A total of 51 patients (biosimilar-only arm: n=18, switching arm: n=33) were included (Figure 1). Key demographics are summarised in Table 1. No patients died during the study period, and a total of six patients discontinued treatment before completion [n=3 (17%) and n=3 (9%) in biosimilar-only and switching arms, respectively]. Reasons for discontinuation included renal failure attributed to dehydration (n=1) and unspecified reasons (n = 2) for the biosimilar-only arm. For the switching arm, the reasons were exacerbated heart failure and disease progression (n=1), toxicity and reduced QOL with chemotherapy (n=1), and haematological toxicity (n=1). There appeared to be no increase in odds of discontinuation for any reason associated with the switching arm [odds ratio (OR): 0.8, 95% CI: 0.1 – 5.3, p-value=.82]. Immunogenicity, namely ADAs and Nabs formed in patients nor deaths were not reported in any of the records.
Table 1. Participant demographics
Subgroup
|
GP2013/GP2013 (n = 18)
|
R/GP2013 (n = 33)
|
p-value
|
Age (years), median (IQR)a
|
74 (52 – 79)
|
69 (59 – 76)
|
.615
|
Gender, male, n (%)b
|
10 (56)
|
20 (61)
|
.772
|
Pathological type, n (%)c
CLL
DLBCL
Follicular lymphoma
Hodgkin’s lymphoma
MALT lymphoma
Marginal zone lymphoma
Waldenström's macroglobulinemia
Uncertain subtypes of B cell lymphoma
|
0 (0.0)
6 (33.3)
1 (5.6)
1 (5.6)
0 (0.0)
0 (0.0)
1 (5.6)
9 (50.0)
|
2 (6.1)
9 (27.3)
4 (12.1)
0 (0.0)
2 (6.1)
1 (3.0)
2 (6.1)
13 (39.4)
|
.803
|
ECOG Performance Status, median (IQR)a
|
1.0 (1.0 – 2.0)
|
1.5 (1.0 – 2.0)
|
.424
|
Cycle no. of first administration of biosimilar (cycle), median (IQR) a
|
1.0 (1.0 – 1.0)
|
3.0 (2.0 – 4.0)
|
.001
|
Treatment naïve, n (%)b
|
13 (72)
|
27 (82)
|
.634
|
CLL: Chronic lymphocytic leukaemia, DLBCL: Diffuse large B cell lymphoma, ECOG: Eastern Cooperative Oncology Group
a. Mann-Whitney U test
b. Chi-squared test
c. Fisher’s Exact test
Table 2. Number of patients who died or discontinued for any reason
|
GP2013/GP2013, n (%)
|
R/GP2013, n (%)
|
OR (95% CI)
|
p-value
|
Discontinued for any other reason
|
3 (17)
|
6 (9)
|
0.8 (0.1 – 5.3)
|
.82
|
Treatment-Emergent Adverse Events (TEAEs)
There were five TEAEs in the biosimilar-only group compared to 24 events in the switching arm (Table 1).
TEAEs which were experienced most frequently in the switching arm were low-grade nausea and vomiting (n=10, 30.3%), followed by constipation (n=4, 12.1%), then anaemia (n=2, 6.1%), cardiac failure (n=2, 6.1%), and infection/infestation (n=2, 6.1%). Similarly, the TEAEs that were experienced most frequently in the biosimilar-only arm were nausea and vomiting (n=3, 16.7%), followed by constipation (n=1, 5.6%) and anaemia (n=1, 5.6%). There was no statistically significant increase in any TEAE in the switching arm compared to the biosimilar-only arm. Where reported, severity of TEAEs were mild or moderate and did not exceed Grade 2.
Table 3. Summary of TEAEs in biosimilar-only and switched arms
TEAEs, n (%)
|
GP2013/GP2013 (n = 18)
|
R/GP2013 (n = 33)
|
p-value
|
Anaemia
|
1 (5.6)
|
2 (6.1)
|
1.00
|
Arthralgia
|
0 (0.0)
|
1 (3.0)
|
1.00
|
Cardiac failure
|
0 (0.0)
|
2 (6.1)
|
.534
|
Constipation
|
1 (5.6)
|
4 (12.1)
|
.645
|
Cough
|
0 (0.0)
|
1 (3.0)
|
1.00
|
Infection/infestation
|
0 (0.0)
|
2 (6.1)
|
.534
|
Nausea and vomiting
|
3 (16.7)
|
10 (30.3)
|
.336
|
Neutropenia
|
0 (0.0)
|
1 (3.0)
|
1.00
|
Pulmonary nephropathy
|
0 (0.0)
|
1 (3.0)
|
1.00
|
aFisher’s Exact test