- Three patients have started treatment on Spark Therapeutics Inc.'s hemophilia A drug — and so far, the results are positive.
- The gene therapy company claimed that preliminary data from a dose-escalating, Phase 1/2 study shows human proof-of-concept for its investigational candidate, SPK-8011. As of Aug. 1, Factor VIII activity levels for two patients who received lower doses of the drug were a steady 11% and 14% of normal, respectively, while a third patient recently treated with a higher dose is "tracking proportionally higher, consistent with the dose escalation," according to Spark's Chief Scientific Officer Kathy High.
- The announcement headlined Spark's second quarter earnings presentation on Wednesday morning, and surely contributed to a subsequent spike in the company's stock price. Shares rose nearly 17% to $77.72 apiece by market's open, and climbed even further Wednesday afternoon to close out at $79.72 apiece.
Spark intends to enroll 30 patients in the Phase 1/2 trial, meaning that a full readout is still a ways off. But the initial results raised the company's confidence that SPK-8011 will have success similar to its hemophilia B drug SPK-9001, which it's developing in collaboration with Pfizer.
At the International Society on Thrombosis and Haemostasis (ISTH) 2017 Congress, Spark presented Phase 1/2 data for SPK-9001 demonstrating a reduction in the annualized infusion rate by 99% and the annual bleeding rate by 96^ across 10 patients who received treatment.
What's more, there were no serious adverse events (SAEs) and just one participant had experienced a bleed since their initial infusion.
Investigators thus far also haven't seen any SAEs among the few patients treated with SPK-8011. The two patients treated on the lower dose of the drug (5 x 1011 vector genomes (vg) per kilogram of body weight) were evaluated 12 weeks and 23 weeks after first administration. Following approval from a Data Safety and Monitoring Board, investigators doubled that dose to for a third patient to 1 x 1012 vg per kilogram.
"We are especially gratified that the first dose we selected for investigation in this study has been both safe and yielded clinically meaningful factor activity levels," High said during the call. "Neither initial dose participant has reported a spontaneous bleed. The third important attribute of an optimal hemophilia gene therapy is consistency of factor level expression in terms of keeping interpatient variability within an appropriate range."
"The consistency in the [Factor VIII] levels seen in our first dose cohort of SPK-8011 in hemophilia A is as good as we had hoped to achieve as the study outset and remarkably consistent with our hemophilia B experience," she added.
Spark intends to present further results from the trial at a future medical meeting.
In addition to the positive updates on its hemophilia pipeline, Spark used its second quarter earnings call to tout the "significant regulatory milestones" its lead candidate, Luxturna (voretigene neparvovec), has achieved.
The Food and Drug Administration recently accepted a Biologics License Application for the treatment for a rare kind of inherited retinal disease. An approval decision should come by mid-January, and, if it's positive, it would give Spark its first market-ready product as well as a priority review voucher — a highly sought after commodity that the drugmaker could sell for big bucks or use to speed another candidate through regulatory review.
A thumbs up on Luxturna could also shake up U.S. drug pricing models, as it would bring the first true gene therapy to the stateside market. While Spark hasn't disclosed any concrete decisions on the potential cost of its drug, the company likely to be one of the first in the industry to navigate the pricing challenges associated with one-off cures.