Mechanism of Action
Ranibizumab binds to the receptor binding site of active forms of VEGF-A, including
the biologically active, cleaved form of this molecule, VEGF110.
VEGF-A has been shown to cause neovascularization and leakage in models of ocular
angiogenesis and is thought to contribute to the progression of the neovascular
form of age-related macular degeneration (AMD). The binding of ranibizumab to
VEGF-A prevents the interaction of VEGF-A with its receptors (VEGFR1 and VEGFR2)
on the surface of endothelial cells, reducing endothelial cell proliferation,
vascular leakage, and new blood vessel formation.
Pharmacodynamics
Neovascular AMD is associated with foveal retinal thickening as assessed by
optical coherence tomography (OCT) and leakage from choroidal neovascularization
(CNV) as assessed by fluorescein angiography.
In Study 3, foveal retinal thickness was assessed by OCT in 118/184 patients.
OCT measurements were collected at baseline, Months 1, 2, 3, 5, 8, and 12. In
patients treated with LUCENTIS, foveal retinal thickness decreased, on average,
more than the sham group from baseline through Month 12. Retinal thickness decreased
by Month 1 and decreased further at Month 3, on average. Foveal retinal thickness
data did not provide information useful in influencing treatment decisions [see Clinical Studies].
In patients treated with LUCENTIS, the area of vascular leakage, on average,
decreased by Month 3 as assessed by fluorescein angiogra-phy. The area of vascular
leakage for an individual patient was not correlated with visual acuity.
Pharmacokinetics
In animal studies, following intravitreal injection, ranibizumab was cleared
from the vitreous with a half-life of approximately 3 days. After reaching a
maximum at approximately 1 day, the serum concentration of ranibizumab declined
in parallel with the vitreous concentration. In these animal studies, systemic
exposure of ranibizumab is more than 2000-fold lower than in the vitreous.
In patients with neovascular AMD, following monthly intravitreal administration,
maximum ranibizumab serum concentrations were low (0.3 ng/mL to 2.36 ng/mL).
These levels were below the concentration of ranibizumab (11 ng/mL to 27 ng/mL)
thought to be necessary to inhibit the biological activity of VEGF-A by 50%,
as measured in an in vitro cellular proliferation assay. The maximum observed
serum concentration was dose proportional over the dose range of 0.05 to 1.0
mg/eye. Based on a population pharmacokinetic analysis, maximum serum concentrations
of 1.5 ng/mL are predicted to be reached at approximately 1 day after monthly
intravitreal administration of LUCENTIS 0.5 mg/eye. Based on the disappearance
of ranibizumab from serum, the estimated average vitreous elimination half-life
was approximately 9 days. Steady-state minimum concentration is predicted to
be 0.22 ng/mL with a monthly dosing regimen. In humans, serum ranibizumab concentrations
are predicted to be approximately 90,000-fold lower than vitreal concentrations.
Clinical Studies
The safety and efficacy of LUCENTIS were assessed in three randomized, double-masked,
sham- or active-controlled studies in patients with neovascular AMD. A total
of 1323 patients (LUCENTIS 879, Control 444) were enrolled in the three studies.
Study 1 and Study 2
In Study 1, patients with minimally classic or occult (without classic)
CNV lesions received monthly LUCENTIS 0.3 mg or 0.5 mg intravitreal injections
or monthly sham injections. Data are available through Month 24. Patients treated
with LUCENTIS in Study 1 received a mean of 22 total treatments out of a possible
24 from Day 0 to Month 24.
In Study 2, patients with predominantly classic CNV lesions received one of
the following: 1) monthly LUCENTIS 0.3 mg intravitreal injections and sham PDT;
2) monthly LUCENTIS 0.5 mg intravitreal injections and sham PDT; or 3) sham
intravitreal injections and active verteporfin PDT. Sham PDT (or active verteporfin
PDT) was given with the initial LUCENTIS (or sham) intravitreal injection and
every 3 months thereafter if fluorescein angiography showed persistence or recurrence
of leakage. Data are available through Month 24. Patients treated with LUCENTIS
in Study 2 received a mean of 21 total treatments out of a possible 24 from
Day 0 through Month 24.
In both studies, the primary efficacy endpoint was the proportion of patients
who maintained vision, defined as losing fewer than 15 letters of visual acuity
at 12 months compared with baseline. Almost all LUCENTIS-treated patients (approximately
95%) maintained their visual acuity. 34%–40% of LUCENTIS-treated patients experienced
a clinically significant improvement in vision, defined as gaining 15 or more
letters at 12 months. The size of the lesion did not significantly affect the
results. Detailed results are shown in the tables below.
Table 3: Outcomes at Month 12 and Month 24 in Study 1
| Outcome Measure |
Month |
Sham
n = 238 |
LUCENTIS
0.5 mg
n = 240 |
Estimated
Difference
(95% CI)a |
| Loss of < 15 letters in visual acuity (%)b |
12 |
62% |
95% |
32% (26%, 39%) |
| 24 |
53% |
90% |
37% (29%, 44%) |
| Gain of ≥ 15 letters in visual acuity (%)b |
12 |
5% |
34% |
29% (22%, 35%) |
| 24 |
4% |
33% |
29% (23%, 35%) |
| Mean change in visual acuity (letters) (SD)b |
12 |
-10.5 (16.6) |
+7.2 (14.4) |
17.5 (14.8, 20.2) |
| 24 |
-14.9 (18.7) |
+6.6 (16.5) |
21.1 (18.1, 24.2) |
a Adjusted estimate based on the
stratified model.
b p < 0.01. |
Table 4: Outcomes at Month 12 and Month 24 in Study 2
| Outcome Measure |
Month |
Verteporfin
PDT
n = 143 |
LUCENTIS
0.5 mg
n = 139 |
Estimated
Difference
(95% CI)a |
| Loss of < 15 letters in |
12 |
64% |
96% |
33% (25%, 41%) |
| visual acuity (%)b |
24 |
66% |
90% |
25% (16%, 34%) |
| Gain of ≥ 15 letters in |
12 |
6% |
40% |
35% (26%, 44%) |
| visual acuity (%)b |
24 |
6% |
41% |
35% (26%, 44%) |
| Mean change in visual acuity |
12 |
–9.5 (16.4) |
+11.3 (14.6) |
21.1 (17.5, 24.6) |
| (letters) (SD)b |
24 |
–9.8 (17.6) |
+10.7 (16.5) |
20.7 (16.8, 24.7) |
a Adjusted estimate based on the
stratified model.
b p < 0.01. |
Figure 1: Mean Change in Visual Acuity from Baseline to Month
24 in Study 1 and Study 2
Patients in the group treated with LUCENTIS had minimal observable CNV lesion
growth, on average. At Month 12, the mean change in the total area of the CNV
lesion was 0.1–0.3 DA for LUCENTIS versus 2.3–2.6 DA for the control arms. At
Month 24, the mean change in the total area of the CNV lesion was 0.3–0.4 DA
for LUCENTIS versus 2.9–3.1 DA for the control arms.
The use of LUCENTIS beyond 24 months has not been studied.
Study 3
Study 3 was a randomized, double-masked, sham-controlled, two-year study designed
to assess the safety and efficacy of LUCENTIS in patients with neovascular AMD
(with or without a classic CNV component). Data are available through Month
12. Patients received LUCENTIS 0.3 mg or 0.5 mg intravitreal injections or sham
injections once a month for 3 consecutive doses, followed by a dose administered
once every 3 months. A total of 184 patients were enrolled in this study (LUCENTIS
0.3 mg, 60; LUCENTIS 0.5 mg, 61; sham, 63); 171 (93%) completed 12 months of
this study. Patients treated with LUCENTIS in Study 3 received a mean of 6 total
treatments out of possible 6 from Day 0 through Month 12.
In Study 3, the primary efficacy endpoint was mean change in visual acuity
at 12 months compared with baseline (see Figure 2). After an initial increase
in visual acuity (following monthly dosing), on average, patients dosed once
every three months with LUCENTIS lost visual acuity, returning to baseline at
Month 12. In Study 3, almost all LUCENTIS-treated patients (90%) maintained
their visual acuity at Month 12.
Figure 2: Mean Change in Visual Acuity from Baseline to Month
12 in Study 3
Last updated on RxList: 1/26/2009