Table 2.

Prespecified subgroup analysis of progression-free survival.

Subgroup	Clarithromycin Group	Control Group	Clarithromycin Group	Control Group	Hazard ratio (95% CI)
	no. of progression events or deaths/total no.		median progression-free survival (mo)
Sex
Male	37/71	32/64	23	26		1.24 (0.77–1.98)
Female	33/71	29/79	35	39		1.38 (0.84–2.27)
Age
<75yr	26/64	26/59	NR	33		1.02 (0.59–1.75)
≥75yr	44/78	35/84	19	28		1.56 (1.00–2.42)
ISS
I	10/36	11/33	NR	33		0.90 (0.38–2.13)
II	32/52	31/59	15	25		1.35 (0.82–2.20)
III	28/54	19/51	17	NR		1.67 (0.94–2.98)
Baseline creatinine clearance
>60 ml/min	63/131	56/132	23	29		1.29 (0.90–1.84)
≤60 ml/min	7/11	5/11	9	NR		1.65 (0.52–5.20)
Type of MM
IgG	29/74	32/84	35	39		1.06 (0.64–1.74)
Non-IgG	41/68	29/59	16	28		1.50 (0.93–2.40)
Cytogenetic profile
High risk	17/25	9/22	12	NR		2.16 (0.96–4.86)
Standard risk	48/106	43/108	27	33		1.22 (0.81–1.84)
ECOG score
0	11/32	18/41	39	33		0.60 (0.28–1.27)
1	30/64	22/61	26	NR		1.36 (0.79–2.36)
≥2	29/46	21/41	11	29		1.99 (1.13–3.51)
R-ISS
I	3/15	6/17	NR	29		0.68 (0.17–2.74)
II	42/79	36/83	23	29		1.21 (0.77–1.88)
III	16/23	5/18	7	NR		3.89 (1.41–10.7)

Shown are the results of an analysis of progression-free survival in prespecified subgroups of the intention-to-treat population that were defined according to baseline characteristics. The experimental group was treated with clarithromycin, lenalidomide and dexamethasone; the control group received lenalidomide and dexamethasone. The International Staging System (ISS) has three stages defined as follows: I (serum β₂-microglobulin level < 3.5 mg/L and albumin level ≥ 3.5 g/dL; stage II, neither stage I nor III; and stage III serum β₂-microglobulin level ≥ 5.5 mg/L. A high-risk cytogenetic profile was defined by a funding of t(4;14), t(14;16), or del17p on fluorescence in situ hybridization testing. The R-ISS is obtained on the basis of the combination of ISS, chromosomal abnormalities (CA) detected by interphase fluorescent in situ hybridization after CD138 plasma cell purification and serum lactate dehydrogenase (LDH). R-ISS I includes ISS stage I, no high-risk CA [del(17p) and/or t(4;14) and/or t(14;16)], and normal LDH level (less than the upper limit of normal range); R-ISS III including ISS stage III and high-risk CA or high LDH level; and R-ISS II, including all other possible combinations. Eastern Cooperative Oncology Group (ECOG) performance status is scored on a scale from 0 to 5, with higher scores indicating increasing disability.