On June 10, 2011, results were announced for two of the three studies involved in the potential cystic fibrosis drug compound VX-770 clinical trials – the Phase 3 STRIVE study, and the Phase 3 ENVISION study, according to a press release by the potential drug’s manufacturer, Vertex Pharmaceuticals Incorporated (“Vertex”). The potential drug VX-770 is a next generation medication designed to treat those affected by the lung disease, as it is meant to act upon a defective protein in cystic fibrosis patients, and opens a chloride channel in that cell, thereby allowing for the proper flow of salt and fluid in and out of the impaired CF protein.
STRIVE was a 48 week trial which began in May 2009 and evaluated 161 people, aged 12 years and older, who have the CF gene G551D (approximately 4% of cystic fibrosis patients have this gene). While some of the 161 participants received VX-770, a portion of individuals received a placebo. STRIVE contained four endpoints that were being reviewed for success with the compound VX-770: lung function, weight gain, pulmonary exacerbation frequencies, and the production of sweat chloride.
With regard to lung function, greater than 10% improvement was witnessed through week 24 of this study for those dosed with VX-770, and that improvement level remained the same at week 48. As for patients’ weight gain, those in this STRIVE study receiving VX-770 gained approximately 7 pounds through 48 weeks, versus a weight gain of 0.9 pounds among the placebo group. A decrease in pulmonary exacerbations in this study was also realized, as 67% of VX-770 patients had not experienced an exacerbation, compared to only 41% of participants in the placebo group.
Lastly, a reduction of VX-770 patients’ sweat chloride was noted as well. The reduction of sweat chloride is considered to be a marker of improved cystic fibrosis transmembrane conductance regulator (CFTR) function. CFTR is widely viewed as the defective protein that causes cystic fibrosis. People with CF typically have sweat chloride levels of greater than 60 mmol/L (millimoles per liter), while people without cystic fibrosis generally have levels of less than 40 mmol/L. Improvement in this area was notable, as VX-770 patients in this study experienced an average sweat chloride reduction of 45mmol/L, while participants receiving the placebo showed no reduction in sweat chloride.
Also, brief results were announced for the 48-week ENVISION study, which began in August 2009. ENVISION was intended to evaluate the effect of VX-770 on children between the ages of 6 years and 11 years old. Significant improvements in lung function, weight gain, and sweat chloride production were observed for these younger participants, as well, at the end of the study. Complete data on ENVISION will be made available in the second half of 2011.
Results for another leg of the VX-770 clinical trials, the Phase 2 DISCOVER study, were announced by Vertex in February 2011.
Finally, Vertex unveiled a plan to provide the drug to cystic fibrosis patients in the U.S. who have the G551D gene mutation, and are in critical need, as early as July 2011. Vertex also anticipates submitting global regulatory applications for VX-770 approval in the U.S., Canada, and Europe in the second half of 2011.
Source:
Phase 3 STRIVE Study of VX-770 Showed Durable Improvements in Lung Function (FEV1) and Other Measures of Disease Among People With a Specific Type of Cystic Fibrosis , Vertex Pharmaceuticals Incorporated