#117 Generic Versus Brand Name: The other drug war

CLINICAL QUESTION

QUESTION CLINIQUE

Is there any benefit to prescribing brand name medications versus generic brands?

BOTTOM LINE

RÉSULTAT FINAL

Based on the best available evidence, generic medications are bioequivalent and produce similar clinical outcomes to brand name medications.

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EVIDENCE

DONNÉES PROBANTES

Bioequivalence:¹

Regulators require 90% confidence intervals (CI) for the maximum peak concentration (Cmax) and total drug exposure over time (AUC) of generic drug be within limits of 0.80-1.25.
- This means the absolute differences in bioequivalence must be ≤~5-7%.
Between 1996-2007, 2070 single-dose bioequivalence studies showed the average difference in Cmax and AUC was 4.35% and 3.56%, respectively.
98% of studies showed AUC of generic and innovator products’ differed by <10%.
Generic and brand name levothyroxine have been shown to be bioequivalent.²
One study found that of 42 randomly selected brand-generic drug comparisons, 98% met AUC criteria and 88% met Cmax criteria for bioequivalence.³

Clinical outcomes (brand name versus generic medications):

Two systematic reviews [38-74 randomized control trials (RCTS)] of cardiovascular medications including anti-hypertensives, statins, anti-platelets, anticoagulants:^4,5
- Both showed no difference in clinical outcomes.
- The largest and most recent SR:⁵
  - Composite of soft outcomes (e.g. systolic blood pressure, LDL): no statistical difference.
  - Major adverse cardiovascular events (MACE) or death (3 RCTs): no statistical difference.
  - Adverse effects:
    - Mild/moderate: no difference.
    - Serious: no difference.
Systematic review of warfarin:⁶
- Five trials (higher level evidence): No statistically significant difference in INR or dosage changes required.
- Six observational studies (lower level evidence): Inconsistent results at higher risk of bias.
Systematic review of clopidogrel (3 studies, mixed design) ⁷. For RCT data, no differences observed for:
- MACE: 5% versus 4% generic, no statistical difference.
- Bleeding: 2% versus 1%, no statistical difference.
- Withdrawal: 4% versus 7%, no statistical difference.
Systematic review of antiepileptic drugs (7 RCT, 204 patients)⁸:
- Uncontrolled seizures: no difference.

Context:

Of 43 editorials on generic medication issues, 23 (53%) expressed a negative view of generic substitution,4 while only 8% of trials found any differences in any outcomes.4
If there were important clinical differences between generic and brand name medications, companies would do studies to prove brand name superiority and prevent losing millions of dollars from generic substitution.
- In fact, one company tried to suppress data demonstrating equivalence of its product and related generics.⁹
Brand name and generic medications may contain different inactive components (fillers and binders) and may look different.