Assessing the Potential Risk of Cross-Reactivity Between Anti-Bococizumab Antibodies and Other Anti-PCSK9 Monoclonal Antibodies.

BACKGROUND: Anti-drug antibodies (ADAs) to bococizumab were detected in > 40% of subjects in the SPIRE lipid-lowering trials. The risk of cross-reactivity between anti-bococizumab antibodies and other approved anti-proprotein convertase subtilisin/kexin type-9 (PCSK9) monoclonal antibodies (mAbs) was investigated using a single-assay approach. METHODS: Bococizumab immunogenicity was assessed in SPIRE-HR, a 52-week study. The highest ADA titer sample from each ADA-positive subject (n = 155) was tested in vitro for cross-reactivity to alirocumab and evolocumab using a novel ADA assay approach. Additional specificity tiers within the bococizumab ADA assay against each drug were validated using recombinant PCSK9 as a surrogate cross-reactive positive control. If the highest ADA titer sample showed cross-reactivity, additional samples from that subject were analyzed. Cross-reactivity was determined by the ability of alirocumab or evolocumab to inhibit the sample signal greater than or equal to the cross-reactivity cut-points. RESULTS: ADAs were detected in 44.0% (155/352) of bococizumab-treated subjects, and 27.0% also developed neutralizing antibodies (NAbs). Median ADA and NAb titers ranged from 276 to 526 and 8 to 12 over the course of the study, respectively. From 155 ADA-positive subjects tested for cross-reactivity, one (0.6%) subject showed weak cross-reactivity to both alirocumab and evolocumab. This cross-reactivity signal was transient (from Days 337 to 373) and undetectable at the last ADA-positive timepoint (Day 407). CONCLUSION: A novel, single-assay approach was validated to assess the potential cross-reactivity of anti-bococizumab antibodies to alirocumab and evolocumab. In subjects who developed ADAs to bococizumab, the likelihood of clinically relevant cross-reactivity to marketed anti-PCSK9 mAbs is remote, based on the low frequency of cross-reactivity observed, which was weak in signal inhibition and transient in nature. CLINICAL TRIAL REGISTRATION: The SPIRE-HR study is registered on ClinicalTrials.gov under the identifier NCT01968954.

Multiple-dose ponezumab for mild-to-moderate Alzheimer's disease: Safety and efficacy.

INTRODUCTION: Multiple intravenous doses of ponezumab, an anti-amyloid antibody, were evaluated in subjects with mild-to-moderate Alzheimer's disease (AD). METHODS: In part A, 77 subjects were randomized to ponezumab 0.1, 0.5, or 1 mg/kg (75 treated) and 26 to placebo (24 treated). In part B, 63 subjects were randomized and treated with ponezumab 3 or 8.5 mg/kg and 32 with placebo. Subjects received 10 infusions over 18 months and were followed for 6 months thereafter. RESULTS: Ponezumab was generally safe and well tolerated. Most common adverse events were fall (16.7% ponezumab, 21.4% placebo), headache (13.8%, 21.4%), and cerebral microhemorrhage (13.8%, 19.6%). Plasma ponezumab increased dose-dependently with limited accumulation. Cerebrospinal fluid penetration was low. Plasma Aß1-x and Aß1-40 showed robust increases, but cerebrospinal fluid biomarkers showed no dose response. Ponezumab had no effects on cognitive/functional outcomes or brain volume. CONCLUSIONS: Multiple-dose ponezumab was generally safe, but not efficacious, in mild-to-moderate AD.

Ponezumab in mild-to-moderate Alzheimer's disease: Randomized phase II PET-PIB study.

INTRODUCTION: The safety, pharmacokinetics, and effect on peripheral and central amyloid ß (Aß) of multiple doses of ponezumab, an anti-Aß monoclonal antibody, were characterized in subjects with mild-to-moderate Alzheimer's disease treated for 1 year. METHODS: Subjects were aged ≥50 years with Mini-Mental State Examination scores 16 to 26. Cohort Q was randomized to ponezumab 10 mg/kg (n = 12) or placebo (n = 6) quarterly. Cohort M was randomized to a loading dose of ponezumab 10 mg/kg or placebo, followed by monthly ponezumab 7.5 mg/kg (n = 12) or placebo (n = 6), respectively. RESULTS: Ponezumab was generally well tolerated. Plasma concentrations increased dose dependently, but cerebrospinal fluid (CSF) penetration was low. Plasma Aß increased dose dependently with ponezumab, but CSF biomarkers, brain amyloid burden, cognition, and function were not affected. CONCLUSIONS: Both ponezumab dosing schedules were generally safe and well tolerated but did not alter CSF biomarkers, brain amyloid burden, or clinical outcomes.

Lipid-Reduction Variability and Antidrug-Antibody Formation with Bococizumab.

BACKGROUND: Bococizumab, a humanized monoclonal antibody targeting proprotein convertase subtilisin-kexin type 9 (PCSK9), reduces levels of low-density lipoprotein (LDL) cholesterol. However, the variability and durability of this effect are uncertain. METHODS: We conducted six parallel, multinational lipid-lowering trials enrolling 4300 patients with hyperlipidemia who were randomly assigned to receive 150 mg of bococizumab or placebo subcutaneously every 2 weeks and who were followed for up to 12 months; 96% were receiving statin therapy at the time of enrollment. The patients were assessed for lipid changes over time, stratified according to the presence or absence of antidrug antibodies detected during the treatment period. RESULTS: At 12 weeks, patients who received bococizumab had a reduction of 54.2% in the LDL cholesterol level from baseline, as compared with an increase of 1.0% among those who received placebo (absolute between-group difference, -55.2 percentage points). Significant between-group differences were also observed in total cholesterol, non-high-density lipoprotein cholesterol, apolipoprotein B, and lipoprotein(a) (P<0.001 for all comparisons). However, high-titer antidrug antibodies developed in a substantial proportion of the patients who received bococizumab, which markedly diminished the magnitude and durability of the reduction in LDL cholesterol levels. In addition, among patients with no antidrug antibodies, there was wide variability in the reduction in LDL cholesterol levels at both 12 weeks and 52 weeks. Major cardiovascular events occurred in 57 patients (2.5%) who received bococizumab and in 55 (2.7%) who received placebo (hazard ratio, 0.96; 95% confidence interval, 0.66 to 1.39; P=0.83). The most common adverse event among patients who received bococizumab was injection-site reaction (12.7 per 100 person-years). CONCLUSIONS: In six multinational trials evaluating bococizumab, antidrug antibodies developed in a large proportion of the patients and significantly attenuated the lowering of LDL cholesterol levels. Wide variation in the relative reduction in cholesterol levels was also observed among patients in whom antidrug antibodies did not develop. (Funded by Pfizer; SPIRE ClinicalTrials.gov numbers, NCT01968954 , NCT01968967 , NCT01968980 , NCT02100514 , NCT02135029 , and NCT02458287 .).

Cardiovascular Efficacy and Safety of Bococizumab in High-Risk Patients.

BACKGROUND: Bococizumab is a humanized monoclonal antibody that inhibits proprotein convertase subtilisin-kexin type 9 (PCSK9) and reduces levels of low-density lipoprotein (LDL) cholesterol. We sought to evaluate the efficacy of bococizumab in patients at high cardiovascular risk. METHODS: In two parallel, multinational trials with different entry criteria for LDL cholesterol levels, we randomly assigned the 27,438 patients in the combined trials to receive bococizumab (at a dose of 150 mg) subcutaneously every 2 weeks or placebo. The primary end point was nonfatal myocardial infarction, nonfatal stroke, hospitalization for unstable angina requiring urgent revascularization, or cardiovascular death; 93% of the patients were receiving statin therapy at baseline. The trials were stopped early after the sponsor elected to discontinue the development of bococizumab owing in part to the development of high rates of antidrug antibodies, as seen in data from other studies in the program. The median follow-up was 10 months. RESULTS: At 14 weeks, patients in the combined trials had a mean change from baseline in LDL cholesterol levels of -56.0% in the bococizumab group and +2.9% in the placebo group, for a between-group difference of -59.0 percentage points (P<0.001) and a median reduction from baseline of 64.2% (P<0.001). In the lower-risk, shorter-duration trial (in which the patients had a baseline LDL cholesterol level of ≥70 mg per deciliter [1.8 mmol per liter] and the median follow-up was 7 months), major cardiovascular events occurred in 173 patients each in the bococizumab group and the placebo group (hazard ratio, 0.99; 95% confidence interval [CI], 0.80 to 1.22; P=0.94). In the higher-risk, longer-duration trial (in which the patients had a baseline LDL cholesterol level of ≥100 mg per deciliter [2.6 mmol per liter] and the median follow-up was 12 months), major cardiovascular events occurred in 179 and 224 patients, respectively (hazard ratio, 0.79; 95% CI, 0.65 to 0.97; P=0.02). The hazard ratio for the primary end point in the combined trials was 0.88 (95% CI, 0.76 to 1.02; P=0.08). Injection-site reactions were more common in the bococizumab group than in the placebo group (10.4% vs. 1.3%, P<0.001). CONCLUSIONS: In two randomized trials comparing the PCSK9 inhibitor bococizumab with placebo, bococizumab had no benefit with respect to major adverse cardiovascular events in the trial involving lower-risk patients but did have a significant benefit in the trial involving higher-risk patients. (Funded by Pfizer; SPIRE-1 and SPIRE-2 ClinicalTrials.gov numbers, NCT01975376 and NCT01975389 .).

Evaluating bococizumab, a monoclonal antibody to PCSK9, on lipid levels and clinical events in broad patient groups with and without prior cardiovascular events: Rationale and design of the Studies of PCSK9 Inhibition and the Reduction of vascular Events (SPIRE) Lipid Lowering and SPIRE Cardiovascular Outcomes Trials.

BACKGROUND: Although statins significantly reduce vascular event rates, residual cholesterol risk remains high in many patient groups, including those with known vascular disease as well as in the setting of high-risk primary prevention. Bococizumab is a humanized monoclonal antibody that inhibits proprotein convertase subtilisin-kexin type 9 (PCSK9), prolongs the half-life of hepatic low-density lipoprotein (LDL) receptors, and reduces circulating atherogenic cholesterol levels. DESIGN: The SPIRE program comprises 6 lipid-lowering studies and 2 cardiovascular outcomes trials, each comparing bococizumab (150 mg subcutaneously every 2 weeks) to matching placebo. The 6 SPIRE lipid-lowering studies include 3 parallel 12-month assessments of bococizumab on atherogenic lipids among statin-treated individuals at high residual risk (SPIRE-HR, SPIRE-LDL, SPIRE-LL), one 12-month study of bococizumab among individuals with familial hypercholesterolemia (SPIRE-FH), one 6-month study of bococizumab among those with statin intolerance (SPIRE-SI), and one 3-month study of bococizumab delivery using an auto-injector device (SPIRE-AI). The SPIRE-1 and SPIRE-2 event-driven cardiovascular outcome trials will assess the efficacy and safety of bococizumab in the prevention of incident vascular events in high-risk populations with and without clinically evident cardiovascular disease who have directly measured entry LDL cholesterol levels ≥70 mg/dL (SPIRE-1, n = 17,000) or ≥100 mg/dL (SPIRE-2, n = 11,000). SUMMARY: The SPIRE trials, inclusive of more than 30,000 participants worldwide, will ascertain the magnitude of reduction in atherogenic lipids that accrue with bococizumab and determine whether the addition of this PCSK9 inhibitor to standard treatment significantly reduces cardiovascular morbidity and mortality in high-risk patients, including those without a history of clinical cardiovascular events.

Trough insulin levels in bronchoalveolar lavage following inhaled human insulin (Exubera) in patients with diabetes mellitus.

BACKGROUND/AIM: There are few data regarding insulin levels in the lungs during diabetes therapy with inhaled insulin. We examined the disposition of inhaled human insulin (Exubera(®) [EXU] human insulin [recombinant DNA origin], Pfizer, New York, NY) in the lungs by measuring trough insulin levels in bronchoalveolar lavage (BAL) fluid after 12 weeks of EXU treatment. METHODS: After a 4-week run-in period of subcutaneous insulin therapy, 24 subjects with type 1 diabetes mellitus (T1DM) and 26 with type 2 diabetes mellitus (T2DM) continued their basal insulin regimen and received premeal subcutaneous (SC) insulin for 13 weeks, followed by 12 weeks of premeal EXU. BAL was performed approximately 12 h after the last insulin dose at (1) baseline, (2) following SC insulin, and (3) following EXU. RESULTS: Twenty patients with T1DM and 24 patients with T2DM completed all three bronchoscopies. BAL trough insulin levels were undetectable at baseline or following SC insulin. After EXU therapy, they increased to a median of 4.5 nM (1.6-9.0 nM) and 2.3 nM (0.5-9.4 nM) in T1DM and T2DM, respectively. BAL trough insulin levels did not correlate with treatment efficacy, adverse effects, plasma insulin levels, or changes in pulmonary function. A larger proportion of previous EXU doses was present in the BAL in patients with T1DM. We found no correlation between average daily insulin doses and BAL trough insulin levels. CONCLUSIONS: BAL trough insulin increased following EXU therapy, but this increase did not correlate with other clinical or laboratory parameters, suggesting no significant biological action. Further studies are warranted to better understand inhaled insulin deposition and clearance and possible effects of increased insulin levels on the lungs.

Assessment of long-term immunological and pulmonary safety of inhaled human insulin with up to 24 months of continuous therapy.

BACKGROUND: This study was performed to characterize the long-term safety and efficacy of inhaled human insulin (EXU; Exubera * (insulin human [rDNA origin]) Inhalation Powder). * Pfizer Inc, New York, NY, USA. SCOPE: Patients with type 1 or type 2 diabetes (N = 1290) who had successfully completed one of six controlled EXU open-label trials elected to receive open-label treatment with EXU for up to 3 years, after which they were randomized to discontinue EXU or to continue therapy for 6 months, then discontinue. Immunologic safety was assessed by insulin antibody (IAb) binding, and pulmonary safety was assessed by tests for forced expiratory volume in 1 second (FEV(1)) and carbon monoxide diffusing capacity (DL(CO)). In addition, changes over time in IAbs were compared with changes in FEV(1), DL(CO), hypoglycemia, and efficacy. FINDINGS: Antibody binding increased in patients with either type 1 or type 2 diabetes after initiation of EXU and plateaued within 6-12 months (increases were higher in patients with type 1 diabetes than in patients with type 2 diabetes). Decreases in FEV(1) occurred primarily during the first 3-6 months of EXU therapy. Among adult patients in the All Subjects set, the mean (± SE) annualized rate of decline in FEV(1) was -0.053 ± 0.007 liters/year (95% CI, -0.065, -0.040) in adult patients with type 1 diabetes, and -0.076 ± 0.005 liters/year (95% CI, -0.085, -0.067) in patients with type 2 diabetes. Changes in DL(CO) occurred primarily during the first 3-6 months of EXU therapy. Among adult patients, in the All Subjects set, the mean (± SE) annual decline in DL(CO) was -0.738 ± 0.097 mL/min/mmHg/year (95% CI, -0.927, -0.548) and -0.688 ± 0.082 mL/min/mmHg/year (95% CI, -0.849, -0.527) in patients with type 1 and type 2 diabetes, respectively. Antibody binding did not correlate with changes in glycemic control, lung function, dose, or hypoglycemia. Following discontinuation of EXU, IAbs decreased to near baseline levels. CONCLUSION: These results are consistent with other trials showing long-term maintenance of safety and efficacy of EXU despite insulin antibody formation and small treatment group differences in pulmonary function. A limitation of the study was the lack of a comparator therapy.

Intersession variability in single-breath diffusing capacity in diabetics without overt lung disease.

RATIONALE: American Thoracic Society guidelines state that a 10% or greater intersession change in diffusing capacity of the lung (DL(CO)) should be considered clinically significant. However, little is known about the short-term intersession variability in DL(CO) in untrained subjects or how variability is affected by rigorous external quality control. OBJECTIVES: To characterize the intersession variability of DL(CO) and the effect of different quality control methods in untrained individuals without significant lung disease. METHODS: Data were pooled from the comparator arms of 14 preregistration trials of inhaled insulin that included nonsmoking diabetic patients without significant lung disease. A total of 699 participants performed repeated DL(CO) measurements using a highly standardized technique. A total of 948 participants performed repeated measurements using routine clinical testing. MEASUREMENTS AND MAIN RESULTS: The mean intersession absolute change in DL(CO) using the highly standardized method was 1.45 ml/minute/mm Hg (5.64%) compared with 2.49 ml/minute/mm Hg (9.52%) in the routine testing group (P < 0.0001 for both absolute and percent difference). The variability in absolute intersession change in DL(CO) increased with increasing baseline DL(CO) values, whereas the absolute percentage of intersession change was stable across baseline values. Depending on the method, 15.5 to 35.5% of participants had an intersession change of 10% or greater. A 20% or greater threshold would reduce this percentage of patients to 1 to 10%. CONCLUSIONS: Intersession variability in DL(CO) measurement is dependent on the method of testing used and baseline DL(CO). Using a more liberal threshold to define meaningful intersession change may reduce the misclassification of normal variation as abnormal change.

Standardization of the single-breath diffusing capacity in a multicenter clinical trial.

BACKGROUND: Standardization of the measurement of single-breath diffusing capacity of the lung for carbon monoxide (DLCO) is difficult to implement in multicenter trials as differences in equipment, training, and performance guidelines have led to high variability between and within centers. The safety assessment of inhalable insulin required the standardization of measurement of single-breath DLCO in multicenter clinical trials to optimize test precision. METHODS: This was an open-label, 24-week, parallel-group, outpatient study of inhaled human insulin in participants with type 1 diabetes who were randomly assigned to receive treatment with daily premeal inhaled or subcutaneous (SC) insulin for 12 weeks, followed by SC insulin for 12 weeks. Monitoring of single-breath DLCO using standardized methodology was performed. Standardization included uniform instrumentation, centrally trained study coordinators, and centralized data monitoring and review of quality control. Sites received feedback within 24 h for any tests of unacceptable quality with recommendations for improvement. RESULTS: A total of 226 study participants at 33 sites completed 11,335 DLCO efforts during 4,797 test sessions; 3,607 (75.2%) and 4,581 (95.5%) of all testing sessions yielded two American Thoracic Society-acceptable efforts that varied by < 1 and 2 mL/min/mm Hg, respectively. Only 65 sessions produced one or fewer acceptable efforts. The root mean square intrasubject coefficient of variation in DLCO at the end of the comparative dosing phase was 6.01%. CONCLUSIONS: The standardized methodology employed in this study demonstrates the feasibility of collecting high-quality single-breath DLCO data in the setting of a multicenter clinical trial with reliability that is comparable to spirometry.