By Amy Norton
SATURDAY, March 28, 2015 (HealthDay News) -- An experimental vaccine and a drug already on the market each may help slow down advanced ovarian cancer, two new studies suggest.
In one, of just 31 patients, researchers found that adding the vaccine to standard treatment staved off a recurrence in women who had advanced-stage ovarian cancer.
The other study, involving women with recurrent ovarian cancer, found that administering the drug Avastin after surgery and chemotherapy stalled the cancer's progression, versus surgery and chemo alone.
The findings are to be presented Saturday at the annual meeting of the Society of Gynecologic Oncology (SGO), in Chicago. Studies reported at meetings are usually considered preliminary until they're published in a medical journal.
Still, experts expressed cautious optimism, saying the findings represent progress against the deadliest form of gynecologic cancer.
There is no screening test for ovarian cancer, and in its early stages it often causes no symptoms or only vague ones -- like abdominal bloating or pain, explained Dr. Krishnansu Tewari, a gynecologic oncologist at the University of California, Irvine.
So most women aren't diagnosed until the tumor has spread, he said. And while current treatments often beat back the cancer initially, it usually returns.
The new vaccine study was a preliminary look at the safety and efficacy of the therapy, known as FANG. But the results are nonetheless "exciting," said Tewari, a spokesperson for the SGO who was not involved in the study.
The vaccine proved "so effective" at delaying a recurrence that the study was stopped early, so that a larger trial could move forward, Tewari added.
In the study, 11 women were randomly assigned to standard treatment alone -- namely, surgery and chemotherapy. The other 20 women went through standard therapy, then had monthly injections of the vaccine, for four months to a year.
Women on standard treatment typically saw a recurrence after about 14 months. In contrast, most of the vaccine patients have gone "well beyond" that time without a recurrence, according to an SGO press release on the findings.
The trial is reportedly moving on to the next phase, with close to 400 women.
The FANG vaccine, Tewari said, is one example of various types of "immunotherapy" under study for ovarian cancer. Those treatments aim to enhance the immune system's cancer-fighting abilities.
The FANG vaccine is personalized, using cells from a patient's own tumor. It's designed to stimulate the immune response against the cancer, and block proteins that help tumors evade the immune system, according to the company Gradalis, the vaccine's developer and funder of the study.
"This is promising because it's a highly personalized therapy, and they haven't seen any significant side effects so far," said Tewari, who has no relationship with Gradalis.
But as with any experimental therapy, he stressed, larger studies are needed to look at the long-term effectiveness and safety.
The other study involved 748 women with recurrent ovarian cancer, where the outlook has traditionally been grim. Researchers tested the effects of adding the drug Avastin to surgery and standard chemo.
Avastin (bevacizumab) was approved in the United States late last year for women with recurrent ovarian cancer that had become resistant to chemo drugs known as platinums.
That approval was based on a clinical trial finding that Avastin helped shrink or stall ovarian tumors, though it did not prolong women's lives.
The new study is different, partly because it involved women who were still sensitive to platinum drugs, said lead researcher Dr. Robert Coleman, of the University of Texas MD Anderson Cancer Center, in Houston.
It also looked at the benefits of having a second surgery: Half of the study patients were assigned to surgery plus chemo; the other half had the same treatment, plus Avastin -- which works by cutting off tumors' blood supply.
Overall, women who received Avastin lived longer -- typically 42 months, versus 37 months. They also went longer with no cancer progression (about 14 months, vs. 10 months.)
However, that difference in survival did not quite reach "statistical significance," noted Dr. Leslie Randall, another SGO spokesperson who was not involved in the study. That means it could be a chance finding.
"I think there will be a lot of debate over how significant that overall-survival finding is," said Randall. "It's positive, but not overwhelmingly so."
Still, she stressed the "good news": The trial confirms that Avastin can prolong the time a woman remains progression-free.
The drug is pricey -- costing several thousand per month -- and carries side effects: In this trial, infections, joint pain and gut perforations were among the most serious ones.
But most women did not suffer those problems, Coleman noted. And in general, he said, Avastin is "well-tolerated."
Randall said more research is needed to figure out which women stand to benefit most from the drug. It's not only extra time that patients value, she added -- it's also the quality of that time.
Everyone agreed that the research being reported at the meeting shows progress against a disease where there had long been little headway.
"It's still largely incurable," Randall said. "But it is becoming increasingly treatable with newer surgeries, chemotherapy and targeted therapies."
According to the American Cancer Society, about 21,300 U.S. women will be diagnosed with ovarian cancer this year, and 14,200 will die from the disease.
The American Cancer Society has more on ovarian cancer.