‘Failure to Warn’ at Heart of Onglyza Lawsuits

San Francisco, CAOnce the procedural wrangling is over, the argument that patients were hurt because drug manufacturers, AstraZeneca and Bristol-Meyers Squibb, failed to warn them of the dangers of Onglyza side effects will be at the heart of the Onglyza lawsuits.

But that argument is complicated, and facts can be ambiguous. Plaintiffs’ attorneys will march purposefully through showing that the drug is dangerous, the manufacturers knew or had reason to know of the danger, that they failed to warn patients and that patients were injured by the inadequate warning. AstraZeneca is waiting, watchfully.

Is Onglyza really dangerous?

The FDA’s 2016 decision to require a warning that Onglyza could increase the risk of heart failure would seem to put that question to rest. Not so fast, though.

The evidence that has emerged since the drug was first approved in 2009 has been surprisingly muddy. One study, sponsored by AstraZeneca, found no link between Onglyza and heart failure. Still another drew a fine distinction between an increased risk of heart failure (of which it found none) and the risk of hospitalization, for which there did seem to be evidence.

And when did the manufacturers know about the risk of Onglyza heart attack? Was it in 2009, when the FDA expressed reservations about the completeness of clinical studies? Or was it as late as 2015, when clinical trials suggested the existence of a connection. Why was the new warning not required until 2016? Eight years is a long time when the risk is deadly.

As court watchers have recently seen in the Johnson & Johnson talcum powder cases, a good defense counsel can make hay with warring scientific studies and a jumble of dates -- creating just enough doubt to sink a plaintiff’s case.

When to warn of what?

At least for claim that the drug manufacturers failed to warn of the risk of heart failure, the 2016 warning label date creates a deadline. Although they may have other legal arguments, patients who began to take the drug only after 2016 probably cannot claim that they were hurt by a faulty warning. Since the drug was widely prescribed and symptoms may take years to develop, pre-2016 cases are likely to appear for years to come.

But the fact that earlier versions of the label warned of other side effects, including pancreatitis, pain and infections, complicates the issue for even those patients. These conditions may exacerbate or mask a cardiovascular issue. Could a warning about one condition mitigate AstraZeneca’s liability for the failure to warn of a related one?

Causation is the devil

The real problem, however, is that patients with Type 2 diabetes are already sick. Heart failure is one of the complications of the disease itself. Particularly if the cases go forward as individual lawsuits, defense counsel will look for every opportunity to argue that some other individualized cause, such as diabetes, a dental infection or a pre-existing heart murmur, rather than Onglyza, was the immediate case of a patient’s heart attack.

Pharmaceutical product liability cases can be an important way for patients to hold drug manufacturers accountable. But they are rarely quick, easy or straightforward. Plaintiffs should be prepared for drug companies to mount a vigorous defense.