Safety scare with AstraZeneca's diabetes drug could shake up the DPP-4 field

AstraZeneca's headquarters in London--Courtesy of AstraZeneca

The FDA raised some alarming concerns tied to AstraZeneca's ($AZN) Onglyza ahead of a committee meeting to discuss the safety of so-called DPP-4 inhibitors, sounding a worrying note for a blockbuster class of drugs.

In a briefing issued ahead of an April 14 meeting of the FDA's metabolic, agency staff reviewed an outcomes trial of Onglyza's long-term effect and pointed to increases in all-cause mortality among patients taking the drug, particularly from heart failure. At the same time, the same group reviewed outcomes data on Takeda's DPP-4-blocking Nesina and found no significant increase in mortal risk.

At next week's meeting, the panel will discuss each drug separately, weighing whether to recommend the agency take any sort of action tied to the new data. Some investors fear the group will recommend a labeling change for DPP-4 drugs, and AstraZeneca's shares fell nearly 2% on Friday in response to the briefing.

The shoe yet to drop is an outcomes trial on Januvia, Merck's ($MRK) top-selling DPP-4 treatment, which won't be discussed at the committee meeting. Merck is expected to unveil results from that study, which has already concluded, at this summer's American Diabetes Association meeting. And the stakes are high: If Januvia charts similarly alarming cardio signals, the whole class could lose billions in value, but if Merck's drug comes through safely, it could get a major boost over its rivals.

DPP-4 is of particular importance to Merck and its ambitions in diabetes. Beyond Januvia, the company is developing a weekly DPP-4 blocker called omarigliptin, last year heralding Phase III results in which the new formulation measured up to the old blockbuster. And, in 2013, Merck struck a $60 million deal with rival Pfizer ($PFE) to get its hands on the Phase III ertugliflozin, which works by forcing excess glucose out through the urine. That drug holds promise as a monotherapy, Merck said, but its brightest future may come as a fixed-dose partner to a DPP-4 blocker, and the pair is working to prove that hypothesis.

- read the briefing

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