What is a Breakthrough Therapy?

Breakthrough therapy is a United States Food and Drug Administration designation that expedites drug development. Section 902 of the July 9, 2012 Food and Drug Administration Safety and Innovation Act, allows the FDA to grant priority review to drug candidates if preliminary clinical trials indicate that the therapy may offer substantial treatment advantages over existing options for patients with serious or life-threatening diseases.[1][2]

A breakthrough therapy designation can be assigned to a drug if "it as a drug which is intended alone or in combination with one or more other drugs to treat a serious or life threatening disease or condition" and if the preliminary clinical evidence indicates that the drug may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development."[3]

Critics complain that most of these drugs are not actually "breakthroughs," because they are based on preliminary evidence, including changes in surrogate markers such as laboratory measurements, that often don't reflect "meaningful clinical benefit." Even when they do, many of these benefits are not eventually confirmed in large clinical trials. And calling a drug a "breakthrough" drug gives the drug a marketing advantage which makes people believe that it is more effective than it actually is.[4]

According to the FDA,[5] in 2013 breakthrough therapy designations were assigned to obinutuzumab (tradename Gazyva) by Hoffmann-La Roche for treatment of chronic lymphocytic leukemia,[6] ibrutinib and sofosbuvir. In 2014 ivacaftor, ofatumumab, pimavanserin, ceritinib, idelalisib, ibrutinib (2nd approval), eltrombopag, pembrolizumab, ledipasvir/sofosbuvir, nintedanib, pirfenidone, blinatumomab, Viekira Pak (a combination product of three antiviral drugs, ombitasvir, paritaprevir, ritonavir in combination use with the drug dasabuvir) and nivolumab received the breakthrough therapy designation.[5] In 2015, ibrutinib (3rd approval) and palbociclib received FDA breakthrough therapy designation;[5] in 2016, the investigational antidepressant rapastinel.

1-Fact Sheet: Breakthrough Therapies, Food and Drug Administration
2- "FDA Advisory Committee Supports Approval of Gilead's Sofosbuvir for Chronic Hepatitis C Infection". Drugs.com. October 25, 2013.
3- Food and Drug Administration Safety and Innovation Act (FDASIA), Silver Spring, MD: Food and Drug Administration, January 29, 2015, retrieved July 20, 2015
4-Joseph S. Ross, Rita F. Redberg (September 21, 2015). "Editor's Note: Would a Breakthrough Therapy by Any Other Name Be as Promising?". JAMA Intern Med. doi:10.1001/jamainternmed.2015.5311.
5-: a b c CBER Approvals for Breakthrough Therapy Designated Drugs, FDA, February 3, 2015, retrieved July 20, 2015
6-"Final Recommendation for Obinutuzumab (Gazyva) for CLL Pan-Canadian Oncology Drug Review (pERC) Meeting: December 18, 2014; Early Conversion: pCODR" (PDF). Pan-Canadian Oncology Drug Review via Canadian Agency for Drugs and Technologies in Health. 27 January 2015. Retrieved 22 November 2015.