Safety and Efficacy of (α1Proteinase Inhibitor, α1PI) in HIV Disease

This study protocol is designed to investigate the benefit of a well-tolerated, FDA approved biological product that has been extensively used in a different patient population.

For more than 20 years, α1proteinase inhibitor (α1PI or α1antitrypsin) therapy has been the standard treatment for people with insufficient α1PI blood levels. This disorder, also known as α1antitrypsin deficiency, was previously thought to be caused only as an inherited trait due to the gene PIzz. Recent evidence shows that it can also be an acquired disease. Specifically, individuals with HIV-1 disease have been found to have severely low α1PI blood levels (Bristow et al., 2001; Bristow et al., 2010; Bristow et al., 2012). Many people with the inherited version of α1PI deficiency eventually develop emphysema, and among individuals with HIV-1 disease, 90% have acquired α1PI deficiency. Whether they go on to develop emphysema is still unresolved.

HIV-1 infected individuals are the first patient population identified so far in which severe α1PI deficiency is acquired through infection rather than being inherited.

It was found that a decrease in α1PI blood levels is directly correlated to a decrease in CD4 lymphocytes (Bristow et al., 2001; Bristow et al., 2012): In a pilot study to determine whether α1PI therapy might benefit the CD4 counts in HIV-1 infected patients (Clinicaltrials.gov NCT01370018), HIV-1 patients with infection-related α1PI deficiency received weekly α1PI therapy (120mg/kg) for a period of 8 weeks and results were compared with those of patients having the inherited version of α1PI deficiency who were simultaneously receiving weekly α1PI therapy (60mg/kg). None of the patients in the study had ever previously received α1PI therapy. It was found that CD4 cells rose to normal levels following 2 weeks of intravenous α1PI therapy with no adverse effects observed in the HIV-1 patients (n=3) or the control group of HIV-1 uninfected, α1PI deficiency patients (n=2). The new crop of CD4 cells were functional, capable of fighting infection, and appeared to be generated from bone marrow-derived stem cells (Bristow et al., 2010). As a bonus, it was found in the HIV-1 patients that LDL levels (bad cholesterol) decreased and HDL levels (good cholesterol) increased {Bristow et al., in review).

The information gained from the initial pilot study will be incorporated into this study design to further characterize the mechanism of lymphocyte renewal and to increase the number of patients observed. Only minor modifications to the pilot protocol are proposed including the sample size, addition of volunteers not receiving therapy, and a double-blind design: Ten (10) HIV-1 infected patients will be dosed with PROLASTIN®-C (Grifols Therapeutics Inc.), five (5) will be dosed with placebo, and five (5) uninfected volunteers not receiving therapy will be monitored.

It has been observed that CD4 counts and cholesterol levels are correlated and that there is cyclic variation in individuals with and without HIV. To examine whether there are differences due to HIV infection in cyclic variation of CD4 counts, cholesterol levels, and other values monitored during this study, five (5) volunteers, who do not have HIV, will be included in the study for blood collection only.

In a previous study, we determined that in individuals with abnormally low active α1PI levels, CD4 counts exhibit sinusoidal cycling with 23 day periodicity. Wave form appearance of CD4 cells with a peak every 23 days is a pattern that is indicative of adult thymopoiesis. We showed that in response to α1PI therapy, HIV infected and uninfected individuals exhibited an increased CD4 counts axis of oscillation, but no change in periodicity. In contrast, one uninfected individual who was not receiving therapy, exhibited no change in the axis of oscillation, but periodicity was 27 days. Human adult thymopoiesis is not well characterized, and based on these results, we have two hypotheses.

One hypothesis is that in response to α1PI therapy, thymopoiesis will increase, manifested by an increased axis of oscillation and increased numbers of recent thymic emigrants. In the proposed study, we will perform weekly TREC analysis which measures recent thymic emigrants and is definitive for thymopoiesis. We will test whether the changes in TREC numbers corresponds with changes in the CD4 counts axis of oscillation in HIV infected individuals receiving α1PI therapy as compared with HIV infected individuals with abnormally low active α1PI levels not on α1PI therapy, and HIV uninfected individuals with normal active α1PI levels not on α1PI therapy.

The second hypothesis is that in individuals with abnormally low active α1PI levels, the periodicity of CD4 counts is shorter than in individuals with normal active α1PI levels. Although we will measure periodicity in only 5 individuals with normal active α1PI levels and 15 with abnormal active α1PI levels, this will allow us to determine whether active α1PI is a linear determinate of periodicity or whether there are other variables that regulate periodicity. In an 8-week study, only 2 periods can be observed. Thus, following an 8-week regimen of therapy, one study subject may be asked to continue for a second 8-week regimen of therapy to allow the observation of 5 periods.

In addition to these two primary hypotheses regarding CD4 counts, we have found that HDL and LDL levels are linearly dependent on the balance of active and inactive α1PI levels (manuscript in review). This phenomenon is due the transport of HDL and LDL by CD4 cells. We found that in HIV infected individuals with abnormally low active α1PI and abnormally high inactive α1PI, HDL and LDL increased or decreased differently from individuals with normal active α1PI. Based on these results, our hypothesis is that in HIV infected individuals with abnormally low active α1PI receiving α1PI therapy, LDL levels will decrease and HDL levels will increase as active α1PI levels increase in contrast to HIV uninfected individuals with normal active α1PI levels not on therapy and in contrast to HIV infected individuals with abnormally low active α1PI levels not on therapy.

Prolastin-C treatment will be given weekly for eight (8) to sixteen (16) weeks by intravenous infusion. Blood will be collected immediately prior to each infusion. As in the previous study, complete blood count, lymphocyte phenotype, extended lymphocyte phenotype, lymphocyte function; HIV-1 viral load, lipid levels, blood chemistry, and markers of inflammation will be measured. The present study will also include measurements for HIV-1 tropism and markers for recent thymic emigrants.