?me-too? Drugs: Good or Bad?
?me-too? Drugs: Good or Bad?
Introduction
A drug that is structurally very similar to already known drugs, with only minor differences. The term “me-too” carries a negative connotation. However, me-too products may create competition and drive prices down1.
The majority of the new products the industry puts out, are “me-too” drugs, which are almost identical to current treatments but “no better than drugs already on the market to treat the same condition.” Around 75 percent of new drugs approved by the FDA are me-too drugs. They can be less effective than current drugs, but as long as they’re more effective than a placebo, they can get the regulatory green light2.
This isn’t surprising at all, as someone who works in the field, but these so-called “me-too” drugs, which are reportedly better than their forebears, is driving costs. A “me-too” drug is a drug that has its origins in another drug. Probably the most famous example of this is Prilosec (“The Purple Pill”) and Nexium (“Today’s Purple Pill”). Prilosec’s active ingredient is omeprazole. Nexium’s active ingredient is called esomeprazole. The difference is that Nexium is the left-handed version of omeprazole. In chemistry, S stands for sinister, which means the molecular conformation has a left-handed orientation. (D would be right handed.) So this S-omeprazole is one half of the mixture that comprises its predecessor. By specifically picking only the S conformation, the drug is made more potent. This sounds great, but its efficacy is only marginally better than Prilosec-, which has a generic version, and costs about a third less than Nexium. Some other “me-too” drugs are: Claritin (loratidine) and Clarinex (desloratidine), Celexa (citalopram) and Lexapro (escitalopram)3.
What are “Me-Too” drugs?
Ever since the advent of modern chemotherapy, when drugs were discovered and developed through the process of screening thousands of molecules for a variety of disease conditions, using animal models, there has been a growing criticism that too many molecules were developed with similar chemical structure and the same pharmacological profile, with very little to distinguish them from each other in terms of their therapeutic utility. In other words, once the first breakthrough discovery is made of a new pharmacological activity for a new molecule, subsequent years saw the emergence of a host of new molecules or “me-too” drugs from the same chemical class and possessing the same pharmacological profile.
Such follow-up drugs have been termed molecular modifications, molecular roulettes or copycats, the development of which are alleged to be motivated by purely commercial considerations. They are also deemed to involve lower levels of innovation, compared to the original molecule. It is important to analyze in a historical perspective the end results of such efforts in different therapeutic areas of developing new molecular entities, as later generation products, after an initial breakthrough discovery has been made and the technical, medical and commercial merits of developing such drugs.
Development of “Me-Too” drugs
The success rate in the discovery of new chemical entities with fundamentally new chemical and biological profiles of activity are very low. In fact, even chemical entities within the same structural class of an approved drug are becoming rare now, compared to the period of sixties to eighties. In 2001, $ 26 billion was spent on developing new drugs and the U.S. FDA approved only 9 new chemical entities. At the same time, two thirds of the drugs approved from 1989 to 2000 were modified versions of existing drugs or even identical to those, in newer forms and formulations4.
Of the 1,035 drugs approved by FDA during 1989 to 2000, only 361 or 35% contained new active ingredients. Of these, only fewer than half were granted priority review status by the FDA. One impression is that these drugs are slightly altered versions of existing drugs, with little to offer in terms of better activity or tolerance, let alone new pharmacological profiles. The implication is that such drugs are developed, as patents on top-selling original drugs run out and not many truly new medicines are discovered. The indication that many of these drugs do not offer any major advantages over existing drugs is given by FDA’s unwillingness to grant priority review for most of them.
On the other hand, conventionally, the Regulatory Agencies, including the FDA, are not obliged to consider better efficacy over existing drugs as a criterion for approval; rather, they require only the establishment of efficacy and safety of the new drug over a placebo.
How good are they?
Notwithstanding such perceptions, historically, many “me-too” drugs have