Baxter and its controversial partner CTI claim a win in PhIII blood cancer study

Some 15 months after Baxter ($BAX) signed on with CTI BioPharma--then called Cell Therapeutics--on a late-stage therapy for myelofibrosis called pacritinib, the partners say they have come up with statistically significant topline data on its effectiveness and safety. But after the biotech's many twists and turns taken trying to advance pixantrone over the years, a few longtime observers preferred to wait and see the actual numbers before deciding for themselves.

CTI ($CTIC) got $60 million upfront and a promise of $112 million in development milestones from Baxter back in the fall of 2013 for their partnership, gaining some badly needed credibility for itself after the FDA scorned pixantrone and the biotech's failed attempt to win an approval for lymphoma. This morning investigators say that their blood cancer drug produced a statistically significant response in reduction of spleen volume, even regardless of low initial platelet counts, but said the details will be held back for a scientific conference. The primary endpoint was a reduction of 35% or more in spleen volume compared with best available therapy--aside from JAK2 inhibitors.

There was also a reduction in transfusion dependence in a group of 50 patients. On the safety front three patients stopped therapy and 9 more had to have their doses reduced due to diarrhea, though the researchers say that the safety profile looked "consistent" with Phase II.

CTI's shot jumped about 17% on the news in premarket trading, evidence of the skepticism that the biotech generates.

"Despite the introduction of JAK2 inhibitors as effective therapies for patients with myelofibrosis, there remains a treatment gap for patients with disease-related or treatment emergent thrombocytopenia. The currently approved drug may require dose titration to less effective doses in this patient population, thus limiting our ability to effectively treat them. Results from the PERSIST-1 randomized trial demonstrate that pacritinib could address this unmet medical need," said Claire Harrison, one of the principal investigators for PERSIST-1.

There is some historical data on pacritinib. In S*Bio's Phase II with 34 patients 24% of patients had a reduction in spleen volume of 35% or more.

Its history suggests CTI faces a painstaking review by regulators before it can expect to get to the market with this drug.

Dr. Richard Pazdur

In early 2010, regulators and experts scathingly objected to CTI's (Cell Therapeutics') development process and application for Pixuvri (pixantrone), bluntly objecting to the data as inadequate for an approval. Cell Therapeutics found itself opposed by Richard Pazdur, the powerful oncology drug-review chief at the agency. And later the biotech sparked considerable controversy when it unexpectedly yanked its new application for the treatment after claiming it needed more time to prep for an advisory committee review. The EU provided a conditional approval for Pixuvri, though, which generated a little more than $4 million in net product sales in the first 9 months of 2014.

- here's the release

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