Freezing of the Lattice in the Kagome Lattice Heisenberg Antiferromagnet Zn-Barlowite ZnCu_{3}(OD)_{6}FBr.

We use ^{79}Br nuclear quadrupole resonance (NQR) to demonstrate that ultraslow lattice dynamics set in below the temperature scale set by the Cu-Cu superexchange interaction J (≃160 K) in the kagome lattice Heisenberg antiferromagnet Zn-barlowite. The lattice completely freezes below 50 K, and ^{79}Br NQR line shapes become twice broader due to increased lattice distortions. Moreover, the frozen lattice exhibits an oscillatory component in the transverse spin echo decay, a typical signature of pairing of nuclear spins by indirect nuclear spin-spin interaction. This indicates that some Br sites form structural dimers via a pair of kagome Cu sites prior to the gradual emergence of spin singlets below ∼30 K. Our findings underscore the significant roles played by subtle structural distortions in determining the nature of the disordered magnetic ground state of the kagome lattice.

FDA Supplemental Approval Summary: Lenvatinib for the Treatment of Unresectable Hepatocellular Carcinoma.

On August 16, 2018, the U.S. Food and Drug Administration approved lenvatinib (Lenvima, Eisai Inc.) for first-line treatment of patients with unresectable hepatocellular carcinoma (HCC). Approval was based on an international, multicenter, randomized, open-label, noninferiority trial (REFLECT; NCT01761266) conducted in 954 patients with previously untreated metastatic or unresectable HCC. Patients were randomized (1:1) to receive lenvatinib (12 mg orally once daily for patients with a baseline body weight ≥60 kg and 8 mg orally once daily for patients with a baseline body weight <60 kg) or sorafenib (400 mg orally twice daily) until radiological disease progression or unacceptable toxicity. REFLECT demonstrated that lenvatinib was noninferior but not statistically superior to sorafenib for overall survival (OS; hazard ratio, [HR] 0.92; 95% confidence intervals [CI], 0.79-1.06), with median OS of 13.6 and 12.3 months in the lenvatinib and sorafenib arms, respectively. REFLECT also demonstrated statistically significant improvements in investigator-assessed progression-free survival (PFS; HR, 0.66; 95% CI, 0.57-0.77]; p < 0.001), corresponding to median PFS of 7.4 and 3.7 months and overall response rate of 24.1% vs 9.2% per modified RECIST for HCC (mRECIST) in the lenvatinib and sorafenib arms, respectively. Consistent results were observed by an independent review facility per RECISTv1.1 and per mRECIST. The most common adverse reactions observed in the lenvatinib-treated patients (≥20%) in decreasing frequency were hypertension, fatigue, diarrhea, decreased appetite, arthralgia/myalgia, decreased weight, abdominal pain, palmar-plantar erythrodysesthesia syndrome, proteinuria, dysphonia, hemorrhagic events, hypothyroidism, and nausea. IMPLICATIONS FOR PRACTICE: This article describes the U.S. Food and Drug Administration's review of data from a single trial, REFLECT, that supported the approval of lenvatinib, as a single agent, for the first-line treatment of unresectable hepatocellular carcinoma (HCC). REFLECT was an open-label, noninferiority trial that randomized 954 patients with HCC who were ineligible for liver-directed therapy with no prior systemic therapy for HCC to lenvatinib or sorafenib. REFLECT demonstrated that lenvatinib-treated patients had similar survival, more responses, and longer time to progression than those receiving sorafenib. Serious side effects were more common among lenvatinib-treated patients. Lenvatinib is an effective treatment for patients with previously untreated HCC.

A review of the experience with pediatric written requests issued for oncology drug products.

BACKGROUND: Pediatric anticancer drug development has numerous challenges. The Pediatric Research Equity Act (PREA) and the Best Pharmaceuticals for Children Act (BPCA) were passed to address pediatric drug development deficiencies in general. Until recently, the requirements for pediatric evaluation of most oncology products developed for adult cancers have been waived. Because children typically do not have the same type of cancers, which occur commonly in adults, or the indication or drug had been granted an orphan designation, PREA therefore has had no impact. Pediatric studies for labeling updates are largely done through BPCA by a written request (WR) issued by the Food and Drug Administration (FDA). Because the cancers that occur in pediatric and adult populations do not share the same etiology or natural history, there are limited opportunities to extrapolate adult efficacy and safety to the pediatric population. The characteristics of individual pediatric studies included in WRs have varied greatly over time. PROCEDURE: In this study, we searched WRs that were issued by the FDA since 2001. We found 40 such requests issued for oncology drugs and biologics, which had been accepted by sponsors. RESULTS: Clinical trials included in 23 of the WRs have been concluded, 19 have resulted in exclusivity, and three drugs that were studied have been approved for use in pediatric populations. Herein, we present the spectrum of WRs from a regulatory, study design, dosing, formulation, analysis plan, evidentiary standard of efficacy, and safety perspective. CONCLUSIONS: This provides information on requests issued in the past nearly 20 years and studies that are completed. As WRs have provided the only regulatory mechanism to assure pediatric cancer drug development, this can potentially provide insight on how pediatric cancer drug development may change in the future.

FDA Approval Summary: Tocilizumab for Treatment of Chimeric Antigen Receptor T Cell-Induced Severe or Life-Threatening Cytokine Release Syndrome.

On August 30, 2017, the U.S. Food and Drug Administration approved Actemra (tocilizumab, Genentech, Inc., South San Francisco, CA) for the treatment of severe or life-threatening chimeric antigen receptor (CAR) T cell-induced cytokine release syndrome (CRS) in adults and in pediatric patients 2 years of age and older. The approval was based on a retrospective analysis of data for patients who developed CRS after treatment with CTL019 and KTE-C19 on prospective clinical trials. Evaluable patients had been treated with intravenous tocilizumab 8 mg/kg (12 mg/kg for patients <30 kg) for severe or life-threatening CRS; only the first episode of CRS was included in the analysis. The efficacy population for the CTL019 cohort included 24 male and 21 female patients (total 45 patients) of median age 12 years. The median time from the start of CRS to the first dose of tocilizumab was 4 days (range, 0-18 days). Patients were considered responders if CRS resolved within 14 days of the first dose of tocilizumab, if no more than 2 doses of tocilizumab were needed, and if no drugs other than tocilizumab and corticosteroids were used for treatment. Thirty-one patients (69%; 95% confidence interval, 53%-82%) achieved a response as defined. In an independent cohort of 15 patients with KTE-C19-induced CRS, 53% responded. Further study is needed to determine the optimal dose of tocilizumab and to confirm the safety of its use for treatment of patients with CAR T cell-induced CRS. IMPLICATIONS FOR PRACTICE: Severe or life-threatening chimeric antigen receptor (CAR) T cell-induced cytokine release syndrome (CRS) requires urgent treatment to prevent fatal outcomes. In two independent cohorts, the majority of patients with severe or life-threatening CAR T cell-induced CRS responded to treatment with one or two doses of tocilizumab in addition to advanced supportive care. More research is needed to determine the optimal dose and schedule of tocilizumab for treatment of CAR T cell-induced CRS.

FDA Approval Summary: Pembrolizumab for the Treatment of Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma with Disease Progression on or After Platinum-Containing Chemotherapy.

On August 5, 2016, the U.S. Food and Drug Administration granted accelerated approval to pembrolizumab (KEYTRUDA injection, Merck Sharp & Dohme Corp., Kenilworth, NJ) for treatment of patients with recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) with disease progression on or after platinum-containing chemotherapy. Approval was based on the objective response rate (ORR) and duration of response (DoR) in a cohort of patients in a nonrandomized multi-cohort trial (KEYNOTE-012) that included 174 patients with recurrent or metastatic HNSCC who had disease progression on or after platinum-containing chemotherapy. Patients received either intravenous pembrolizumab 10 mg/kg every 2 weeks or 200 mg every 3 weeks. ORR was determined by independent review according to Response Evaluation Criteria in Solid Tumors 1.1. ORR was 16% (95% confidence interval 11, 22) with a complete response rate of 5%. DoR ranged from 2.4+ months to 27.7+ months. Twenty-three of 28 responding patients (82%) had response durations of ≥6 months. Safety was evaluated in 192 patients with HNSCC receiving at least one dose of pembrolizumab. Frequent (≥2%) serious adverse reactions were pneumonia, dyspnea, confusional state, vomiting, pleural effusion, and respiratory failure. Clinically significant immune-mediated adverse reactions included pneumonitis, colitis, hepatitis, adrenal insufficiency, diabetes mellitus, skin toxicity, myositis, and thyroid disorders. The benefit-risk profile of pembrolizumab was considered acceptable in this patient population. As a condition of accelerated approval, Merck is required to conduct a confirmatory trial; this trial, KEYNOTE-040, is ongoing. IMPLICATIONS FOR PRACTICE: This accelerated approval expands the U.S. Food and Drug Administration-approved indications for pembrolizumab, providing health care providers with new information regarding pembrolizumab for the treatment of patients with recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) with disease progression on or after platinum-containing chemotherapy. Pembrolizumab is the first drug to receive approval for treatment of patients with HNSCC since cetuximab was approved for this indication in 2006.

IDH1 and IDH2 mutations in gliomas.

BACKGROUND: A recent genomewide mutational analysis of glioblastomas (World Health Organization [WHO] grade IV glioma) revealed somatic mutations of the isocitrate dehydrogenase 1 gene (IDH1) in a fraction of such tumors, most frequently in tumors that were known to have evolved from lower-grade gliomas (secondary glioblastomas). METHODS: We determined the sequence of the IDH1 gene and the related IDH2 gene in 445 central nervous system (CNS) tumors and 494 non-CNS tumors. The enzymatic activity of the proteins that were produced from normal and mutant IDH1 and IDH2 genes was determined in cultured glioma cells that were transfected with these genes. RESULTS: We identified mutations that affected amino acid 132 of IDH1 in more than 70% of WHO grade II and III astrocytomas and oligodendrogliomas and in glioblastomas that developed from these lower-grade lesions. Tumors without mutations in IDH1 often had mutations affecting the analogous amino acid (R172) of the IDH2 gene. Tumors with IDH1 or IDH2 mutations had distinctive genetic and clinical characteristics, and patients with such tumors had a better outcome than those with wild-type IDH genes. Each of four tested IDH1 and IDH2 mutations reduced the enzymatic activity of the encoded protein. CONCLUSIONS: Mutations of NADP(+)-dependent isocitrate dehydrogenases encoded by IDH1 and IDH2 occur in a majority of several types of malignant gliomas.

FDA review summary: Mozobil in combination with granulocyte colony-stimulating factor to mobilize hematopoietic stem cells to the peripheral blood for collection and subsequent autologous transplantation.

PURPOSE: On December 15, 2008, the US Food and Drug Administration approved plerixafor (Mozobil; Genzyme Corp.), a new small-molecule inhibitor of the CXCR4 chemokine receptor, for use in combination with granulocyte colony-stimulating factor (G-CSF) to mobilize hematopoietic stem cells (HSC) to the peripheral blood for collection and subsequent autologous transplantation in patients with non-Hodgkin's lymphoma (NHL) and multiple myeloma (MM). This summary reviews the database supporting this approval. EXPERIMENTAL DESIGN: The safety and efficacy of plerixafor were demonstrated by 2 multicenter, randomized, placebo-controlled studies in patients with NHL and MM who were eligible for autologous HSC transplantation. The primary efficacy end points were the collection of > or = 5 x 10(6) CD34+ cells/kg from the peripheral blood in 4 or fewer apheresis sessions in patients with NHL or > or = 6 x 10(6) CD34+ cells/kg from the peripheral blood in 2 or fewer apheresis sessions in patients with MM. RESULTS: The 2 randomized studies combined enrolled 600 patients (298 with NHL and 302 with MM). Fifty-nine percent of patients with NHL who were mobilized with G-CSF and plerixafor had peripheral blood HSC collections of > or = 5 x 10(6) CD34+ cells/kg in 4 or fewer apheresis sessions, compared with 20% of patients with NHL who were mobilized with G-CSF and placebo (p < 0.001). Seventy-two percent of patients with MM who were mobilized with Mozobil and G-CSF had peripheral blood HSC collections of > or = 6 x 10(6) CD34+ cells/kg in 2 or fewer apheresis sessions, compared with 34% of patients with MM who were mobilized with placebo and G-CSF (p < 0.001). Common adverse reactions included diarrhea, nausea, vomiting, flatulence, injection site reactions, fatigue, arthralgia, headache, dizziness, and insomnia. CONCLUSIONS: This report describes the Food and Drug Administration review supporting the approval of plerixafor.

beta-Estradiol attenuates the anti-HIV-1 efficacy of Stavudine (D4T) in primary PBL.

BACKGROUND: Female hormones are known to play an important role in predisposition for many infectious diseases. Recent work suggests there are gender effects in HIV/AIDS progression. Here we ask whether the sex steroid hormone beta-estradiol affects the replication of HIV-1 or the efficacy of a common anti-retroviral drug, Stavudine (D4T). RESULTS: Human PBL were infected with HIV-1 in the presence or absence of combinations of sex steroid hormones and the anti-retroviral drug, D4T. After seven days in culture, viral supernatants were assayed for HIV-1 p24 protein. beta-estradiol resulted in a modest inhibition of HIV-1 replication of approximately 26%. However, 2 nM beta-estradiol increased the amount of HIV-1 replication in the presence of 50 nM D4T from a baseline of 33% (+/- SE = 5.4) to 74% (+/- SE = 5.4) of control virus levels in the absence of drug. Both results were statistically highly significant (p < 0.001). beta-estradiol did not increase the replication of a D4T-resistant strain of HIV in the presence of D4T. The effects were unlikely to be due to general cell inhibition or toxicity because these concentrations of drug and hormone cause no cytotoxicity in PBL as measured by trypan blue exclusion. CONCLUSION: beta-estradiol inhibited both HIV-1 replication in primary human PBL and the antiretroviral efficacy of D4T in PBL cultures. To optimize antiretroviral drug therapy, it may be necessary to monitor patient hormonal status.

FDA's Approval of the First Biosimilar to Bevacizumab.

Passage of the Biologics Price Competition and Innovation Act of 2009 created an abbreviated licensure pathway for biosimilar products. The FDA approved ABP215 (MVASI, bevacizumab-awwb; Amgen) as a biosimilar to U.S.-licensed Avastin (bevacizumab; Genentech) based on an extensive comparative analytic characterization, data obtained in a pharmacokinetic similarity study in healthy subjects, and a comparative clinical study in patients with non-small cell lung cancer. The totality of the evidence for biosimilarity supported extrapolation of the data to support licensure as a biosimilar for other approved indications of U.S.-licensed Avastin, without the need of additional clinical studies. Clin Cancer Res; 24(18); 4365-70. ©2018 AACR.

FDA Approval Summary: TAS-102.

The FDA approved TAS-102 (Lonsurf; Taiho Oncology, Inc.) for the treatment of patients with metastatic colorectal cancer (mCRC) who have been previously treated with fluoropyrimidine-, oxaliplatin-, and irinotecan-based chemotherapy; an anti-VEGF biological therapy; and if RAS wild type, an anti-EGFR therapy. In an international, multicenter, double-blinded, placebo-controlled trial (TPU-TAS-102-301, herein referred to as RECOURSE), 800 patients with previously treated mCRC were randomly allocated (2:1) to receive either TAS-102 35 mg/m2 orally twice daily after meals on days 1 through 5 and 8 through 12 of each 28-day cycle (n = 534) or matching placebo (n = 266). The trial demonstrated a statistically significant improvement in overall survival for those randomized to receive TAS-102, with a median survival of 7.1 months in the TAS-102 arm [confidence interval (CI), 6.5-7.8] and 5.3 months in the placebo arm [CI, 4.6-6.0; hazard ratio (HR), 0.68; 95% CI, 0.58-0.81; P < 0.001, stratified log-rank test]. The trial also demonstrated a statistically significant prolongation of progression-free survival (HR, 0.47; 95% CI, 0.40-0.55; P < 0.001). The most common adverse reactions, in order of decreasing frequency, observed in the patients who received TAS-102 were anemia, neutropenia, asthenia/fatigue, nausea, thrombocytopenia, decreased appetite, diarrhea, vomiting, abdominal pain, and pyrexia. Adverse events led to discontinuation of TAS-102 in 3.6% of patients, and 13.7% required a dose reduction. The most common adverse reactions leading to dose reduction were neutropenia, anemia, febrile neutropenia, fatigue, and diarrhea. Clin Cancer Res; 23(12); 2924-7. ©2017 AACR.

FDA Approval of Gefitinib for the Treatment of Patients with Metastatic EGFR Mutation-Positive Non-Small Cell Lung Cancer.

On July 13, 2015, the FDA approved gefitinib (Iressa; AstraZeneca UK Limited) for the treatment of patients with metastatic non-small cell lung cancer (NSCLC) whose tumors have EGFR exon 19 deletions or exon 21 (L858R) substitution mutations as detected by an FDA-approved test. Concurrently, a labeling expansion of the therascreen EGFR RGQ PCR Kit (Qiagen) as a companion diagnostic test was approved. The approval was based on the results of a multicenter, single-arm, open-label clinical study of 106 treatment-naïve patients with metastatic EGFR mutation-positive NSCLC who received gefitinib, 250 mg daily, until disease progression or intolerable toxicity. The major efficacy outcome was RECIST v1.1 objective response rate (ORR). The blinded independent central review (BICR) ORR was 50% [95% confidence interval (CI), 41-59] with a median duration of response (DoR) of 6.0 months. Efficacy results were supported by a retrospective exploratory analysis of a subset of a randomized, multicenter, open-label trial on 1,217 patients with metastatic NSCLC. Of the patients randomized, 186 (15%) were retrospectively determined to be EGFR positive and evaluable for a BICR assessment. The HR for progression-free survival (PFS) was 0.54 (95% CI, 0.38-0.79), favoring gefitinib over platinum-doublet chemotherapy. The most common (≥20%) adverse reactions were skin reactions, increased aspartate and alanine aminotransferase, proteinuria, and diarrhea. Approximately 5% of patients discontinued treatment due to an adverse reaction. Given the safety profile and clinically meaningful ORR, DoR, and PFS, the benefit-risk analysis was deemed favorable for FDA approval.

Regression models for unbalanced longitudinal ordinal data: computer software and a simulation study.

A computer program GGOREX in the form of a SAS macro is developed for the analysis of longitudinal ordinal data. It is extended from GEECAT and GEEGOR developed by Williamson, Lipsitz and Kim in their paper in 1999. An illustrative example with some preliminary data from a study conducted by the National Institute of Child Health and Human Development and the University of Alabama at Birmingham is given. Another set of computer programs is developed to make it possible to conduct a simulation study to validate the GGOREX procedure in a finite sample. A simple computer program in FORTRAN using the IMSL software library is developed to solve for the probability distribution of the longitudinal ordinal responses according to the correlation specification.

Eribulin mesylate for the treatment of patients with refractory metastatic breast cancer: use of a "physician's choice" control arm in a randomized approval trial.

This work describes the considerations that led to the approval by the U.S. Food and Drug Administration (FDA), on November 15, 2010, of eribulin mesylate (Halaven; Eisai, Inc.) for the treatment of patients with refractory metastatic breast cancer. The FDA review focused primarily on the results of a single randomized, open-label, multicenter trial of 762 patients with refractory locally advanced or metastatic breast cancer. The patients were randomized to receive eribulin or any single-agent treatment of the physician's choice, selected prior to randomization. The FDA's approval of eribulin mesylate was based on demonstration of a statistically significant prolongation of overall survival (OS) in patients who had been randomized to receive eribulin. The median OS was 13.1 months in the eribulin arm compared with 10.6 months in the control arm [HR 0.81 (95% CI, 0.66-0.99); P = 0.041]. Treatment with eribulin did not show a statistically significant treatment effect [HR 0.87 (95% CI, 0.71-1.05)] on progression-free survival as determined by independent review. This approval highlights the appropriate use of an innovative trial design and shows that improvement in OS is an achievable endpoint in the setting of advanced breast cancer. On the basis of the different conclusions arising from the OS and progression-free survival results, investigators should consider using OS as a primary endpoint in clinical trials for refractory breast cancer.