. 1998 Jul 7;95(14):8369–8374. doi: 10.1073/pnas.95.14.8369

Table 3.

Synergism between DX and NAA in combination against P388/0 and P388 cell growth

Tumor cells	Drug	IC₅₀ μM	CI values^*				Dose reduction index^†	Parameters^‡
Tumor cells	Drug	IC₅₀ μM	IC₅₀	IC₇₅	IC₉₀	IC₉₅	Dose reduction index^†	m	r
P388/0	DX	0.23 ± 0.034					2.71	1.5 ± 0.053	0.99 ± 0.005
	NAA	44 ± 20					104	0.87 ± 0.45	0.99 ± 0.015
	Combination^§	0.084 + 0.42	0.41	0.36	0.31	0.28		1.9 ± 0.56	0.92 ± 0.079
	DX + NAA		±0.025	±0.095	±0.16	±0.20
P388/DX	DX	2.1 ± 0.089					5.14	1.0 ± 0.017	0.97 ± 0.013
	NAA	66 ± 1.1					31.7	0.88 ± 0.059	0.95 ± 0.005
	Combination^§	0.42 + 2.1	0.23	0.17	0.12	0.099		1.4 ± 0.085	0.99 ± 0.004
	DX + NAA		±0.068	±0.056	±0.046	±0.040

CI < 1, synergism; CI > 1, antagonism; CI = 1, additivism, as described (29).

^†

Folds of dose reduction allowed for each drug caused by synergism at a given effect level (30) (e.g., the dose-reduction index values at IC₅₀ effect level for this table).

^‡

m, the slope of the median-effect plot (29) signifying the shapes of dose-effect curves (i.e., m = 1, >1, and <1 indicates hyperbolic, sigmodal and shallow sigmoidal shapes, respectively. r, the linear correlation coefficient of the medium-effect plot (29) signifying the conformity of the dose-effect data to the method of data analysis.

^§

NAA/DX 5:1 ratio.