Unlike the vaccine that helps prevent cervical cancer in healthy women,
these vaccines are designed to help people who already have cancer.
Tumor cells often grow and spread because the body doesn't recognize them as
foreign. The vaccines aim to re-educate the immune system to recognize cancer
cells as alien invaders that need to be attacked and annihilated.
Both studies were presented here at the annual meeting for the American
Association for Cancer Research (AACR).
Vaccine Targets HER2/neu
The breast cancer vaccine targets a protein called HER2/neu that is
associated with aggressive tumors. In high amounts, the protein speeds up tumor
growth and the risk of death.
About 25% of women with breast cancer fall into this category. In the new
study, the vaccine reduced their risk of death by 50%.
Importantly, the vaccine worked even better in women who had lower but still
elevated levels of HER2/neu, says researcher Linda C. Benavides, MD, of Brooke
Army Medical Center in San Diego.
None of the women in this category -- which accounts for about half of
breast cancer patients -- died.
If the vaccine pans out in future study, "we'll have an option for the
largest subset of breast cancer patients, who really haven't been considered
before," Benavides tells WebMD.
She notes that women with high expression of Her2/neu can benefit from
targeted therapies, such as Herceptin. But the only options for women with
lower expression are conventional chemo, surgery, or radiation, she says.
Breast Cancer Vaccine Cuts Deaths
The study involved 165 women, about one-third of whom had high levels of
HER2/neu. The rest had lower or intermediate levels.
All the women had been treated for breast cancer but were disease-free at
the time of the study.
Just over half of the women got the vaccine -- one shot every three to four
weeks, for a total of six injections.
Immunity was boosted in all the women who got the vaccine. But tests showed
that women with low or intermediate HER2/neu levels mounted a stronger immune
response than those with high levels. "This was surprising," Benavides
By 30 months later, breast cancer came back in similar numbers of women who
had high HER2/neu levels, whether or not they got the vaccine. But among those
whose disease recurred, those who got the vaccine were 50% less likely to
Among women with low or intermediate HER2/neu levels, only about 10% of
those who were vaccinated suffered a recurrence, compared with nearly 20% who
didn't get the vaccine.
And none of the vaccinated women with recurrent disease died vs. 38% who
didn't get the vaccine.