Eculizumab (Soliris) is a first-in-class terminal complement inhibitor discovered, developed, and commercialized by Alexion Pharmaceuticals (Cheshire, CT). It has received approval from the US Food and Drug Administration (FDA) for four conditions: paroxysmal nocturnal hemoglobinuria (PNH), on March 16, 2007; atypical hemolytic–uremic syndrome (aHUS), on September 23, 2011; generalized myasthenia gravis (gMG) on October 23, 2017; and neuromyelitis optica spectrum disorder (NMOSD) on June 27, 2019. Eculizumab (Soliris) is a monoclonal antibody (mAb) that specifically binds to the complement protein with high affinity, thereby inhibiting its cleavage to C5a and C5b and preventing the generation of the terminal complement complex C5b-9. It is administered by intravenous infusion.
Biosimilar agents for eculizumab (Soliris) have been filed with the FDA for development. The time frame for approval is unknown.
Ravulizumab-cwvz (Ultomiris), a complement inhibitor, is a humanized mAb produced in Chinese hamster ovary (CHO) cells. Ravulizumab-cwvz is an antibody that is a terminal complement inhibitor that specifically binds with high affinity to the complement protein C5, inhibiting its cleavage to C5a (the proinflammatory anaphylatoxin) and C5b (the initiating subunit of the terminal complement complex [C5b-9]) and preventing generation of the terminal complement complex C5b9. The C5 inhibition of complement-mediated hemolysis achieved by ravulizumab-cwvz in individuals with PNH is immediate, thorough, and sustained. Ravulizumab-cwvz (Ultomiris) was approved by the FDA for the treatment of PNH in adult individuals only and atypical aHUS in individuals 1 month of age and older.
PAROXYSMAL NOCTURNAL HEMOGLOBINURIA
PNH is a rare condition caused by genetic mutation in the production of red blood cells (RBCs). The mutation causes RBCs to form without terminal complement inhibitors. The absence of complement inhibitors leads to the constant premature destruction and loss of RBCs (hemolysis) by the individual’s own immune system. The premature loss of RBCs can result in anemia, fatigue, difficulty in functioning, dark urine, pain, shortness of breath, and blood clots. Eculizumab (Soliris) inhibits RBC mutation and prevents intravascular hemolysis.
The safety and efficacy of eculizumab (Soliris) in individuals with PNH with hemolysis were assessed in a randomized, double-blind, placebo-controlled 26-week study (Study 1). Individuals with PNH were also treated with eculizumab (Soliris) in a single-arm 52-week study (Study 2), and in a long-term extension study. Individuals received meningococcal vaccination prior to receipt of eculizumab (Soliris). In all studies, the dose of eculizumab (Soliris) was 600 mg every 7 ± 2 days for 4 weeks, followed by 900 mg 7 ± 2 days later, then 900 mg every 14 ± 2 days for the study duration. Eculizumab (Soliris) was administered as an intravenous infusion over 25 to 45 minutes.
In Study 1, individuals with PNH with at least four transfusions in the prior 12 months, flow cytometric confirmation of at least 10% PNH cells, and platelet counts of at least 100,000/microliter were randomly assigned to either eculizumab (Soliris) (n=43) or placebo (n=44). Prior to randomization, all individuals underwent an initial observation period to confirm the need for RBC transfusion and to identify the hemoglobin concentration (the "set-point"), which would define each individual’s hemoglobin stabilization and transfusion outcomes. The hemoglobin set-point was less than or equal to 9 g/dL in individuals with symptoms and was less than or equal to 7 g/dL in individuals without symptoms. Endpoints related to hemolysis included the numbers of individuals achieving hemoglobin stabilization, the number of RBC units transfused, fatigue, and health-related quality of life. To achieve a designation of hemoglobin stabilization, an individual had to maintain a hemoglobin concentration above the hemoglobin set-point and avoid any RBC transfusion for the entire 26-week period. Hemolysis was monitored mainly by the measurement of serum lactate dehydrogenase (LDH) levels, and the proportion of PNH RBCs was monitored by flow cytometry. Individuals receiving anticoagulants and systemic corticosteroids at baseline continued these medications. Individuals treated with eculizumab (Soliris) had significantly reduced (P<0.001) hemolysis resulting in improvements in anemia as indicated by increased hemoglobin stabilization and reduced need for RBC transfusions compared to individuals receiving placebo. These effects were seen among individuals within each of the three pre-study RBC transfusion strata (4 to 14 units; 15 to 25 units; >25 units). After 3 weeks of eculizumab (Soliris) treatment, individuals reported less fatigue and improved health-related quality of life. Because of the study sample size and duration, the effects of eculizumab (Soliris) on thrombotic events could not be determined.
In Study 2 and the long-term extension study, individuals with PNH with at least one transfusion in the prior 24 months and a platelet count of at least 30,000 platelets/microliter received eculizumab (Soliris) over a 52-week period. Concomitant medications included antithrombotic agents in 63% of the individuals and systemic corticosteroids in 40% of the individuals. Overall, 96 of the 97 enrolled individuals completed the study (one individual died following a thrombotic event). A reduction in intravascular hemolysis as measured by serum LDH levels was sustained for the treatment period and resulted in a reduced need for RBC transfusion and less fatigue. A total of 187 individuals treated with eculizumab (Soliris) were enrolled in a long-term extension study. All individuals sustained a reduction in intravascular hemolysis over a total eculizumab (Soliris) exposure time ranging from 10 to 54 months. There were fewer thrombotic events with eculizumab (Soliris) treatment than during the same period of time prior to treatment. However, the majority of individuals received concomitant anticoagulants; the effect of anticoagulant withdrawal during eculizumab (Soliris) therapy was not studied.
In a study titled "A Phase 3, Randomized, Open-Label, Active-Controlled Study of ALXN1210 Versus Eculizumab in Complement Inhibitor-Naïve Adult individuals With Paroxysmal Nocturnal Hemoglobinuria (PNH)," with primary outcome measures of normalization of LDH levels within a time frame of 26 weeks, individuals with LDH ≥1.5 times the upper limit of normal and at least one PNH symptom were randomly assigned 1:1 to receive ravulizumab or eculizumab for 183 days (N=246). Coprimary efficacy endpoints were proportion of individuals remaining transfusion-free and LDH normalization. Secondary endpoints were percent change from baseline in LDH, change from baseline in Functional Assessment of Chronic Illness Therapy (FACIT)–Fatigue score, proportion of individuals with breakthrough hemolysis, stabilized hemoglobin, and change in serum free C5. Ravulizumab was noninferior to eculizumab for both coprimary and all key secondary endpoints (Pinf <0.0001): transfusion avoidance (73.6% vs 66.1%; difference of 6.8% [95% confidence interval [CI], −4.66–18.14]), LDH normalization (53.6% vs 49.4%, odds ratio [OR] 1.19 [0.80–1.77]), percent reduction in LDH (−76.8% vs −76.0%; difference [95% CI], −0.83% [−5.21, 3.56]), change in FACIT–Fatigue score (7.07 vs 6.40; difference [95% CI], 0.67 [−1.21−2.55]), breakthrough hemolysis (4.0% vs 10.7%; difference [95% CI], −6.7%
[−14.21–0.18]), and stabilized hemoglobin (68.0% vs 64.5%; difference [95% CI], 2.9 [−8.80–14.64]). The safety and tolerability of ravulizumab and eculizumab were similar; no meningococcal infections occurred. In conclusion, ravulizumab given every 8 weeks achieved noninferiority compared with eculizumab given every 2 weeks for all efficacy endpoints, with a similar safety profile.
Ravulizumab was investigated in two large, phase 3 studies (study 301 and study 302) of PNH individuals who were either naïve to or receiving prior complement inhibitor therapy. In study 301, 246 individuals received study drug (ravulizumab, n=125; eculizumab, n=121); 195 received study drug in study 302 (ravulizumab, n=97; eculizumab, n=98). Ravulizumab met the primary objective of statistically significant noninferiority compared with eculizumab for all primary and key secondary endpoints in both studies. Complete suppression of free C5 was attained by the end of first ravulizumab infusion (mean serum free C5 concentrations <0.5 mcg/mL) and was sustained throughout the entire 183-day treatment period for all individuals at all time points in both studies. In contrast, mean free C5 concentrations did not consistently remain less than 0.5 mcg/mL with eculizumab in either study (Panels 1 and 2). In studies 301 and 302, 15 (12.4%) and 7 (7.1%) eculizumab-treated individuals experienced one or more individual postbaseline serum free C5 level ≥0.5 mcg/mL over the 183-day treatment period.
In those studies of PNH individuals who were either naïve to or receiving prior complement inhibitor therapy, ravulizumab every 8 weeks led to immediate, complete, and sustained complement C5 inhibition in all individuals, whereas the effect of eculizumab every 2 weeks was less consistent. In individuals treated with ravulizumab, free C5 suppression below the free C5 threshold was associated with complete inhibition of intravascular hemolysis, providing a mechanistic basis for the consistency of the point estimates for all endpoints.
The pediatric study, ALXN1210-PNH-304, was a multicenter, open-label Phase 3 study conducted in eculizumab-experienced and complement inhibitor treatment-naïve pediatric individuals with PNH. All individuals received a loading dose of ravulizumab-cwvz (Ultomiris) on day 1, followed by maintenance treatment on day 15 and once every 8 weeks (q8w) thereafter (for individuals weighing ≥20 kg), or once every 4 weeks (q4w) (for individuals weighing <20 kg). For individuals who entered the study on eculizumab therapy, day 1 of study treatment was planned to occur 2 weeks from the individual's last dose of eculizumab (Soliris). The regimens of ravulizumab-cwvz provided inhibition of terminal complement in all individuals throughout the entire 26-week treatment period regardless of prior experience with eculizumab. Following initiation of ravulizumab-cwvz treatment, steady-state therapeutic serum concentrations of ravulizumab-cwvz were achieved after the first dose and maintained throughout the primary evaluation period in both cohorts. Three of five complement inhibitor treatment-naïve individuals and six of eight eculizumab experienced individuals achieved hemoglobin stabilization by Week 26, respectively. Avoidance of a transfusion was reached in 11 out of 13 individuals during the 26-week Primary Evaluation Period. One individual experienced breakthrough hemolysis during the extension period.
A clinically relevant improvement from baseline in fatigue as assessed by Pediatric FACIT–Fatigue (i.e., mean improvement of >3 units for Pediatric FACIT–Fatigue scores) was sustained throughout the primary evaluation period in the five-complement inhibitor treatment naïve individuals. A slight improvement was also observed in eculizumab-experienced individuals. However, individual-reported fatigue may be a subjective estimation, because the study was not blinded to treatment assignment. The efficacy of ravulizumab-cwvz (Ultomiris) in pediatric individuals with PNH is similar to that observed in adult individuals with PNH enrolled in pivotal studies.
ATYPICAL HEMOLYTIC–UREMIC SYNDROME
aHUS is a rare and chronic blood disease that primarily affects kidney function. This condition can occur at any age but disproportionately affects children. The syndrome causes abnormal blood clots (thrombi) to form in small blood vessels in the kidneys. These clots can cause serious medical problems if they restrict or block blood flow. aHUS is characterized by three major features related to abnormal clotting: hemolytic anemia, thrombocytopenia, and kidney failure. Studies revealed that eculizumab (Soliris) was effective in improving kidney function and platelet count in pediatric and adult individuals, and in some cases eliminated the need for dialysis.
Five single-arm studies (four prospective [aHUS Studies 1, 2, 4 and 5] and one retrospective [aHUS Study 3]) evaluated the safety and efficacy of eculizumab (Soliris) for the treatment of aHUS. Individuals with aHUS received meningococcal vaccination prior to receipt of eculizumab (Soliris) or received prophylactic treatment with antibiotics until 2 weeks after vaccination. In all studies, the dose of eculizumab (Soliris) in adults and adolescents was 900 mg every 7 ± 2 days for 4 weeks, followed by 1200 mg 7 ± 2 days later, then 1200 mg every 14 ± 2 days thereafter. The dosing and frequency regimen for pediatric individuals weighing less than 40 kg enrolled in aHUS study 3 and study 5 was based on body weight. Efficacy evaluations were based on thrombotic microangiopathy (TMA) endpoints. Endpoints related to TMA included the following:
- Platelet count change from baseline
- Hematologic normalization (maintenance of normal platelet counts and LDH levels for at least 4 weeks)
- Complete TMA response (hematologic normalization plus at least a 25% reduction in serum creatinine for a minimum of 4 weeks)
- TMA-event free status (absence for at least 12 weeks of a decrease in platelet count of >25% from baseline, plasma exchange or plasma infusion, and new dialysis requirement)
- Daily TMA intervention rate (defined as the number of plasma exchange or plasma infusion interventions and the number of new dialyses required per individual per day)
aHUS Study 1 enrolled individuals who displayed signs of TMA despite receiving at least four plasma exchange/plasma infusion (PE/PI) treatments the week prior to screening. One individual had no PE/PI the week prior to screening because of PE/PI intolerance. To qualify for enrollment, individuals were required to have a platelet count ≤150 × 109 /L, evidence of hemolysis such as an elevation in serum LDH, and serum creatinine above the upper limits of normal, without the need for chronic dialysis. The median age was 28 (range, 17–68 years). Individuals enrolled in aHUS Study 1 were required to have thrombospondin type 1 motif, member 13 (ADAMTS13) activity level above 5%; observed range of values in the trial were 70% to 121%. Seventy-six percent of individuals had an identified complement regulatory factor mutation or autoantibody. Individuals in aHUS Study 1 received eculizumab (Soliris) for a minimum of 26 weeks. In aHUS Study 1, the median duration of eculizumab (Soliris) therapy was approximately 100 weeks (range, 2 weeks to 145 weeks). Renal function, as measured by eGFR, was improved and maintained during eculizumab (Soliris) therapy. The mean eGFR (± SD) increased from 23 ± 15 mL/min/1.73m2 at baseline to 56 ± 40 mL/min/1.73m2 by 26 weeks; this effect was maintained through 2 years (56 ± 30 mL/min/1.73m2 ). Four of the five individuals who required dialysis at baseline were able to discontinue dialysis. Reduction in terminal complement activity and an increase in platelet count relative to baseline were observed after commencement of eculizumab (Soliris). Eculizumab (Soliris) reduced signs of complement-mediated TMA activity, as shown by an increase in mean platelet counts from baseline to 26 weeks. In aHUS Study 1, mean platelet count (± SD) increased from 109 ± 32 ×109 /L at baseline to 169 ± 72 × 109 /L by 1 week; this effect was maintained through 26 weeks (210 ± 68 × 109 /L), and 2 years (205 ± 46 × 109 /L). When treatment was continued for more than 26 weeks, two additional individuals achieved hematologic normalization as well as complete TMA response. Hematologic normalization and complete TMA response were maintained by all responders. In aHUS Study 1, responses to eculizumab (Soliris) were similar in individuals with and without identified mutations in genes encoding complement regulatory factor proteins.
aHUS Study 2 enrolled individuals undergoing chronic PE/PI who generally did not display hematologic signs of ongoing TMA. All individuals had received PT at least once every 2 weeks, but no more than three times per week, for a minimum of 8 weeks prior to the first eculizumab (Soliris) dose. Individuals on chronic dialysis were permitted to enroll in aHUS Study 2. The median age was 28 years (range, 13–63 years). Individuals enrolled in aHUS Study 2 were required to have ADAMTS13 activity level above 5%; observed range of values in the trial were 37% to 118%. Seventy percent of individuals had an identified complement regulatory factor mutation or autoantibody. Individuals in aHUS Study 2 received eculizumab (Soliris) for a minimum of 26 weeks. In aHUS Study 2, the median duration of eculizumab (Soliris) therapy was approximately 114 weeks (range, 26–129 weeks). Renal function, as measured by estimated glomerular filtration rate (eGFR), was maintained during eculizumab (Soliris) therapy. The mean eGFR (± SD) was 31 ± 19 mL/min/1.73m2 at baseline, and was maintained through 26 weeks (37 ± 21 mL/min/1.73m2 ) and 2 years (40 ± 18 mL/min/1.73m2 ). No individual required new dialysis with eculizumab (Soliris). Reduction in terminal complement activity was observed in all individuals after the commencement of eculizumab (Soliris). Eculizumab (Soliris) reduced signs of complement-mediated TMA activity, as shown by an increase in mean platelet counts from baseline to 26 weeks. Platelet counts were maintained at normal levels despite the elimination of PE/PI. The mean platelet count (± SD) was 228 ± 78 × 109 /L at baseline, 233 ± 69 × 109 /L at week 26, and 224 ± 52 × 109 /L at 2 years. When treatment was continued for more than 26 weeks, six additional individuals achieved complete TMA response. Complete TMA response and hematologic normalization were maintained by all responders. In aHUS Study 2, responses to eculizumab (Soliris) were similar in individuals with and without identified mutations in genes encoding complement regulatory factor proteins.
The efficacy results for the aHUS retrospective study (aHUS Study 3) were generally consistent with results of the two prospective studies. Eculizumab (Soliris) reduced signs of complement-mediated TMA activity, as shown by an increase in mean platelet counts from baseline. Mean platelet count (± SD) increased from 171 ± 83 × 109 /L at baseline to 233 ±109 × 109 /L after 1 week of therapy; this effect was maintained through 26 weeks (mean platelet count [± SD] at week 26: 254 ± 79 × 109 /L). A total of 19 pediatric individuals (ages 2 months to 17 years) received eculizumab (Soliris) in aHUS Study 3. The median duration of eculizumab (Soliris) therapy was 16 weeks (range, 4–70 weeks) for children 2 to less than 12 years of age (n=10), and 38 weeks (range, 1–69 weeks) for individuals 12 to less than 18 years of age (n=4). Fifty-three percent of pediatric individuals had an identified complement regulatory factor mutation or autoantibody. Overall, the efficacy results for these pediatric individuals appeared consistent with what was observed in individuals enrolled in aHUS Studies 1 and 2. No pediatric individuals required new dialysis during treatment with eculizumab (Soliris).
aHUS Study 4 enrolled individuals who displayed signs of TMA. To qualify for enrollment, individuals were required to have a platelet count less than the lower limit of normal range (LLN), evidence of hemolysis such as an elevation in serum LDH, and serum creatinine above the upper limits of normal, without the need for chronic dialysis. The median age was 35 (range, 18–80 years). All individuals enrolled in aHUS Study 4 were required to have ADAMTS13 activity level above 5%; observed range of values in the trial were 28% to 116%. Fifty-one percent of individuals had an identified complement regulatory factor mutation or autoantibody. A total of 35 individuals received PE/PI prior to eculizumab (Soliris). Individuals in aHUS Study 4 received eculizumab (Soliris) for a minimum of 26 weeks. In aHUS Study 4, the median duration of eculizumab (Soliris) therapy was approximately 50 weeks (range, 13 weeks to 86 weeks). Renal function, as measured by eGFR, was improved during eculizumab (Soliris) therapy. The mean eGFR (± SD) increased from 17 ± 12 mL/min/1.73m2 at baseline to 47 ± 24 mL/min/1.73m2 by 26 weeks. Twenty of the 24 individuals who required dialysis at study baseline were able to discontinue dialysis during eculizumab (Soliris) treatment. Reduction in terminal complement activity and an increase in platelet count relative to baseline were observed after commencement of eculizumab (Soliris). Eculizumab (Soliris) reduced signs of complement-mediated TMA activity, as shown by an increase in mean platelet counts from baseline to 26 weeks. In aHUS Study 4, mean platelet count (± SD) increased from 119 ± 66 × 109 /L at baseline to 200 ± 84 × 109/L by 1 week; this effect was maintained through 26 weeks (mean platelet count [± SD] at week 26: 252 ± 70 × 109/L). In aHUS Study 4, responses to eculizumab (Soliris) were similar in individuals with and without identified mutations in genes encoding complement regulatory factor proteins or autoantibodies to factor H.
aHUS Study 5 enrolled individuals who were required to have a platelet count less than LLN, evidence of hemolysis such as an elevation in serum LDH above the upper limits of normal, serum creatinine level ≥97 percentile for age without the need for chronic dialysis. The median age was 6.5 (range, 5 months to 17 years). Individuals enrolled in aHUS Study 5 were required to have ADAMTS13 activity level above 5%; observed range of values in the trial were 38% to 121%. Fifty percent of individuals had an identified complement regulatory factor mutation or autoantibody. Ten individuals received PE/PI prior to eculizumab (Soliris). Individuals in aHUS Study 5 received eculizumab (Soliris) for a minimum of 26 weeks. In aHUS Study 5, the median duration of eculizumab (Soliris) therapy was approximately 44 weeks (range, 1 dose to 88 weeks). Renal function, as measured by eGFR, was improved during eculizumab (Soliris) therapy. The mean eGFR (± SD) increased from 33 ± 30 mL/min/1.73m2 at baseline to 98 ± 44 mL/min/1.73m2 by 26 weeks. Among the 20 individuals with a CKD stage 2 or higher at baseline, 17 (85%) achieved a CKD improvement of stage 1 or higher. Among the 16 individuals ages 1 month to less than 12 years with a CKD stage 2 or higher at baseline, 14 (88%) achieved a CKD improvement by 1 or higher stage. Nine of the 11 individuals who required daily dialysis at study baseline were able to discontinue dialysis during eculizumab (Soliris) treatment. Responses were observed across all ages from 5 months to 17 years of age. Reduction in terminal compliment activity was observed in all individuals after commencement with eculizumab (Soliris). Eculizumab (Soliris) reduced signs of complement-mediated TMA activity, as shown by an increase in mean platelet counts from baseline to 26 weeks. The mean platelet count (± SD) increased from 88 ± 42 × 109/L at baseline to 281 ± 123 x109/L by 1 week; this effect was maintained through 26 weeks (mean platelet count [±SD] at week 26: 293 ± 106 × 109/L). In aHUS Study 5, responses to eculizumab (Soliris) were similar in individuals with and without identified mutations in genes encoding complement regulatory factor proteins or autoantibodies to factor H.
Ravulizumab-cwvz (Ultomiris) was investigated in two global, single-arm, open-label studies that evaluated the efficacy of ravulizumab-cwvz in adult complement inhibitor-naïve, adolescent and pediatric individuals with aHUS. Study ALXN1210-aHUS-311 enrolled adult individuals and study ALXN1210-aHUS-312 enrolled pediatric (age range, 0.9–17.3 years) individuals, who displayed signs of TMA. Inclusion criteria for individuals were platelet count ≤150 × 109/L, evidence of hemolysis such as an elevation in serum LDH, and serum creatinine above the upper limits of normal or required dialysis, and meningococcal vaccination. In both studies, enrollment criteria excluded individuals presenting with TMA due to a disintegrin and metalloproteinase with a ADAMTS13 deficiency, Shiga toxin Escherichia coli–related hemolytic uremic syndrome (STEC-HUS), and genetic defect in cobalamin C metabolism. Individuals with confirmed diagnosis of STEC-HUS after enrollment were excluded from the efficacy evaluation. The ongoing pediatric study included 14 children in the interim analysis, and the adult study assessed a total of 56 individuals. The primary outcome measures for both studies was based on Complete TMA response during an initial 26-week evaluation period, defined by hematologic normalization parameters (platelet count and LDH) and improved kidney function (as measured by 25% or higher improvement in serum creatinine from baseline).
The studies demonstrated a Complete TMA Response in 71% (interim data; 95% CI, 0.42–0.92) of children and 54% (95% CI, 0.40–0.67) of adults during the initial 26-week treatment period. Other outcomes included platelet count change from baseline, dialysis requirement, and renal function as evaluated by estimated glomerular filtration rate (eGFR). Ravulizumab-cwvz treatment resulted in reduced thrombocytopenia in 93% (95% CI, 0.66–0.99) of children and 84% (95% CI, 0.72–0.92) of adults; reduced hemolysis in 86% (95% CI, 0.57–0.98) of children and 77% (95% CI, 0.64–0.87) of adults; and improved kidney function in 79% (95% CI, 0.49–0.95) of children and 59% (95% CI, 0.45–0.72) of adults. The most common adverse events were upper respiratory tract infection, diarrhea, nausea, vomiting, headache, hypertension, and pyrexia.
GENERALIZED MYASTHENIA GRAVIS
Myasthenia gravis (MG) is a chronic autoimmune neuromuscular disease that causes weakness in the skeletal muscles. The muscle weakness usually worsens after periods of activity and improves after periods of rest. Muscles that control movements of the eye and eyelid, facial expression, chewing, talking, and swallowing are often involved, but those that control breathing and neck and limb movements may also be involved. This weakness is a result of an antibody-mediated, T-cell dependent, immunological attack directed at proteins in the postsynaptic membrane of the neuromuscular junction. MG has an annual incidence of about seven to 23 cases per million. It most often begins before the age of 40 in women and after age 60 in men.
The efficacy of eculizumab (Soliris) for the treatment of generalized MG was established in a 26-week, randomized, double-blind, placebo-controlled, parallel group, multicenter trial (REGAIN) in 125 individuals. Among the inclusion criteria for this trial were a positive serologic test for antiacetylcholine receptor (AChR) antibodies, MG activities of daily living (MG-ADL) score of 6 or higher, and failed treatment over 1 year or more with two or more immunosuppressive therapies, or failed one immunosuppressive treatment and required chronic plasma exchange or IVIG. The primary endpoint of this trial was a change from baseline in the MG-ADL scale total score at week 26 between the placebo group and the eculizumab (Soliris) group. The MG-ADL scale is an individual-reported scale developed to assess eight typical signs and symptoms of MG and their effects on daily activities. Each item is assessed on a four-point scale in which 0 is normal function and 3 indicates loss of ability to perform that function. The change in MG-ADL score in the eculizumab (Soliris) treated group was −4.2 versus −2.3 in the placebo group. This trial narrowly missed statistical significance for the primary endpoint (P=0.0698); however, 18 of 22 pre-specified endpoints and analyses, based on the primary and five secondary endpoints, had results with P values less than 0.05 across the four assessment scales. A secondary endpoint was the change in Quantitative Myasthenia Gravis score. This is a 13-item, four-point categorical scale assessing muscle weakness from 0 (representing no weakness) to 3 (representing severe weakness). A statistically significant difference was observed in the mean change from baseline to week 26, in favor of Soliris, in total QMG scores (−4.6 in Soliris group vs −1.6 in placebo group).
The efficacy of ravulizumab-cwvz (Ultomiris) for the treatment of generalized MG was established in a randomized, double-blind, placebo-controlled, multicenter trial (ALXN1210-MG-306; NCT03920293) involving adult individuals with severe, refractory gMG and a positive serologic test for anti-AChR antibodies, MGFA clinical classification class II to IV. Inclusion criteria were a positive serologic test for AChR antibodies, MG activities of daily living (MG-ADL) score of 6 or higher. The primary efficacy endpoint was a change from baseline in the MG-ADL total score at week 26. One of the secondary endpoints was the change in the Quantitative MG total score (QMG), which is a 13-item categorical scale assessing muscle weakness. Additional secondary endpoints included the proportion of individuals with improvements of at least 5 and 3 points in the QMG and MG-ADL total scores, respectively. Treatment with ravulizumab-cwvz (Ultomiris) demonstrated a statistically significant change in the MG-ADL and QMG total scores from baseline at week 26 in comparison to placebo. The proportion of QMG responded individuals with at least a five-point improvement at week 26 was greater for Ultomiris (30.0%) compared to placebo (11.3%); P=0.005. The proportion of MG-ADL responded individuals with at least a 3-point improvement at week 26 was also greater for Ultomiris (56.7%) compared to placebo (34.1%). The proportion of clinical responders at higher response thresholds (≥ four-, five-, six-, seven-, or eight-point improvement on MG-ADL, and ≥ six-, seven-, eight-, nine-, or 10-point improvement on QMG) was consistently greater for Ultomiris compared to placebo. The most common adverse reactions (incidence ≥10%) were diarrhea and upper respiratory tract infection.
NEUROMYELITIS OPTICA SPECTRUM DISORDER
NMOSD is a relapsing, autoimmune, inflammatory disorder that typically affects the optic nerves and spinal cord. At least two thirds of cases are associated with aquaporin-4 antibodies (AQP4-IgG) and complement-mediated damage to the central nervous system.
The efficacy and safety of eculizumab (Soliris) for the treatment of individuals with AQP4-IgG–positive neuromyelitis optica was evaluated in a phase 3, randomized, double-blind, placebo-controlled, time-to-event trial (PREVENT [Prevention of Relapses in Neuromyelitis Optica]). The study enrolled 143 individuals were enrolled at 70 sites, primarily hospital clinics, in 18 countries. Of the 143 patients, 46 (32%) had received rituximab previously but not within the 3 months before screening. A total of 34 patients (24%) did not receive any concomitant immunosuppressive therapy during the trial. The baseline characteristics of the patients were well balanced between the two groups.
The individuals were stratified across sites according to the score on the Expanded Disability Status Scale (EDSS) on day 1 (≤2.0 or 2.5 to 7.0 on a scale ranging from 0 [no disability] to 10 [death]) and the use of concomitant immunosuppressive therapy. The trial was designed to continue until 24 individuals had a relapse of NMOSD, as adjudicated by an independent panel.
The primary endpoint was the time to the first adjudicated on-trial relapse. An On-trial Relapse was defined as a new onset of neurologic symptoms or worsening of existing neurologic symptoms with an objective change (clinical sign) on neurologic examination that persisted for more than 24 hours as confirmed by the treating physician. Secondary outcomes included the adjudicated annualized relapse rate (ARR), quality-of-life measures, and the score on the Expanded Disability Status Scale (EDSS), which ranges from 0 (no disability) to 10 (death). Adjudicated relapses occurred in 3 of 96 patients (3%) in the eculizumab group and 20 of 47 (43%) in the placebo group (hazard ratio, 0.06; 95% confidence interval [CI], 0.02 to 0.20; P<0.001). The adjudicated annualized relapse rate was 0.02 in the eculizumab group and 0.35 in the placebo group (rate ratio, 0.04; 95% CI, 0.01 to 0.15; P<0.001). The mean change in the EDSS score was -0.18 in the eculizumab group and 0.12 in the placebo group (least-squares mean difference, -0.29; 95% CI, -0.59 to 0.01). Upper respiratory tract infections and headaches were more common in the eculizumab group.
The efficacy and safety of Ultomiris in adult individuals with anti-AQP4 antibody positive NMOSD was studied in an open-label multicenter protocol, Study ALXN1210- NMO-307 (NCT04291262).
Study ALXN1210-NMO-307 enrolled 58 adult individuals with NMOSD who had a positive serologic test for anti-AQP4 antibodies, at least one relapse in the last 12 months prior to the Screening Period, and an Expanded Disability Status Scale (EDSS) score of 7 or less. In the placebo control group, eligibility criteria were similar except individuals were required to have at least two relapses in last 12 months or three relapses in the last 24 months with at least one relapse in the 12 months prior to screening.
The primary endpoint of Study ALXN1210-NMO-307 was the time to first adjudicated on-trial relapse. No relapses were observed in Ultomiris-treated individuals during the Primary Treatment Period, representing a statistically significant difference between the Ultomiris and placebo treatment arms in time to first adjudicated on-trial relapse (P<0.0001). The hazard ratio (95% CI) for Ultomiris compared with placebo was 0.014 (0.000, 0.103), representing a 98.6% reduction in the risk of relapse. Ultomiris-treated individuals experienced similar improvement in time to first adjudicated on-trial relapse with or without concomitant treatment. Most common adverse reactions in adult individuals with NMOSD (incidence ≥10%) were COVID-19, headache, back pain, arthralgia, and urinary tract infection.
RISK EVALUATION AND MITIGATION STRATEGY
Eculizumab (Soliris) and related biosimilars, ravulizumab-cwvz (Ultomiris) were approved by the FDA with a risk evaluation and mitigation strategy (REMS) due to the risk of meningococcal infections. Under the REMS, prescribers must enroll in the program, counsel individuals about the risk of meningococcal infection, provide individuals with the REMS educational materials, and ensure that individuals are vaccinated with a meningococcal vaccine.
OFF-LABEL INDICATIONS
There may be additional indications contained in the policy section of this document due to evaluation of criteria highlighted in the company's off-label policy, and/or review of clinical guidelines issued by leading professional organizations and government entities.