and IBM Research led by Yi Yan Yang and James Hedrick has
developed a more efficient way of delivering Herceptin to breast cancer cells.
The approach promises to improve the effectiveness of treatment for the
HER2-positive form of the disease. Drawing on IBN’s expertise in the
development of novel biomaterials, the researchers recognized the advantages of
using a hydrogel — comprising 96 per cent water and a uniquely designed polymer
— as a carrier for Herceptin in the body.
The
hydrogel is nontoxic, biodegradable and can be injected under the skin without
causing an inflammatory response. By varying the composition and concentration
of the polymer, the researchers were able to fine-tune the hydrogel’s
properties to ensure a slow and sustained release of the anticancer drug, thus
increasing the efficiency of delivering the drug to the target site.
Correspondingly, use of the hydrogel for drug delivery has the potential to
reduce the frequency at which patients need to be injected with Herceptin from
once a week to once every four weeks.
Recently,
the researchers conducted studies in mice, which confirmed that their
Herceptin-loaded hydrogel delivers the drug efficiently, before it degrades
within 6 weeks. They found that 4 weeks after injection, tumors in the mice had
decreased in size by as much as 77 per cent. The researchers say that their
next goal will be to conduct clinical trials in humans, in conjunction with
industrial partners.
Other
teams at IBN are also exploring the innovative use of hydrogels for
controlled-release drug delivery to tackle different types of cancer (see Greater anticancer
potency with less risk). The institute has always cultivated a
multi-pronged approach toward cancer research, notes Jackie Y. Ying, professor
and executive director at IBN.
“Our
multidisciplinary research teams are working with various industrial, clinical
and academic partners to develop new materials and tools to improve cancer
diagnosis and treatment,” she adds. “This latest breakthrough with our
long-term partner IBM Research promises more efficient administration of
anti-cancer drugs and more effective treatment of breast cancer, which we hope
will benefit breast cancer patients worldwide.”
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