Personal Finance

Why Seattle Genetics, Inc. Got Clobbered Today

Image source: Getty Images.

What happened

Seattle Genetics (NASDAQ: SGEN) is down 15% at 11:57 a.m. EST after announcing the Food and Drug Administration has put a clinical hold on multiple early stage clinical trials testing its cancer drug vadastuximab talirine, which used to go by its code name SGN-CD33A, in acute myeloid leukemia (AML).

So what

The FDA took the action after Seattle Genetics disclosed six patients taking vadastuximab talirine had signs of liver toxicity including several cases of veno-occlusive disease, where blood flow is blocked in the liver. Four of the patients died.

Veno-occlusive disease most often occurs in patients undergoing blood cell transplantation, one of the treatments for AML, so it isn't clear if vadastuximab talirine is causing the problem. More than 300 patients have been treated with vadastuximab talirine to date, so it's a fairly rare problem.

The FDA placed a full hold -- meaning no more treatments until it's lifted -- on a phase 1/2 trial testing vadastuximab talirine in pre- and post-allogeneic transplant AML patients. Two other phase 1 trials for vadastuximab talirine are only on a partial hold, so no new patients can be enrolled but existing patients can continue treatment if they want to.

Interestingly, the FDA didn't place other clinical trials testing vadastuximab talirine on clinical hold, including the phase 3 CASCADE trial in older AML patients and a phase 1/2 trial in another blood cancer called myelodysplastic syndrome.

Now what

Seattle Genetics said it's working with the FDA to identify whether vadastuximab talirine is the cause of the liver toxicity and hopes to "identify appropriate protocol amendments for patient safety and to enable continuation of these trials."

The fact that the FDA didn't put all the clinical trials on hold is a good sign that the agency thinks, even if vadastuximab talirine is contributing to the liver toxicity, it's only likely to be a problem in a subset of AML patients. As a cancer treatment, side effects are more likely to be tolerated by the FDA compared to treatments for less-fatal diseases.

Investors should also keep in mind that vadastuximab talirine isn't Seattle Genetics most important drug. While adding a second drug would be helpful to its revenue growth, sales of already-approved Adcetris and expanding the drug's market through ongoing clinical trials contribute more to Seattle Genetics valuation than vadastuximab talirine currently does.

10 stocks we like better than Seattle Genetics

When investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor , has tripled the market.*

David and Tom just revealed what they believe are the 10 best stocks for investors to buy right now... and Seattle Genetics wasn't one of them! That's right -- they think these 10 stocks are even better buys.

Click here to learn about these picks!

*Stock Advisor returns as of Nov. 7, 2016

Brian Orelli has no position in any stocks mentioned. The Motley Fool recommends Seattle Genetics. Try any of our Foolish newsletter services free for 30 days . We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy .

The views and opinions expressed herein are the views and opinions of the author and do not necessarily reflect those of Nasdaq, Inc.

The views and opinions expressed herein are the views and opinions of the author and do not necessarily reflect those of Nasdaq, Inc.

In This Story


Other Topics


Latest Personal Finance Videos

    #TradeTalks: Making the leap from school teacher to financial literacy advocate

    Call to Leap Founder Steve Chen joins Jill Malandrino on Nasdaq #TradeTalks​ for #FinancialLiteracyMonth​ to discuss making the leap from school teacher to financial literacy advocate.

    Apr 13, 2021

    The Motley Fool

    Founded in 1993 in Alexandria, VA., by brothers David and Tom Gardner, The Motley Fool is a multimedia financial-services company dedicated to building the world's greatest investment community. Reaching millions of people each month through its website, books, newspaper column, radio show, television appearances, and subscription newsletter services, The Motley Fool champions shareholder values and advocates tirelessly for the individual investor. The company's name was taken from Shakespeare, whose wise fools both instructed and amused, and could speak the truth to the king -- without getting their heads lopped off.

    Learn More