ASCO: Celldex's glioblastoma vaccine scores a clear survival benefit

CHICAGO--Celldex has added another round of positive data demonstrating that its brain cancer vaccine rindopepimut--more formally called Rintega and less formally "rindo"--provided a clear though relatively modest average survival benefit for recurrent glioblastoma patients in a Phase II study. And with the initial data set from Phase III looming later in the year, the biotech is carefully moving forward with its ongoing dialogue with regulators to gauge just how receptive they may be to speeding up an approval.

MRI image of a glioblastoma tumor--Courtesy of NIH

In the drug arm, which received a combination of rindo plus Avastin, 45% of the patients in the Phase II were alive after 12 months of treatment, compared with 31% of the patients in the Avastin-only arm. The rindo group registered a median overall survival rate of 11.6 months compared with 9.3 months in the control. 

"This is the first data we know of that showed a statistically significant benefit in the survival setting," says Celldex ($CLDX) CEO Anthony Marucci, a feat that Avastin notably failed to accomplish. In addition, 17% of patients were able to stay off of steroids for more than a year, which Celldex scores as another notable potential benefit for patients.

These new data help sustain an ongoing discussion with the FDA about the possibility of accelerating an approval of this drug, which is remarkable for a variety of reasons. Glioblastoma remains one of the toughest targets in the cancer field and cancer vaccines in particular have a troubled history of failure.

But Marucci fingers their targeted approach to targeting EGFRvIII--or v3 in shorthand lingo--for their against-the-odds success, noting that they don't need a massive T cell response to wipe out the v3 cells to get a clear response.

Marucci and his crew at Celldex took some interim positive numbers from the Phase II to the FDA last fall to gauge its appetite for an accelerated approval pitch. The FDA didn't go for it at that time. But out of those discussions, says the CEO, the FDA handed out its coveted breakthrough therapy designation, which is intended to keep its doors open to advances just like this as they continue to review Celldex's case for a speedy approval.

Marucci treads carefully when he talks about pursuing an accelerated approval based on data from a study with 78 patients. Physicians and patients are eager to try new drugs for a ruthless and typically quick killer, so even though the median survival benefit wasn't stunning, the agency won't need to see spectacular responses before they act. Also, some more durable responses seen in this study could contribute an added element of hope for many people who currently don't have much to be positive about. But the agency may also want to wait to see at least initial data from the larger Phase III before it acts.

Celldex has had its ups and down with this cancer vaccine over the years. Pfizer dumped its collaboration with the biotech close to 5 years ago. Peak sales estimates, meanwhile, tend to gyrate between a few hundred million to more than $1 billion in annual revenue.

- here's the release

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