Bridging Animal and Human Data in Pursuit of Vaccine Licensure.

The FDA Animal Rule was devised to facilitate approval of candidate vaccines and therapeutics using animal survival data when human efficacy studies are not practical or ethical. This regulatory pathway is critical for candidates against pathogens with high case fatality rates that prohibit human challenge trials, as well as candidates with low and sporadic incidences of outbreaks that make human field trials difficult. Important components of a vaccine development plan for Animal Rule licensure are the identification of an immune correlate of protection and immunobridging to humans. The relationship of vaccine-induced immune responses to survival after vaccination and challenge must be established in validated animal models and then used to infer predictive vaccine efficacy in humans via immunobridging. The Sabin Vaccine Institute is pursuing licensure for candidate filovirus vaccines via the Animal Rule and has convened meetings of key opinion leaders and subject matter experts to define fundamental components for vaccine licensure in the absence of human efficacy data. Here, filoviruses are used as examples to review immune correlates of protection and immunobridging. The points presented herein reflect the presentations and discussions during the second meeting held in October 2021 and are intended to address important considerations for developing immunobridging strategies.

Estimation of ELISA results using a parallel curve analysis.

We introduce a new method for the analysis of enzyme-linked immunosorbent assay (ELISA) data. The new method can use data near the asymptotes and does not give undue weight to responses on the flatter parts of the dose-response curve. We apply it to simulated data and to two real-world assays and show it is more accurate and more precise than the traditional interpolation method. In particular, the new method works much better for very low-concentration samples for which the traditional method is often unable to give a result.

Systematic review and meta-analysis: the effects of fermented milk with Bifidobacterium lactis CNCM I-2494 and lactic acid bacteria on gastrointestinal discomfort in the general adult population.

BACKGROUND: It has been suggested that probiotics may improve gastrointestinal discomfort. Not all probiotics exhibit the same effects and consequently meta-analyses on probiotics should be confined to well-defined strains or strain combinations. The aim of this study was to evaluate the effectiveness of a probiotic fermented milk (PFM) that includes Bifidobacterium lactis (B. lactis) CNCM I-2494 and lactic acid bacteria on gastrointestinal discomfort in the general adult population. METHODS: Double-blind randomized controlled trials in the general adult population comparing PFM with a control dairy product for at least 4 weeks were searched from multiple literature databases (up to February 2015). Meta-analyses using random-effects models, with individual participant data were undertaken to calculate an odds ratio (OR) or standard mean difference (SMD), with a 95% confidence interval (CI). RESULTS: The search strategy identified 12,439 documents. Overall, three trials with a total of 598 adults (female = 96.5%) met the inclusion criteria. Consumption of the PFM product was associated with a significant improvement in overall gastrointestinal discomfort compared with the control product (OR = 1.48; 95% CI 1.07-2.05), with a number needed to treat (NNT) of 10.24 (95% CI 5.64-55.93). PFM was also superior to the control in reducing digestive symptoms, as measured using a composite score (SMD = -0.21; 95% CI -0.37 to -0.05). Sensitivity analyses produced similar results, and the heterogeneity between studies was minimal. CONCLUSIONS: This meta-analysis shows that the consumption of PFM with B. lactis CNCM I-2494 and lactic acid bacteria is associated with a modest but consistent and significant improvement of outcomes related to gastrointestinal discomfort in healthy adults.

Parallelism in practice: approaches to parallelism in bioassays.

UNLABELLED: Relative potency bioassays are used to estimate the potency of a test biological product relative to a standard or reference product. It is established practice to assess the parallelism of the dose-response curves of the products prior to calculating relative potency. This paper provides a review of parallelism testing for bioassays. In particular three common methods for parallelism testing are reviewed: two significance tests (the F-test, the χ(2)-test) and an equivalence test. Simulation is used to compare these methods. We compare the sensitivity and specificity and receiver operating characteristic curves, and find that both the χ(2)-test and the equivalence test outperform the F-test on average, unless the assay-to-assay variation is considerable. No single method is optimal in all situations. We describe how bioassay scientists and statisticians can work together to determine the best approach for each bioassay, taking into account its properties and the context in which it is applied. LAY ABSTRACT: Bioassays are experiments that use living organisms, tissues, or cells to measure the concentration of a pharmaceutical. Typically the response of the living matter to a test sample with an unknown concentration of a pharmaceutical is compared to the response to a standard reference sample with a known concentration. An important step in the analysis of bioassays is checking that the test sample is responding like a diluted copy of the reference sample; this is known as testing for parallelism. There are three statistical methods commonly used to test for parallelism: the F-test, the χ(2)-test, and the equivalence test. This paper compares the three methods using computer simulations. We conclude that different methods are best in different situations, and we provide guidelines to help bioassay scientists and statisticians decide which method to use.

Estimating vaccine efficacy using animal efficacy data.

Animal models are used to predict the effect of an intervention in humans. An example is the prediction of the efficacy of a vaccine when it is considered unethical or infeasible to challenge humans with the target disease to assess the effect of the vaccine on the disease in humans directly. In such cases, data from animal studies are used to develop models relating antibody level to protection probability in the animal, and then data from a study or studies in human subjects vaccinated with the proposed vaccine regimen are used in combination with the relevant animal models to predict protection in humans, and hence estimate vaccine efficacy. We explain the statistical techniques required to provide an estimate of vaccine efficacy and its precision. We present simulated examples showing that precise estimation of the relationship between antibody levels and protection in animals, at levels likely to be induced in humans by the vaccine regimen, is key to precise estimation of the vaccine efficacy. Because the confidence interval for the estimate of vaccine efficacy cannot be expressed in analytical form, but must be estimated from resampling, or bootstrapping, it is not possible to design studies with required power analytically. Therefore we propose that a simulation-based design of experiments approach using preliminary data is used to maximise the power of further studies and thus minimise the human and animal experimentation required.

Epithelium-off photochemical corneal collagen cross-linkage using riboflavin and ultraviolet a for keratoconus and keratectasia: a systematic review and meta-analysis.

This report presents the results of a systematic review and meta-analyses of studies on epithelium-off photochemical corneal collagen cross-linkage for the management of keratoconus and secondary ectasia. The literature search identified 3,400 records of which 49 were considered for inclusion in the meta-analyses. Eight papers reported 4 unique randomized controlled trials, 29 studies were prospective, and 12 were retrospective studies. The majority of the studies (39/49) were graded as very low quality evidence. Twenty-six studies described adverse events and were included in the safety analysis. Meta-analyses are presented for changes in four outcomes: visual acuity, topography, refraction and astigmatism, and central corneal thickness. Statistically significant improvements were found in all efficacy outcomes at 12 months after the operation. Common side effects were pain, corneal edema, and corneal haze, which resolved usually within a few days after the procedure. The remaining uncertainty is duration of benefit to establish the procedure's potential benefit in avoiding or delaying disease progression and possibly reducing the need for corneal transplantation.

Nitroglycerin 0.4% ointment vs placebo in the treatment of pain resulting from chronic anal fissure: a randomized, double-blind, placebo-controlled study.

BACKGROUND: Complications of chronic anal fissure (CAF) treatments are prompting interest in lower-risk therapies. This study was conducted to compare nitroglycerin (NTG) 0.4% ointment with placebo for pain associated with CAF. METHODS: In this randomized, double-blind, placebo-controlled trial, patients with one CAF and moderate-to-severe pain (≥50 mm on a 100 mm visual analog scale [VAS]) received 375 mg NTG 0.4% (1.5 mg active ingredient) or 375 mg placebo ointment applied anally every 12 hours for 21 days. The primary end point was change from baseline VAS score in 24-hour pain averaged over days 14-18. Review of data from patients who withdrew early was blinded to treatment. To control for the confounding effects of analgesics, all patients received 650 mg acetaminophen for headache prophylaxis before each application. RESULTS: A total of 247 patients were enrolled (NTG, n = 123; placebo, n = 124). The prespecified baseline observation carried forward (BOCF) analysis found no significant difference between groups; however, a last observation carried forward (LOCF) analysis showed a significant advantage for NTG. A post hoc analysis (LOCF/BOCF hybrid) demonstrated a significant adjusted mean difference of -7.0 mm in favor of NTG 0.4% (95% CI -13.6, -0.4; P = .038). Headache was the most common adverse event in the NTG (69.9%) and placebo (47.6%) groups. CONCLUSIONS: This was the first placebo-controlled study that also controlled for the confounding effects of analgesics used to treat NTG-induced headache. In patients with moderate-to-severe CAF pain, NTG 0.4% ointment effectively reduced CAF pain compared with placebo. TRIAL REGISTRATION: ClinicalTrials.gov, NCT00522041.

Radical radiotherapy with or without gemcitabine in patients with early stage medically inoperable non-small cell lung cancer.

BACKGROUND: Preclinical and phase I data suggest gemcitabine to be a potent radiosensitiser. This multicentre study addressed whether the addition of low dose gemcitabine to radical radiotherapy improved 2 year event-free survival in patients with medically inoperable stages I-II non-small cell lung cancer. AIM: To determine whether low dose gemcitabine increased event-free survival in patients with T1-2 N0-1 M0 NSCLC deemed unfit for surgery. METHODS: Patients with T1-2 N0-1 M0 NSCLC deemed unfit for surgery were randomised to 3D conformal radiotherapy delivering 55 Gy in 20 fractions over 4 weeks to known sites of cancer with (Arm B) or without (Arm A) 100mg/m(2) weekly gemcitabine. RESULTS: Study entry was terminated early because of slow accrual. 111 patients were randomised between March 2003 and December 2005, of whom 4 withdrew consent and 2 were lost to follow-up. Median age was 75 (range 49-88)years and 67 (63%) were male. 86 (81%) were PS 0-1 and 31 (30%) Charlson index 2 or greater. Event-free survival in arm A and B, respectively, was 42% and 46% at 2 years and 20% and 31% at 5 years (p=0.72), while overall survival was 56% and 52% at 2 years and 20% and 33% at 5 years (p=0.87). Two deaths from accelerated interstitial lung disease were seen in arm B, but toxicity was otherwise mild. CONCLUSION: No evidence of an improvement in event-free survival was seen with the addition of weekly gemcitabine at this dose for patients with early stage NSCLC unfit for surgery, although the power of the study was low.

Testosterone replacement in hypogonadal men with type 2 diabetes and/or metabolic syndrome (the TIMES2 study).

OBJECTIVE: This study evaluated the effects of testosterone replacement therapy (TRT) on insulin resistance, cardiovascular risk factors, and symptoms in hypogonadal men with type 2 diabetes and/or metabolic syndrome (MetS). RESEARCH DESIGN AND METHODS: The efficacy, safety, and tolerability of a novel transdermal 2% testosterone gel was evaluated over 12 months in 220 hypogonadal men with type 2 diabetes and/or MetS in a multicenter, prospective, randomized, double-blind, placebo-controlled study. The primary outcome was mean change from baseline in homeostasis model assessment of insulin resistance (HOMA-IR). Secondary outcomes were measures of body composition, glycemic control, lipids, and sexual function. Efficacy results focused primarily on months 0-6 (phase 1; no changes in medication allowed). Medication changes were allowed in phase 2 (months 6-12). RESULTS: TRT reduced HOMA-IR in the overall population by 15.2% at 6 months (P = 0.018) and 16.4% at 12 months (P = 0.006). In type 2 diabetic patients, glycemic control was significantly better in the TRT group than the placebo group at month 9 (HbA(1c): treatment difference, -0.446%; P = 0.035). Improvements in total and LDL cholesterol, lipoprotein a (Lpa), body composition, libido, and sexual function occurred in selected patient groups. There were no significant differences between groups in the frequencies of adverse events (AEs) or serious AEs. The majority of AEs (>95%) were mild or moderate. CONCLUSIONS: Over a 6-month period, transdermal TRT was associated with beneficial effects on insulin resistance, total and LDL-cholesterol, Lpa, and sexual health in hypogonadal men with type 2 diabetes and/or MetS.

Efficacy, safety and tolerability of escitalopram in doses up to 50 mg in Major Depressive Disorder (MDD): an open-label, pilot study.

BACKGROUND: Escitalopram is licensed for use at doses up to 20 mg but is used clinically at higher doses. There is limited published data at higher doses and none in the treatment of Major Depressive Disorder (MDD). METHODS: This open-label, pilot study was designed to investigate the efficacy, safety and tolerability of escitalopram in doses up to 50 mg in MDD. It was conducted in 60 primary care patients with MDD who had not responded to adequate treatment with citalopram. Patients were treated with escalating doses of escitalopram up to 50 mg for up to 32 weeks until they achieved remission (Montgomery-Asberg Depression Rating Scale [MADRS] ≤ 8) or failed to tolerate the dose. RESULTS: Forty-two patients (70%) completed the study. Twenty-one patients (35%) achieved remission with 8 of the 21 patients (38%) needing the 50 mg dose to achieve remission. Median time to remission was 24 weeks and median dose in remission was 30 mg. No significant safety issues were identified although tolerability appeared to decline above a dose of 40 mg with 26% of patients unable to tolerate 50 mg. Twelve (20%) patients had adverse events leading to discontinuation. The most common adverse events were headache (35%), nausea, diarrhoea and nasopharyngitis (all 25%). Minor mean weight gain was found during the study, which did not appear to be dose-related. Half of the patients who completed the study chose to continue treatment with escitalopram rather than taper down the dose at 32 weeks. CONCLUSIONS: Dose escalation with escitalopram above 20 mg may have a useful role in the management of patients with MDD, although further studies are needed to confirm this finding. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00785434.

Five-year outcome for women randomised in a phase III trial comparing doxorubicin and cyclophosphamide with doxorubicin and docetaxel as primary medical therapy in early breast cancer: an Anglo-Celtic Cooperative Oncology Group study.

To compare the long-term outcome of women with primary or locally advanced breast cancer randomised to receive either doxorubicin and cyclophosphamide (AC) or doxorubicin and docetaxel (AD) as primary chemotherapy. Eligible patients with histologic-proven breast cancer with primary tumours > or = 3 cm, inflammatory or locally advanced disease, and no evidence of distant metastases, were randomised to receive a maximum of 6 cycles of either doxorubicin (60 mg/m(2)) plus cyclophosphamide (600 mg/m(2)) i/v or doxorubicin (50 mg/m(2)) plus docetaxel (75 mg/m(2)) i/v every 3 weeks, followed by surgery on completion of chemotherapy. Clinical and pathologic responses have previously been reported. Time to relapse, site of relapse, and all-cause mortality were recorded. This updated analysis compares long-term disease-free (DFS) and overall survival (OS) using stratified log rank methods. A total of 363 patients were randomised to AC (n = 181) or AD (n = 182). A complete pathologic response was observed in 16% for AC and 12% for AD (P = 0.43). The number of patients with positive axillary nodes at surgery with AC was 61% and AD 66% (P = 0.36). At a median follow-up of 99 months there is no significant difference between the two groups for DFS (P = 0.20) and OS (P = 0.24). Deaths were due to metastatic breast cancer in 96% of patients. Our data do not support a clinical benefit for simultaneous administration of AD compared with AC. However, the data do not exclude a smaller benefit than the study was powered to detect and are consistent with an increase in both disease-free and overall survival of about 5% for AD compared with AC. Outcome is consistent with the pathologic complete response following surgery.

Phase III randomized trial of doxorubicin and docetaxel versus doxorubicin and cyclophosphamide as primary medical therapy in women with breast cancer: an anglo-celtic cooperative oncology group study.

PURPOSE To compare the clinical and pathologic response rates of doxorubicin and cyclophosphamide (AC) with doxorubicin and docetaxel (AD) as primary chemotherapy in women with primary or locally advanced breast cancer. PATIENTS AND METHODS Eligible patients with histologically proven breast cancer with primary tumors >/= 3 cm, inflammatory or locally advanced disease, and no evidence of metastases were randomly assigned to receive a maximum of six cycles of either doxorubicin (60 mg/m(2)) plus cyclophosphamide (600 mg/m(2)) administered intravenously (IV) every 3 weeks or doxorubicin (60 mg/m(2)) plus docetaxel (75 mg/m(2)) IV every 3 weeks, followed by surgery on completion of chemotherapy. Results A total of 363 patients were randomly assigned to AC (n = 180) or AD (n = 183). A complete clinical response was observed in 17% and 20% of patients treated with AC and AD, respectively (P = .42). Overall (complete and partial) clinical response rates for AC and AD were 61% and 70%, respectively (P = .06). There was no significant difference in either the pathologic complete response rates in the breast with AC (24%) and AD (21%; P = .61) or in the number of patients with positive axillary nodes at surgery with AC (61%) and AD (66%; P = .28). At a median follow-up of 32 months, there is no significant difference between the two groups for the number of relapses. CONCLUSION In contrast to the positive results reported for sequential docetaxel after AC as primary chemotherapy of breast cancer, our data do not suggest a benefit for simultaneous AD over AC.

Conventional adjuvant chemotherapy versus single-cycle, autograft-supported, high-dose, late-intensification chemotherapy in high-risk breast cancer patients: a randomized trial.

BACKGROUND: Breast cancer patients with four or more positive axillary lymph nodes who are treated with conventional adjuvant therapy have a poor prognosis. In uncontrolled studies, high-dose chemotherapy produced much better results than conventional therapy. We compared the benefits of a single cycle of high-dose chemotherapy and the benefits of conventional chemotherapy in patients with high-risk breast cancer in a prospective, unblinded, randomized trial. METHODS: Between February 23, 1995, and June 29, 1999, 605 patients with breast cancer who had four or more positive lymph nodes were randomly assigned to treatment (307 to high-dose therapy and 298 to conventional therapy). The conventional chemotherapy regimen was four cycles of doxorubicin (75 mg/m2) followed by eight cycles of CMF (cyclophosphamide [600 mg/m2], methotrexate [50 mg/m2], and 5-fluorouracil [600 mg/m2]), all given intravenously on day 1 of a 21-day cycle. The high-dose regimen was four cycles of doxorubicin (75 mg/m2), followed by a single cycle of intermediate-dose cyclophosphamide (4000 mg/m2) supported by filgrastim (300 microg/day) for up to 10 days followed by high-dose cyclophosphamide (6000 mg/m2) and thiotepa (800 mg/m2). Peripheral blood progenitor cells were harvested by leukapheresis after treatment with cyclophosphamide and filgrastim and then re-infused after the high-dose cycle. Log-rank tests were used to compare survival rates. All statistical analyses were two-sided. RESULTS: At a median follow-up of 6 years, no statistically significant differences were detected between the arms in 5-year relapse-free survival (high-dose arm = 57%, 95% confidence interval [CI] = 51% to 63%; conventional-dose arm = 54%, 95% CI = 48% to 61% (P =.73) or in 5-year overall survival (high-dose arm = 62%, 95% CI = 56% to 68%; conventional-dose arm = 64%, 95% CI = 57% to 70%) (P =.38). CONCLUSION: Autograft-supported, high-dose therapy is not superior to conventional chemotherapy in patients with breast cancer who have multiple involved lymph nodes. This conclusion should be viewed in the context of improving the success of conventional chemotherapy.