For subjects in all sites early withdrawal was reported in 48.11% (102/212) of subjects in BCD-021 group and 45.52% (66/145) in reference bevacizumab group. The most frequent reason for early withdrawal was progression of disease during the study: 11.79% (25/212) and 10.34% (15/145) in BCD-021 and reference bevacizumab groups, respectively (Fig. 1).
For pooled ITT population most subjects had Asian race (67.32% and 52.21% for groups that received BCD-021 and reference bevacizumab respectively) and most subjects were male (69.27% and 64.71% for groups that received BCD-021 and reference bevacizumab respectively). Most subjects had ECOG = 1 (75.12% and 74.26% for groups that received BCD-021 and reference bevacizumab respectively). Most subjects had Stage IV disease (86.34% and 82.35%) and most subjects had adenocarcinoma as a tumor histology (98.54% and 98.53% for groups that received BCD-021 and reference bevacizumab respectively).
The groups were similar in all demographic and other baseline characteristics except the race in pooled ITT population: there were more subjects with reference bevacizumab race in BCD-021 group compared to reference bevacizumab group (p=0.005, Pearson’s chi-squared test). Also, there were more white subjects in reference bevacizumab group compared to BCD-021 group (p=0.0075, Pearson’s chi-squared test)..
Efficacy
According to CT-scan results, the overall response rate was 34.63% (71/205) and 33.82% (46/136) in BCD-021 and reference bevacizumab groups, respectively (Table 1).
Table 1. Efficacy endpoints assessment results (pooled mITT population)
Parameter
|
BCD-021 (N=205) N % (95% CI)
|
Reference bevacizumab (N=136) N % (95% CI)
|
p-value
|
|
Primary outcome measure
|
|
|
|
ORR (confirmed)
|
71 34.63 (28.46 - 41.38)
|
46 33.82 (26.41 - 42.12)
|
0.8773²
|
Secondary outcome measure
|
|
|
|
CR rate (confirmed)
|
3 1.46 (0.5 - 4.21)
|
1 0.74 (0.13 - 4.05)
|
1.0000¹
|
PR rate (confirmed)
|
68 33.17 (27.09 - 39.87)
|
45 33.09 (25.74 - 41.37)
|
0.9874²
|
PR rate (unconfirmed)
|
5 2.44 (1.05 - 5.58)
|
4 2.94 (1.15 - 7.32)
|
0.7458¹
|
Stable disease
|
65 31.71 (25.72 - 38.36)
|
46 33.82 (26.41 - 42.12)
|
0.6830²
|
Progressive disease
|
27 13.17 (9.21 - 18.48)
|
15 11.03 (6.8 - 17.4)
|
0.5557²
|
Note: ORR – overall response rate; CR – complete response; PR – partial response; N = number of subjects in Analysis Set; n = number of subjects with responses. ¹ Fisher's exact test, ² Pearson's chi-squared test
|
The difference in ORR between BCD-021 and reference bevacizumab groups in pooled mITT population was 0.81%, with 95% CI for the difference: [-9.47%; 11.09%], i.e. within pre-determined equivalence margin [-18%; 18%].
The result of 90% CI calculation for the ratio of overall response rate (risk ratio, RR) between BCD-021 and reference bevacizumab groups in pooled mITT population was [79.6%; 131.73%]; i.e. lies within the predefined range of equivalence margin [67%; 150%].
For both approaches CI was completely within the predefined range of clinically insignificant difference, thus equivalent efficacy of BCD-021 and reference bevacizumab was established.
Comparison of other efficacy assessment parameters (secondary outcome measures) did not show any statistically significant differences between the study groups in pooled mITT population (Fig.2).
Sensitivity analysis was done by the same 90% CI calculation for relative risk between BCD-021 and reference bevacizumab in three analysis sets (randomized subjects, intent-to-treat, per protocol population) to compare CI boundaries with pre-defined equivalence margins. Given that all sensitivity analyses confirmed the primary analyses outcomes in mITT population, the robustness in veracity of the latter is confirmed.
Table 2 Sensitivity analysis for overall response rate
Analysis Set
|
Treatment
|
n/N
|
(%)
|
Relative Risk
|
90% CI
|
Randomized
|
BCD-021 (N=212)
|
71/212
|
33.49
|
1.0557
|
[81.79%; 136.26%]
|
reference bevacizumab (N=145)
|
46/145
|
31.72
|
ITT
|
BCD-021 (N=205)
|
71/205
|
34.63
|
1.024
|
[79.6%; 131.73%]
|
reference bevacizumab (N=136)
|
46/136
|
33.82
|
PP
|
BCD-021 (N=163)
|
71/163
|
43.56
|
1.0133
|
[80.2%; 128.04%]
|
reference bevacizumab (N=107)
|
46/107
|
42.99
|
Note: ITT- intent to treat, PP- per protocol, N = number of subjects in reference bevacizumab Set, n = number of subjects with responses.
Stratified analysis was done for ethnic group as the stratification factor with levels “Indian” and “Not-Indian” in mITT and PP populations. The non-significant p-values (>0.6) of the Breslow-Day test for both mITT and PP correspondingly indicate no significant difference between ethnic groups in the odds ratios.
Safety
In the pooled safety population treatment discontinuation due to AEs/SAEs was reported in 1.75% (6/343) of the subjects: 1.94% (4/206) subjects from BCD-021 group and 1.46% (2/137) subjects in the comparator group (p = 1.0000).
Study groups had no significant difference regarding the frequency of any SAE as well as no differences in frequency of SAEs related to the study therapy (р > 0.05).
In the pooled population SAE were registered in 12.54% (43/343) subjects: 13.59% (28/206) subjects from BCD-021 group and 10.95% (15/137) subjects from the comparator group (p = 0.4690). According to investigators, there were 2.92% (10/343) SAEs related to the study therapy: 3.40% (7/206) SAEs in BCD-021 and 2.19% (3/137) SAEs in comparator group (p = 0.7454) (Table 3).
Table 3. Safety endpoints (pooled safety population)
Deviation
|
BCD-021 (N = 206) n (%)
|
Reference bevacizumab (N = 137) n (%)
|
Total (N=343) n (%)
|
p-value
|
|
Any AE (including SAE)
|
188 (91.26)
|
128 (93.43)
|
316 (92.13)
|
0.4651¹
|
|
SAEs
|
28 (13.59)
|
15 (10.95)
|
43 (12.54)
|
0.4690¹
|
|
Therapy-related SAE
|
7 (3.40)
|
3 (2.19)
|
10 (2.92)
|
0.7454²
|
|
Treatments discontinued due to AE/SAE
|
4 (1.94)
|
2 (1.46)
|
6 (1.75)
|
1.0000²
|
|
Deaths
|
14 (6.80)
|
8 (5.84)
|
22 (6.41)
|
0.7232¹
|
|
Note: ¹ - Pearson’s chi-suared test, ² - Fisher’s exact test; Comparisons and calculation of the statistical significance of the differences between the groups BCD-021 and reference bevacizumab;
N: number of subjects; n: number of observations; Percent is calculated: [100 x (n / N)]
|
Generally, SAEs were associated with the underlying pathology, chemotherapy agents used in combination therapy or with other factors unrelated to the study therapy.
In total, during the study, 22 lethal outcomes were reported in pooled population: 6.80% (14/206) subjects from BCD-021 group and 5.84% (8/137) subjects from the comparator group, with no significant difference showed (р = 0.7232).
Thus, both the study drug BCD-021 and the reference bevacizumab were adequately tolerated by subjects throughout the entire study. No differences in safety profile with respect to the pre-determined safety endpoints were observed.
Immunogenicity
Throughout the study neutralizing antibodies were detected in 9 subjects: 1.94% (4/206) from BCD-021 group and 3.65% (5/174) from comparator group (p = 0.4924).
Thus, no statistically significant differences regarding anti-drug antibody occurrence rate were found. The immunogenicity of BCD-021 is similar to that of reference bevacizumab; both drug products are characterized with low occurrence rate and short life of anti-bevacizumab antibodies.
Pharmacokinetics
In Indian population the pharmacokinetic analysis at the first cycle of therapy, the mean Cmax was 185.25 (±106.45) and 182.39 (±118.54) µg/mL, and AUC was 27786.61 (±13180.14) and 29271.17 (±15474.17) µg·h/mL, respectively, for study and reference bevacizumab. Mean Tmax was achieved at 13.8 h (median: 4.5 h) and 13.6 h (median: 4.5 h), respectively, for study and reference bevacizumab. For the comparisons of study to reference bevacizumab, the 90 % CIs for the test-to-reference ratios of Cmax and AUC were all within the bioequivalence window of 80.00–125.00 % (Table 4).
Table 4. Statistical comparison of pharmacokinetic parameters (Indian population)
Parameter
|
Geometric mean
|
90% CI
|
BCD-021
|
Reference bevacizumab
|
Cmax (µg/ml)
|
157.34
|
153.48
|
87.58% - 120.01%
|
AUC (µg·h/ml)
|
24519.49
|
25849.40
|
82.72% - 108.78%
|
In the pharmacokinetic analysis at the sixth cycle of therapy, the mean Cmax was 351.46 (±205.33) and 345.27 (±254.91) µg/mL, and AUC was 58949.16 (±32489.24) and 60137.29 (±42136.03) µg·h/mL, respectively, for study and reference bevacizumab. Mean Tmax was achieved at 10.9 h (median: 6.0 h) and 17.5 h (median: 4.5 h), respectively, for study and reference bevacizumab. Statistically, mean Cmax, AUC, and Tmax were comparable in both groups.
In the pharmacokinetic analysis of trough concentrations statistical comparison of concentrations of study and reference bevacizumab prior to each bevacizumab administration and at 504 h after the 6th drug administration demonstrated the absence of any significant differences between the study groups.
In Non-Indian population the pharmacokinetic analysis at the first cycle of therapy, the mean Cmax was 459.25 (±216.51) and 452.64 (±183.03) µg/mL, and AUC was 62237.55 (±29468.90) and 65381.93 (±32161.78) µg·h/mL, respectively, for study and reference bevacizumab. Mean Tmax was achieved at 6.1 h (median: 3.0 h) and 5.6 h (median: 3.0 h), respectively, for study and reference bevacizumab. For the comparisons of study and reference bevacizumab, the 90 % CIs for the test-to-reference ratios of Cmax and AUC were within the bioequivalence window of 80.00–125.00 % (Table 5).
Table 5. Statistical comparison of pharmacokinetic parameters (Non-Indian population)
Parameter
|
Geometric mean
|
90% CI
|
BCD-021
|
Reference bevacizumab
|
Cmax (µg/ml)
|
420.93
|
422.53
|
89.12% - 111.35%
|
AUC (µg·h/ml)
|
54556.29
|
57999.13
|
80.67% - 109.69%
|
In the pharmacokinetic analysis at the sixth cycle of therapy, the mean Cmax was 418.45 (±106.98) and 453.22 (±157.48) µg/mL, and AUC was 107942.90 (±39924.57) and 118810.50 (±45122.83) µg·h/mL, respectively, for study and reference bevacizumab. Mean Tmax was achieved at 7.0 h (median: 3.0 h) and 8.0 h (median: 4.5 h), respectively, for study and reference bevacizumab. Statistically, mean Cmax, AUC, and Tmax were comparable in both groups.
In the pharmacokinetic analysis of trough concentrations statistical comparison of concentrations of study and reference bevacizumab prior to each bevacizumab administration and in 504 h after the 6th drug administration demonstrated the absence of any significant differences between the study groups.
Overall Conclusion
The efficacy, safety and pharmacokinetics analysis has found no significant differences between BCD-021 and reference bevacizumab groups. The efficacy analysis showed the similar number of complete and partial responses in subjects who received BCD-021 (JSC BIOCAD, Russia) and Avastin (F. Hoffmann-La Roche Ltd., Switzerland). All sensitivity analyses confirmed the primary analyses outcomes in mITT population, the robustness in veracity of the latter is confirmed.
According to EMA «Guideline on the investigation of bioequivalence»: «In parallel design studies, the treatment groups should be comparable in all known variables that may affect the pharmacokinetics of the active substance (e.g. age, body weight, sex, ethnic origin, smoking status, extensive/poor metabolic status). This is an essential pre-requisite to give validity to the results from such studies» [5]. Indian and non-Indian populations of subjects included in the analysis of pharmacokinetics were statistically different by weight and height. Mean weight was 56.6 (±11.4) and 74.5 (±13.5) kg, respectively, for Indian and non-Indian population. Mean height was 161 (±9) and 169 (±8) cm, respectively, for Indian and non-Indian population. As such differences could affect the pharmacokinetics, analysis of pooled population data was not considered appropriate to give valid results.