The year 2014 was a big one for FDA Breakthrough Therapies, with FDA approving nine drugs under the designation compared with but three in 2013, according to a note from Evercore ISI analyst Mark Schoenebaum.

Five of the nine drugs approved this year under the BTS fast track program were cancer drugs: GlaxoSmithKline’s Arzerra (ofatumumab) supplement for CLL, Novartis’s Zykadia (ceritinib), Gilead’s Zydelig (idelalisib), Imbruvica (ibrutinib) supplement for CLL, and Keytruda (pembrolizumab).

Non-cancer drugs approved were Vertex CF med Kalydeco (ivacaftor), GSK’s Promacta (eltromopag) supplement for aplastic anemia, Boehringer Ingelheim’s Ofev (nintedanib) for IPF, and InterMune’s Esbriet for IPF. One BTS drug was denied approval–Serelaxin, the experimental Novartis heart-failure drug.

The analyst also tabulated the number of instances were BTS was granted. Since the program’s launch two year’s ago, CDER has fielded 206 applications for the status, granting 62 and denying 101, with two withdrawals; CBER received 37 applications, of which 27 were denied and seven granted, the analyst reported.

“Bear in mind, these stats are dynamic – thus many of the . . . applications are presumably still being evaluated,” Schoenebaum wrote.

In the BTS track, FDA speeds up its drug development and review process for drugs for serious or life-threatening conditions where early evidence suggests a substantial improvement over existing therapies.

While median enrollment for granted applications was 88, factors which did not appear to influence likelihood of success included rare/orphan status and existence of randomized trial evidence, he pointed out.

Schoenebaum notes the agency has indicated the biggest factor in granting BTS is the “magnitude of the treatment effect.”  

According to FDA documents, he wrote, successful requests “in general” showed a reduction in the risk of the event of interest of “over 50%.”  If the endpoint is survival, the FDA specifically notes that “lesser improvements” could be adequate.