- Shares in uniQure spiked Thursday morning as early clinical data showed hemophilia B patients injected with one of the biotech’s gene therapies developed enough blood-clotting protein to significantly reduce the risk of bleeding events.
- The data encompass just three patients, each with moderately severe to severe hemophilia B. Six weeks after administering a one-time dose of uniQure’s AMT-061, researchers found mean Factor IX activity for the patients was 31% of normal. “Epidemiological data indicate that factor activity above 12% of normal is associated with substantial reduction or elimination of spontaneous bleeds and factor usage,” uniQure noted in a Nov. 15 statement.
- The biotech expects to submit results from this Phase 2b trial to regulators in the U.S. and Europe before 2018 closes out, as well as present them at an upcoming medical conference.
Though uniQure has more work to do to validate AMT-061, the early readout from the Phase 2b dose-confirmation study seems to have stirred optimism among investors. Company shares opened at $29.62 apiece on Thursday, a 30% increase from the prior day’s close. They continued to rise throughout morning trading too, nearly reaching $35 apiece by noon, up roughly 50% on the day and elevating the biotech’s market cap to $1.3 billion.
Of the three patients enrolled in the study, all experienced increasing and sustained Factor IX levels after receiving AMT-061. The levels were 37% of normal at 10 weeks for the first patient, 23% of normal at eight weeks for the second patient and 30% of normal at six weeks for the third patient.
On safety, investigators haven’t reported any serious adverse events or patients in need of immunosuppressants. The patients also haven’t experienced bleeding events, demonstrated material loss of Factor IX activity or required infusions of Factor IX replacement therapy, according to uniQure. One patient did, however, have an increase in liver enzyme levels, but the biotech said it was “mild, asymptomatic and transient” and “resolved quickly without any additional treatment.”
The positive data should help AMT-061, which consists of an adeno-associated virus 5 vector carrying a gene cassette with the Padua variant of Factor IX, hold its own against rival treatments, according to investment bank Leerink.
Spark Therapeutics, for instance, is collaborating with Pfizer on its own hemophilia B gene therapy called fidanacogene elaparvovec or SPK-9001. The therapy is currently in Phase 3 testing.
“With the caveat of cross-trial comparisons, we remind investors that at 12 weeks, SPK-9001 also showed [Factor IX] levels in the mid-to-high 30% range with a larger sample size. Assuming similar kinetics, we would anticipate AMT-061-treated [patients] to reach similar levels by week 12,” Leerink analyst Joseph Schwartz wrote in a Nov. 15 note.
The data monitoring committee for the Phase 2b study will meet before year’s end and potentially select the dose of AMT-061 that will be used in late-stage testing. Dosing of that study, dubbed HOPE-B, should begin in the first quarter of 2019, according to uniQure. Estimated enrollment for HOPE-B is 56, and the estimated primary completion date is March 2020.