Clinical pharmacology considerations for first-in-human clinical trials for enzyme replacement therapy.

Inborn errors of metabolism (IEM) such as lysosomal storage disorders (LSDs) are conditions caused by deficiency of one or more key enzymes, cofactors, or transporters involved in a specific metabolic pathway. Enzyme replacement therapy (ERT) provides an exogenous source of the affected enzyme and is one of the most effective treatment options for IEMs. In this paper, we review the first-in-human (FIH) protocols for ERT drug development programs supporting 20 Biologic License Applications (BLA) approved by the Center for Drug Evaluation and Research (CDER) at the US Food and Drug Administration (FDA) in the period of May 1994 to September 2023. We surveyed study design elements across these FIH protocols including study population, dosage form, dose selection, treatment duration, immunogenicity, biomarkers, and study follow-up. A total of 18 FIH trials from 20 BLAs were identified and of those, 72% (13/18) used single ascending dose (SAD) and/or multiple ascending dose (MAD) study design, 83% (15/18) had a primary objective of assessing the safety and tolerability, 72% (13/18) included clinical endpoint assessments, and 94% (17/18) included biomarker assessments as secondary or exploratory endpoints. Notably, the majority of ERT products tested the approved route of administration and the approved dose was tested in 83% (15/18) of FIH trials. At last, we offer considerations for the design of FIH studies.

FDA approval summary for lonafarnib (Zokinvy) for the treatment of Hutchinson-Gilford progeria syndrome and processing-deficient progeroid laminopathies.

The U.S. Food and Drug Administration recently approved lonafarnib as the first treatment for Hutchinson-Gilford progeria syndrome (HGPS) and processing-deficient progeroid laminopathies. This approval was primarily based on a comparison of patients with HGPS treated with lonafarnib in 2 open-label trials with an untreated patient cohort. With up to 11 years of follow-up, it was found that the lonafarnib treated patients with HGPS had a survival benefit of 2.5 years compared with the untreated patients with HGPS. This large treatment effect on the objective endpoint of mortality using a well-matched comparator group mitigated potential sources of bias and together with other evidence, established compelling evidence of a drug effect with benefits that outweighed the risks. This approval is an example of U.S. Food and Drug Administration's regulatory flexibility for a rare disease while ensuring that standards for drug approval are met.

FDA Approval Summary: Selinexor for Relapsed or Refractory Diffuse Large B-Cell Lymphoma.

In June 2020, the U.S. Food and Drug Administration granted accelerated approval to selinexor for the treatment of adult patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL), not otherwise specified, including DLBCL arising from follicular lymphoma, after at least two lines of systemic therapy. Approval was based on SADAL, a multicenter trial of selinexor monotherapy in patients with DLBCL after two to five systemic regimens. Efficacy was based on independent review committee-assessed objective response rate (ORR) and duration of response using Lugano criteria. In 134 patients treated with the approved dosage (60 mg orally on days 1 and 3 of each week), the ORR was 29% (95% confidence interval, 22-38), with complete response in 13% and with 38% of responses lasting at least 6 months. Gastrointestinal toxicity developed in 80% of patients, hyponatremia in 61%, central neurological toxicity (such as dizziness and mental status changes) in 25%, and ocular toxicity in 18%. New or worsening grade 3 or 4 thrombocytopenia, lymphopenia, neutropenia, anemia, or hyponatremia developed in ≥15%. Adverse reactions led to selinexor dose interruption in 61% of patients, dose reduction in 49%, and permanent discontinuation in 17%, with thrombocytopenia being the leading cause of dose modifications. Postmarketing studies will evaluate reduced dosages of selinexor and further evaluate clinical benefit in patients with relapsed or refractory DLBCL. IMPLICATIONS FOR PRACTICE: Selinexor is a new potential option for adults with relapsed or refractory diffuse large B-cell lymphoma, not otherwise specified, in the third-line setting or beyond. Toxicities are typically manageable but can be difficult to tolerate and necessitate close monitoring and supportive care.

Inositol Polyphosphate Multikinase Inhibits Angiogenesis via Inositol Pentakisphosphate-Induced HIF-1α Degradation.

RATIONALE: Inositol polyphosphate multikinase (IPMK) and its major product inositol pentakisphosphate (IP5) regulate a variety of cellular functions, but their role in vascular biology remains unexplored. OBJECTIVE: We have investigated the role of IPMK in regulating angiogenesis. METHODS AND RESULTS: Deletion of IPMK in fibroblasts induces angiogenesis in both in vitro and in vivo models. IPMK deletion elicits a substantial increase of VEGF (vascular endothelial growth factor), which mediates the regulation of angiogenesis by IPMK. The regulation of VEGF by IPMK requires its catalytic activity. IPMK is predominantly nuclear and regulates gene transcription. However, IPMK does not apparently serve as a transcription factor for VEGF. HIF (hypoxia-inducible factor)-1α is a major determinant of angiogenesis and induces VEGF transcription. IPMK deletion elicits a major enrichment of HIF-1α protein and thus VEGF. HIF-1α is constitutively ubiquitinated by pVHL (von Hippel-Lindau protein) followed by proteasomal degradation under normal conditions. However, HIF-1α is not recognized and ubiquitinated by pVHL in IPMK KO (knockout) cells. IP5 reinstates the interaction of HIF-1α and pVHL. HIF-1α prolyl hydroxylation, which is prerequisite for pVHL recognition, is interrupted in IPMK-deleted cells. IP5 promotes HIF-1α prolyl hydroxylation and thus pVHL-dependent degradation of HIF-1α. Deletion of IPMK in mouse brain increases HIF-1α/VEGF levels and vascularization. The increased VEGF in IPMK KO disrupts blood-brain barrier and enhances brain blood vessel permeability. CONCLUSIONS: IPMK, via its product IP5, negatively regulates angiogenesis by inhibiting VEGF expression. IP5 acts by enhancing HIF-1α hydroxylation and thus pVHL-dependent degradation of HIF-1α.

Discovery of a Potent GLUT Inhibitor from a Library of Rapafucins by Using 3D Microarrays.

Glucose transporters play an essential role in cancer cell proliferation and survival and have been pursued as promising cancer drug targets. Using microarrays of a library of new macrocycles known as rapafucins, which were inspired by the natural product rapamycin, we screened for new inhibitors of GLUT1. We identified multiple hits from the rapafucin 3D microarray and confirmed one hit as a bona fide GLUT1 ligand, which we named rapaglutin A (RgA). We demonstrate that RgA is a potent inhibitor of GLUT1 as well as GLUT3 and GLUT4, with an IC50 value of low nanomolar for GLUT1. RgA was found to inhibit glucose uptake, leading to a decrease in cellular ATP synthesis, activation of AMP-dependent kinase, inhibition of mTOR signaling, and induction of cell-cycle arrest and apoptosis in cancer cells. Moreover, RgA was capable of inhibiting tumor xenografts in vivo without obvious side effects. RgA could thus be a new chemical tool to study GLUT function and a promising lead for developing anticancer drugs.

Antifungal drug itraconazole targets VDAC1 to modulate the AMPK/mTOR signaling axis in endothelial cells.

Itraconazole, a clinically used antifungal drug, was found to possess potent antiangiogenic and anticancer activity that is unique among the azole antifungals. Previous mechanistic studies have shown that itraconazole inhibits the mechanistic target of rapamycin (mTOR) signaling pathway, which is known to be a critical regulator of endothelial cell function and angiogenesis. However, the molecular target of itraconazole that mediates this activity has remained unknown. Here we identify the major target of itraconazole in endothelial cells as the mitochondrial protein voltage-dependent anion channel 1 (VDAC1), which regulates mitochondrial metabolism by controlling the passage of ions and small metabolites through the outer mitochondrial membrane. VDAC1 knockdown profoundly inhibits mTOR activity and cell proliferation in human umbilical vein cells (HUVEC), uncovering a previously unknown connection between VDAC1 and mTOR. Inhibition of VDAC1 by itraconazole disrupts mitochondrial metabolism, leading to an increase in the cellular AMP:ATP ratio and activation of the AMP-activated protein kinase (AMPK), an upstream regulator of mTOR. VDAC1-knockout cells are resistant to AMPK activation and mTOR inhibition by itraconazole, demonstrating that VDAC1 is the mediator of this activity. In addition, another known VDAC-targeting compound, erastin, also activates AMPK and inhibits mTOR and proliferation in HUVEC. VDAC1 thus represents a novel upstream regulator of mTOR signaling in endothelial cells and a promising target for the development of angiogenesis inhibitors.

Inositol Hexakisphosphate Kinase-3 Regulates the Morphology and Synapse Formation of Cerebellar Purkinje Cells via Spectrin/Adducin.

The inositol hexakisphosphate kinases (IP6Ks) are the principal enzymes that generate inositol pyrophosphates. There are three IP6Ks (IP6K1, 2, and 3). Functions of IP6K1 and IP6K2 have been substantially delineated, but little is known of IP6K3's role in normal physiology, especially in the brain. To elucidate functions of IP6K3, we generated mice with targeted deletion of IP6K3. We demonstrate that IP6K3 is highly concentrated in the brain in cerebellar Purkinje cells. IP6K3 physiologically binds to the cytoskeletal proteins adducin and spectrin, whose mutual interactions are perturbed in IP6K3-null mutants. Consequently, IP6K3 knock-out cerebella manifest abnormalities in Purkinje cell structure and synapse number, and the mutant mice display deficits in motor learning and coordination. Thus, IP6K3 is a major determinant of cytoskeletal disposition and function of cerebellar Purkinje cells. SIGNIFICANCE STATEMENT: We identified and cloned a family of three inositol hexakisphosphate kinases (IP6Ks) that generate the inositol pyrophosphates, most notably 5-diphosphoinositol pentakisphosphate (IP7). Of these, IP6K3 has been least characterized. In the present study we generated IP6K3 knock-out mice and show that IP6K3 is highly expressed in cerebellar Purkinje cells. IP6K3-deleted mice display defects of motor learning and coordination. IP6K3-null mice manifest aberrations of Purkinje cells with a diminished number of synapses. IP6K3 interacts with the cytoskeletal proteins spectrin and adducin whose altered disposition in IP6K3 knock-out mice may mediate phenotypic features of the mutant mice. These findings afford molecular/cytoskeletal mechanisms by which the inositol polyphosphate system impacts brain function.

FDA Approval Summary: Ivosidenib in Combination with Azacitidine for Treatment of Patients with Newly Diagnosed Acute Myeloid Leukemia with an IDH1 Mutation.

On May 25, 2022, FDA approved a supplemental application for ivosidenib (Tibsovo; Servier) extending the indication in patients with newly diagnosed IDH1-mutated acute myeloid leukemia (AML) in older adults or those with comorbidities to include the combination with azacitidine. The efficacy of ivosidenib in combination with azacitidine was evaluated in Study AG120-C-009, a phase 3, multicenter, double-blind, randomized (1:1), controlled study of ivosidenib or matched placebo in combination with azacitidine in adults with previously untreated AML with an IDH1 mutation who were 75 years or older or had comorbidities that precluded use of intensive induction chemotherapy. Efficacy was established on the basis of improved event-free survival and overall survival on the ivosidenib + azacitidine arm [HR, 0.35; 95% confidence interval (CI), 0.17-0.72; P = 0.0038, and HR, 0.44; 95% CI, 0.27-0.73; P = 0.0010], respectively. Furthermore, the rate and duration of complete remission (CR) were improved with ivosidenib versus placebo [CR 47% versus 15%, two-sided P < 0.0001; median duration of CR not estimable (NE; 95% CI, 13.0-NE) months versus 11.2 (95% CI, 3.2-NE) months. The safety profile of ivosidenib in combination with azacitidine was consistent with that of ivosidenib monotherapy, with important adverse reactions including differentiation syndrome (15%) and QT interval prolongation (20%).

Model-Informed Approach Supporting Approval of Nexviazyme (Avalglucosidase Alfa-ngpt) in Pediatric Patients with Late-Onset Pompe Disease.

In August 2021, the US Food and Drug Administration approved Nexviazyme (avalglucosidase alfa-ngpt) for intravenous infusion to treat patients 1 year of age and older with late-onset Pompe disease (LOPD). The effectiveness and safety were studied in patients with LOPD and patients with infantile-onset Pompe disease (IOPD). The dosage(s) tested in clinical trials was 20 mg/kg every other week (qow) in patients with LOPD and 20 mg/kg and 40 mg/kg qow in patients with IOPD. While patients 3 years old and greater with LOPD were eligible for participation in the pivotal trial, the youngest patient enrolled was 16 years old. Therefore, pediatric patients with LOPD were not well represented in the clinical trial. The prevalence of LOPD in pediatrics is extremely low. Thus, conducting a clinical trial in pediatric patients with LOPD would be challenging. Given the similar pathophysiology, mechanism of action, and disease manifestations across the age spectrum of patients with LOPD, the approved dosages for pediatric patients younger than 16 years old with LOPD were based on extrapolation of efficacy using a model-informed exposure bridging strategy, leveraging the safety data from pediatric patients with IOPD. Specifically, the exposure associated with 20 mg/kg qow in adult patients with LOPD was the target exposure for bridging of efficacy. The safety data obtained with 40 mg/kg qow in patients with IOPD was leveraged to support approval in pediatric patients with LOPD aged 1 year and older. This article illustrates a regulatory use of model-informed extrapolation approach for dose selection in pediatric patients with a rare disease.

Timing of surgical operation for patients with intra-abdominal infection: A systematic review and meta-analysis.

BACKGROUND: Intra-abdominal infections (IAIs) is the most common type of surgical infection, with high associated morbidity and mortality rates. In recent years, due to the use of antibiotics, various drug-resistant bacteria have emerged, making the treatment of abdominal infections more challenging. Early surgical exploration can reduce the mortality of patients with abdominal infection and the occurrence of complications. However, available evidence regarding the optimal timing of IAI surgery is still weak. In study, we compared the effects of operation time on patients with abdominal cavity infection and tried to confirm the best timing of surgery. AIM: To assess the efficacy of early vs delayed surgical exploration in the treatment of IAI, in terms of overall mortality. METHODS: A systematic literature search was performed using PubMed, EMBASE, Cochrane Central Register of Controlled Trials, Ovid, and ScienceDirect. The systematic review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-analyses method. Based on the timing of the surgical operation, we divided the literature into two groups: Early surgery and delayed surgery. For the early and delayed surgery groups, the intervention was performed with and after 12 h of the initial surgical intervention, respectively. The main outcome measure was the mortality rate. The literature search was performed from May 5 to 20, 2021. We also searched the World Health Organization International Clinical Trials Registry Platform search portal and ClinicalTrials.gov on May 20, 2021, for ongoing trials. This study was registered with the International Prospective Register of Systematic Reviews. RESULTS: We identified nine eligible trial comparisons. Early surgical exploration of patients with IAIs (performed within 12 h) has significantly reduced the mortality and complications of patients, improved the survival rate, and shortened the hospital stay. CONCLUSION: Early surgical exploration within 12 h may be more effective for the treatment of IAIs relative to a delayed operation.

Model-Informed Approach Supporting Approval of Adalimumab (HUMIRA) in Pediatric Patients with Ulcerative Colitis from a Regulatory Perspective.

On February 24, 2021, the U.S. Food and Drug Administration (FDA) approved an efficacy supplement for HUMIRA® (adalimumab) injection to expand the indication of treatment of moderately to severely active ulcerative colitis (UC) to include pediatric patients 5 years of age and older. The effectiveness in pediatric patients with moderately to severely active UC was studied in a multicenter, randomized, double-blind trial (Study PUC-I, NCT02065557) in 93 pediatric patients 5 to 17 years of age. Adalimumab has been widely studied in multiple indications in adult and pediatric populations with a well-established safety profile; no apparent exposure-safety relationship has been identified in various pediatric populations treated with adalimumab across multiple indications. The approved dosing regimen in pediatric patients with UC differs from the regimen studied in the clinical trial and was determined based on a model-informed exposure bridging strategy, incorporating both efficacy and safety considerations. Specifically, the differences included switches from body weight-based (mg/kg) dosing regimens used in the pediatric trial to body weight-tiered, fixed-dose regimens, changes in dosing schedule, and the addition of an option of a less frequent dosing regimen for maintenance that was not studied in the clinical trial. This article provides a case example of successful model-informed drug development (MIDD), where modeling and simulation were utilized in combination with observed data from a clinical trial of limited size and scope to ultimately support the adalimumab approval in pediatric patients with UC.

Model-Informed Approach Supporting Drug Development and Regulatory Evaluation for Rare Diseases.

A rare disease is defined as a condition affecting fewer than 200 000 people in the United States by the Orphan Drug Act. For rare diseases, it is challenging to enroll a large number of patients and obtain all critical information to support drug approval through traditional clinical trial approaches. In addition, over half of the population affected by rare diseases are children, which presents additional drug development challenges. Thus, maximizing the use of all available data is in the interest of drug developers and regulators in rare diseases. This brings opportunities for model-informed drug development to use and integrate all available sources and knowledge to quantitatively assess the benefit/risk of a new product under development and to inform dosing. This review article provides an overview of 4 broad categories of use of model-informed drug development in drug development and regulatory decision making in rare diseases: optimizing dose regimen, supporting pediatric extrapolation, informing clinical trial design, and providing confirmatory evidence for effectiveness. The totality of evidence based on population pharmacokinetic simulation as well as exposure-response relationships for efficacy and safety, provides the regulatory ground for the approval of an unstudied dosing regimen in rare diseases without the need for additional clinical data. Given the practical and ethical challenges in drug development in rare diseases, model-informed approaches using all collective information (eg, disease, drug, placebo effect, exposure-response in nonclinical and clinical settings) are powerful and can be applied throughout the drug development stages to facilitate decision making.

FDA Approval Summary: Belumosudil for Adult and Pediatric Patients 12 Years and Older with Chronic GvHD after Two or More Prior Lines of Systemic Therapy.

On July 16, 2021, the FDA approved belumosudil, a kinase inhibitor, for adult and pediatric patients 12 years and older with chronic GvHD (cGvHD) after failure of at least two prior lines of systemic therapy. Approval was based on the results of Study KD025-213, which included 65 patients with cGvHD treated with belumosudil 200 mg daily in an open-label, single-arm cohort. Efficacy was determined by the overall response rate (ORR) through Cycle 7 Day 1, which included complete response (CR) or partial response (PR) according to the 2014 NIH consensus criteria, and durability of response. The ORR through Cycle 7 Day 1 was 75% [95% confidence interval (CI), 63-85]; 6% of patients achieved a CR, and 69% achieved a PR. The median duration of response was 1.9 months (95% CI, 1.2-2.9), and 62% (95% CI, 46-74) of responding patients remained alive without new systemic therapy for at least 12 months from response. The common adverse reactions were infections, asthenia, nausea, diarrhea, dyspnea, cough, edema, hemorrhage, abdominal pain, musculoskeletal pain, headache, phosphate decreased, gamma-glutamyl transferase increased, lymphocytes decreased, and hypertension. Additional study is warranted to confirm safety with long-term use.

Targeting therapy with mitosomal daunorubicin plus amlodipine has the potential to circumvent intrinsic resistant breast cancer.

Intrinsic resistance of cancers is a major cause of failure in chemotherapy. We proposed here a strategy to overcome intrinsic resistance by constructing cancer cell mitochondria-specifically targeting drug-loaded liposomes, namely, mitosomal daunorubicin plus amlodipine. Anticancer agent daunorubicin and apoptotic inducer amlodipine were loaded together into the mitosomes, and targeting molecule dequalinium was modified on the surface. Evaluations were performed on the breast cancer MCF-7 and resistant MCF-7/adr cells and in animals. Mitosomal daunorubicin plus amlodipine were about 97 nm, selectively accumulated in mitochondria, induced the swelling and disruption of mitochondria, dissipated the mitochondrial membrane potential, released a large amount of cytochrome C by translocation, cleaved Bid, and initiated a cascade of caspase 8 and 3 reactions. A robust anticancer effect was evidenced in vivo. Mitochondria-specifically targeting drug-loaded liposomes would provide a new strategy for treating resistant cancers.

Model-Informed Drug Development in Pediatric Dose Selection.

Model-informed drug development (MIDD) has been a powerful and efficient tool applied widely in pediatric drug development due to its ability to integrate and leverage existing knowledge from different sources to narrow knowledge gaps. The dose selection is the most common MIDD application in regulatory submission related to pediatric drug development. This article aims to give an overview of the 3 broad categories of use of MIDD in pediatric dose selection: leveraging from adults to pediatric patients, leveraging from animals to pediatric patients, and integrating mechanism in infants and neonates. Population pharmacokinetic analyses with allometric scaling can reasonably predict the clearance in pediatric patients aged >5 years. A mechanistic-based approach, such as physiologically based pharmacokinetic accounting for ontogeny, or an allometric model with age-dependent exponent, can be applied to select the dose in pediatric patients aged ≤2 years. The exposure-response relationship from adults or from other drugs in the same class may be useful in aiding the pediatric dose selection and benefit-risk assessment. Increasing application and understanding of use of MIDD have contributed greatly to several policy developments in the pediatric field. With the increasing efforts of MIDD under the Prescription Drug User Fee Act VI, bigger impacts of MIDD approaches in pediatric dose selection can be expected. Due to the complexity of model-based analyses, early engagement between drug developers and regulatory agencies to discuss MIDD issues is highly encouraged, as it is expected to increase the efficiency and reduce the uncertainty.

Effects of stealth liposomal daunorubicin plus tamoxifen on the breast cancer and cancer stem cells.

PURPOSE: The cancer stem cells play an important role in the invasion, metastasis and relapse of cancers as they are resistant to regular chemotherapy. In the present study, stealth liposomal daunorubicin plus tamoxifen was developed for eradicating breast cancer cells together with cancer stem cells. METHODS: Inhibitory effects were performed on the bulk human breast cancer cells (MCF-7), the sorted MCF-7 cancer stem-like cells (side population, SP), and the sorted MCF-7 cancer cells (NSP), respectively. Antitumor activity and TUNEL analysis were evaluated on the MCF-7 xenografts in nude mice. RESULTS: The encapsulation efficiencies of daunorubicin and tamoxifen were 95% and 90%, respectively. The mean particle size of the stealth liposomes was about 100 nm. Breast cancer stem cells were identified by the specific markers CD44+/CD24-, and isolated from bulk MCF-7 cells. When applying stealth liposomal daunorubicin plus tamoxifen, the inhibitory effects on both the breast cancer cells and the cancer stem cells were significantly increased in vitro, respectively. In the MCF-7 xenografts in mice, stealth liposomal daunorubicin plus tamoxifen showed the most favorable antitumor activity due to the passive targeting the tumor tissue and the synergistic effects in eliminating breast cancer cells and cancer stem cells. CONCLUSION: Stealth liposomal daunorubicin plus tamoxifen could have the potentials in eliminating both breast cancer cells and cancer stem cells.

Design and Synthesis of Tetrazole- and Pyridine-Containing Itraconazole Analogs as Potent Angiogenesis Inhibitors.

Itraconazole, a widely used antifungal drug, was found to possess antiangiogenic activity and is currently undergoing multiple clinical trials for the treatment of different types of cancer. However, it suffers from extremely low solubility and strong interactions with many drugs through inhibition of CYP3A4, limiting its potential as a new antiangiogenic and anticancer drug. To address these issues, a series of analogs in which the phenyl group is replaced with pyridine or fluorine-substituted benzene was synthesized. Among them the pyridine- and tetrazole-containing compound 24 has significantly improved solubility and reduced CYP3A4 inhibition compared to itraconazole. Similar to itraconazole, compound 24 inhibited the AMPK/mTOR signaling axis and the glycosylation of VEGFR2. It also induced cholesterol accumulation in the endolysosome and demonstrated binding to the sterol-sensing domain of NPC1 in a simulation study. These results suggested that compound 24 may serve as an attractive candidate for the development of a new generation of antiangiogenic drug.

FDA Approval Summary: Calaspargase Pegol-mknl For Treatment of Acute Lymphoblastic Leukemia in Children and Young Adults.

On December 20, 2018, the Food and Drug Administration approved calaspargase pegol-mknl (CALASP), an asparagine-specific enzyme, as a component of a multi-agent chemotherapeutic regimen for acute lymphoblastic leukemia (ALL) in pediatric and young adult patients age 1 month to 21 years. Efficacy was determined on the basis of achievement and maintenance of steady-state nadir serum asparaginase activity (NSAA) above 0.1 U/mL when using CALASP, 2,500 U/m2 intravenously, every 3 weeks. In a randomized comparison to pegaspargase (PEGASP) every 2 weeks, treatment with CALASP every 3 weeks had a similar safety profile and no substantial impairment in event-free survival. The pharmacokinetics of CALASP were studied when administered in combination with multiagent chemotherapy in 124 patients with B-cell ALL in Study AALL07P4 and Study DFCI 11-001. The results showed that 123 [99%, 95% confidence interval (CI), 96%-100%] of the 124 patients maintained NSAA >0.1 U/mL at weeks 6, 12, 18, 24, and 30 of post-induction phase. Maintaining adequate NSAA levels is critical to successful treatment of ALL. Herein, we describe the FDA review and approval of CALASP.See related commentary by Lew, p. 325.

Role of Model-Informed Drug Development in Pediatric Drug Development, Regulatory Evaluation, and Labeling.

The unique challenges in pediatric drug development require efficient and innovative tools. Model-informed drug development (MIDD) offers many powerful tools that have been frequently applied in pediatric drug development. MIDD refers to the application of quantitative models to integrate and leverage existing knowledge to bridge knowledge gaps and facilitate development and decision-making processes. This article discusses the current practices and visions of applying MIDD in pediatric drug development, regulatory evaluation, and labeling, with detailed examples. The application of MIDD in pediatric drug development can be broadly classified into 3 categories: leveraging knowledge for bridging the gap, dose selection and optimization, and informing clinical trial design. In particular, MIDD can provide evidence for the assumption of exposure-response similarity in bridging existing knowledge from reference to target population, support the dose selection and optimization based on the "exposure-matching" principle in the pediatric population, and increase the efficiency and success rate of pediatric trials. In addition, the role of physiologically based pharmacokinetics in drug-drug interaction in children and adolescents and in utilizing ontogeny data to predict pharmacokinetics in neonates and infants has also been illustrated. Moving forward, MIDD should be incorporated into all pediatric drug development programs at every stage to inform clinical trial design and dose selection, with both its strengths and limitations clearly laid out. The accumulated experience and knowledge of MIDD has and will continue to drive regulatory policy development and refinement, which will ultimately improve the consistency and efficiency of pediatric drug development.

Novel Tetrazole-Containing Analogues of Itraconazole as Potent Antiangiogenic Agents with Reduced Cytochrome P450 3A4 Inhibition.

Itraconazole has been found to possess potent antiangiogenic activity, exhibiting promising antitumor activity in several human clinical studies. The wider use of itraconazole in the treatment of cancer, however, has been limited by its potent inhibition of the drug metabolizing enzyme cytochrome P450 3A4 (CYP3A4). In an effort to eliminate the CYP3A4 inhibition while retaining its antiangiogenic activity, we designed and synthesized a series of derivatives in which the 1,2,4-triazole ring is replaced with various azoles and nonazoles. Among these analogues, 15n with tetrazole in place of 1,2,4-triazole exhibited optimal inhibition of human umbilical vein endothelial cell proliferation with an IC50 of 73 nM without a significant effect on CYP3A4 (EC50 > 20 µM). Similar to itraconazole, 15n induced Niemann-Pick C phenotype (NPC phenotype) and blocked AMPK/mechanistic target of rapamycin signaling. These results suggest that 15n is a promising angiogenesis inhibitor that can be used in combination with most other known anticancer drugs.