Steven Y. Hua

Travoprost 0.004% with and without benzalkonium chloride: a comparison of safety and efficacy.

PurposeTo compare the safety and efficacy of travoprost 0.004% without benzalkonium chloride (BAC) to that of the marketed formulation of travoprost 0.004% in patients with open-angle glaucoma or ocular hypertension. MethodsThe study was a double-masked, randomized, parallel group, multicenter, noninferiority design. Adult patients with open-angle glaucoma or ocular hypertension with qualifying intraocular pressure (IOP) on 2 eligibility visits received either travoprost 0.004% with BAC (n=346), or travoprost 0.004% without BAC (n=344) dosed once-daily each evening. Patients were followed for a period of 3 months. IOP measurements at 8 AM, 10 AM, and 4 PM were taken at study visits on week 2, week 6, and month 3. ResultsMean IOP reductions, across all 9 study visits and times ranged from 7.3 to 8.5 mm Hg for travoprost 0.004% without BAC and from 7.4 to 8.4 mm Hg for travoprost 0.004% with BAC. Statistical equivalence was also demonstrated for the comparison of mean IOP changes; 95% confidence limits were within ±0.8 mm Hg at 9 of 9 study visits and times in both the per protocol and intent-to-treat data sets. Adverse events and the number of patients discontinued owing to adverse events were similar for both treatment groups. Adverse events due to hyperemia occurred in 6.4% and 9.0% of patients treated with travoprost 0.004% without BAC and travoprost 0.004% with BAC, respectively. ConclusionTravoprost 0.004% without BAC is equivalent to travoprost 0.004% with BAC in both safety and efficacy.

Safety and Clinical Activity of a Combination Therapy Comprising Two Antibody-Based Targeting Agents for the Treatment of Non-Hodgkin Lymphoma: Results of a Phase I/II Study Evaluating the Immunoconjugate Inotuzumab Ozogamicin With Rituximab

PURPOSE Inotuzumab ozogamicin (INO) is an antibody-targeted chemotherapy agent composed of a humanized anti-CD22 antibody conjugated to calicheamicin, a potent cytotoxic agent. We performed a phase I/II study to determine the maximum-tolerated dose (MTD), safety, efficacy, and pharmacokinetics of INO plus rituximab (R-INO) for treatment of relapsed/refractory CD20(+)/CD22(+) B-cell non-Hodgkin lymphoma (NHL). PATIENTS AND METHODS A dose-escalation phase to determine the MTD of R-INO was followed by an expanded cohort to further evaluate the efficacy and safety at the MTD. Patients with relapsed follicular lymphoma (FL), relapsed diffuse large B-cell lymphoma (DLBCL), or refractory aggressive NHL received R-INO every 4 weeks for up to eight cycles. RESULTS In all, 118 patients received one or more cycles of R-INO (median, four cycles). Most common grade 3 to 4 adverse events were thrombocytopenia (31%) and neutropenia (22%). Common low-grade toxicities included hyperbilirubinemia (25%) and increased AST (36%). The MTD of INO in combination with rituximab (375 mg/m(2)) was confirmed to be the same as that for single-agent INO (1.8 mg/m(2)). Treatment at the MTD yielded objective response rates of 87%, 74%, and 20% for relapsed FL (n = 39), relapsed DLBCL (n = 42), and refractory aggressive NHL (n = 30), respectively. The 2-year progression-free survival (PFS) rate was 68% (median, not reached) for FL and 42% (median, 17.1 months) for relapsed DLBCL. CONCLUSION R-INO demonstrated high response rates and long PFS in patients with relapsed FL or DLBCL. This and the manageable toxicity profile suggest that R-INO may be a promising option for CD20(+)/CD22(+) B-cell NHL.

Intraocular Pressure-Lowering Efficacy of Brinzolamide 1%/Timolol 0.5% Fixed Combination Compared with Brinzolamide 1% and Timolol 0.5%

PURPOSE To compare the safety and intraocular pressure (IOP)-lowering efficacy of brinzolamide 1%/timolol 0.5% fixed combination with brinzolamide 1% or timolol 0.5% alone in patients with open-angle glaucoma (OAG) or ocular hypertension (OHT). DESIGN Randomized, double-masked, parallel group, multicenter study. PARTICIPANTS Five hundred twenty-three patients were randomized to the study treatments. METHODS Patients with OAG or OHT were recruited to the study. Qualifying eyes had IOPs of 24 to 36 mmHg at 8 am and 21 to 36 mmHg at 10 am on 2 eligibility visits after an appropriate washout period from previous treatment. Patients were assigned randomly to either brinzolamide 1%/timolol 0.5%, brinzolamide 1% (Azopt; Alcon Laboratories, Fort Worth, TX), or timolol 0.5%, dosed twice daily and were followed up while receiving therapy for 6 months. At selected sites, additional IOP measurements were performed at 12 pm, 4 pm, and 8 pm during the 2 eligibility visits, at month 3, and at month 6. MAIN OUTCOME MEASURE Mean IOP. RESULTS Brinzolamide 1%/timolol 0.5% produced statistically significant and clinically relevant reductions from baseline ranging from 8.0 to 8.7 mmHg, which were statistically and clinically superior to that of either brinzolamide 1% (5.1-5.6 mmHg) or timolol 0.5% (5.7-6.9 mmHg). No safety concerns were identified based on an assessment of ocular and cardiovascular parameters and a review of adverse events. CONCLUSIONS Brinzolamide 1%/timolol 05% is superior in IOP-lowering efficacy to either brinzolamide 1% or timolol 0.5%.

Efficacy of brinzolamide and levobetaxolol in pediatric glaucomas: A randomized clinical trial

PURPOSE To describe the safety and clinical response on elevated intraocular pressure (IOP) of brinzolamide and levobetaxolol in pediatric patients under 6 years of age. METHODS A double-masked, randomized design. Pediatric patients were randomized to brinzolamide suspension, 1%, or levobetaxolol suspension, 0.5%, both dosed twice daily. IOPs at 9 AM were taken at screening, baseline, and weeks 2, 6, and 12. A descriptive study with mean change from baseline IOP, the primary efficacy parameter. RESULTS Seventy-eight evaluable patients (32 brinzolamide and 46 levobetaxolol). Patients on no prestudy IOP-lowering therapy randomized to brinzolamide had mean IOP change from baseline ranging from -4.1 mm Hg (week 2) to -5.0 mm Hg (week 6). When all brinzolamide patients are considered, there was little mean change from baseline IOP due to the large number of patients enrolled without a washout of prior IOP-lowering therapy. Levobetaxolol patients had mean change from baseline, ranging from -1.8 mm Hg (week 6) to -2.9 mm Hg (week 2). Levobetaxolol patients on no prestudy therapy had mean IOP change from baseline ranging from -2.9 mm Hg (week 12) to -4.0 mm Hg (week 2). Brinzolamide was more efficacious for glaucoma associated with systemic or ocular abnormalities and less efficacious for primary congenital glaucoma. Levobetaxolol was most efficacious for primary congenital glaucoma. Adverse events were predominantly nonserious and did not interrupt patient continuation in the study. CONCLUSIONS Both brinzolamide and levobetaxolol were well tolerated. Both drugs provided clinically relevant IOP reductions for patients not on a previous medication, although efficacy is, in part, contingent upon diagnosis.

SAT0142 Immunogenicity Assessment of PF-06438179, A Potential Biosimilar to Infliximab, In Healthy Volunteers

Background PF-06438179 is being developed as a potential biosimilar to Remicade® (infliximab) in a stepwise approach following globally accepted regulatory guidelines. PF-06438179 was shown to have an identical primary amino acid sequence and similar physicochemical, in vitro and in vivo functional properties to infliximab reference products sourced from the European Union (infliximab-EU) and United States (infliximab-US). Objectives PF-06438179 was evaluated for immunogenicity in a Phase I pharmacokinetic (PK) similarity study; safety was also evaluated. Methods In this double-blind trial (NCT01844804), 146 healthy volunteers received a single 10-mg/kg IV dose of PF-06438179 (n=49), infliximab-EU (n=48) or infliximab-US (n=49). All subjects provided informed consent. Safety and immunogenicity were evaluated over 12 weeks and PK over 8 weeks. Serum samples for detecting anti-drug antibodies (ADA) and neutralizing antibodies (NAb) were collected up to 12 weeks postdose. ADA samples were analyzed using 2 validated electrochemiluminescent immunoassays, 1 each to detect ADA against PF-06438179 and reference drugs (infliximab-EU or -US). A tiered approach of screening, confirmation and titer quantitation was used. Samples were tested first for ADA against the dosed product and confirmed ADA-positive samples were tested for ADA cross-reactivity using the alternate ADA assay. ADA-positive samples were analyzed for NAb using a validated semi-quantitative cell-based assay against the dosed product and for NAb cross-reactivity using the alternative NAb assay. Cross-reactivity was also examined using the alternate ADA assay for the week 12 samples that tested negative against the dosed product. Results Samples for immunogenicity assessment were collected from 146 subjects. No subject tested positive for ADA at baseline. Six out of 37 (16.2%), 14/43 (32.6%) and 11/39 (28.2%) subjects in the PF-06438179, infliximab-EU and infliximab-US groups, respectively, had ≥1 ADA-positive sample through Day 85. Of these 31 subjects, 27 (6/6 PF-06438179; 10/14 infliximab-EU; 11/11 infliximab-US) also tested positive for cross-reactivity by alternative assay, suggesting that ADA were likely developed against epitopes shared among study drugs. Of the 31 subjects who tested ADA positive, 26 tested positive for NAb (5/6 PF-06438179; 12/14 infliximab-EU; 9/11 infliximab-US). Cross-reactivity was further demonstrated by negative ADA samples, which were confirmed by alternative assay. Overall safety profiles were similar across the three cohorts and no infusion related reactions were reported. Conclusions The three study drugs had comparable immunogenicity profiles, however, a lower incidence of ADA response was observed in the PF-06438179 group. The majority of ADA-positive subjects also developed NAb. PF-06438179 demonstrated PK similarity and comparable safety profiles to infliximab-EU and -US in healthy subjects. An ongoing global, comparative study assessing the efficacy and safety of PF-06438179 and infliximab-EU in subjects with active rheumatoid arthritis who had an inadequate response to methotrexate will include a comparative assessment of immunogenicity. Disclosure of Interest C. Udata Employee of: Pfizer Inc, D. Yin Shareholder of: Pfizer Inc, Employee of: Pfizer Inc, C.-H. Cai Employee of: Pfizer Inc, S. Hua Employee of: Pfizer Inc, S. Salts Employee of: Pfizer Inc, M. Rehman Employee of: Pfizer Inc, A. AL-Sabbagh Employee of: Pfizer Inc, J. McClellan Employee of: Pfizer Inc, X. Meng Employee of: Pfizer Inc

Statistical considerations in bioequivalence of two area under the concentration–time curves obtained from serial sampling data

In this paper, we study the bioequivalence (BE) inference problem motivated by pharmacokinetic data that were collected using the serial sampling technique. In serial sampling designs, subjects are independently assigned to one of the two drugs; each subject can be sampled only once, and data are collected at K distinct timepoints from multiple subjects. We consider design and hypothesis testing for the parameter of interest: the area under the concentration–time curve (AUC). Decision rules in demonstrating BE were established using an equivalence test for either the ratio or logarithmic difference of two AUCs. The proposed t-test can deal with cases where two AUCs have unequal variances. To control for the type I error rate, the involved degrees-of-freedom were adjusted using Satterthwaites approximation. A power formula was derived to allow the determination of necessary sample sizes. Simulation results show that, when the two AUCs have unequal variances, the type I error rate is better controlled by the proposed method compared with a method that only handles equal variances. We also propose an unequal subject allocation method that improves the power relative to that of the equal and symmetric allocation. The methods are illustrated using practical examples.

Multiplicity adjustments in testing for bioequivalence

Bioequivalence of two drugs is usually demonstrated by rejecting two one-sided null hypotheses using the two one-sided tests for pharmacokinetic parameters: area under the concentration-time curve (AUC) and maximum concentration (Cmax). By virtue of the intersection-union test, there is no need for multiplicity adjustment in testing the two one-sided null hypotheses within each parameter. However, the decision rule for bioequivalence often requires equivalence to be achieved simultaneously on both parameters that contain four one-sided null hypotheses together; without adjusting for multiplicity, the family wise error rate (FWER) could fail to be controlled at the nominal type-I error rate α. The multiplicity issue for bioequivalence in this regard is scarcely discussed in the literature. To address this issue, we propose two approaches including a closed test procedure that controls FWER for the simultaneous AUC and Cmax bioequivalence and requires no adjustment of the type-I error, and an alpha-adaptive sequential testing (AAST) that controls FWER by pre-specifying the significance level on AUC (α1) and obtaining it for Cmax (α2) adaptively after testing of AUC. While both methods control FWER, the closed test requires testing of eight intersection null hypotheses each at α, and AAST is at times accomplished through a slight deduction in α1 and no deduction in α2 relative to α. The latter considers equivalence reached in AUC a higher importance than that in Cmax. Illustrated with published data, the two approaches, although operate differently, can lead to the same substantive conclusion and are better than a traditional method like Bonferroni adjustment.

A randomized study comparing the pharmacokinetics of the potential biosimilar PF-06438179/GP1111 with Remicade® (infliximab) in healthy subjects (REFLECTIONS B537-01)

ABSTRACT Background: To demonstrate pharmacokinetic (PK) similarity of PF-06438179/GP1111, a potential biosimilar to Remicade®, to Remicade® sourced from European Union (infliximab-EU) and United States (infliximab-US), and of infliximab-EU to infliximab-US. Methods: In this phase I, parallel-group, three-arm trial, healthy adult subjects were randomized to receive a single 10-mg/kg intravenous infusion of PF-06438179/GP1111, infliximab-EU, or infliximab-US. PK, and safety and immunogenicity evaluations were performed over 8 and 12 weeks, respectively. PK similarity was established if the 90% confidence intervals (CIs) of the test-to-reference ratios for PK parameters, Cmax, AUCT, and AUCinf, were within the 80.00–125.00% pre-specified equivalence window. Results: Of 151 subjects randomized, 146 received study treatment; 130 were eligible for PK similarity assessment. Serum concentration–time profiles were similar across the three treatments. The 90% CIs for test-to-reference ratios for Cmax, AUCT, and AUCinf were within 80.00–125.00% for comparison of PF-06438179/GP1111 to infliximab-EU and infliximab-US, and of infliximab-EU to infliximab-US. Similar numbers of subjects across treatment groups experienced adverse events. Anti-drug and neutralizing antibody profiles were largely similar among groups. Conclusions: This study demonstrated PK similarity of PF-06438179/GP1111 to infliximab-EU and infliximab-US, and of infliximab-EU to infliximab-US. All three products displayed comparable safety and immunogenicity profiles. Trial registration: CT.gov identifier NCT01844804

Inference of bioequivalence for log‐normal distributed data with unspecified variances

Two drugs are bioequivalent if the ratio of a pharmacokinetic (PK) parameter of two products falls within equivalence margins. The distribution of PK parameters is often assumed to be log-normal, therefore bioequivalence (BE) is usually assessed on the difference of logarithmically transformed PK parameters (δ). In the presence of unspecified variances, test procedures such as two one-sided tests (TOST) use sample estimates for those variances; Bayesian models integrate them out in the posterior distribution. These methods limit our knowledge on the extent that inference about BE is affected by the variability of PK parameters. In this paper, we propose a likelihood approach that retains the unspecified variances in the model and partitions the entire likelihood function into two components: F-statistic function for variances and t-statistic function for δ. Demonstrated with published real-life data, the proposed method not only produces results that are same as TOST and comparable with Bayesian method but also helps identify ranges of variances, which could make the determination of BE more achievable. Our findings manifest the advantages of the proposed method in making inference about the extent that BE is affected by the unspecified variances, which cannot be accomplished either by TOST or Bayesian method.

A comparative clinical study of PF-06410293, a candidate adalimumab biosimilar, and adalimumab reference product (Humira®) in the treatment of active rheumatoid arthritis

BackgroundThis double-blind, randomized, 78-week study evaluated the efficacy, safety, immunogenicity, pharmacokinetics, and pharmacodynamics of PF-06410293, a candidate adalimumab biosimilar, versus adalimumab reference product (Humira®) sourced from the EU (adalimumab-EU) in biologic-naïve patients with active rheumatoid arthritis (RA) despite methotrexate (MTX) (10–25 mg/week). We report results for the first 26 weeks of treatment.MethodsPatients with active RA (N = 597) were randomly assigned (1:1) to PF-06410293 or adalimumab-EU, while continuing with MTX treatment. The primary endpoint was American College of Rheumatology 20% improvement (ACR20) at week 12. Therapeutic equivalence was concluded if the two-sided 95% confidence interval (CI) for the ACR20 difference between the two arms was entirely contained within the symmetric equivalence margin (±14%). Additionally, a two-sided 90% CI was calculated by using an asymmetric equivalence margin (−12%, 15%). Secondary efficacy endpoints to week 26 included ACR20/50/70, change from baseline Disease Activity Score based on high-sensitivity C-reactive protein [DAS28–4(CRP)], European League Against Rheumatism (EULAR) response, DAS28–4(CRP) of less than 2.6, and ACR/EULAR remission. QuantiFERON-TB testing was performed at screening and week 26.ResultsPatients (78.7% of whom were female and whose mean age was 52.5 years) had a mean baseline RA duration of 6.8 years. The mean baseline DAS28–4(CRP) values were 5.9 (PF-06410293) and 6.1 (adalimumab-EU). The observed week-12 ACR20 values were 68.7% (PF-06410293) and 72.7% (adalimumab-EU) in the intention-to-treat population. With non-responder imputation, the treatment difference in week-12 ACR20 was −2.98% and corresponding CIs—95% CI (−10.38%, 4.44%) and 90% CI (−9.25%, 3.28%)—were entirely contained within the equivalence margins (symmetric and asymmetric, respectively). The secondary efficacy endpoints were similar between arms. Over 26 weeks, injection-site reactions occurred in 1.7% versus 2.0%, hypersensitivity events in 4.4% versus 8.4%, pneumonia in 0.7% versus 2.0%, and opportunistic infections in 2.4% versus 1.7% in the PF-06410293 and adalimumab-EU arms, respectively. One death due to myocardial infarction occurred (adalimumab-EU arm). Rates of anti-drug antibody incidence were 44.4% (PF-06410293) and 50.5% (adalimumab-EU).ConclusionsThe study results demonstrate that efficacy, safety, and immunogenicity of PF-06410293 and adalimumab-EU were similar during the first 26 weeks of treatment in patients with active RA on background MTX.Trial registrationClinicalTrials.gov Identifier: NCT02480153. First posted on June 24, 2015; EU Clinical Trials Register EudraCT number: 2014-000352-29. Start date: October 27, 2014.