(I don’t think so, and here’s why.)

The FDA just announced its approval of linagliptin (Tradjenta), a new diabetes medication developed by Eli Lilly and Company and Boehringer Inglheim. Linagliptin is the third drug to be approved in the class of medications commonly known as gliptins (scientifically known as dipeptidyl peptidase-4 (DPP-4) inhibitors) which block the destruction of a glucose controlling hormone, GLP-1. Januvia, developed by Merck and Company, was the first of the gliptins to be approved in 2006. Three years later in 2009, Onglyza, developed by AstraZeneca was approved while two other similar drugs were withdrawn from the approval process in the meantime.

Diabetes drugs are evaluated by the FDA for safety and for their ability to combat diabetes by lowering blood sugar. Assuming the drug being evaluated is safe then we will want to know how effectively the new medicine lowers the blood sugar. The glycohemoglobin A1c blood test represents the average blood sugar for the prior 3 months, and is the most concise way of assessing an individuals over all blood sugar control. By determining the ability of a medicine to lower the “glycoA1c” we can get a very accurate idea of the strength of the medicine for diabetes treatment. In general, physicians set a glycoA1c goal of 7% or less for their diabetic patients which equates to an average blood sugar level of 154 mg/dl or 8.6 mmol/L.

Linagliptin passed the FDA’s strigent safety review. Several large studies sponsored by the drug developers show the linagliptin lowers glycohemoglobin A1c by about 0.5. For example, if a person has a glycoA1c of 7.5 % before starting linagliptin, they can anticipate it will be 7.0% when on the medication. This translates to an average blood sugar of 169 mg/dl dropping to 154. This is virtually the same effect found with Januvia and Onglyza, the other medicines in this group.This amount of blood sugar lowering seems feeble but the benefit is even worse then that. Here’s why.

Blood tests are accurate enough for the clinical purposes of physician’s diagnosing and treating their patients. “Clinical purposes” allow for some fuzziness in measurements. Does it matter to a patient’s health if the blood sugar is 200 or 210? Not really. In general, a variation of 10% is acceptable for clinical blood tests, meaning that if a result is given as 100, a repeat measurement of the same blood sample could read between 95 and 105. For the glycohemoglobin A1c test a variation of 0.5 is common with standard laboratory techniques. For an individual on linagliptin there is virtually no way to determine if the change in glycoA1c is due to the medication or is simply within the variation of the blood test. Not very impressive is it?

How much is the average person going to pay for this unimpressive effect? I researched the retail cost of Januvia, the sister drug to linagliptin. Drugstore.com lists a price of $216 for 30 pills after a 18% saving. $7 per pill….wow!! I assume linagliptin will be priced competitively. Compare this to the price of $13 for a month’s supply of metformin, currently the most prescribed oral agent for treating diabetes. In contrast, metformin shows a 1.5% to 2% drop in glycohemoglobin A1c, more than three times that of the gliptins such as linagliptin.

I have used both Januvia and Onglyza in my medical practice. As advertised, I haven’t encountered significant side effects. Also, as advertised the effect of these medicines to lower blood sugar has been disappointing and complaints by patients about the cost has been a constant theme. At the same time my email inbox is stuffed with invitations to join online symposiums with paid experts inevitably focusing on how to ramp up my use of these drugs. The sales pitch is given in inflated marketing lingo as a “change in the treatment paradigm” for treating diabetes. Buyer beware, is my advice for the health care consumer starting a new medication for treating type 2 diabetes.

Gary Pepper, M.D.
Editor-in-Chief, metabolism.com