What Makes a Drug Best-in-Class?

How a Follow-on Drug Can Create Value After a First-in-Class Drug

Novel drugs can make a big impact in two main ways—by being first-in-class (FIC) or by being best-in-class (BIC). A novel drug that produces its therapeutic effect by interacting with a new target or that is used to treat a new condition is considered first-in-class (FIC). These drugs go through intense scrutiny by regulators, require a great deal of effort and resources to demonstrate efficacy and safety for the first time, and provide significant value to patients since they provide a treatment option that didn’t exist before. 

It’s best to be first, but drugs that are approved later with the same mechanism of action can also create significant value for patients and society by being best-in-class (BIC), or what clinicians refer to as “gold standard.” This article explains what properties can make a follow-on drug best-in-class (BIC) and provides historical examples across therapeutic indications where a best-in-class strategy was employed. 

Factors That Can Make a Drug Considered Best-in-Class (BIC)

A follow-on drug can become best-in-class within an established mechanism of action by providing superior efficacy, safety, patient compliance, and/or lowering the costs or burden of treatment:

Therapeutic superiority:

A follow-on drug that offers a significantly improved efficacy when compared to a first-in-class (FIC) or prior best-in-class drug (BIC) can become considered the new gold standard. A best-in-class drug strategy may involve demonstrating therapeutic superiority without compromising safety or quality of life to become the first choice of treatment.

Some examples of blockbusters that followed this path include atorvastatin (vs. lovastatin), dulaglutide (vs. exenatide), and nab-paclitaxel (Abraxane) (vs. docetaxel and paclitaxel).

One of the best examples of a drug’s ability to surpass performance of those in its class is Lipitor (atorvastatin), developed by Warner-Lambert and acquired by Pfizer in 2000. Although atorvastatin was the fifth statin to enter the market for the treatment of high cholesterol, its favorable clinical outcomes quickly resulted in its best-in-class status. Atorvastatin remains one of the top selling drugs of the last 25 years.

It is important to note that the data supporting initial “best-in-class” characterization may change over time. For example, while docetaxel was considered superior to paclitaxel initially, today this position is challenged based on larger clinical datasets. This however, is now a moot point as nab-paclitaxel has become considered by many to be the new “best-in-class” drug among taxanes.

Improved safety:

Offering an improved safety profile with similar efficacy to the FIC drug or previous gold standard drug is another path. The improvement in safety could come from fewer types of side effects, a lower rate of side effects, or a lower risk of overdose or other treatment complications.

Some examples of blockbusters that have followed this strategy include lisinopril (vs. captopril), rasagiline (vs. selegiline), and tacrolimus (vs. ciclosporin).

Improved patient acceptance and lower cost/burden of treatment:

A follow-on drug that improves treatment compliance by increasing patient acceptance (either ease of taking the drug or simpler dosing regimen) without compromising therapeutic efficacy or safety can also be best-in-class.

Similarly, a follow-on drug that reduces treatment costs/burden while maintaining the same therapeutic efficacy/safety is more likely to be favored by patients, insurance companies and other stakeholders (Medicare, PPRS [UK], PMPRB [Canada] etc.). This ultimately leads to improved patient adherence to the treatment regimen and superior outcomes. It also helps to lower overall treatment costs and may decrease strain on healthcare systems.

Some examples include doxycycline (vs. oxytetracycline), azithromycin (vs. erythromycin), diltiazem (vs. verapamil) (non-dihydropyridines calcium channel blockers), and adalimumab (vs. infliximab).

In Part II, we’ll explore these case studies in more detail. We hope this list of factors that make a drug best-in-class is helpful for prioritizing your research programs.

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