Merrimack Heads to FDA as Pancreatic Cancer Drug Succeeds in Phase 3

Why is Merrimack soaring this morning?

May 1, 2014 at 9:55AM

Merrimack Pharmaceuticals (NASDAQ:MACK) has taken its share of punches from investors over the past year while trying to prove that its computer-aided drug discovery approach can lead to effective therapeutics. But the Cambridge, MA-based company can finally talk about some good clinical news today, because it might have a shot to break into the notoriously tough field of pancreatic cancer.

Merrimack today is releasing the top-line results from a 417-patient late-stage study of MM-398, a nanotherapeutic derivative of the old chemotherapy drug irinotecan. The results are mixed, but ultimately positive for Merrimack. On one hand, MM-398 met its study goal. When taken in combination with chemotherapy drugs 5-flourouracil (5-FU) and leucovorin, it helped pancreatic cancer patients who hadn't responded to prior therapies—very sick patients—live some 1.9 months longer than patients who got only 5-FU and leucovorin. Merrimack also said the drug, in combination with 5-FU and leucovorin, helped slow the progression of patients' tumors in a statistically significant way, though it didn't provide any specific details. Merrimack will present more data from the study at a medical meeting in June, according to CEO Bob Mulroy.

On the other hand, MM-398 failed to produce similar results when given to patients on its own, and led to more side effects. Patients on MM-398 alone lived a median of 4.9 months, compared to 4.2 months for those on chemo alone.

"The trial was set up to test two different regimens, and we were trying to thread a needle of finding a regimen that was tolerable in a very sick patient population, and be [strong] enough to have activity on the tumor," Mulroy says. "And what we saw was there was evidence of activity with the monotherapy—and we will look at the data and examine it—but we were able to thread that needle with tolerability of the [combination] regimen as well as [get] good solid activity on the tumor."

This is important for Merrimack, because it's the first time one of its nanoparticle chemo drugs—which are essentially supposed to hit tumors more specifically, and for longer, than regular chemotherapies—have provided a clinically meaningful benefit in a large trial. MM-398 is designed to use tiny lipid nanoparticles to ferry the chemo drug irinotecan to hard-to-reach pancreatic cancer tumors, for instance, by piggybacking on the body's own immune cells.

[Updated with stock price] Shares of Merrimack soared about 70 percent, to $7.15 apiece, in pre-market trading early Thursday.

The most common side effects attributed to MM-398 were diarrhea, vomiting, and neutropenia, a depletion of infection-fighting white blood cells. But Merrimack also noted that 2 percent more of the patients on the MM-398 combination regimen suffered sepsis—a potentially fatal bloodstream infection—than those given chemotherapy alone.

"The top line safety data we were very pleased with, particularly relative to this cancer patient population," Mulroy says.

Indeed, Merrimack believes the data are good enough to submit a new drug application with the FDA, particularly given how few effective options there are for pancreatic cancer patients, and how tough it is to show a benefit. Pancreatic cancer is extremely fast-moving—by the time it is detected, the cancer typically can't be surgically removed, and patients usually die within months. As such, it's the fourth-leading cause of cancer death in the U.S., despite the fact that it accounts for just over 2 percent of the cancers diagnosed annually. About 46,000 people in the U.S. are diagnosed with pancreatic cancer every year, and around 40,000 of them die, according to the American Cancer Society.

Front-line treatment options for pancreatic cancer are mostly built around the chemo drug gemcitabine. Celgene, for example, won FDA approval late last year to begin selling protein-bound paclitaxel (Abraxane) in combination with gemcitabine as a first-line pancreatic cancer regimen after it extended patients' lives in a study by an average of 1.8 months. But Mulroy notes that there's little alternative to such regimens for people who don't respond—all of the pancreatic cancer drugs approved over the past 25 years are part of front-line treatments. Yet about half the patients diagnosed are eligible to move on to some sort of second-line therapies, Mulroy says.

"We have the first drug to show a survival benefit for patients who are refractory to front-line gemcitabine-based therapies," he says. "We're hopeful that we can be a great option for those patients now."

The company plans to file an NDA with the FDA "as soon as possible," seeking approval of a regimen of MM-398 in tandem with the two chemo drugs, according to Mulroy. The FDA granted Merrimack an orphan drug designation for MM-398, giving it longer market exclusivity.

Mulroy also believes the trial shows that the company's approach for making nanotherapeutics out of chemotherapy drugs can produce a benefit. He says that MM-398, for instance, was specifically designed to try to go after very tough-to-treat tumors with poor blood supply, which are harder to treat with drugs injected into the bloodstream. MM-398 is supposed to avoid this delivery problem and accumulate around these tumors by targeting macrophages, immune cells that surround pancreatic cancer tumors. The idea is that the macrophages would potentially help deliver, rather than block, the nanoparticle chemo drug, and the drug's toxic effects would last longer. Mulroy says that seeing MM-398 benefit a patient group that has seen "really no benefit from most therapies for awhile" has given the company more confidence to think about it as a potential first-line treatment for pancreatic cancer, or a possible drug in other cancer types. The company is testing MM-398 in lung and brain cancer as well, for instance.

This is the type of benefit Merrimack is hoping to show by making nanotherapeutics out of other chemotherapy drugs, like doxorubicin. It's also the type of news the company hasn't been able to give to investors yet. The company, founded by scientists at Harvard University and MIT, is based on a drug discovery approach leaning heavily on computer models and companion diagnostics, trying to accurately predict who should take its drug candidates, and who shouldn't, with the idea of designing cheap, efficient late-stage trials. Another cancer drug, MM-121, for instance, is in a number of mid-stage trials that Merrimack has said are designed to find the right subgroups of people for a prospective Phase 3.

Still, those studies haven't yet produced statistically positive results, leading to a few investor sell-offs, and not much upside in Merrimack's stock since the companywent public in early 2012. That's why Mulroy is touting today's data as so important to Merrimack's future.

"We view this as a proof of concept for the technology as it was engineered," he says.

Will this stock be your next multi-bagger?
Give me five minutes and I'll show how you could own the best stock for 2014. Every year, The Motley Fool's chief investment officer hand-picks 1 stock with outstanding potential. But it's not just any run-of-the-mill company. It's a stock perfectly positioned to cash in on one of the upcoming year's most lucrative trends. Last year his pick skyrocketed 134%. And previous top picks have gained upwards of 908%, 1,252% and 1,303% over the subsequent years! Believe me, you don't want to miss what could be his biggest winner yet! Just click here to download your free copy of "The Motley Fool's Top Stock for 2014" today.

This article originally appeared on Xconomy, along with:

Ben Fidler has no position in any stocks mentioned. The Motley Fool recommends Celgene. 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.

1 Key Step to Get Rich

Our mission at The Motley Fool is to help the world invest better. Whether that’s helping people overcome their fear of stocks all the way to offering clear and successful guidance on complicated-sounding options trades, we can help.

Feb 1, 2016 at 4:54PM

To be perfectly clear, this is not a get-rich action that my Foolish colleagues and I came up with. But we wouldn't argue with the approach.

A 2015 Business Insider article titled, "11 websites to bookmark if you want to get rich" rated The Motley Fool as the #1 place online to get smarter about investing.

"The Motley Fool aims to build a strong investment community, which it does by providing a variety of resources: the website, books, a newspaper column, a radio [show], and [newsletters]," wrote (the clearly insightful and talented) money reporter Kathleen Elkins. "This site has something for every type of investor, from basic lessons for beginners to investing commentary on mutual funds, stock sectors, and value for the more advanced."

Our mission at The Motley Fool is to help the world invest better, so it's nice to receive that kind of recognition. It lets us know we're doing our job.

Whether that's helping the entirely uninitiated overcome their fear of stocks all the way to offering clear and successful guidance on complicated-sounding options trades, we want to provide our readers with a boost to the next step on their journey to financial independence.

Articles and beyond

As Business Insider wrote, there are a number of resources available from the Fool for investors of all levels and styles.

In addition to the dozens of free articles we publish every day on our website, I want to highlight two must-see spots in your tour of

For the beginning investor

Investing can seem like a Big Deal to those who have yet to buy their first stock. Many investment professionals try to infuse the conversation with jargon in order to deter individual investors from tackling it on their own (and to justify their often sky-high fees).

But the individual investor can beat the market. The real secret to investing is that it doesn't take tons of money, endless hours, or super-secret formulas that only experts possess.

That's why we created a best-selling guide that walks investors-to-be through everything they need to know to get started. And because we're so dedicated to our mission, we've made that available for free.

If you're just starting out (or want to help out someone who is), go to, drop in your email address, and you'll be able to instantly access the quick-read guide ... for free.

For the listener

Whether it's on the stationary exercise bike or during my daily commute, I spend a lot of time going nowhere. But I've found a way to make that time benefit me.

The Motley Fool offers five podcasts that I refer to as "binge-worthy financial information."

Motley Fool Money features a team of our analysts discussing the week's top business and investing stories, interviews, and an inside look at the stocks on our radar. It's also featured on several dozen radio stations across the country.

The hosts of Motley Fool Answers challenge the conventional wisdom on life's biggest financial issues to reveal what you really need to know to make smart money moves.

David Gardner, co-founder of The Motley Fool, is among the most respected and trusted sources on investing. And he's the host of Rule Breaker Investing, in which he shares his insights into today's most innovative and disruptive companies ... and how to profit from them.

Market Foolery is our daily look at stocks in the news, as well as the top business and investing stories.

And Industry Focus offers a deeper dive into a specific industry and the stories making headlines. Healthcare, technology, energy, consumer goods, and other industries take turns in the spotlight.

They're all informative, entertaining, and eminently listenable ... and I don't say that simply because the hosts all sit within a Nerf-gun shot of my desk. Rule Breaker Investing and Answers contain timeless advice, so you might want to go back to the beginning with those. The other three take their cues from the market, so you'll want to listen to the most recent first. All are available at

But wait, there's more

The book and the podcasts – both free ... both awesome – also come with an ongoing benefit. If you download the book, or if you enter your email address in the magical box at the podcasts page, you'll get ongoing market coverage sent straight to your inbox.

Investor Insights is valuable and enjoyable coverage of everything from macroeconomic events to investing strategies to our analyst's travels around the world to find the next big thing. Also free.

Get the book. Listen to a podcast. Sign up for Investor Insights. I'm not saying that any of those things will make you rich ... but Business Insider seems to think so.

Compare Brokers