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create the side effects of chemo. What’s more, AG-120 is a pill (as is AG-221), which makes it possible—depending on how safe and effective the drug proves to be, of course—that AML patients could take it once or twice a day to manage their disease, turning what’s now often a death sentence into a chronic illness.
“Maybe it’ll be chronic therapy, or maybe we’ll actually eradicate the disease, either as a single agent or potentially in combination [with chemotherapy],” Schenkein says. “Our plan is to go fast and broad, and make the biggest impact we can in these diseases.”
The longer patients take the drug, the more Agios learns about the breadth and durability of that impact. All patients who responded to AG-120, for instance, remain on the drug today, and haven’t relapsed. Schenkein says the four that have had complete remissions have been on treatment anywhere from one month to more than five months.
All told, the company enrolled a group of IDH1-mutated patients with either AML or myelodysplastic syndrome (when the bone marrow doesn’t produce enough healthy blood cells). They all had previously failed at least one and up to five rounds of chemotherapy. Those patients, who were a median age of 73, were given AG-120 for 28 days, at doses of either 300 milligrams, 500 mg, or 800 mg once a day, or 100 mg twice a day.
Here’s a deeper breakdown of the 14 patients in the study (another three are enrolled but not long enough to evaluate):
—Four of seven responders have no trace of cancer in their system (complete remissions).
—Two of the responders had “marrow complete remissions,” meaning the leukemia was cleared from their blood and bone marrow, but their blood count hadn’t returned to normal yet.
—One responder had a partial remission, meaning some of the leukemia is gone, but the patient now has a normal blood count.
—One patient has stable disease, meaning the leukemia hasn’t neither progressed nor gotten better.
—Seven did not respond to treatment, although all but one of the non-responders had “stable disease for a while,” says Schenkein, before they came off the drug (“for a variety of reasons—not side effects”) and the leukemia progressed.
Schenkein says AG-120 was particularly effective at higher doses, which might be “an early sign that with increasing doses we’re seeing more responses, but that will have to play out over time just a little bit more.”
Here’s more déjà vu: These data from AG-120 echo the first data from AG-221, which Agios released in April. Six of the first seven patients who could be evaluated responded to treatment, and three had no trace of cancer.
Shares shot up more than 30 percent, from $35.48 to $45.35, and they’ve continued to climb. Earlier today, shares closed around $84 apiece, near five times the IPO price when Agios went public in 2013. That’s a big boon for Agios development partner Celgene (NASDAQ: CELG), which held 15.12 percent of Agios as of an April proxy filing, second only to VC firm Third Rock Ventures (17.83 percent as of the filing).
The response rate to AG-221 has tailed off as patient numbers have increased, but it’s still promising. To date, 20 of 32 patients who could be evaluated for treatment with AG-221 have responded: Eight with complete remissions, and four have complete remissions but either their platelet or blood cell counts haven’t returned to normal yet.
Agios is updating the AG-221 results at the American Society of Hematology’s annual meeting in a few weeks.
While AG-120 is Agios’s second drug, its success is much more important to the company’s financial future than AG-221. Summit, NJ-based Celgene holds worldwide rights to AG-221 under a $130 million deal the two companies struck in 2009; Agios will only get milestone payments and royalties if it continues forward.
Celgene has an option to grab international rights to AG-120, but Agios has held onto U.S. rights, which means a much larger portion of the rewards if the drug proves successful.