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GlycoMimetics Sickle Cell Drug Flops as Others Creep Forward

Xconomy New York — 

New treatments could soon be on the way for sickle cell disease, an inherited and debilitating blood disorder. But a drug from GlycoMimetics won’t be among them.

GlycoMimetics (NASDAQ: GLYC) had been aiming to show that a drug called rivipansel could help sickle cell patients who are hospitalized with severe pain episodes, or “crises.” The drug is meant to reduce inflammation thought to contribute to those pain episodes, and thus help patients get rid of them more quickly.

But the company and its partner Pfizer (NYSE: PFE) disclosed late Friday that a 345-patient Phase 3 study, RESET, failed its primary and secondary goals. Rivipansel didn’t get sickle cell patients out of the hospital faster than a placebo, and it didn’t reduce the amount of opioids needed to deal with the pain.

“We are both surprised and deeply disappointed by this outcome, as we had strongly hoped that rivipansel would have a positive benefit for people living with sickle cell disease,” said CEO Rachel King, in a statement. GlycoMimetics and Pfizer didn’t disclose details, but they’ll be shared at a future medical meeting.

GlycoMimetics shares plummeted more than 46 percent, to $4.85 apiece, in pre-market trading Monday morning. The drug is one of two that the Rockville, MD, company has in Phase 3 testing—the other is a treatment for acute myeloid leukemia. Pfizer held rights to rivipansel through a 2011 alliance. GlycoMimetics could’ve seen up to $285 million in milestones, plus a royalty stream, if the drug had succeeded and reached the market.

The news means there is one less potential drug on the horizon for sickle cell disease, an inherited blood disease that affects some 100,000 Americans yet has few available treatments. “We recognize this is a significant setback for the [sickle cell] community, who are eagerly awaiting new treatment options, and we share in their disappointment,” Pfizer chief patent officer and executive vice president Freda Lewis-Hall said in a statement.

Sickle cell occurs when a defective gene causes the bone marrow to produce abnormal, flatter, crescent or “sickle” shaped red blood cells. These cells don’t move freely through the bloodstream like normal red blood cells; they’re stiff and liable to get stuck and block blood flow, causing chronic pain that can last for weeks or months at a time, anemia, and damage to organs. These severe pain episodes put patients in the hospital.

Sickle cell patients often require blood transfusions to boost their levels of normal hemoglobin, the protein in healthy red blood cells that carries oxygen. A drug called hydroxyurea, which helps the body make fetal hemoglobin (the type newborns have), is also approved for the condition.

New treatments could be on the way, however. Some gene therapy and gene editing medicines promise long-lasting relief with a single treatment, though they have much to prove. A gene therapy from Bluebird Bio (NASDAQ: BLUE) has been working its way through human testing. CRISPR Therapeutics (NASDAQ: CRSP) reported last week that the first patient to get its CRISPR-based gene editing treatment for sickle cell has gone more than months without a blood transfusion. (NPR interviewed the patient here.)

Others are meant to better manage the severe pain, anemia, and other debilitating symptoms of the disease. The most advanced is voxelotor, a drug from Global Blood Therapeutics (NASDAQ: GBT) that is meant to boost peoples’ hemoglobin levels. GBT believes that doing so should lead to better health outcomes for sickle cell patients, but aims to file for approval this year without direct proof.

Here’s more on the evolving treatment landscape for sickle cell disease.