What happened

In response to providing investors with data from an important phase 2 study, shares of Global Blood Therapeutics (NASDAQ:GBT), a clinical-stage biotech focused on blood disorders, slumped 12% as of 11:30 a.m. EDT Friday.

So what

Global Blood released updated data from its Hope-kids 1 study today. This trial is testing its experimental drug voxelotor as a hopeful treatment for kids aged six to 17 who have sickle cell disease. The data is being presented at the 23rd annual European Hematology Association Congress later today.

Here are the headline numbers from the 22 patient study that took place over 24-weeks:

  • 43% of patients showed a hemoglobin response of greater than 1 gram per decilitre. The median change from baseline was 0.7 g/dL. 
  • 62% of patients showed reduced daily symptoms as measured by the total symptom scores (TSS).
  • 55% percent of patients experienced a decrease in transcranial doppler (TCD) flow at 24 weeks. This number was 88% among the cohort of patients who showed a greater than 1 g/dL improvement in their hemoglobin response.
  • The tolerability results were "consistent" with what has been observed in studies of the drug that are used on adults. Specifically, the most common reported adverse events were nausea, vomiting, headache, and rash. However, no patients discounted the study due to their adverse events.
A medical professional in a white coat gives a presentation with a white board to seven spectators.

Image source: Getty Images.

Global Blood's CEO Ted Love offered investors the following commentary on the study:

We continue to be encouraged by the results of the ongoing HOPE-KIDS 1 study, which are consistent with inhibition of HbS polymerization by voxelotor and support its ongoing clinical evaluation as a potential disease-modifying therapy for both adults and adolescents with SCD. Results to date support our ongoing development of voxelotor in a broad range of patients, including in our Phase 3 HOPE Study, which is also evaluating voxelotor at doses of 900 mg and 1500 mg per day in adolescents and adults.

So if the news was good, why are shares falling today? The most likely answer is that Wall Street was expecting even stronger clinical results. Last December, management presented data showing that 55% of adolescent patients (6 out of 11) achieved a hemoglobin response greater than 1 g/dL and the median change was 1.1 g/dL. Today's updated numbers of 43% and 0.7 g/dL, respectively, are probably being view as disappointing by comparison.

So what

Love told investors that top-line data from its large phase 3 Hope study will be released before the end of this quarter. Investors might want to wait until they have that data in hand before determining their next move.

Brian Feroldi has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.