Hemophilia B Gene Therapy with a High-Specific-Activity Factor IX Variant.

BACKGROUND: The prevention of bleeding with adequately sustained levels of clotting factor, after a single therapeutic intervention and without the need for further medical intervention, represents an important goal in the treatment of hemophilia. METHODS: We infused a single-stranded adeno-associated viral (AAV) vector consisting of a bioengineered capsid, liver-specific promoter and factor IX Padua (factor IX-R338L) transgene at a dose of 5×1011 vector genomes per kilogram of body weight in 10 men with hemophilia B who had factor IX coagulant activity of 2% or less of the normal value. Laboratory values, bleeding frequency, and consumption of factor IX concentrate were prospectively evaluated after vector infusion and were compared with baseline values. RESULTS: No serious adverse events occurred during or after vector infusion. Vector-derived factor IX coagulant activity was sustained in all the participants, with a mean (±SD) steady-state factor IX coagulant activity of 33.7±18.5% (range, 14 to 81). On cumulative follow-up of 492 weeks among all the participants (range of follow-up in individual participants, 28 to 78 weeks), the annualized bleeding rate was significantly reduced (mean rate, 11.1 events per year [range, 0 to 48] before vector administration vs. 0.4 events per year [range, 0 to 4] after administration; P=0.02), as was factor use (mean dose, 2908 IU per kilogram [range, 0 to 8090] before vector administration vs. 49.3 IU per kilogram [range, 0 to 376] after administration; P=0.004). A total of 8 of 10 participants did not use factor, and 9 of 10 did not have bleeds after vector administration. An asymptomatic increase in liver-enzyme levels developed in 2 participants and resolved with short-term prednisone treatment. One participant, who had substantial, advanced arthropathy at baseline, administered factor for bleeding but overall used 91% less factor than before vector infusion. CONCLUSIONS: We found sustained therapeutic expression of factor IX coagulant activity after gene transfer in 10 participants with hemophilia who received the same vector dose. Transgene-derived factor IX coagulant activity enabled the termination of baseline prophylaxis and the near elimination of bleeding and factor use. (Funded by Spark Therapeutics and Pfizer; ClinicalTrials.gov number, NCT02484092 .).

Substance P-mediated chemokine production promotes monocyte migration.

The neuropeptide SP has physiologic and pathophysiologic roles in CNS and peripheral tissues and is involved in crosstalk between nervous and immune systems in various conditions, including HIV and SIV infection. Increased SP levels were demonstrated in plasma of HIV+ individuals as well as in the CNS of SIV-infected, nonhuman primates. SP increases HIV infection in macrophages through interaction with its receptor, NK1R. The SP effect on immune system is both pro- and anti-inflammatory and includes up-regulation of a number of cytokines and cell receptors. The main goal of this study was to determine whether there is interplay between monocyte exposure to SP and recruitment into sites of inflammation. We now demonstrate that exposure of either human macrophages or PBMCs to SP leads to increased production of chemokines, including MCP-1, for which expression is limited to cells of the myeloid lineage. This effect is inhibited by the NK1R antagonist, aprepitant. Exposure to conditioned medium derived from SP-treated PBMCs resulted in increased monocyte migration through semipermeable membranes and an in vitro human BBB model. Monocyte migration was blocked by anti-MCP-1 antibodies. Our results suggest that increased SP levels associated with HIV and other inflammatory conditions may contribute to increased monocyte migration into the CNS and other tissues through a MCP-1-dependent mechanism.

Pharmacologic rationale for the NK1R antagonist, aprepitant as adjunctive therapy in HIV.

BACKGROUND: Many HIV infected individuals with suppressed viral loads experience chronic immune activation frequently developing neurological impairment designated as HIV associated neurocognitive disorder (HAND). Adjunctive therapies may reduce HIV associated inflammation and therefore decrease the occurrence of HAND. METHODS: We have conducted in vitro, animal and clinical studies of the neurokinin 1 receptor (NK1R) antagonist aprepitant in HIV/SIV infection. RESULTS: Aprepitant inhibits HIV infection of human macrophages ex vivo with an ED50 ~ 5 µM. When administered at 125 mg once daily for 12 months to SIV-infected rhesus macaques, aprepitant reduced viral load by approximately tenfold and produced anti-anxiolytic effects. The anti-viral and anti-anxiolytic effects occur at approximately the third month of dosing; and the effects are sustained throughout the duration of drug administration. Protein binding experiments in culture media and animal and human plasma indicate that the free fraction of aprepitant is lower than previously reported supporting usage of higher doses in vivo. The analysis of blood samples from HIV positive individuals treated for 2 weeks with aprepitant at doses up to 375 mg demonstrated reduced levels of pro-inflammatory cytokines including G-CSF, IL-6, IL-8 and TNFα. Decreased pro-inflammatory cytokines may reduce HIV comorbidities associated with chronic inflammation. CONCLUSIONS: Our results provide evidence for a unique combination of antiretroviral, anti-inflammatory and behavioral modulation properties of aprepitant in vitro and in vivo. These results provide robust support for a clinical exposure target above that recommended for chemotherapy-induced nausea and vomiting. Doses up to 375 mg once daily in HIV-infected patients still elicit sub-therapeutic exposure of aprepitant though effective plasma concentrations can be achievable by proper dose modulation.

Reduction of soluble CD163, substance P, programmed death 1 and inflammatory markers: phase 1B trial of aprepitant in HIV-1-infected adults.

OBJECTIVE: We evaluated safety, antiviral, immunomodulatory and anti-inflammatory properties of aprepitant - a neurokinin 1 receptor antagonist. DESIGN: Phase IB randomized, placebo-controlled, double-blinded study. METHODS: Eighteen patients were randomized (nine to aprepitant and nine to placebo). The patients received once-daily treatment (375 mg aprepitant or placebo by oral administration) for 2 weeks and were followed off drug for 4 weeks. RESULTS: There were no significant changes in the plasma viremia or CD4(+) T cells during the dosing period. Aprepitant treatment was associated with significant decreases of median within patient change in percentages of CD4(+) T cells expressing programmed death 1 (-4.8%; P = 0.04), plasma substance P (-34.0 pg/ml; P = 0.05) and soluble CD163 (-563 ng/ml; P = 0.02), with no significant changes in the placebo arm. Mean peak aprepitant plasma concentration on day 14 was 7.6 ± 3.1 µg/ml. The use of aprepitant was associated with moderate increases in total cholesterol, low-density lipoprotein and high-density lipoprotein (median change = +31 mg/dl, P = 0.01; +26 mg/dl, P = 0.02; +3 mg/dl, P = 0.02, respectively). CONCLUSION: Aprepitant was safe and well tolerated. At the dose used in this proof-of-concept phase IB study, aprepitant did not show a significant antiviral activity. Aprepitant-treated patients had decreased numbers of CD4(+) programmed death 1-positive cells and decreased plasma levels of substance P and soluble CD163, suggesting that blockade of the neurokinin 1 receptor pathway has a role in modulating monocyte activation in HIV infection. Prospective studies in virologically-suppressed individuals are warranted to evaluate the immunomodulatory properties of aprepitant. Exposures exceeding those attained in this trial are more likely to elicit clinical benefit.