Breast Cancer Bombshell: Vulcan-Backed BiPar Wows Scientists, Helps Women Live Longer

[[Updated with scientist comment, 1:20 pm ET]]

Billionaire Paul Allen made windfall profits from his investment in BiPar Sciences, and today we can really see why. The Brisbane, CA-based biotech company founded by Allen’s Vulcan investment firm said today that its drug candidate for women with an aggressive form of breast cancer was able to help them live longer without adding side effects to standard chemotherapy.

Women who were randomly assigned to get the BiPar drug, BSI-201, in combination with chemotherapy lived a median time of 9.2 months, compared with 5.7 months for those who just got the chemo, gemcitabine and carboplatin, researchers said today at the American Society of Clinical Oncology meeting in Orlando, FL. The trial of 116 women also demonstrated BiPar’s treatment shrank or stabilized tumors, and slowed the spread of malignancy, researchers said today in a plenary presentation at the conference, which has attracted 30,000 cancer specialists.

These impressive results were what prompted Paris-based Sanofi-Aventis to pay $500 million to acquire BiPar last month, in a deal that gave Allen a $100 million return on $13 million he has invested since 2005.

The findings will also surely trigger new scientific interest in BiPar’s unusual method of action, in which it aims to block an enzyme called PARP. This enzyme is thought to help cancer cells repair their own DNA after it’s been hammered by chemotherapy. That means a drug that blocks PARP ought to make chemotherapy work better, and reduce relapses. It also could lead to an important new treatment option for about one out of every five breast cancer patients with a tough-to-treat form known as the “triple negative” variety, which means their disease has spread, and they can’t be helped by hormone blockers or Genentech’s trastuzumab (Herceptin). About 194,000 women are diagnosed with breast cancer in the U.S. each year, according to the American Cancer Society.

This result is so impressive that Powel Brown, a cancer prevention researcher at the Baylor College of Medicine, told Bloomberg News that BiPar’s drug is “the biggest story in breast cancer, by far, and it’s going to be a huge bombshell.” The result is so positive, he predicted the drug would be FDA approved in a year or two.

Based on the results, BiPar and Sanofi-Aventis plan to start a pivotal clinical trial this summer to provide more evidence supporting the drug’s effect in this same patient population.

About 62 percent of patients had some clinical benefit when they got the BiPar treatment, which researchers defined as complete or partial tumor shrinkage, or stable tumors for at least six months. Only 21 percent did that well in the control group. When expressed through an important statistical measure known as the hazard ratio, women on the BiPar drug had a 65 percent lower risk of dying than those who didn’t get it. The p-value for this finding was 0.0005, which means there was a 5 in 10,000 possibility that this result was due to chance, or a fluke, which is far greater confidence than the FDA needs to see to approve a new drug.

The most common side effects were neutropenia—a depletion of infection-fighting white blood cells—but there were actually more cases of that in the control group than among those who got the BiPar treatment.

It will be interesting to see what the opinion-makers at ASCO, and the regulators at FDA have to say about these results. Inhibiting PARP is thought to be useful in a number of different cancers, so this could lead to aggressive new investment in the field across the pharma and biotech industry. Nine days ago, when I previewed the importance of this BiPar trial, Vulcan consultant Michael Kranda suggested that a small number of thought leaders who saw the data before today were bowled over by what they saw.

“This is potentially a fundamental advance against solid tumors,” said Kranda, who pulled together the founding syndicate of venture investors in BiPar. “When you talk to the leading companies and the leading doctors in this space, we’re seeing them compare the impact of this to (Novartis’ Gleevec). That drug obliterates tumors, and you don’t see many drugs get mentioned in conversation like that.”

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4 responses to “Breast Cancer Bombshell: Vulcan-Backed BiPar Wows Scientists, Helps Women Live Longer”

  1. A number of PARP inhibitors have shown promise in retarding breast cancer growth, and are particularly promising in women with BRCA1 or BRCA2 mutations, which impair the ability of the cancer cells to repair DNA damage, and thus increase sensitivity to the inhibitors. However, the word “Bombshell” is very unfortunate in that it will raise expectations beyond what has been achieved to date. The results are modest. They should be celebrated and built upon, but not exaggerated with attention-grabbing headlines.