Comparative pharmacokinetics and bioavailability of monomethyl fumarate following a single oral dose of Bafiertam® (monomethyl fumarate) versus Vumerity® (diroximel fumarate).

BACKGROUND: Bafiertam® (monomethyl fumarate [MMF]) and Vumerity® (diroximel fumarate [DRF]) are two FDA approved drug products for the treatment of relapsing forms of multiple sclerosis (MS) to include clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease, in adults. Vumerity® is a prodrug of MMF which requires enzymatic conversion of DRF to the active drug MMF, the moiety responsible for the therapeutic efficacy; whereas Bafiertam® contains MMF, providing the active drug directly without any need for enzymatic conversion. OBJECTIVE: The objective of this study was to evaluate the pharmacokinetics and relative bioavailability of MMF from oral administration of two Bafiertam® capsules each containing 95 mg of MMF in comparison to two Vumerity® capsules each containing 231 mg of DRF, the therapeutic doses of each product. METHODS: This was a single-dose, open-label, randomized, 2-way crossover study evaluating two treatments over two periods with a washout interval between treatments. Forty-four healthy male or female subjects were planned to receive each of the two treatments to assure 40 completed dosing: a single dose of 2  ×  95 mg Bafiertam® capsules and a single dose of 2  ×  231 mg Vumerity® capsules under fasting conditions in a randomized crossover fashion. Blood samples were obtained prior to dosing and at prespecified time points through 24 h post-dose to determine plasma concentrations of MMF. MMF pharmacokinetic [PK] parameters were calculated and included maximum observed concentration (Cmax), time to reach Cmax (tmax), apparent half-life of MMF in plasma (t1/2), AUC0-t which is the area under the plasma concentration vs. time curve (AUC) from time zero (dosing time) to the last time point, t, with quantifiable MMF concentration, and AUC0-inf which is AUC0-t plus the extrapolated AUC from time t to infinity. RESULTS: Forty-one subjects completed the study as planned. MMF in Bafiertam® capsules was well and readily absorbed with a median tmax occurring at 4 h post dose, approximately 1 h later than that of Vumerity® capsules. However, the mean MMF Cmax from Bafiertam® (1969 ng/mL) was higher than that from Vumerity® (1121 ng/mL). The mean MMF AUC0-t and AUC0-inf from Bafiertam® (3503 and 3531 h*ng/mL) were also higher than those from Vumerity® (3123 and 3227 h*ng/mL), respectively. The geometric least-squares mean (GLSM) ratios (90% confidence interval), Bafiertam® vs. Vumerity®, for MMF Cmax, AUC0-t and AUC0-inf were 181.8 (158.2 - 208.8)%, 116.8 (107.9-126.5)% and 113.8 (105.3 - 123.0)%, respectively.  Both products were safe and well tolerated, as expected, with flushing being the most common adverse event for both products. CONCLUSIONS: The mean MMF AUC0-t and AUC0-inf were 14-17% higher after administration of Bafiertam® as compared to Vumerity® at their respective therapeutic doses under fasting conditions, however, this difference was not statistically or clinically significant. Although more clinical studies would be needed before making strong recommendations, results of this study may help with selecting appropriate fumarate products, especially when administering the product with food is clinically recommended.

Pharmacokinetics and Bioavailability of Monomethyl Fumarate Following a Single Oral Dose of Bafiertam™ (Monomethyl Fumarate) or Tecfidera® (Dimethyl Fumarate).

BACKGROUND: Tecfidera® (dimethyl fumarate [DMF]) is an approved product for the treatment of relapsing forms of multiple sclerosis. Monomethyl fumarate (MMF) is the only active metabolite of DMF and is responsible for its therapeutic efficacy. OBJECTIVE: The objective of this study was to determine whether two Bafiertam™ capsules each containing 95 mg of MMF is bioequivalent to one Tecfidera® capsule containing 240 mg of DMF, a prodrug of MMF. METHODS: This was a single-dose, open-label, randomized, two-way crossover study evaluating two treatments over two periods with a washout interval between treatments. Fifty healthy subjects were randomized to receive a single dose of the test drug MMF 190 mg as 2 × 95 mg delayed-release capsules or the reference drug DMF 240 mg as a 1 × 240-mg delayed-release capsule. Blood samples were obtained prior to dosing and at prespecified time points through 24 h post-dose to determine plasma concentrations of MMF. The pharmacokinetic parameters of MMF were calculated including maximum observed concentration, time to reach maximum observed concentration, apparent half-life of the drug in plasma, AUC0-t which is the area under the plasma concentration-time curve (AUC) from time zero (dosing time) to the last time point, t, with measurable analyte concentration, and AUC0-inf, which is AUC0-t plus the extrapolated AUC from time t to infinity. RESULTS: The geometric least-squares mean ratios (90% confidence interval) of the test drug MMF vs the reference drug DMF were 96.80% (92.18-101.64), 96.35% (91.81-101.12), and 104.84% (95.54-115.05) for AUC0-t, AUC0-inf, and maximum observed concentration, respectively. Two capsules of Bafiertam™ was safe and generally well tolerated. The most common adverse event for both products was flushing, 60% and 51%, for Bafiertam™ and Tecfidera®, respectively. CONCLUSIONS: Based on the statistical analysis results of the pharmacokinetic parameters of MMF, a single oral dose of two Bafiertam™ DR 95 mg capsules is bioequivalent to a single oral dose of one Tecfidera® DR 240 mg capsule. CLINICAL TRIAL REGISTRATION: This study was retrospectively registered with ClinicalTrials.gov (NCT04570670) on 30 September, 2020.

Performance of the Transport Layer Security Handshake Over 6TiSCH.

This paper presents a thorough comparison of the Transport Layer Security (TLS) v1.2 and Datagram TLS (DTLS) v1.2 handshake in 6TiSCH networks. TLS and DTLS play a crucial role in protecting daily Internet traffic, while 6TiSCH is a major low-power link layer technology for the IoT. In recent years, DTLS has been the de-facto security protocol to protect IoT application traffic, mainly because it runs over lightweight, unreliable transport protocols, i.e., UDP. However, unlike the DTLS record layer, the handshake requires reliable message delivery. It, therefore, incorporates sequence numbers, a retransmission timer, and a fragmentation algorithm. Our goal is to study how well these mechanisms perform, in the constrained setting of 6TiSCH, compared to TCP's reliability algorithms, relied upon by TLS. We port the mbedTLS library to OpenWSN, a 6TiSCH reference implementation, and deploy the code on the state-of-the-art OpenMote platform. We show that, when the peers use an ideal channel, the DTLS handshake uses up to 800 less and completes 0.6 s faster. Nonetheless, using an unreliable communication link, the DTLS handshake duration suffers a performance penalty of roughly 45%, while TLS' handshake duration degrades by merely 15%. Similarly, the number of exchanged bytes doubles for DTLS while for TLS the increase is limited to 15%. The results indicate that IoT product developers should account for network characteristics when selecting a security protocol. Neglecting to do so can negatively impact the battery lifetime of the entire constrained network.

Monomethyl fumarate has better gastrointestinal tolerability profile compared with dimethyl fumarate.

BACKGROUND: Monomethyl fumarate (MMF) is the pharmacologically active metabolite of dimethyl fumarate (DMF). MMF formulated as Bafiertam™ 190 mg and DMF formulated as Tecfidera 240 mg deliver bioequivalent exposure of MMF and therefore possess the same efficacy/safety profiles. DMF is a widely used oral treatment for relapsing-remitting forms of multiple sclerosis (RRMS) but is limited in some patients, primarily female, by issues with gastrointestinal (GI) tolerability. METHODS: This was a randomized, double-blind, head-to-head, 5-week study evaluating the GI tolerability of MMF 190 mg vs DMF 240 mg, administered twice daily in healthy subjects, using a derivative of the self-administered Modified Overall Gastrointestinal Symptom Scale (MOGISS). Subjects were stratified (3:1, female:male) and randomized (1:1) to the treatments. The primary endpoint was the Area Under the Curve (AUC) in each of the individual symptoms in the MOGISS over the 5-week treatment period. Other endpoints included the AUC over the 5-week treatment period in the MOGISS composite and total scores; duration and severity of GI events; Number and percentage of subjects reporting GI events during the overall treatment period, and assessment of safety/tolerability. RESULTS: Inferential analysis of the hierarchical testing of overall treatment differences in each MOGISS symptom AUC occurred in a predefined sequence starting with Abdominal Pain. For each symptom, LSMean AUC values were lower for MMF than DMF, however, the first primary endpoint, Abdominal Pain, was not statistically different between treatments; thus, all subsequent statistical analyses were considered exploratory. The side effects and safety profiles observed were consistent with the known profiles of DMF, with no new or unique safety concerns noted. CONCLUSIONS: Bafiertam showed an improved gastrointestinal tolerability profile compared with Tecfidera, with less severe GI events and fewer days of self-assessed GI symptoms, fewer GI adverse events, and lower discontinuation rates because of GI adverse events.

Preemptive adefovir versus lamivudine for prevention of hepatitis B reactivation in chronic hepatitis B patients undergoing chemotherapy.

BACKGROUND: This proof-of-concept study compared lamivudine (LAM) with a newer antiviral agent, adefovir dipivoxil (ADF), in preventing hepatitis B virus (HBV) reactivation in chronic HBV patients undergoing chemotherapy. METHODS: Hepatitis B surface antigen (HBsAg) positive patients intended to undergo chemotherapy were randomized to receive either LAM 100 mg daily or ADF 10 mg daily. Anti-viral therapy was started 1 week prior to chemotherapy and until 6 months after completing chemotherapy. The primary outcome was HBV reactivation rate. All patients with viral breakthrough were screened for resistance mutations by direct sequencing. RESULTS: Seventy treatment-naïve patients were consecutively randomized 1:1 to LAM or ADF. The median baseline HBV DNA levels were similar (LAM 3.36 vs. ADF 3.17 log10 copies/mL, p = 0.860). The median duration was 8.3 months on LAM and 10.6 months on ADF (p = 0.220). HBV reactivation was observed in 13/35 (37.1%) on LAM compared with 10/35 (28.6%) on ADF (p = 0.611). The median time to HBV reactivation was 4.6 and 8.1 months, on LAM and ADF respectively. Among these 13 patients, 8/13 (61.5%) on LAM had developed drug resistance mutations but none on ADF had developed drug resistance mutations to ADF (p = 0.003). Both drugs were well tolerated and no severe drug-related toxicities were reported. CONCLUSION: In this randomized clinical study, adefovir and lamivudine demonstrated similar efficacy in preventing hepatitis B reactivation in HBsAg-positive patients undergoing chemotherapy. In patients whose hepatitis B reactivated, adefovir was associated with a lower resistance profile.

Hepatitis B screening and vaccination practices in asian american primary care.

BACKGROUND/AIMS: Screening for hepatitis B virus (HBV) is recommended in populations with anticipated prevalence ≥2%. This study surveyed HBV screening and vaccination practices of Asian American primary care providers (PCPs). METHODS: Approximately 15,000 PCPs with Asian surnames in the New York, Los Angeles, San Francisco, Houston, and Chicago areas were invited to participate in a web-based survey. Asian American PCPs with ≥25% Asian patients in their practice were eligible. RESULTS: Of 430 (2.9%) survey respondents, 217 completed the survey. Greater than 50% followed ≥200 Asian patients. Although 95% of PCPs claimed to have screened patients for HBV, 41% estimated that ≤25% of their adult Asian patients had ever been screened, and 50% did not routinely screen all Asian patients. In a multivariable analysis, the proportion of Asian patients in the practice, provider geographic origin and the number of liver cancers diagnosed in the preceding 12 months were significantly associated with a higher likelihood of screening for HBV. Over 80% of respondents reported that ≤50% of their adult Asian patients had received the HBV vaccine. CONCLUSIONS: Screening and vaccination for HBV in Asian American patients is inadequate. Measures to improve HBV knowledge and care by primary-care physicians are critically needed.

Safety and efficacy of ulimorelin administered postoperatively to accelerate recovery of gastrointestinal motility following partial bowel resection: results of two randomized, placebo-controlled phase 3 trials.

BACKGROUND: Gastrointestinal recovery is a critical milestone after bowel resection with postoperative ileus resulting in increased risk of complications and prolonged hospitalization. OBJECTIVE: The aim of this study is to evaluate the efficacy and safety of ulimorelin, a ghrelin receptor agonist given postoperatively in 2 identically designed phase 3 studies (ClinicalTrials.gov NCT01285570 and NCT01296620). DESIGN: This investigation is designed as a multicenter, double-blind, randomized, parallel-group study. SETTINGS: This study involves hospital inpatients. PATIENTS: Adult patients undergoing partial bowel resection were included. INTERVENTION: Thirty-minute intravenous infusions (160 µg/kg, 480 µg/kg ulimorelin, or placebo) once daily were started within 60 minutes after the end of surgery and ended at the first of the following: primary efficacy end point fulfilled (defined below), hospital discharge, or 7 days treatment. MAIN OUTCOME MEASURES: The primary efficacy end point was the time from the end of surgery to the composite end point of the later of first bowel movement and tolerance of solid food. Safety was assessed with the use of standard assessments including adverse events and laboratory tests. RESULTS: Ulimorelin Study of Efficacy and Safety 007, n = 332 patients; Ulimorelin Study of Efficacy and Safety 008, n = 330 patients: in both studies, the primary efficacy end point and the secondary efficacy outcomes, which included postsurgical time to first bowel movement, tolerance of solid food, and discharge eligibility, did not differ significantly among patients treated with either dose of ulimorelin versus placebo. Rates of serious adverse events were comparable across all treatment groups. There was no statistically significant difference from placebo in regard to events of interest, namely nausea, vomiting, ileus as an adverse event, nasogastric tube reinsertion, anastomotic complications, and infections. LIMITATIONS: A possible limitation is the variance inherent in surgery and comorbidities. CONCLUSIONS: Although the efficacy of ulimorelin in reducing the duration of postoperative ileus was not demonstrated in these studies, intravenous ulimorelin at doses of 160 µg/kg and 480 µg/kg was generally well tolerated in postcolectomy patients. Similar to other promotility agents, ulimorelin may find an application in other indications better suited to its attributes.

Efficacy and safety of long-term adefovir dipivoxil therapy in children with chronic hepatitis B infection.

BACKGROUND: The safety and efficacy of adefovir dipivoxil (ADV) for chronic hepatitis B infection in children was demonstrated in a randomized, placebo-controlled trial. Those children were followed for 4 more years, and many continued to receive ADV for all or part of this time. OBJECTIVES: To examine the therapeutic effects and safety of prolonged ADV therapy in children with chronic hepatitis B infection. METHODS: After 48 weeks of double-blind treatment, all placebo-treated subjects who did not exhibit HBeAg seroconversion at week 44, and all ADV-treated subjects, were offered open-label ADV for up to 192 additional weeks. Treatment was discontinued if there was no virologic effect, except for adolescents with previous lamivudine exposure, in whom lamivudine was added to ADV. Durability of HBeAg seroconversion was assessed. Annual resistance surveillance was conducted in subjects who had detectable hepatitis B virus DNA. RESULTS: Of the 170 subjects who completed the 48-week study, 162 participated in the open-label study. ADV was discontinued in 61 subjects due to virologic failure. In subjects who continued treatment, either as monotherapy or with lamivudine, continued viral suppression and alanine aminotransferase normalization were noted. HBeAg seroconversions were observed in 55 subjects, and hepatitis B surface antigen seroconversion in 5. Mean duration of HBeAg seroconversion at last observation was 762 ± 371.2 days in the ADV-ADV group and 643 ± 291.5 days in the PLB-ADV group. ADV was safe and well-tolerated. Resistance to ADV was observed in 1 child on ADV monotherapy. Nine treatment-experienced subjects entered the study with mutations associated with lamivudine resistance. All responded to ADV therapy. CONCLUSIONS: Prolonged ADV treatment is safe in children. If reserved only for those with virologic response within 6 months, viral resistance was minimal.

A phase 2, randomized, double-blind, placebo-controlled study of GS-9450 in subjects with nonalcoholic steatohepatitis.

UNLABELLED: In nonalcoholic steatohepatitis (NASH), the extent of hepatocyte apoptosis correlates with disease severity. Reducing hepatocyte apoptosis with the selective caspase inhibitor GS-9450 has a potential for altering the course of the liver disease. In this phase 2, double-blind study, 124 subjects with biopsy-proven NASH were randomized to once-daily placebo or 1, 5, 10, or 40 mg GS-9450 for 4 weeks. Absolute and percent changes from baseline in ALT levels, AST levels, and caspase-3-cleaved cytokeratin (CK)-18 fragments at week 4 were assessed by an analysis of covariance model with adjustment for baseline values. In the 40-mg group, mean (SD) ALT decreased by 47 (43) U/L from baseline to week 4 (P < 0.0001 versus placebo), and the proportion of subjects with normal ALT increased from 0% to 35% at week 4. In the 40-mg group, mean AST decreased by 13 U/L from baseline (not significant), and the proportion with normal AST increased from 20% at baseline to 48% at week 4. By week 4, mean CK-18 fragment levels had decreased to 393 (723) U/L in the GS-9450 10-mg group and 125 (212) U/L in the 40-mg group, but these reductions were not statistically significant. No serious adverse events were reported during treatment, and the percentage of subjects with at least one treatment-emergent grade 3 or 4 laboratory abnormality ranged from 11.5% to 17% across the GS-9450 treatment groups versus 35% in the placebo group. CONCLUSION: GS-9450 treatment induced significant reductions in ALT levels in NASH patients. Reductions in CK-18 fragment levels also occurred, although they were not statistically significant. At appropriate therapeutic indices, selective caspase inhibitors may be a promising treatment option in patients with NASH.

Tenofovir disoproxil fumarate (TDF), emtricitabine/TDF, and entecavir in patients with decompensated chronic hepatitis B liver disease.

UNLABELLED: Data are limited on the safety and effectiveness of oral antivirals other than lamivudine and adefovir dipivoxil for treatment of chronic hepatitis B (CHB) in patients with decompensated liver disease. This Phase 2, double-blind study randomized 112 patients with CHB and decompensated liver disease to receive either tenofovir disoproxil fumarate (TDF; n = 45), emtricitabine (FTC)/TDF (fixed-dose combination; n = 45), or entecavir (ETV; n = 22). The primary endpoint was safety; more specifically, tolerability failure (adverse events resulting in permanent treatment discontinuation) and confirmed serum creatinine increase ≥ 0.5 mg/dL from baseline or confirmed serum phosphorus <2 mg/dL. Patients with insufficient viral suppression (e.g., confirmed HBV DNA ≥ 400 copies/mL at week 8 or 24) could begin open-label FTC/TDF but were considered failures in this interim week 48 analysis for efficacy endpoints. Tolerability failure was infrequent across arms: 6.7% TDF, 4.4% FTC/TDF, and 9.1% ETV (P = 0.622) as were confirmed renal parameters meeting threshold 8.9%, 6.7%, and 4.5% (P = 1.000), respectively. Six patients died (none considered related to study drug) and six received liver transplants (none had HBV recurrence). The adverse event and laboratory profiles were consistent with advanced liver disease and complications, with no unexpected safety signals. At week 48, HBV DNA was <400 copies/mL (69 IU/mL) in 70.5% (TDF), 87.8% (FTC/TDF), and 72.7% (ETV) of patients. Proportions with normal alanine aminotransferase were: 57% (TDF), 76% (FTC/TDF), and 55% (ETV). Hepatitis B e antigen (HBeAg) loss/seroconversion occurred in 21%/21% (TDF), 27%/13% (FTC/TDF), and 0%/0% (ETV). Child-Turcotte-Pugh and Modification for End-stage Liver Disease scores improved in all groups. CONCLUSION: All treatments were well tolerated in patients with decompensated liver disease due to CHB with improvement in virologic, biochemical, and clinical parameters.

Three-year efficacy and safety of tenofovir disoproxil fumarate treatment for chronic hepatitis B.

BACKGROUND & AIMS: Tenofovir disoproxil fumarate (TDF), a nucleotide analogue and potent inhibitor of hepatitis B virus (HBV) polymerase, showed superior efficacy to adefovir dipivoxil in treatment of chronic hepatitis B through 48 weeks. We evaluated long-term efficacy and safety of TDF monotherapy in patients with chronic hepatitis B who were positive or negative for hepatitis B e antigen (HBeAg(+) or HBeAg(-)). METHODS: After 48 weeks of double-blind comparison of TDF to adefovir dipivoxil, patients who underwent liver biopsy were eligible to continue the study on open-label TDF for 7 additional years; data presented were collected up to 3 years (week 144) from 85% of participants. Primary efficacy end points at week 144 included levels of HBV DNA and alanine aminotransferase, development of resistance mutations, and presence of HBeAg or hepatitis B surface antigen (HBsAg). RESULTS: At week 144, 87% of HBeAg(-) and 72% of HBeAg(+) patients treated with TDF had levels of HBV DNA <400 copies/mL. Among patients who had previously received adefovir dipivoxil and then received TDF, 88% of the HBeAg(-) and 71% of the HBeAg(+) patients had levels of HBV DNA <400 copies/mL; overall, 81% and 74%, respectively, maintained normalized levels of alanine aminotransferase and 34% had lost HBeAg. Amino acid substitutions in HBV DNA polymerase that are associated with resistance to tenofovir were not detected in any patient. Cumulatively, 8% of HBeAg(+) patients lost HBsAg. TDF maintained a favorable safety profile for up to 3 years. CONCLUSIONS: TDF was safe and effective in the long-term management of HBeAg(+) and HBeAg(-) patients with chronic hepatitis B.

Efficacy and pharmacokinetics of adefovir dipivoxil liquid suspension in patients with chronic hepatitis B and renal impairment.

The study evaluated whether a liquid suspension of adefovir dipivoxil (ADV) is effective and safe when dose adjusted based on varying degrees of renal impairment in patients with chronic hepatitis B. Patients had stable mild, moderate, or severe renal impairment or end-stage renal disease. Twenty-eight patients were enrolled: 10 (mild), 12 (moderate), and 6 severe renal impairment or end-stage renal disease with hemodialysis. Statistical testing demonstrated that daily dosages of ADV liquid suspension at 10 mg and 5 mg in the mild and moderate renal impairment groups, respectively, were clinically similar to ADV 10-mg tablets. However, the antiviral effect observed with the 5-mg/d dose was clearly numerically less than that observed with the 10-mg/d dose. Steady-state adefovir plasma exposures after administration of the ADV liquid suspension were generally within the ranges observed in patients with normal renal function. Treatment with ADV liquid suspension for up to 48 weeks was generally well tolerated. The daily dose-adjustment approach was not clearly safer or more efficacious than the dosing-interval adjustment. Therefore, the results do not support daily ADV dosing using a liquid suspension over the current strategy of adjustment of the ADV dosing interval in patients with impaired renal function.

Tenofovir is effective alone or with emtricitabine in adefovir-treated patients with chronic-hepatitis B virus infection.

BACKGROUND & AIMS: We compared treatments for patients with chronic hepatitis B virus (HBV) infection who had an incomplete response to adefovir dipivoxil (ADV). We evaluated a combination of fixed-dose emtricitabine (FTC) and tenofovir disoproxil fumarate (TDF) from the start (early combination) versus TDF as monotherapy. METHODS: Patients (n = 105) were randomly assigned to groups given TDF (n = 53) or FTC/TDF (n = 52). End points included HBV DNA suppression, biochemical and serologic response, and response by baseline or developed resistance mutations through 48 weeks of treatment. Patients given TDF monotherapy had the option to receive FTC, as fixed-dose FTC/TDF, if viremia persisted after week 24. RESULTS: At baseline, patients' mean HBV DNA level was 5.97 log(10) copies/mL, and 58% had received lamivudine (LAM); LAM- and ADV-associated mutations were detected in 13 and 10 patients, respectively, by population sequencing and in 14 and 18 patients, respectively, by reverse hybridization line probe assay (INNO-LiPA HBV DR). Through week 24 (direct comparison of blinded therapy), viral decay curves were identical between groups. At week 48, 81% of patients initially given TDF or TDF/FTC had HBV DNA levels below 400 copies/mL. The presence of baseline LAM- or ADV-associated mutations did not affect response. Adherence to therapy appeared to be the primary factor associated with HBV DNA levels below 400 copies/mL at week 48. CONCLUSIONS: TDF monotherapy and the combination of FTC and TDF had similar efficacy in patients with incomplete viral suppression after therapy with ADV; response was not influenced by the presence of baseline LAM- or ADV-associated mutations. Initial monotherapy followed by combination therapy was as effective as early combination therapy.

Tenofovir disoproxil fumarate versus adefovir dipivoxil for chronic hepatitis B.

BACKGROUND: Tenofovir disoproxil fumarate (DF) is a nucleotide analogue and a potent inhibitor of human immunodeficiency virus type 1 reverse transcriptase and hepatitis B virus (HBV) polymerase. METHODS: In two double-blind, phase 3 studies, we randomly assigned patients with hepatitis B e antigen (HBeAg)-negative or HBeAg-positive chronic HBV infection to receive tenofovir DF or adefovir dipivoxil (ratio, 2:1) once daily for 48 weeks. The primary efficacy end point was a plasma HBV DNA level of less than 400 copies per milliliter (69 IU per milliliter) and histologic improvement (i.e., a reduction in the Knodell necroinflammation score of 2 or more points without worsening fibrosis) at week 48. Secondary end points included viral suppression (i.e., an HBV DNA level of <400 copies per milliliter), histologic improvement, serologic response, normalization of alanine aminotransferase levels, and development of resistance mutations. RESULTS: At week 48, in both studies, a significantly higher proportion of patients receiving tenofovir DF than of those receiving adefovir dipivoxil had reached the primary end point (P<0.001). Viral suppression occurred in more HBeAg-negative patients receiving tenofovir DF than patients receiving adefovir dipivoxil (93% vs. 63%, P<0.001) and in more HBeAg-positive patients receiving tenofovir DF than patients receiving adefovir dipivoxil (76% vs. 13%, P<0.001). Significantly more HBeAg-positive patients treated with tenofovir DF than those treated with adefovir dipivoxil had normalized alanine aminotransferase levels (68% vs. 54%, P=0.03) and loss of hepatitis B surface antigen (3% vs. 0%, P=0.02). At week 48, amino acid substitutions within HBV DNA polymerase associated with phenotypic resistance to tenofovir DF or other drugs to treat HBV infection had not developed in any of the patients. Tenofovir DF produced a similar HBV DNA response in patients who had previously received lamivudine and in those who had not. The safety profile was similar for the two treatments in both studies. CONCLUSIONS: Among patients with chronic HBV infection, tenofovir DF at a daily dose of 300 mg had superior antiviral efficacy with a similar safety profile as compared with adefovir dipivoxil at a daily dose of 10 mg through week 48. (ClinicalTrials.gov numbers, NCT00116805 and NCT00117676.)

Sustained hepatitis B e antigen seroconversion in patients with chronic hepatitis B after adefovir dipivoxil treatment: analysis of precore and basal core promoter mutants.

BACKGROUND: This study evaluated the persistence of hepatitis B e antigen (HBeAg) seroconversion (which is considered to be an important therapeutic end point) after adefovir dipivoxil treatment. METHODS: Forty-five patients who experienced confirmed HBeAg seroconversion and had a serum hepatitis B virus DNA level < 10(5) copies/mL while receiving 10 mg of adefovir dipivoxil in a prior study were enrolled in the present study. At the time of the last dose of adefovir dipivoxil (baseline), the median age of the patients was 35 years, 64% were male, 73% were Asian, 27% were white, the median alanine aminotransferase level was 25 IU/L, and the median serum hepatitis B virus DNA level was 3.0 log copies/mL. The median follow-up time was 150 weeks (range, 13-252 weeks). RESULTS: Forty-one patients maintained sustained seroconversion at the last 2 assessments, and 4 experienced seroreversion at weeks 12 (3 patients) and 16 (1 patient) of follow-up. Approximately 50% of patients had a hepatitis B virus DNA level < 1000 copies/mL at the last visit of the study period. Of 13 patients who were viremic and had available samples at the last visit, 11 had basal core promoter and/or precore mutations. Notably, 8 of these 11 patients had basal core promoter and/or precore mutations before adefovir dipivoxil therapy despite being HBeAg positive. The median duration of adefovir dipivoxil treatment was shorter before seroconversion (48 vs. 108 weeks; P = .03) and longer after seroconversion (41 vs. 22 weeks; P = .02) for patients who experienced sustained seroconversion, compared with the patients who experienced seroreversion. CONCLUSIONS: Prolonged adefovir dipivoxil therapy after HBeAg seroconversion appeared to increase the likelihood of sustained HBeAg seroconversion. Most patients who experienced HBeAg seroconversion and had viremia had precore and/or basal core promoter mutants, which usually existed before initiation of adefovir dipivoxil therapy.

Long-term efficacy and safety of adefovir dipivoxil for the treatment of hepatitis B e antigen-positive chronic hepatitis B.

UNLABELLED: Treatment of 171 patients with hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) with adefovir dipivoxil (ADV) 10 mg over 48 weeks resulted in significant histological, virological, serological, and biochemical improvement compared with placebo. The long-term efficacy and safety of ADV in a subset of these patients was investigated for up to 5 years. Sixty-five patients given ADV 10 mg in year 1 elected to continue in a long-term safety and efficacy study (LTSES). At enrollment, the 65 LTSES patients were a median 34 years old, 83% male, 74% Asian, 23% Caucasian, median baseline serum hepatitis B virus (HBV) DNA 8.45 log(10) copies/mL, and median baseline alanine aminotransferase (ALT) 2.0 x upper limit of normal. At 5 years on study, the median changes from baseline in serum HBV DNA and ALT for the 41 patients still on ADV were 4.05 log(10) copies/mL and -50 U/L, respectively. HBeAg loss and seroconversion were observed in 58% and 48% of patients by end of study, respectively. Fifteen patients had baseline and end of follow-up liver biopsies; improvements in necroinflammation and fibrosis were seen in 67% and 60% of these patients, respectively. Adefovir resistance mutations A181V or N236T developed in 13 LTSES patients; the first observation was at study week 195. There were no serious adverse events related to ADV. CONCLUSION: Treatment with ADV beyond 48 weeks was well tolerated and produced long-term virological, biochemical, serological, and histological improvement.

Safety, efficacy, and pharmacokinetics of adefovir dipivoxil in children and adolescents (age 2 to <18 years) with chronic hepatitis B.

UNLABELLED: This study investigated the efficacy, safety, and pharmacokinetics of adefovir dipivoxil (ADV) in children and adolescents with chronic hepatitis B (CHB). A total of 173 treatment-naive and treatment-experienced children with hepatitis B e antigen (HBeAg)+ CHB were randomized to ADV or placebo. Randomization was stratified by age (2 to <7 years; >7 to <12 years; >12 to <18 years) and prior treatment. Significantly more ADV-treated subjects aged 12 to <18 years achieved the primary efficacy endpoint (serum hepatitis B virus [HBV] DNA <1,000 copies/mL and normal alanine aminotransferase) compared to placebo-treated subjects (23% versus 0%; P = 0.007). In the younger groups, differences between ADV and placebo at the end of blinded treatment were not statistically significant. More ADV-treated subjects had HBeAg seroconversion: 18 of 113 (15.9%) versus three of 57 (5.3%) (but P = 0.051), and more met the combined endpoint of HBeAg seroconversion, HBV DNA <1,000 copies/mL and normal alanine aminotransferase (12/113 versus 0/57; P = 0.009). No subject developed an ADV-associated mutation that has been linked to HBV DNA rebound (that is, mutations rtN236T or rtA181V). ADV plasma concentrations were comparable across groups and within the target range. ADV treatment was well tolerated; no new safety issues were identified. Treatment-related adverse events were reported for 12% of ADV-treated and 10% of placebo-treated subjects. After 48 weeks of ADV treatment, antiviral efficacy in subjects ages 12 to <18 years with HBeAg+ CHB was similar to that observed in a study in adult treatment-naive subjects with HBeAg+ CHB. ADV was not different from placebo in subjects aged 2 to 11 years despite adequate plasma ADV exposure in all three age groups. CONCLUSION: ADV showed significant antiviral efficacy in subjects aged 12 to 17 years with HBeAg+ CHB, but was not different from placebo in subjects aged 2 to 11 years.

Long-term safety and efficacy results of once-daily emtricitabine-based highly active antiretroviral therapy regimens in human immunodeficiency virus-infected pediatric subjects.

OBJECTIVES: The purpose of this work was to obtain long-term safety and efficacy data for antiretroviral regimens containing emtricitabine in HIV-infected pediatric subjects and confirm that a pediatric dose of 6 mg/kg once daily would provide steady-state emtricitabine concentrations comparable to those observed in adults given 200 mg of emtricitabine once daily. PATIENTS AND METHODS: HIV-infected subjects between 3 months and 16 years of age were enrolled, including 71 antiretroviral-naïve subjects and 45 antiretroviral-experienced subjects. Naive subjects received emtricitabine plus stavudine plus lopinavir or ritonavir. Experienced subjects replaced the lamivudine in their existing regimens with emtricitabine. Tolerance, safety, disease progression, and virologic and immunologic responses were evaluated. RESULTS: The Kaplan-Meier probability of persistent virologic response in the intent-to-treat population through week 164 at < or = 400 copies per mL and < or = 50 copies per mL was 74% and 62%, respectively. Three subjects (3%) discontinued the study for adverse events, 8 (7%) for virologic failure, and 1 died through a median follow-up of 164 weeks. The annualized incidence rate of grade 3 to 4 adverse events and grade 3 to 4 laboratory abnormalities was 6% and 3%, respectively. The annualized incidence rate of serious adverse events was 9%, with 1% attributed as related to emtricitabine. Genotypic analysis showed the emergence of the M184V mutation in 4 of the 15 subjects who experienced virologic failure through week 164. Pharmacokinetic evaluation demonstrated plasma drug exposures in these children comparable to adults receiving the approved dose of 200 mg once daily. CONCLUSIONS: These results demonstrate the safety and efficacy of emtricitabine in pediatric patients. They also support that the safety and efficacy profile of emtricitabine in children is similar to that demonstrated in adults.

Impact of early viral kinetics on T-cell reactivity during antiviral therapy in chronic hepatitis B.

BACKGROUND: The patterns of hepatitis B viral dynamics during different antiviral therapies and the associated changes in HBV-specific T-cell reactivity are not well defined. METHODS: We investigated the impact of early viral load decline on virus-specific T-cell reactivity in 30 hepatitis B e antigen (HBeAg)-positive patients with chronic hepatitis B randomized to monotherapy with adefovir dipivoxil (ADV) or in combination with emtricitabine (ADV/FTC). Viral kinetics were analysed by mathematical modelling. T-cell reactivity to HBV core and/or surface antigens and natural killer T cell frequency were tested longitudinally, baseline to week 48, using EliSPOT assays and/or flow cytometry. RESULTS: Mathematical modelling of early HBV kinetics identified two subsets of patients: 11 fast responders (undetectable viraemia by week 12; eight on ADV/FTC three on ADV) and 19 slow responders who remained viremic (six on ADV/FTC 13 on ADV). The rate of infected hepatocyte loss was higher in fast than in slow responders (P = 0.0007), and correlated inversely with pre-treatment levels of intrahepatic covalently closed circular HBV DNA. The frequency of HBV core-specific CD4+ T-cells increased significantly only in fast responders, peaking between week 16 and 24, while the HBV surface-specific CD4+ T-cells increased in both subsets. These changes in CD4+ T-cell reactivity were transient however, and no increase in HBV-specific CD8+ T-cells was observed. By week 48, HBeAg seroconversion occurred only in 3/30 (10%) patients. CONCLUSIONS: Early viraemia clearance facilitates recovery of virus-specific CD4+ T-cell reactivity, but appears insufficient to establish clinically relevant antiviral immunity.