Multifactorial Choices in GLAUCOMA

Considering drugs, pricing, and packaging in an area where long-term adherence is vitally important

Questions of efficacy, adherence, and price have made the branded-versus-generic decision a constant in the treatment of glaucoma. Some of the doctors we interviewed prescribe branded prostaglandin analogues, but most prescribe generic latanoprost because payers prefer it and it may be less expensive for patients. However, they have some concerns.

“All glaucoma drugs cause dry eye to some degree. Most payers will not cover preservative-free branded medications, so patients are using preserved generic latonoprost. As a result, we either treat ocular surface disease in these patients to preserve their vision, or discomfort drives them to pay for the branded drug,” says Mitchell A. Jackson, MD, of Jackson Eye in Lake Villa, Ill. “Bottles are another concern. Generic manufacturers do not work to make products more consumer-friendly. Some of the bottle designs for glaucoma medications affect the drug itself, or are more difficult for patients to manipulate.”

Indeed, in a controlled degradation study, seven generic versions of latanoprost ranged from 90% to 330% of the labeled concentration, while branded Xalatan (Pfizer) was 97%.¹ The same study also looked at bottles of latanoprost that patients used through time, finding that concentrations ranged from 20% to 250%. The authors pointed to packaging construction as a primary culprit.

Another study found that some bottles used for generic glaucoma medications required greater strength to squeeze, concluding, “… a representative sampling of clinic patients suggests that many likely struggle with the force requirements of several bottle designs. These data further support standardization of topical glaucoma drug delivery and design.”²

A 2016 study of the bottle quantity and costs of generic glaucoma latanoprost found, “Annual cost and number of doses per bottle, factors important to patients, vary significantly depending on the manufacturer of latanoprost.”³

These variables are difficult to predict in the course of prescribing. Physicians ultimately have to decide what is best for their patients clinically, as well as financially. Adding to the puzzlement, if the primary purpose of prescribing generic glaucoma medications is to save patients money, it turns out generics may not meet that goal.

Pricing’s Tangled Web

According to a 2016 survey of the eyecare market sponsored by Allergan, doctors say that ease and comfort of dosing and acceptable out-of-pocket cost do the most to promote adherence.⁴ Everything we’ve ever known about generics tells us they should be cheaper for patients. Less research and development, no advertising, even cheaper ingredients in some cases — it’s a recipe for a bargain. But sometimes the recipe fails.

“The assumption that generic medications will save patients money needs to be carefully considered, as it is often wrong,” says Nathan M. Radcliffe, MD, of NYU Langone Ophthalmology Associates in New York. “Starting with the arrival of generic versions of Cosopt (dorzolamide HCI-timolol maleate, Merck) around 7 years ago, we noticed that some generics are actually more expensive than their branded competitors. This became a trend that has amplified in recent years. We’ve all seen examples of generic atropine, pilocarpine, prednisolone, and other glaucoma and surgical medications with copays of more than $100.”

Dr. Radcliffe encountered one hospital formulary that put all generic medications in the preferred category. When he entered the branded medications his patients were already taking, it would instruct him to select generics.

“Patients began complaining to me that their costs were going up,” he recalls. “If a patient on a brand name drug is happy with the copay, it is potentially costly and disruptive to change him [to a generic] without direct knowledge beforehand that the new drug will be less expensive.”

The Subtleties of Adherence

Adherence to glaucoma medications is closely studied. Are patients using their medications? Do they use them as directed? Why do they miss doses or discontinue use? These are important questions to ask about a population whose adherence to one or more prescription drops can be the difference between sight and blindness.

Poor adherence can stem from frequent, inconvenient dosing, forgetfulness, busy lives, and a lack of glaucoma and/or general health knowledge.⁵ Anything physicians and drug manufacturers can do to understand and respond to these barriers to adherence will ultimately help preserve vision in patients.

In discussing the challenges of adherence to glaucoma treatments related to branded and generic drugs, Dr. Radcliffe raises concerns about brand recognition, particularly among patients with low health literacy. He points out that many patients, particularly those on multiple glaucoma medications, have problems keeping their medications straight. They get confused about which medication is taken once at bedtime and which one is twice a day, and they tend to resort to visual aids, such as cap colors, to keep their drops straight. He says one inherent visual aid that helps people keep their medications straight is a recognizable name.

“Every single brand name is more recognizable than that of its generic competitor. The brand name Trusopt (Merck) is inherently easier to remember and recognize than the chemical name dorzolamide hydrochloride. Without question, the brand name Cosopt is easier to remember and recognize than dorzolamide hydrochloride-timolol maleate fixed combination,” says Dr. Radcliffe.

“I have seen patients have profound visual loss because they failed to recognize a generic chemical name, took their medication incorrectly, and their pressures got out of control. So, it isn’t just a nice, handy thing for a drug to have a clearly identifiable brand name,” he says. “To patients with low health literacy in particular, the name can be the difference between sight and vision loss. This is one reason why I don’t see the change from a branded to a generic as benign or inconsequential.”

Dr. Radcliffe’s experiences with brand names represent just one way that the differences between generic and branded drugs can affect adherence. A drug that costs less — branded or generic — may boost adherence. Other factors, such as dosing schedule convenience and easier- to-use bottles, may affect adherence as well.

Dr. Radcliffe recommends making well-informed, thoughtful, tailored drug decisions for each patient and avoiding a one-size-fits-all approach that may not serve each patient’s unique needs. Clearly, the multifactorial estimation of efficacy, tolerability, and adherence continues to carry great weight in prescribing decisions for glaucoma. ■

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