Two Novel Sickle Cell Disease Treatments Have Received Orphan Drug and Rare Pediatric Disease Designation

Global Blood Therapeutics (GBT) has just announced that their therapeutics called GBT021601 (GBT601) and inclacumab for sickle cell disease (SCD) have received both Rare Pediatric Disease Designation and Orphan Drug Designation by the FDA. These designations are both provided to rare disease treatments which have the potential to improve the lives of those living with these conditions. They provide various incentives such as tax credits, priority review, and market exclusivity for developing these treatments with such demonstrated potential.

Sickle Cell Disease

Sickle cell disease (SCD) is a rare blood condition which affects the hemoglobin in the blood, causing it to form in a sickled, or crescent shape. The blood cells change shape through a process which is called hemoglobin polymerization. This process is recurrent and leads to hemolytic anemia, blockages within the capillaries, and constricted blood flow due to narrow blood vessels. This leads to a diminished flow of oxygen within the body, including flow to vital organs and tissues.

A lack of blood flow to major organs leads to complications which can be life-threatening such as organ damage, stroke, acute chest damage, neurocognitive impairment, and more. This lack of blood flow is called a vaso-occlusive crisis (VOC).

SCD commonly affects people from sub-Saharan Africa but also affects those of Hispanic, Middle Eastern, Southern European, and South Asian decent.


Inclacumab is a human monoclonal antibody which is a P-selectin inhibitor. P-selectin is a protein which is responsible for mediating cell adhesion. Preclinical data has shown that by inhibiting P-selectin, VOC may be reduced.

Additionally, researchers are optimistic that this treatment may be able to be dosed quarterly instead of monthly, decreasing the burden for patients.

The therapy is currently being evaluated in Phase 3 trials (which can be found here and here). Enrollment is still ongoing for both investigations. Inclacumab has already been administered to more than 700 individuals who are not diagnosed with SCD.


GBT601 is a sickle hemoglobin (HbS) polymerization inhibitor. This therapy uses the same mode of action as a treatment called Oxbryta, but researchers are optimistic GBT601 may have increased efficacy potential. In other words, researchers think it may be able to achieve higher levels of hemoglobin at a lower dose of treatment.

GBT601 is currently being investigated in a Phase 1 study which is assessing the safety, pharmacodynamics, pharmacokinetics, and tolerability of the treatment for SCD patients between 18 and 60 years of age. Researchers expect the Phase 2 part of the trial to begin in the middle of 2022.

You can read more about these novel treatments and their potential in SCD here.

Share this post

Share on facebook
Share on twitter
Share on linkedin
Share on pinterest
Share on print
Share on email