A machine learning case study to predict rare clinical event of interest: imbalanced data, interpretability, and practical considerations.

Accurate prediction of a rare and clinically important event following study treatment has been crucial in drug development. For instance, the rarity of an adverse event is often commensurate with the seriousness of medical consequences, and delayed detection of the rare adverse event can pose significant or even life-threatening health risks to patients. In this machine learning case study, we demonstrate with an example originated from a real clinical trial setting how to define and solve the rare clinical event prediction problem using machine learning in pharmaceutical industry. The unique contributions of this work include the proposal of a six-step investigation framework that facilitates the communication with non-technical stakeholders and the interpretation of the model performance in terms of practical consequences in the context of patient screenings for conducting a future clinical trial. In terms of machine learning methodology, for data splitting into the training and test sets, we adapt the rare-event stratified split approach (from scikit-learn) to further account for group splitting for multiple records of a patient simultaneously. To handle imbalanced data due to rare events in model training, the cost-sensitive learning approach is employed to give more weights to the minor class and the metrics precision together with recall are used to capture prediction performance instead of the raw accuracy rate. Finally, we demonstrate how to apply the state-of-the-art SHAP values to identify important risk factors to improve model interpretability.

Multicenter, Prospective, Randomized Study of Dexamethasone Intravitreal Implant in Patients with Center-Involved Diabetic Macular Edema in the Asia-Pacific Region.

PURPOSE: To evaluate the safety and efficacy of dexamethasone intravitreal implant 0.7 mg (DEX) compared with laser photocoagulation in patients with diabetic macular edema (DME). PATIENTS AND METHODS: This Phase 3, multicenter, randomized, efficacy evaluator-masked, parallel-group, 12-month clinical study enrolled adults in China and the Philippines with reduced visual acuity secondary to fovea-involved DME in the study eye. Participants were randomized 1:1 to study eye treatment with laser photocoagulation every 3 months as needed (n = 139) or DEX every 5 months (n = 145). The main efficacy measures were best-corrected visual acuity (BCVA), central retinal thickness (CRT), and leakage area. The primary endpoint was the average change in BCVA from baseline over 12 months (area-under-the-curve method). Preplanned subgroup analyses evaluated outcomes in Chinese patients. RESULTS: Mean average change in BCVA from baseline during the study (letters) was 4.3 with DEX (n = 145) versus 1.4 with laser (n = 127) overall (P = 0.001) and 4.6 with DEX (n = 129) versus 0.6 with laser (n = 113) in Chinese patients (P < 0.001). At Month 12, mean change in CRT from baseline was -209.5 µm with DEX versus -120.3 µm with laser (P < 0.001) and mean change in total leakage area from baseline was -8.367 mm2 with DEX versus -0.637 mm2 with laser (P < 0.001). The most common treatment-emergent adverse events in the DEX group were increased intraocular pressure and cataract. CONCLUSION: DEX administered every 5 months provided significantly greater improvement in BCVA, CRT, and total leakage area compared with laser treatment. DEX demonstrated an acceptable safety profile, consistent with an intraocular corticosteroid, and similar to that reported in completed global registration studies.

Evaluation of alternative confidence intervals to address non-inferiority through the stratified difference between proportions.

The confidence interval (CI) for the difference between two proportions has been an important and active research topic, especially in the context of non-inferiority hypothesis testing. Issues concerning the Type 1 error rate, power, coverage rate and aberrations have been extensively studied for non-stratified cases. However, stratified confidence intervals are frequently used in non-inferiority trials and similar settings. In this paper, several methods for stratified confidence intervals for the difference between two proportions, including existing methods and novel extensions from unstratified CIs, are evaluated across different scenarios. When sparsity across the strata is not a concern, adding imputed observations to the stratification analysis can strengthen Type-1 error control without substantial loss of power. When sparseness of data is a concern, most of the evaluated methods fail to control Type-1 error; the modified stratified t-test CI is an exception. We recommend the modified stratified t-test CI as the most useful and flexible method across the respective scenarios; the modified stratified Wald CI may be useful in settings where sparsity is unlikely. These findings substantially contribute to the application of stratified CIs for non-inferiority testing of differences between two proportions.

Two-Year Results of the Phase 3 Randomized Controlled Study of Abicipar in Neovascular Age-Related Macular Degeneration.

PURPOSE: To report the 2-year efficacy and safety of abicipar every 8 weeks and quarterly (after initial doses) compared with monthly ranibizumab in patients with treatment-naïve neovascular age-related macular degeneration (nAMD). DESIGN: Two multicenter, randomized, phase 3 clinical trials with identical protocols (CEDAR and SEQUOIA). Analyses used pooled trial data. PARTICIPANTS: The trials enrolled 1888 patients (1 eye/patient) with active choroidal neovascularization secondary to age-related macular degeneration and best-corrected visual acuity (BCVA) of 24 to 73 Early Treatment Diabetic Retinopathy Study letters. METHODS: At enrollment, patients were assigned to study eye treatment with abicipar 2 mg every 8 weeks after initial doses at baseline and weeks 4 and 8 (abicipar Q8, n = 630), abicipar 2 mg every 12 weeks after initial doses at baseline and weeks 4 and 12 (abicipar Q12, n = 628), or ranibizumab 0.5 mg every 4 weeks (ranibizumab Q4, n = 630). MAIN OUTCOME MEASURES: Efficacy measures included stable vision (<15-letter loss in BCVA from baseline) and change from baseline in BCVA and central retinal thickness (CRT). Safety measures included adverse events (AEs). RESULTS: For patients who completed the study, efficacy of abicipar after initial doses was maintained through week 104. At week 104, the proportion of patients with stable vision was 93.0% (396/426), 89.8% (379/422), and 94.4% (470/498); mean change in BCVA from baseline was +7.8 letters, +6.1 letters, and +8.5 letters, and mean change in CRT from baseline was -147 µm, -146 µm, and -142 µm in the abicipar Q8 (14 injections), abicipar Q12 (10 injections), and ranibizumab Q4 (25 injections) groups, respectively. The overall incidence of intraocular inflammation (IOI) AEs was 15.4%, 15.3%, and 0.3% from baseline through week 52 and 16.2%, 17.6%, and 1.3% from baseline through week 104 in the abicipar Q8, abicipar Q12, and ranibizumab Q4 groups, respectively. CONCLUSIONS: Two-year results show efficacy of abicipar Q8 and Q12 in nAMD. First onset of IOI events with abicipar was much reduced in the second year and comparable with ranibizumab (0.8% and 2.3% vs. 1.0%). The extended duration of effect of abicipar allows for quarterly dosing and reduced treatment burden.

Efficacy and Safety of Abicipar in Neovascular Age-Related Macular Degeneration: 52-Week Results of Phase 3 Randomized Controlled Study.

PURPOSE: To compare the efficacy and safety of abicipar every 8 weeks and quarterly (after initial doses) versus ranibizumab every 4 weeks in treatment-naïve patients with neovascular age-related macular degeneration (AMD). DESIGN: Two randomized, multicenter, double-masked, parallel-group, active-controlled, phase 3 clinical trials (CEDAR, SEQUOIA) with identical protocols were conducted. Data from both trials were pooled for analysis. PARTICIPANTS: Patients with active choroidal neovascularization secondary to AMD and best-corrected visual acuity (BCVA) of 24-73 Early Treatment Diabetic Retinopathy Study letters in the study eye were enrolled. METHODS: Patients (n = 1888) were randomized in a 1:1:1 ratio to study eye treatment with abicipar 2 mg every 8 weeks after 3 initial doses at baseline and weeks 4 and 8 (Q8), abicipar 2 mg every 12 weeks after 3 initial doses at baseline and weeks 4 and 12 (Q12), or ranibizumab 0.5 mg every 4 weeks (Q4). MAIN OUTCOME MEASURES: The primary efficacy end point was proportion of patients with stable vision (defined as <15-letter loss in BCVA from baseline) in the study eye at week 52. Secondary end points included change from baseline in BCVA and central retinal thickness (CRT) at week 52. Safety measures included adverse events (AEs). RESULTS: The proportion of patients with stable vision at week 52 was 93.2%, 91.3%, and 95.8% in the abicipar Q8, abicipar Q12, and ranibizumab Q4 groups, respectively, with both abicipar Q8 and Q12 noninferior to ranibizumab Q4. Week 52 mean change from baseline in BCVA was 7.5, 6.4, and 8.4 letters and in CRT was -144, -145, and -144 µm in the abicipar Q8, abicipar Q12, and ranibizumab Q4 groups, respectively. Incidence of intraocular inflammation (IOI) AEs was 15.4%, 15.3%, and 0.3%, respectively. The IOI AEs were typically mild or moderate in severity and treated with topical corticosteroids; 62 of 192 patients (32.3%) received oral and/or injectable corticosteroids. CONCLUSIONS: Abicipar Q8 and Q12 were both noninferior to ranibizumab Q4 in the primary end point of stable vision at week 52. Intraocular inflammation was more frequent with abicipar. Quarterly and Q8 abicipar reduce nAMD disease and treatment burden compared with monthly treatment.

Post-marketing surveillance study of the safety of dexamethasone intravitreal implant in patients with retinal vein occlusion or noninfectious posterior segment uveitis.

PURPOSE: To evaluate the long-term safety of dexamethasone intravitreal implant (DEX) in patients treated for macular edema associated with retinal vein occlusion (RVO) or noninfectious posterior segment uveitis (NIPSU) in clinical practice. PATIENTS AND METHODS: Multicenter (102 sites in France, Germany, Spain, UK), prospective, observational, post-authorization safety study in adult patients treated with DEX. Data collected up to 2 years after enrollment included serious adverse events (SAEs) and adverse events of special interest (AESIs; adverse drug reactions that are considered important risks associated with DEX and listed in the European Union Ozurdex Risk Management Plan). RESULTS: Overall, 803 patients (652 RVO, 151 NIPSU) received on-study DEX treatment, and 73.1% completed 24 months of follow-up; 72.6% were DEX-naïve. Median number of on-study injections per treated eye was 2 (range, 1-7); median reinjection interval was 27.1 weeks. Nonocular SAEs affected 9.5% of patients; none were considered DEX-related. Ocular SAEs (most common: cataract progression) occurred in 3.2% of treated eyes. SAEs were similar in eyes stratified by previous DEX use and number of on-study DEX injections (≤2 or >2), in both RVO and NIPSU. The most common AESIs were cataract formation and progression (20.0% and 19.2% of treated phakic eyes, n=551), increased intraocular pressure (19.0% of treated eyes), and vitreous hemorrhage (3.3% of treated eyes). Cataract progression was more frequent in baseline phakic eyes that were previously treated with DEX or received >2 on-study DEX injections. CONCLUSION: The long-term safety profile of DEX was acceptable. No new safety concerns were identified.

Safety and efficacy of dexamethasone intravitreal implant for treatment of macular edema secondary to retinal vein occlusion in Chinese patients: randomized, sham-controlled, multicenter study.

PURPOSE: The purpose of this study was to evaluate the safety and efficacy of dexamethasone intravitreal implant 0.7 mg (DEX) for treatment of macular edema associated with retinal vein occlusion (RVO). METHODS: This study was a six-month, randomized, double-masked, sham-controlled, multicenter, phase 3 clinical trial with a 2-month open-label study extension. Patients with branch or central RVO received DEX (n = 129) or sham procedure (n = 130) in the study eye at baseline; all patients who met re-treatment criteria received DEX at month 6. Efficacy measures included Early Treatment Diabetic Retinopathy Study (ETDRS), best-corrected visual acuity (BCVA), and central retinal thickness (CRT) on optical coherence tomography. RESULTS: Time to ≥15-letter BCVA improvement from baseline during the first 6 months (primary endpoint) was earlier with DEX than sham (p < 0.001). At month 2 (peak effect), the percentage of patients with ≥15-letter BCVA improvement from baseline was DEX: 35%, sham: 12%; mean BCVA change from baseline was DEX: +10.6 letters, sham: +1.7 letters; and mean CRT change from baseline was DEX: -407 µm, sham: -62 µm (all p < 0.001). Outcomes were better with DEX than sham in both branch and central RVO. The most common treatment-emergent adverse event was increased intraocular pressure (IOP). Increases in IOP generally were controlled with topical medication. Mean IOP normalized by month 4, and no patient required incisional glaucoma surgery. CONCLUSIONS: DEX had a favorable safety profile and provided clinically significant benefit in a Chinese patient population with RVO. Visual and anatomic outcomes were improved with DEX relative to sham for 3-4 months after a single implant.

Safety and efficacy of dexamethasone intravitreal implant for treatment of macular edema secondary to retinal vein occlusionin Chinese patients: randomized, sham-controlled, multicenter study / 中华眼底病杂志

Objective To evaluate the safety and efficacy ofdexamethasone intravitreal implant 0.7 mg (DEX) for treatment of macular edema associated with retinal vein occlusion (RVO).Methods This study was a six-month,randomized,double-masked,sham-controlled,multicenter,phase 3 clinical trial with a 2-month open-label study extension.Patients with branch or central RVO received DEX (n=129) or sham procedure (n=130) in the study eye at baseline;all patients who met re-treatment criteria received DEX at month 6.Efficacy measures included Early Treatment Diabetic Retinopathy Study (ETDRS),best-corrected visual acuity (BCVA),and central retinal thickness (CRT) on optical coherence tomography.Results Time to ＞ 15-letter BCVA improvement from baseline during the first 6 months (primary endpoint) was earlier with DEX than sham (P＜ 0.001).At month 2 (peak effect),the percentage of patients with ≥ 15-letter BCVA improvement from baseline was DEX:34.9％,sham:11.5％;mean BCVA change from baseline was DEX:10.6± 10.4 letters,sham:1.7 ± 12.3 letters;and mean CRT change from baseline was DEX:-407 ± 212 μm,sham:-62 ± 224 μm (all P＜0.001).Outcomes were better with DEX than sham in both branch and central RVO.The most common treatment-emergent adverse event was in-creased intraocular pressure (IOP).Increase sin IOP generally were controlled with topical medication.Mean IOP normalized by month 4,and no patient required incisional glaucoma surgery.Conclusions DEX had a favorable safety profile and provided clinically significant benefit in a Chinese patient population with RVO.Visual and anatomic outcomes were improved with DEX relative to sham for 3-4 months after a single implant.

A multicenter, 12-month randomized study comparing dexamethasone intravitreal implant with ranibizumab in patients with diabetic macular edema.

PURPOSE: To evaluate whether treatment with dexamethasone intravitreal implant (DEX implant) 0.7 mg every 5 months provides a similar average change in best-corrected visual acuity (BCVA) from baseline as ranibizumab 0.5 mg administered as per its European Summary of Product Characteristics in patients with diabetic macular edema (DME). METHODS: This was a multicenter, open-label, 12-month, randomized, parallel-group, noninferiority study in patients with DME (one eye/patient). The primary efficacy measure was BCVA using the Early Treatment Diabetic Retinopathy Study (ETDRS) method. Secondary efficacy measures included area of leakage on fluorescein angiography and central retinal thickness (CRT) on optical coherence tomography. RESULTS: Baseline patient characteristics were similar in the two treatment groups (DEX implant, n = 181; ranibizumab, n = 182); mean DME duration was ∼33 months. The mean average BCVA change from baseline over 12 months was 4.34 letters with DEX implant and 7.60 letters with ranibizumab. The lower limit of the 95 % confidence interval of the between-group difference was -4.74 letters, and therefore, DEX was demonstrated to be noninferior to ranibizumab based on the prespecified noninferiority margin of 5 letters. At monthly follow-up visits, the percentage of patients with ≥15-letter BCVA gain from baseline ranged from 7.2 to 17.7 % with DEX implant and 4.4 to 26.9 % with ranibizumab. Both DEX implant and ranibizumab effectively reduced CRT and reduced the area of fluorescein leakage. Between-group differences in change from baseline CRT favored DEX implant at 1, 2, 6, and 7 months (p ≤ 0.007) and ranibizumab at 4, 5, 9, and 10 months (p < 0.001); the decrease in fluorescein leakage area was greater with DEX implant than ranibizumab at month 12 (p < 0.001). Ocular adverse events in the study eye were more frequent in the DEX implant group because of the occurrence of intraocular pressure (IOP) increases and cataract. IOP increases were transient and generally managed with topical medication. CONCLUSIONS: Both DEX implant and ranibizumab were well tolerated and improved BCVA and anatomic outcomes in patients with DME. DEX implant met the a priori criterion for noninferiority to ranibizumab in average change from baseline BCVA over 12 months. Noninferiority was achieved with an average of 2.85 DEX implant injections and 8.70 ranibizumab injections per patient.

RELATIONSHIP BETWEEN RETINAL THICKNESS AND VISUAL ACUITY IN EYES WITH RETINAL VEIN OCCLUSION TREATED WITH DEXAMETHASONE IMPLANT.

PURPOSE: To evaluate the relationship between changes in best-corrected visual acuity (BCVA) and central retinal thickness (CRT) in eyes from two clinical trials of dexamethasone intravitreal implant 0.7 mg for macular edema after branch or central retinal vein occlusion. METHODS: Patients with vision loss as a result of macular edema (≥6-week duration) after branch retinal vein occlusion or central retinal vein occlusion were treated with a single dexamethasone intravitreal implant or sham. Prospectively defined outcomes included BCVA and CRT (as assessed by optical coherence tomography). RESULTS: There was a modest but statistically significant negative linear correlation between changes in CRT and changes in BCVA in both treatment groups at Days 90 and 180 (correlation coefficient: -0.23 to -0.34; P < 0.001). Improvements in BCVA at Day 180 were significantly greater (P < 0.001) in eyes that achieved and maintained CRT ≤250 µm from Day 90 to 180 (mean BCVA improvement: 14 letters; 49% of eyes with ≥15-letter gain) than in eyes that never achieved CRT ≤250 µm (mean BCVA improvement: 2 letters; 13% of eyes with ≥15-letter gain). CONCLUSION: The greatest improvements in BCVA were seen in eyes that achieved and maintained the greatest improvements in CRT.

Onset and duration of visual acuity improvement after dexamethasone intravitreal implant in eyes with macular edema due to retinal vein occlusion.

PURPOSE: To evaluate the onset and duration of improvement in best-corrected visual acuity (BCVA) in eyes treated with dexamethasone intravitreal implant 0.7 mg (DEX implant) for macular edema after branch or central retinal vein occlusion. METHODS: Post hoc analysis of data from 2 previously reported multicenter, 6-month, randomized sham-controlled clinical trials. Patients received a single DEX implant (n = 427) or sham procedure (n = 426) in the study eye. The primary endpoint was the percentage of eyes with ≥ 15-letter improvement in BCVA from baseline at postimplant Day 7. RESULTS: The baseline mean BCVA was 20/80. At Day 7, 10.3% of DEX implant-treated eyes versus 4.0% of sham-treated eyes (P < 0.001) had ≥ 15-letter improvement in the BCVA, and 27.2% of DEX implant-treated eyes versus 10.6% of sham-treated eyes had ≥ 10-letter improvement (P < 0.001). The mean improvement at Day 7 was 5.3 letters (branch retinal vein occlusion, 5.1; and central retinal vein occlusion, 5.8) with DEX implant and 1.6 letters (branch retinal vein occlusion, 2.3; and central retinal vein occlusion, 0.1) with sham (P < 0.001). The mean time from initial observation of ≥ 15-letter BCVA gain to the last observation of ≥ 15-letter BCVA gain was 70 days. CONCLUSION: Dexamethasone intravitreal implant treatment led to improvement in BCVA compared with sham procedure as early as postimplant Day 7. The duration of ≥ 3-line improvement was typically 2 to 3 months.

Vascular changes in eyes treated with dexamethasone intravitreal implant for macular edema after retinal vein occlusion.

OBJECTIVE: To evaluate the angiographic findings in eyes from 2 clinical trials of the dexamethasone intravitreal implant (DEX implant) 0.7 mg in the treatment of macular edema (ME) after branch retinal vein occlusion (BRVO) or central retinal vein occlusion (CRVO). DESIGN: Post hoc analysis of pooled data from 2 identical phase 3 clinical trials. PARTICIPANTS: Patients with vision loss as a result of ME (≥ 6 weeks' duration) after BRVO or CRVO for whom angiographic data were available (n = 329 eyes). METHODS: Fluorescein angiography (FA) results assessed by masked, certified graders using standardized grading protocols. MAIN OUTCOME MEASURES: The primary outcome measure in the parent studies was change from baseline in best-corrected visual acuity. Prospectively defined secondary outcomes included FA measurements (to assess macular capillary leakage, neovascularization, and nonperfusion) and optical coherence tomography results (to assess central retinal thickness [CRT]). RESULTS: At baseline, 42% of eyes in the DEX implant group and 38% of eyes in the sham group had unreadable assessments because of hemorrhage. At day 180, significantly fewer DEX implant-treated eyes (2%) than sham-treated eyes (9%) had unreadable assessments because of hemorrhage (P = 0.029). Among eyes with gradable assessments, the incidence of nonperfusion remained fairly steady from baseline to day 180. The proportion of eyes with active neovascularization increased from baseline to day 180 in the sham group, but stayed relatively constant in the DEX implant group (P = 0.026 for DEX vs. sham). The mean area of overall nonperfusion and the mean area of macular capillary nonperfusion increased from baseline to day 180 in both treatment groups (no statistically significant between-group difference). There was a statistically significant positive correlation between changes in macular leakage and changes in CRT in both the DEX implant group (r = 0.22; 95% confidence interval, 0.03-0.40; P = 0.023) and the sham group (r = 0.29; 95% confidence interval, 0.10-0.46; P = 0.003). CONCLUSIONS: This study demonstrated that the clinical improvements observed with the DEX implant were accompanied by significant improvements in vascular parameters and suggests that treatment with the DEX implant may be associated with some clinically significant improvements in angiographic findings, specifically active neovascularization.

Dexamethasone intravitreal implant in patients with macular edema related to branch or central retinal vein occlusion twelve-month study results.

OBJECTIVE: To evaluate the safety and efficacy of 1 or 2 treatments with dexamethasone intravitreal implant (DEX implant) over 12 months in eyes with macular edema owing to branch or central retinal vein occlusion (BRVO or CRVO). DESIGN: Two identical, multicenter, prospective studies included a randomized, 6-month, double-masked, sham-controlled phase followed by a 6-month open-label extension. PARTICIPANTS: We included 1256 patients with vision loss owing to macular edema associated with BRVO or CRVO. METHODS: At baseline, patients received DEX implant 0.7 mg (n = 421), DEX implant 0.35 mg (n = 412), or sham (n = 423) in the study eye. At day 180, patients could receive DEX implant 0.7 mg if best-corrected visual acuity (BCVA) was <84 letters or retinal thickness was >250 µm. MAIN OUTCOME MEASURES: The primary outcome for the open-label extension was safety; BCVA was also evaluated. RESULTS: At day 180, 997 patients received open-label DEX implant. Except for cataract, the incidence of ocular adverse events was similar in patients who received their first or second DEX implant. Over 12 months, cataract progression occurred in 90 of 302 phakic eyes (29.8%) that received 2 DEX implant 0.7 mg injections versus 5 of 88 sham-treated phakic eyes (5.7%); cataract surgery was performed in 4 of 302 (1.3%) and 1 of 88 (1.1%) eyes, respectively. In the group receiving two 0.7-mg DEX implants (n = 341), a ≥ 10-mmHg intraocular pressure (IOP) increase from baseline was observed in (12.6% after the first treatment, and 15.4% after the second). The IOP increases were usually transient and controlled with medication or observation; an additional 10.3% of patients initiated IOP-lowering medications after the second treatment. A ≥ 15-letter improvement in BCVA from baseline was achieved by 30% and 32% of patients 60 days after the first and second DEX implant, respectively. CONCLUSIONS: Among patients with macular edema owing to BRVO or CRVO, single and repeated treatment with DEX implant had a favorable safety profile over 12 months. In patients who qualified for and received 2 DEX implant injections, the efficacy and safety of the 2 implants were similar with the exception of cataract progression. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

High Performance IT-MS Sequencing of Glycans (Spatial Resolution of Ovalbumin Isomers).

This report outlines and applies a high performance sequencing technology to evaluate the glycome of a common model glycoprotein, ovalbumin. The targets were the N-linked glycans enzymatically released from the protein, the N-glycoproteome. These product glycans were reduced, methylated and directly infused into the MS using a chip-based nanoelectrospray with the ions structurally characterized by sequential disassembly. Ten major ions were selected for detailed analysis. Isomer topologies (glycan connectivity) were determined from ion pathways of disassembly. Linkage information was revealed by specific cross-ring cleavage fragments within smaller oligomers. Both connectivity and linkage features were assisted with described bioinformatic tools and details confirmed with a standards library of fragments. The number of isomeric structures found within these 10 parent ions were 37, more than double earlier reports, and setting a new goal for developing technology. In this non-chromatographic, high performance spatial approach, the focus has been patterned to be comprehensive, and stay within the bounds of a plausible high throughput strategy consistent with automation. Selective structures are described in the text to appraise readers of the general approach; a more comprehensive coverage has been included in supplemental material.

Randomized, sham-controlled trial of dexamethasone intravitreal implant in patients with macular edema due to retinal vein occlusion.

OBJECTIVE: To evaluate the safety and efficacy of dexamethasone intravitreal implant (DEX implant; OZURDEX, Allergan, Inc., Irvine, CA) compared with sham in eyes with vision loss due to macular edema (ME) associated with branch retinal vein occlusion (BRVO) or central retinal vein occlusion (CRVO). DESIGN: Two identical, multicenter, masked, randomized, 6-month, sham-controlled clinical trials (each of which included patients with BRVO and patients with CRVO). PARTICIPANTS: A total of 1267 patients with vision loss due to ME associated with BRVO or CRVO. INTERVENTION: A single treatment with DEX implant 0.7 mg (n = 427), DEX implant 0.35 mg (n = 414), or sham (n = 426). MAIN OUTCOME MEASURES: The primary outcome measure for the pooled data from the 2 studies was time to achieve a > or =15-letter improvement in best-corrected visual acuity (BCVA). Secondary end points included BCVA, central retinal thickness, and safety. RESULTS: After a single administration, the time to achieve a > or =15-letter improvement in BCVA was significantly less in both DEX implant groups compared with sham (P<0.001). The percentage of eyes with a > or =15-letter improvement in BCVA was significantly higher in both DEX implant groups compared with sham at days 30 to 90 (P<0.001). The percentage of eyes with a > or =15-letter loss in BCVA was significantly lower in the DEX implant 0.7-mg group compared with sham at all follow-up visits (P< or =0.036). Improvement in mean BCVA was greater in both DEX implant groups compared with sham at all follow-up visits (P< or =0.006). Improvements in BCVA with DEX implant were seen in patients with BRVO and patients with CRVO, although the patterns of response differed. The percentage of DEX implant-treated eyes with intraocular pressure (IOP) of > or =25 mmHg peaked at 16% at day 60 (both doses) and was not different from sham by day 180. There was no significant between-group difference in the occurrence of cataract or cataract surgery. CONCLUSIONS: Dexamethasone intravitreal implant can both reduce the risk of vision loss and improve the speed and incidence of visual improvement in eyes with ME secondary to BRVO or CRVO and may be a useful therapeutic option for eyes with these conditions.

Optimal assessment of baseline treadmill walking performance in claudication clinical trials.

Treadmill testing is frequently used to assess the functional capacity of patients with claudication, but the optimal application of treadmill testing in the setting of multicenter clinical trials remains uncertain. The current study used data from a recent clinical trial of the drug NM-702, which employed three baseline assessments of peak walking time (PWT) using a graded treadmill. These data were used to describe the different methods of defining the baseline peak treadmill performance with respect to reproducibility, stability over time and detection of treatment effect. A series of baseline definitions (first test only, last test only, highest PWT of the three tests, arithmetic mean of the three tests, mean of the first two tests, median of the three tests and a reproducibility-based criterion) were used to calculate the population (n = 386) variability in baseline testing, the placebo response over the 24 weeks of treatment, and the effect size of NM-702. Placebo responses and NM-702 effect sizes were not substantively affected by the method used to calculate baseline PWT. Changes in PWT on placebo were less than 25% for all methods of baseline quantitation. No method yielded an NM-702 effect size quantitatively greater than that obtained using only the first baseline test in the analysis for either PWT or claudication onset time. The graded treadmill test quantifies PWT with high reproducibility and stability over time. These characteristics may obviate the need for multiple treadmill tests, potentially saving study costs and improving patient acceptance of trial participation.

Adjunctive parenteral therapy with lipo-ecraprost, a prostaglandin E1 analog, in patients with critical limb ischemia undergoing distal revascularization does not improve 6-month outcomes.

PURPOSE: In patients with critical limb ischemia (CLI), distal revascularization remains the procedure of choice for preventing limb loss, but long-term outcomes for pain relief, wound healing, and prevention of amputation remain suboptimal. Prostaglandin drug therapy as an adjuvant to revascularization may improve these outcomes. The current trial was designed to test the hypothesis that the use of lipo-ecraprost, a lipid encapsulated prostaglandin E(1) prodrug, as an adjunctive therapy after distal revascularization would improve amputation-free survival in patients with CLI. METHODS: The study was randomized, multicenter, double blind, and placebo controlled. Patients meeting clinical and hemodynamic criteria for CLI who were undergoing either bypass or endovascular revascularization of the below knee popliteal or more distal arteries were randomized to receive placebo or a 60-microg dose of lipo-ecraprost administered intravenously starting

The novel phosphodiesterase inhibitor NM-702 improves claudication-limited exercise performance in patients with peripheral arterial disease.

OBJECTIVES: The current study tested the hypothesis that NM-702 improves treadmill exercise performance in peripheral arterial disease patients with claudication-limited exercise performance. BACKGROUND: Patients with claudication experience significant disability, owing to their exercise limitation. Therapeutic options to improve exercise performance in these patients are limited. NM-702 is a novel drug that inhibits phosphodiesterase as well as thromboxane A2 synthase. METHODS: This study was a randomized, multi-center, placebo-controlled, double-blind trial. Patients were randomized to receive 24 weeks of twice-daily treatment with either placebo (intent to treat population, n = 130), 4 mg NM-702 (n = 126), or 8 mg NM-702 (n = 130). RESULTS: After 24 weeks of treatment, 8 mg NM-702 was associated with a statistically significant increased peak walking time on a graded treadmill as compared with placebo (p = 0.004). Peak walking time after 24 weeks was increased by 17.1 +/- 49.0% in the placebo arm, 22.1 +/- 60.1% in the 4-mg NM-702 arm, and 28.1 +/- 50.5% in the 8-mg NM-702 arm. NM-702 at the 8-mg dose for 24 weeks was associated with statistically significant improvements in the treadmill claudication onset time as compared with placebo. In addition, as compared with placebo, NM-702 improved the physical component and physical functioning scores of the Medical Outcomes Study 36-Item Short Form and the walking distance and stair climbing domains of the Walking Impairment Questionnaire. NM-702 was generally well tolerated, but adverse events typical of vasodilators were common. CONCLUSIONS: NM-702 used for 24 weeks by patients with claudication was associated with improvements in laboratory- and ambulatory-based exercise performance.

Parenteral therapy with lipo-ecraprost, a lipid-based formulation of a PGE1 analog, does not alter six-month outcomes in patients with critical leg ischemia.

PURPOSE: Eicosanoids with vasodilating and angiogenic properties have been postulated to be effective therapies for critical leg ischemia (CLI) secondary to atherosclerotic peripheral arterial disease. The ability to deliver active drug to the site of action at adequate doses for sufficient duration has been a major limitation in the clinical development of such therapies. Lipo-ecraprost is a lipid-encapsulated prostaglandin E1 prodrug with the potential to deliver active prostaglandin to the site of critical arterial ischemia. The current trial was designed to test the hypothesis that lipo-ecraprost would improve amputation-free survival in patients with CLI who had no revascularization options. METHODS: The study was randomized, multicenter, double blind, and placebo controlled. Patients who met clinical and hemodynamic criteria were randomized to receive placebo or lipo-ecraprost (60 microg) administered intravenously on each of 5 days per week, for a total of 8 weeks. The study's primary endpoint was the rate of a composite end point of death or amputation above the level of the ankle at 180 days (6 months). RESULTS: The study was terminated on a recommendation from the Data and Safety Monitoring Board after the completion of a protocol-specified interim analysis for futility. At the time of termination, 383 of the planned 560 patients had been randomized, of which 379 received at least one dose of study medication and thus were included in the intention-to-treat population. Twenty-three patients were lost to follow-up and were not available for 6-month assessments. At 6 months of follow-up, there were 23 amputations in the 177 patients who received placebo, and 29 amputations in the 179 patients randomized to lipo-ecraprost. At 6 months, 10 deaths had occurred in the placebo group and 18 deaths had occurred in the lipo-ecraprost arm. Changes in lower-extremity hemodynamics over the 6-month study period did not differ between the placebo and lipo-ecraprost treatment arms. CONCLUSION: Intensive treatment with lipo-ecraprost failed to modify the 6-month amputation rate in patients with CLI who were not candidates for revascularization.