TABLE 4.
In vivo efficacies of three generics and the innovator product of vancomycina
| Model PDP (unit) or statistical test | Vancomycin product PDP magnitude ± SE |
P value by CFA (IP vs GP) | |||
|---|---|---|---|---|---|
| Lilly | Abbott | APP | Proclin | ||
| Hill's Emax (log10 CFU/g)c | 5.65 ± 0.07b | 2.04 ± 0.07b | 2.59 ± 0.18b | 3.48 ± 0.27b | <0.0001 (all GP) |
| Gaussian Emax (log10 CFU/g)c | 6.70 ± 0.29b | 2.30 ± 0.17b | 3.28 ± 0.13b | 5.07 ± 0.39b | <0.0001 (all) |
| Hill's ED50 (mg/kg/day) | 62.7 ± 1.61b | NS | 58.6 ± 7.17b | NS | 0.57 (APP) |
| Gaussian logED50 | 1.90 ± 0.04b | 1.75 ± 0.09b | 1.82 ± 0.02b | 1.80 ± 0.04b | 0.14 (all) |
| Hill's slope (N) | 5.60 ± 0.70b | NS | 6.32 ± 2.78 | NS | 0.72 (APP) |
| Gaussian slope | 0.92 ± 0.06b | 0.91 ± 0.11b | 0.43 ± 0.02b | 0.45 ± 0.04b | <0.001 (APP, Proclin) |
| Hill's BD (mg/kg/day) | 68.2 ± 1.26b | NC | No bacteriostatic effect | NC | NA |
| Hill's 1LKD (mg/kg/day) | 79.6 ± 1.54b | NC | No bactericidal effect | NC | NA |
| Adjusted R2 | 0.99 | 0.94 | 0.96 | 0.85 | NA |
| Sy|x | 0.24 | 0.25 | 0.25 | 0.74 | NA |
| Model probability of being correct | Hill, >0.9999 | Hill, >0.9999 | Gaussian, >0.9999 | Gaussian, 0.9793 | NA |
Simple nonlinear regression analysis of each product based on the pharmacodynamic equation (Hill or Gaussian) best fitting its dose-effect relationship (all equations passed normality and constant variance tests). Abbreviations: GP, generic product; IP, innovator product; NA, nonapplicable; NC, not computable; NS, nonsignificant PDP (the PDP value was not significantly different from zero). Data in bold refer exclusively to the model best fitting each vancomycin product.
P < 0.0001 (other PDP had P values between 0.0001 and 0.050).
Emax values are negative because they represent a decrease in the number of microorganisms. The minus sign is eliminated to facilitate reading.