The novel PARP blocker is found prolonging lives of women with `triple negative’ form of breast cancer.
BSI-201 is showing a great potential as a new class of drugs to treat the most aggressive -triple negative -form of breast cancer which sickens and kill, mostly, young women.
BSI-201 is currently being developed by Sanofi-Aventis, which bought the innovator of the drug BiPar Sciences Inc for $500 million more than a month ago.
Sanofi studies found BSI-201 prolonged survival in women with the aggressive form of breast cancer by 3.5 months, to 9.2 months, when combined with other drugs used in chemotherapy.
BSI-201 heralds the beginning of a new class of drugs, called Poly(ADP-ribose) polymerase (PARP) inhibitors, that could transform treatment outlook for the toughest cancers, according experts at the American Society of Clinical Oncology meeting being held in Orlando, Florida.
BSI-201 is the furthest advanced of the emerging class of PARP inhibitors. BSI-201 blocks the new target PARP enzymes that normally help cells to repair themselves after DNA damages, often caused by cancer treatments like chemotherapy and radiation.
Normally human cells get their DNAs repaired themselves through six different mechanisms. But in cancer cells many of those mechanisms fail, often leaving them with no option but rely on PARP to fix genetic damage.
PARP enzyme is found to be very high in concentration in severe forms of cancer in the ovaries, uterus, lungs and pancreas, meaning they could make good targets for the therapies, said Barry Sherman, BiPar’s chief medical officer.
If the cancer is detected early enough, treatment with a PARP inhibitor may be able to permanently destroy the tumors, Sherman stated.
“There is an opportunity here to actually use the term ‘cure’ when it’s applied to early-stage disease,” Sherman said. “That is perhaps one of the most exciting notions to come out of this. This is the forefront of a field that is about to open up, about DNA repair.”
Experts in the field of cancer research said PARP inhibitors were the biggest story in breast cancer, by far.
In the phase 3 human trials conducted by Sanofi, BSI-201 was given as an intravenous infusion along with a couple of cancer drugs to 116 patients with triple negative breast cancer. Triple negative breast cancer is the toughest form to treat because it lacks three genetic targets needed for the most effective medicines. Triple negative breast cancer is responsible for about 15 percent of breast cancers and affects younger women more than other forms.
Half of patients were given BSI-201 and a combination of chemotherapies, carboplatin and Eli Lilly & Co.’s Gemzar, and half were given chemotherapy and a dummy pill.
When the results were analysed, majority -about 60 percent – of patients who took BSI-201 saw their tumors shrink and cancer slow, almost three times as many as those who took only chemotherapy. The median lifespan after treatment with BSI-201 was 9.2 months, compared with 5.7 months in the control group.
Sanofi plans to expand the study by enrolling 400 patients in the next two months to confirm the results.
U.S. Food and Drug Administration approval for BSI-201 drug is expected to come within two years.
Drugs belonging to PARP inhibitors are also being studied by Abbott Laboratories and Pfizer Inc.
Abbott is investigating ABT-888, in 10 clinical trials.
PARP inhibitors could also work against other cancers and might reduce the amount of chemotherapy needed to treat a variety of patients. There are “hints” that PARP inhibitors may show benefits in diseases other than cancer and may one day be used to limit damage after a heart attack or stroke.
Breast cancer is the second most common malignancy in women, after skin tumors, according to the Atlanta-based U.S. Centers for Disease Control and Prevention. About 187,000 women were diagnosed with breast cancer and 41,000 women died from it in 2005.
BiPar Sciences is a clinical-stage drug development company pioneering novel tumor-selective therapies. BiPar Sciences’ product pipeline also includes BSI-401, a follow-on PARP inhibitor and BSI-302, an anti-tubulin agent that targets cancer cells based on the role of thyroid hormones in cell proliferation and death.
Sanofi-aventis is a leading global pharmaceutical company based in Paris.