Table 3. Combination index and surviving fraction of MCF7, MDA-MB-231, MDA-MB-436, and HCC-1937 cells treated with trabectedin in combination with olaparib.

Cell line	No.	Potency ratio	Concentration ratio	CI values
				ED20	ED50	ED80
MCF7	2	40/60	1:26,600	0.90	0.54	NA
	3	50/50	1:17,700	0.79	0.46	NA
	3	60/40	1:11,800	0.86	0.50	NA
	2	75/25	1:5,900	0.79	0.57	NA
	1	86/14	1:3,000	0.72	0.78	0.27
MDA-MB-231	1	40/60	1:101,600	1.28	0.57	0.34
	1	50/50	1:67,700	1.56	0.75	0.52
	2	60/40	1:45,200	1.10	0.71	0.72
	3	75/25	1:22,600	1.58	0.77	0.69
	2	87/13	1:10,000	0.67	0.68	0.78
	2	93/7	1:5,000	0.81	0.73	0.71
MDA-MB-436	1	40/60	1:189,900	1.30	0.65	NA
	1	50/50	1:126,600	0.52	0.33	NA
	1	60/40	1:84,800	0.58	0.33	NA
	3	75/25	1:42,200	0.70	0.37	NA
	2	93/7	1:10,000	1.76	0.39	NA
	2	96/4	1:5,000	1.03	0.48	NA
HCC-1937	3	60/40	1:39,100	0.74	0.76	0.78
	3	75/25	1:19,600	0.74	0.74	0.75
	2	85/15	1:10,000	0.65	0.72	0.80
	2	92/8	1:5,000	0.69	0.71	0.73

CI=combination index; ED20, ED50, and ED80=effective dose 20, 50, and 80, respectively; NA=not available.