Lilly-Led Research Says Weak-Performing Cymbalta Good For Back Pain

Eli Lilly yesterday announced that its anti-depressant Cymbalta outperformed placebo in reducing low back pain. Cymbalta reduced pain by 50 percent or more in 31 percent of patients while placebo reduced it in 19 percent of patients, according to the company. That's a 12 percent effect size, a very small effect size for this $2 billion-plus a year drug in treating pain. The study was performed by a Lilly scientist.

Lilly recently filed an application for Cymbalta to be approved by the FDA to treat chronic pain.

But as I've previously reported, already released studies don't show that the drug is a particularly robust performer in treating knee pain (a 14 percent effect size here) and last year one academic paper found Lilly's claims of pain reduction in depression via Cymbalta treatment to be overstated and quite small in reality--an 11.5 percent effect size across several trials. As the New York Times' Well blog pointed out earlier this year, one out of four PCPs prescribe anti-depressants such as SSRIs for back pain, but there's no proof that these drugs work either.

But the FDA has already approved the drug for use in treating diabetic neuropathic pain and fibromyalgia. The latter approval came only in June. It's clear that Lilly very much wants to have the drug approved for at least one more pain indication so it can market the hell out of the drug--which is already being used off-label by pain management docs who are too scared of the DEA to treat pain with opiates and the Cymbalta results are not too grand from what patients tell me--but with a 12 percent effect size you've really got to wonder if the FDA would approve the drug because that is barely beating placebo in the real world. And, then, there are the drug's well known side effects--suicidality, nausea, fatigue, and withdrawal problems. One hopes that the FDA takes that sort of thing into consideration.

And if this new study is part of Lilly's application for chronic pain (and I bet it is), then I'd really like to see Lilly put Cymbalta up against medical marijuana, which is approved for chronic pain treatment (and reportedly works pretty well) in several states. Bet the feds never let that trial happen.

We ought to know before year's end.