Combined therapy with saquinavir, ritonavir and stavudine in moderately to severely immunosuppressed HIV-infected protease inhibitor-naive patients

To assess the short-term and long-term effect of a combination of saquinavir, ritonavir and stavudine in moderately to severely immunosuppressed protease inhibitor-naive patients

Combined therapy with saquinavir, ritonavir and stavudine in moderately to severely immunosuppressed HIV-infected protease inhibitor-naive patients

OBJECTIVE: To assess the short-term and long-term effect of a combination of saquinavir, ritonavir and stavudine in moderately to severely immunosuppressed protease inhibitor-naive patients. DESIGN: Prospective open-label multicentre study. PATIENTS AND METHODS: A total of 64 protease inhibitor-naive and stavudine-naive HIV-infected patients with a CD4 count of 10 000 HIV-1 RNA copies/mL received saquinavir hard-gelatin capsules, ritonavir and stavudine. Full (drop in viraemia of > 2 log10 and/or < 500 copies/mL) and partial responders (drop to between 500 and 5000 viraemia copies/mL) at week 9 (end of phase I) entered the second phase (additional 12-month period). RESULTS: Fifty-six patients completed phase I, 45 (70%) full responders and nine (14%) partial responders by intent-to-treat analysis. Thirty-nine patients completed phase II, 33 (52%) full responders and two (3%) partial responders. Six patients had < 50 HIV-1 RNA copies/mL at week 9, and 20 (31%) patients at month 12 of phase II. Mean CD4 cell counts increased significantly in the 56 patients from 89 to 184 cells/microL after 9 weeks and from 100 to 292 cells/microL in the 39 patients treated for another 12 months. Higher baseline viraemia and lower baseline CD4 cell counts were not associated with an unfavourable virological response at week 9 and month 12 of phase II. HIV DNA in peripheral blood monocytes decreased substantially (- 1.5 log10) but was detectable in all except one patient at the end of phase II. CONCLUSION: In protease- and stavudine-naive HIV-infected patients with moderate to severe immunosuppression, saquinavir in combination with ritonavir and stavudine caused a substantial long-term decrease in plasma viral load in approximately half the participants and a substantial increase in CD4 cell counts

Substitutions at residue 211 in the prion protein drive a switch between CJD and GSS syndrome, a new mechanism governing inherited neurodegenerative disorders

Human prion diseases are a heterogeneous group of fatal neurodegenerative disorders, characterized by the deposition of the partially protease-resistant prion protein (PrPres), astrocytosis, neuronal loss and spongiform change in the brain. Among inherited forms that represent 15% of patients, different phenotypes have been described depending on the variations detected at different positions within the prion protein gene. Here, we report a new mechanism governing the phenotypic variability of inherited prion diseases. First, we observed that the substitution at residue 211 with either Gln or Asp leads to distinct disorders at the clinical, neuropathological and biochemical levels (Creutzfeldt-Jakob disease or Gerstmann-Sträussler-Scheinker syndrome with abundant amyloid plaques and tau neurofibrillar pathology). Then, using molecular dynamics simulations and biophysical characterization of mutant proteins and an in vitro model of PrP conversion, we found evidence that each substitution impacts differently the stability of PrP and its propensity to produce different protease resistant fragments that may contribute to the phenotypical switch. Thus, subtle differences in the PrP primary structure and stability are sufficient to control amyloid plaques formation and tau abnormal phosphorylation and fibrillation. This mechanism is unique among neurodegenerative disorders and is consistent with the prion hypothesis that proposes a conformational change as the key pathological event in prion disorders. © The Author 2012. Published by Oxford University Press