The effect of the appearance of drug-resistant human immunodeficiency virus type 1 (HIV-1) on viral RNA load was studied in patients treated with the reverse transcriptase inhibitor lamivudine. During the first 12 weeks of treatment, HIV-1 RNA concentrations and amino acid changes in codon 184, causing high-level resistance to lamivudine, were determined in longitudinal serum samples from HIV-1 p24 antigen-positive and -negative patients. A marked decline in the amount of HIV-1 RNA (approximately 95% below baseline) and HIV-1 p24 antigen was observed within 2 weeks, followed by a rise that coincided with the appearance of lamivudine-resistant viruses in serum (isoleucine mutants initially, which were subsequently replaced by valine variants). After 12 weeks, a partial antiviral effect was observed despite the presence of a complete codon 184 mutant virus population in serum. This study shows that the rapid appearance of drug-resistant virus in serum is followed by an increase in viral RNA load.

The human beta‐globin dominant control region (DCR) was previously identified as a region from the 5′ end of the human beta‐globin locus which directs high level, site of integration‐independent, copy number‐dependent expression on a linked human beta‐globin gene in transgenic mice and stably transfected mouse erythroleukaemia (MEL) cells. We have now analysed the elements comprising the DCR by systematic deletion mutagenesis in stable MEL transfectants. We have identified two independent elements within the DNase I hypersensitive sites 2 and 3, containing fragments which direct strong transcriptional inducibility of a beta‐globin gene. Whilst the remaining two hypersensitive sites do not direct significant transcriptional induction, our data suggest that all four sites may be necessary for the fully regulated expression conferred by the DCR. We have also tested a number of beta‐globin minigene constructs under the control of the DCR to assess if any of the local sequences from the gene may be removed without loss of expression. We find that the 3′ enhancer may be removed without affecting expression, but there is an absolute requirement for the presence of the second intron, not related to the enhancer present in that intron.

We used two kinds of adeno-associated virus (AAV) vectors to transduce the neomycin resistance gene into human cells. The first of these (d152-91) retains the AAV rep genes; the second (d13-94) retains only the AAV terminal repeats and the AAV polyadenylation signal (428 base pairs). Both vectors could be packaged into AAV virions and produced proviral structures that were essentially the same. Thus, the AAV sequences that are required in cis for packaging (pac), integration (int), rescue (res), and replication (ori) of viral DNA are located within a 284-base-pair sequence that includes the terminal repeat. Most of the G418r cell lines (73%)

The human beta-globin dominant control region (DCR) which flanks the multigene beta-globin locus directs high level, site of integration independent, copy number dependent expression on a linked human beta-globin gene in transgenic mice and stably transfected mouse erythroleukemia (MEL) cells. We have assayed each of the individual DNaseI hypersensitive regions present in the full 15kb DCR for position independence and copy number dependence of a linked beta-globin gene in transgenic mice. The results show that at least three of the individual DNaseI hypersensitive site regions (sites 1, 2 and 3), though expressing at lower levels than the full DCR, are capable of position independent, copy number dependent expression. Site 2 alone directs the highest level of expression of the single site constructs, producing nearly 70% of the level of the full DCR. Sites 1 and 3 each provide 30% of the full activity. Deletion of either site 2 or 3 from the complete set significantly reduces the level of expression, but does not effect position independence or copy number dependence. This demonstrates that sites 2 and 3 are required for full expression and suggests that all the sites are required for the full expression of even a single gene from this multigene locus.

Background: Berotralstat (BCX7353) is an oral, once-daily inhibitor of plasma kallikrein in development for the prophylaxis of hereditary angioedema (HAE) attacks. Objective: Our aim was to determine the efficacy, safety, and tolerability of berotralstat in patients with HAE over a 24-week treatment period (the phase 3 APeX-2 trial). Methods: APeX-2 was a double-blind, parallel-group study that randomized patients at 40 sites in 11 countries 1:1:1 to receive once-daily berotralstat in a dose of 110 mg or 150 mg or placebo (Clinicaltrials.gov identifier NCT03485911). Patients aged 12 years or older with HAE due to C1 inhibitor deficiency and at least 2 investigator-confirmed HAE attacks in the first 56 days of a prospective run-in period were eligible. The primary efficacy end point was the rate of investigator-confirmed HAE attacks during the 24-week treatment period. Results: A total of 121 patients were randomized; 120 of them received at least 1 dose of the study drug (n 5 41, 40, and 39 in the 110-mg dose of berotralstat, 150-mg of dose berotralstat, and placebo groups, respectively). Berotralstat demonstrated a significant reduction in attack rate at both 110 mg (1.65 attacks per month; P 5 .024) and 150 mg (1.31 attacks per month; P < .001) relative to placebo (2.35 attacks per month). The most frequent treatment-emergent adverse events that occurred more with berotralstat than with placebo were abdominal pain, vomiting, diarrhea, and back pain. No drug-related serious treatment-emergent adverse events occurred. Conclusion: Both the 110-mg and 150-mg doses of berotralstat reduced HAE attack rates compared with placebo and were safe and generally well tolerated. The most favorable benefit-to-risk profile was observed at a dose of 150 mg per day. (J Allergy Clin Immunol 2020;nnn:nnn-nnn.)

A significant clinical benefit was not demonstrated for peramivir plus SOC compared with placebo plus SOC. Peramivir was generally safe and well tolerated. These findings highlight the challenges in designing studies to evaluate influenza antiviral agents in a hospitalized setting. Clinical Trials Registration. NCT00958776.

Once-daily oral administration of BCX7353 at a dose of 125 mg or more resulted in a significantly lower rate of attacks of hereditary angioedema than placebo. Mild gastrointestinal symptoms were the principal side effect. (Funded by BioCryst Pharmaceuticals; APeX-1 ClinicalTrials.gov number, NCT02870972 .).

This open-label trial of intravenous peramivir in subjects hospitalized predominantly with 2009 influenza A (H1N1) demonstrated that once- or twice-daily administration was associated with decreases in viral shedding and clinical improvement. ClinicalTrials.gov number NCT00957996.