UPDATED: Merck, Endocyte score crucial EMA OK for conditional approval of vintafolide

Endocyte and its Big Pharma partner Merck won the support of the Committee for Medicinal Products for Human Use (CHMP) at the European Medicines Agency (EMA) for conditional approval of the biotech's lead drug in Europe, winning over regulators with mid-stage data demonstrating that vintafolide successfully delayed disease progression for ovarian cancer. And adding to the big day for both, Merck ($MRK) turned in positive Phase IIb lung cancer data for a drug that earned a blockbuster development deal back in 2012.

The CHMP decision is likely to trigger a fresh round of crowing and cackling among the bulls and bears in the market, who have made these two catalysts a flash point on the company's ($ECYT) progress as well as its future prospects with the drug. But Endocyte came out well ahead today, watching its stock price soar more than 175% on the EMA decision and trial results. And the advances are a big plus for Merck, which has identified vintafolide as one of its top cancer prospects in the pipeline as new R&D chief Roger Perlmutter works on a turnaround.

"These positive CHMP opinions bring Merck and Endocyte one step closer to providing a personalized approach to address a significant unmet medical need in platinum-resistant ovarian cancer," said Dr. Eric Rubin, vice president of clinical development for oncology at Merck Research Laboratories, in a statement. 

Binh Nguyen, vice president of medical affairs at Endocyte

There were no data in the non-small cell lung cancer trial announcement, but Merck says the drug hit the primary endpoint in the lung cancer study while demonstrating a "trend" toward a secondary endpoint on overall survival. The trial hasn't reached the point where the company can determine the final median OS rate.

There were originally three arms in the study: vintafolide alone, vintafolide in combination with docetaxel and docetaxel alone. Last October an independent review board told investigators to give up on the vintafolide-alone arm, which was seized by the bear crowd as a sign that the drug isn't all that powerful. That argument will be tested now with the actual results.

"We are pleased with the results of this study, as the vintafolide/docetaxel combination showed meaningful activity in patients with recurrent NSCLC, meeting the primary endpoint of the trial," said Dr. Binh Nguyen, vice president of medical affairs at Endocyte, in a statement. "This is our second randomized study in a very challenging indication, where vintafolide has met the primary endpoint when used in patients selected with the companion imaging agent etarfolatide. These results provide further validation of our targeted approach to treatment using companion imaging and our SMDC technology. We were especially pleased with the results in the adenocarcinoma population and early OS trends, and we have learned important information about the dosing schedule. We look forward to reviewing additional analysis of this study when the OS data has matured later this year to help inform potential further development of the vintafolide/docetaxel combination in NSCLC."

Merck demonstrated an eager affinity for this drug in the spring of 2012 when the pharma giant signed up for a $1 billion partnership--$120 million upfront--for the drug. Merck, at a time Peter Kim was running the R&D shop, grabbed worldwide commercialization rights and agreed to share the U.S. rights with West Lafayette, IN-based Endocyte.

Vintafolide is a conjugated cancer therapy that matches folate to a potent chemotherapy. A variety of cancer cells bristle with folate receptors, allowing the drug to dock on the cancer cell and deliver its toxic payload of vinblastine. And the biotech has developed a diagnostic test that can be used to identify the patients most likely to benefit.

Endocyte reported that in a Phase II study for ovarian cancer their drug plus pegylated liposomal doxorubicin (PLD) posted a median progression-free survival score of 5 months versus 2.7 months in the arm taking PLD alone. And a group of patients with 100% folate-receptor positive ovarian cancer had a PFS rate of 5.5 months versus 1.5 months for the PLD group. That was all statistically significant and something the company felt warranted conditional approval in Europe.

But Endocyte has been at the center of a bull/bear debate for some time now. The bulls have been running with company executives on this one while the bears have been pooh-poohing PFS rates when overall survival is what counts. And there were signs in the Phase II, outlined in a recent "bear thesis" on TheStreet, that the vintafolide arm trended to a higher risk of dying.

That debate is a long way from being finally settled one way or the other. But today belongs to the developers and their investors.

- see the press release on the EMA announcement
- here's the release on the trial