Efficacy and safety of biosimilar trastuzumab (CT-P6) in routine clinical practice in the Republic of Korea: a real-world post-marketing surveillance study

Figures & data

Figure 1. Patient disposition.

^aSome patients were excluded from the safety population for multiple reasons.

Abbreviations: EBC: early breast cancer, MBC: metastatic breast cancer, MGC: metastatic gastric cancer.

Table 1. Summary of patient demographics and baseline characteristics by indication (safety population).

Characteristic	Total (N = 642)	MBC (n = 94)	EBC (n = 494)	MGC (n = 54)
Sex, n (%)
Female	596 (92.8)	94 (100.0)	493 (99.8)	9 (16.7)
Male	46 (7.2)	0	1 (0.2)	45 (83.3)
Age (years), median (range)	55 (29.0–89.0)	57 (34.0–82.0)	53 (29.0–81.0)	67 (40.0–89.0)
Height (cm), mean (SD)	157.4 (6.3)	156.0 (5.0)	156.7 (5.7)	165.5 (7.8)
Weight (kg), mean (SD)^a	60.0 (9.8)	58.1 (10.2)	60.7 (9.7)	57.3 (8.8)
Disease duration (months), median (range)	4.4 (0.0–192.0)	1.0 (0.0–142.7)	4.7 (0.0–72.0)	1.0 (0.0–192.0)
Prior trastuzumab treatment other than CT-P6, n (%)
No – trastuzumab naïve	528 (82.2)	79 (84.0)	396 (80.2)	53 (98.1)
Yes – switched to CT-P6	114 (17.8)	15 (16.0)	98 (19.8)	1 (1.9)
Disease stage at the start of CT-P6 administration, n (%)
0	6 (0.9)	0	6 (1.2)	0
IA	130 (20.2)	0	130 (26.3)	0
IB	15 (2.3)	0	15 (3.0)	0
IIA	146 (22.7)	0	146 (29.6)	0
IIB	97 (15.1)	0	97 (19.6)	0
IIIA	73 (11.4)	0	73 (14.8)	0
IIIB	13 (2.0)	0	13 (2.6)	0
IIIC	14 (2.2)	0	14 (2.8)	0
IV	148 (23.1)	94 (100)	0	54 (100)

^aBody weight measured on the first date of administration or last value before the first drug administration.

Abbreviations: EBC: early breast cancer, MBC: metastatic breast cancer, MGC: metastatic gastric cancer, SD: standard deviation.

Table 2. Summary of the four most common ADRs and serious ADRs by preferred term, per indication (safety population).

	Total (N = 642)	MBC (n = 94)	EBC (n = 494)	MGC (n = 54)
	Patients, n (%)
ADRs
Diarrhea	33 (5.1)	15 (16.0)	17 (3.4)	1 (1.9)
Pruritis	20 (3.1)	7 (7.4)	12 (2.4)	1 (1.9)
Neutrophil count decreased	17 (2.6)	12 (12.8)	3 (0.6)	2 (3.7)
Nausea	17 (2.6)	3 (3.2)	11 (2.2)	3 (5.6)
Serious ADRs
Febrile neutropenia	8 (1.2)	6 (6.4)	2 (0.4)	0
Neutrophil count decreased	3 (0.5)	1 (1.1)	2 (0.4)	0
Asthenia	2 (0.3)	0	2 (0.4)	0
Cardiomyopathy	2 (0.3)	1 (1.1)	1 (0.2)	0

Abbreviations: ADR: adverse drug reaction, EBC: early breast cancer, MBC: metastatic breast cancer, MGC: metastatic gastric cancer.

Table 3. Summary of AEs and ADRs of special interest, per indication (safety population).

	Total (N = 642)	MBC (n = 94)	EBC (n = 494)	MGC (n = 54)
	Patients, n (%)
AEs of special interest	174 (27.1)	55 (58.5)	101 (20.4)	18 (33.3)
Cardiotoxicity	45 (7.0)	13 (13.8)	30 (6.1)	2 (3.7)
IRR	33 (5.1)	13 (13.8)	16 (3.2)	4 (7.4)
Hematotoxicity (e.g. neutropenia)	86 (13.4)	38 (40.4)	35 (7.1)	13 (24.1)
Pulmonary diseases	6 (0.9)	2 (2.1)	4 (0.8)	0
Oligohydramnios	0 (0.0)	0	0	0
Infection	67 (10.4)	15 (16.0)	49 (9.9)	3 (5.6)
ADRs of special interest	81 (12.6)	32 (34.0)	43 (8.7)	6 (11.1)
Cardiotoxicity	28 (4.4)	9 (9.6)	18 (3.6)	1 (1.9)
IRR	24 (3.7)	11 (11.7)	11 (2.2)	2 (3.7)
Hematotoxicity (e.g. neutropenia)	36 (5.6)	19 (20.2)	14 (2.8)	3 (5.6)
Pulmonary diseases	2 (0.3)	0	2 (0.4)	0
Oligohydramnios	0	0	0	0
Infection	12 (1.9)	3 (3.2)	9 (1.8)	0

Abbreviations: ADR: adverse drug reaction, AE: adverse event, EBC: early breast cancer, IRR: infusion-related reaction, MBC: metastatic breast cancer, MGC: metastatic gastric cancer.

Table 4. Summary of effectiveness, by indication (effectiveness population).

	Effective	Ineffective
	Patients, n/N (%)
MBC
Trastuzumab naïve^a	30/74 (40.5)	44/74 (59.5)^b
Switched^c	4/14 (28.6)	10/14 (71.4)^b
MGC
Trastuzumab naïve^a	24/49 (49.0)	25/49 (51.0)
Switched^c	1/1 (100.0)	0/1
EBC
No disease progression before surgery^d
Trastuzumab naïve	101/104 (97.1)	3/104 (2.9)
Switched	9/9 (100.0)	0/9
No disease progression after surgery^d
Trastuzumab naïve	280/289 (96.9)	9/289 (3.1)
Switched	75/78 (96.2)	3/78 (3.9)
Pathological complete response^e
Trastuzumab naïve^f	34/106 (32.1)	64/106 (60.4)
Switched	7/10 (70.0)	3/10 (30.0)

^aIn trastuzumab-naïve patients, CT-P6 was considered to be ‘effective’ if a BOR of complete or partial response was achieved.

^bCT-P6 was considered to be ‘ineffective’ for 1 and 7 patients who had missing baseline effectiveness results in the MBC trastuzumab-naïve and MBC switched groups, respectively.

^cIn switched patients, CT-P6 was considered to be ‘effective’ if BOR either remained the same or improved following switch to CT-P6.

^dCT-P6 was considered to be ‘effective’ if patients with EBC did not report disease progression before or after surgery until the end of CT-P6 administration.

^eCT-P6 was considered to be ‘effective’ in patients with EBC who received CT-P6 as neoadjuvant therapy if they achieved pathological complete response.

^fAmong 106 patients, 8 (7.5%) did not receive surgery; therefore, CT-P6 was not considered to be ‘effective’ or ‘ineffective.’

Abbreviations: BOR: best overall response, EBC: early breast cancer, MBC: metastatic breast cancer, MGC: metastatic gastric cancer.

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article and its supplementary materials.