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CTI Goes Up, And Down, And Back Up On Phase 3 Myelofibrosis News

Xconomy Seattle — 

Seattle’s CTI Biopharma (NADSAQ: CTIC) just ended a rollercoaster trading day.

First thing Monday, the firm released positive Phase 3 trial results for its myelofibrosis treatment, pacritinib, and shares shot up 11 percent higher than the Friday closing price of $2.65.

Before noon, shares had given back all those gains, then immediately began to rise again to end Monday at $2.82 apiece, giving CTI a $473 million market capitalization. CTI shares usually attract about 2.5 million trades a day. On Monday, that figure was 10 times higher.

The instigation of all this activity was a release of top-line results from the PERSIST-1 trial, which is assessing pacritinib in myelofibrosis, a slow-growing form of leukemia that can cause scarring of the bone marrow, an enlarged spleen, and potentially death. About 3,500 people a year in the U.S. are diagnosed with myelofibrosis, and in one third of those cases the disease turns into acute myeloid leukemia or a bone marrow failure.

Nearly 25 years old and formerly known as Cell Therapeutics, CTI has had a cold reception from regulators in the past. In 2010, an FDA committee voted unanimously against its lymphoma drug pixantrone, with one committee member calling the company’s application “disturbing.” In 2012, CTI withdrew another shot at pixantrone review.

If approved, pacritinib would be the second drug of its kind—a so-called janus kinase, or JAK inhibitor —to treat myelofibrosis. Between 50 and 60 percent of myelofibrosis patients have a mutation in the JAK2 gene, according to the Leukemia and Lymphoma Society. In 2011, the FDA approved ruxolitinib (Jakafi), a drug developed by Incyte (NASDAQ: INCY). It brought in $358 million in U.S. sales last year, Incyte reported recently.

But ruxolitinib leaves room for improvement. Its patients often still require blood transfusions. CTI and others, such as Lexington, MA-based Promedior and Gilead Sciences (NASDAQ: GILD), of Foster City, CA—which has spent hundreds of millions of dollars to acquire experimental myelofibrosis treatments—are shooting to provide something better.

CTI’s report of top-line data was far from conclusive on that front. CTI and development partner Baxter International (NYSE: BAX) said they would report more data and results at an upcoming scientific meeting. They also have a second Phase 3 trial, dubbed PERSIST-2.

Here’s what CTI and Baxter said:

— The main goal of PERSIST-1 was to show spleen volume reduction of 35 percent or greater. Pacritinib provided a “clinically and statistically significant response” compared to the control group of patients receiving best alternative therapy available. CTI divulged neither the specific spleen reduction data nor the name of the best alternative therapy or therapies used.

—CTI and Baxter specifically excluded ruxolitinib from the comparator group taking best available therapies. (They are including ruxolitinib as a best available therapy, however, in the PERSIST-2 trial.)

—The results also showed a “significant difference” among patients with platelet counts of less than 100,000 per microliter and less than 50,000 per microliter. (The lower the platelet count, the sicker the patient.)

—Among 50 patients who were dependent on blood transfusions at the start of the trial, “a clinically meaningful” percentage shed the need for transfusions compared to those taking best available therapies.

—79 percent of patients in the control arm crossed over to pacritinib therapy.

Photo courtesy of Ed Uthman via a Creative Commons license.