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FibroGen Pushes Forward With Anemia Pill in China, But Big Test Awaits

Xconomy San Francisco — 

The race to treat kidney disease patients’ anemia with a pill, rather than an injectable biologic, continues. FibroGen this morning announced positive interim results from two Phase 3 trials that could support the first approval application for its anemia pill, roxadustat, in China. But longer studies that could prove how safe the drug is are still underway.

San Francisco, CA-based FibroGen (NASDAQ: FGEN) said that the two studies met their main goals in patients who have anemia caused by chronic kidney disease. The two trials tested roxadustat in CKD patients who either are or aren’t on dialysis and, in both cases, FibroGen succeeded in boosting the levels of oxygen-carrying hemoglobin in their blood. For patients not on dialysis, the drug bested a placebo in increasing hemoglobin levels. For those on dialysis, the drug fared as well as treatment with an injectable biologic.

Specifically, in the non-dialysis study, the 101 patients on roxadustat saw their hemoglobin levels increase by an average of 1.9 grams per deciliter of blood after eight weeks, compared to an average 0.4 g/dL decrease for the 50 placebo patients.

For those on dialysis, FibroGen enrolled patients who had previously gotten epoetin alfa—a so-called erythropoiesis stimulating agent (ESA) that spurs the bone marrow to make red blood cells. 204 of those patients were given roxadustat instead, while 100 stayed on epoetin alfa. Roxadustat was non-inferior to epoetin alfa after 26 weeks..

Importantly, no new safety problems have cropped up. In the non-dialysis study, FibroGen will now switch all patients onto treatment with its drug for another 18 weeks. In both studies, a subset of patients will stay on roxadustat for up to 52 weeks to help gauge how safe it is. The two studies should wrap up this year and FibroGen will provide more details “in due course,” it said in a statement. FibroGen expects to file for approval in China later this year.

Still, while RBC Capital Markets analyst Michael Yee called the data an “incremental de-risking event” in a research note, he cautioned that the two studies are small in size and duration and that the bigger, longer, more important studies in U.S. and Europe won’t produce data until next year. It’s critical for FibroGen to show in these larger, more lengthy studies that the drug doesn’t lead to any long-term safety issues, like heart problems. “So this is a positive today, but the big events are next year,” he wrote.

Pending good data from those studies, FibroGen has said it expects to file for approval of roxadustat in the U.S. in 2018; it has partnerships in place with Astellas Pharma and AstraZeneca on the drug.

FibroGen is in a race with Cambridge, MA-based Akebia Therapeutics (NASDAQ: AKBA) to try to bring the first anemia pill to the market for patients with chronic kidney disease. The huge prize they’re vying for is to replace blockbuster biologic anemia drugs like epoetin alfa (Epogen) and darbapoeitin alfa (Aranesp), which generate billions of dollars despite significant safety concerns. ESAs generate an estimated $3.5 billion in annual sales in the U.S.

Both Akebia and FibroGen are developing drugs that work much differently than these biologic drugs. By essentially tricking the body into thinking it’s at high altitude, these pills stimulate a corrective response to low-oxygen conditions, which is to make more red blood cells. Akebia has partnerships with Otsuka Pharmaceutical and Mitsubishi Tanabe Pharma on its drug, vadadustat. Phase 3 studies are expected to wrap up in 2018.

Shares of FibroGen climbed about 7 percent in pre-market trading Monday.

Here’s more on FibroGen, Akebia, and the race to develop anemia pills.