Perspective: Information, Inspiration and Advocacy for People Living with HIV/AIDS

U p a e coSl.........

Update on
Opportunistic Infections
The management of opportunistic infections (Ols) in the wake
of HAART (highly active antiretroviral therapy) is a challenge
for people living with HIV/AIDS and their clinicians.

Several clinical studies have reported that
the use of effective antiviral therapy can
reduce the first onset of opportunistic infections. Newer studies show that for a great
number of people, HAART can also significantly delay or prevent the recurrence
of opportunistic infections. These studies
show that when HAART results in sustained
increases in CD4+ cell counts and substantial decreases in HIV RNA levels there is a
significant delay in recurrence of a number
of opportunistic infections, but the risk is
not wholly eliminated.
The correlation between HAART and delayed recurrence of disease is not fully understood since it seems to work for some
people and not for others. Studies are ongoing to better understand the relationship
and until more information is available, it
is recommended that people continue on
preventative and maintenance therapy drug
regimens for opportunistic infections. Even
though some people do report success in
dropping preventive or maintenance
therapy, doing so today may be an unwarranted gamble, one which is undertaken
without any idea about the odds for winning or losing.
Pneumonia
Vaccinaticon
Bacterial infections are a major concern for
people living with HIV disease, especially
for people with CD4+ cell counts below
100. In recent years, pneumococci, a leading cause of bacterial pneumonia, have developed increasing antibiotic resistance
making preventative therapy and an effective vaccine even more important. Fortunately, studies have demonstrated the benefit of pneumococcal vaccination for people
living with HIV. However, a recent study
compared a group of HIV-infected individuals who had been vaccinated with Pneumovax@ (the preventative pneumococcal vaccine) more than 5 years before the study,
with another group of HIV-infected individuals who had never been vaccinated.
Those who had received the vaccine had
no greater protective immune responses to
pneumococcal infections than those who
had never been vaccinated. Repeat vaccination improved immune responses mod
estly and there was no evidence that the
vaccination had any harmful effect on the
underlying HIV infection. The new Federal
Guidelines recommend pneumococcal vaccination for people with HIV, repeated every five years. However, those with CD4+
cell counts of less than 100 should consider
the vaccination optional, as it is less likely
that their immune system will respond to
infection even with vaccination, decreasing I
the likelihood of protection against pneumococcal infection.
PCP Prevention
Several studies comparing therapies and
regimens for the prevention of Pneumocystis
carinii pneumonia (PCP) have recently reported data. Together these studies help
refine our understanding of PCP prevention.
The largest PCP prevention study to date,
with more than 2600 participants, compared a regimen of double strength TMP/
SMX (Bactrim@ or Septra@) daily to three
times weekly for the prevention or recurrence of PCP. Interestingly, there were no
significant differences between the two
groups, but the trends consistently supported the daily regimen as more effective,
with slightly lower rates of bacterial pneumonia and PCP among those receiving daily
therapy. However, there were significantly
more side effects among people receiving
the daily dose compared to those receiving
the three times weekly dose. Overall, 13.9%
of people receiving daily TMP/SMX experienced any adverse event compared to
6.3% of people receiving the three times
weekly dose. Although the rates of events
were relatively small, there were more allergic/skin reactions, gastrointestinal upset,
liver abnormalities and hematologic (blood I
markers) abnormalities among people receiving the drug daily.
Previous studies have shown that TMP/
SMX is the drug of choice for PCP prevention, as it is more effective than the alternative options (dapsone or atovaquone).
However, many people have difficulty tolerating TMP/SMX. Because it is such an
important drug in managing HIV-related
conditions, such as toxoplasmosis and PCP,
even those who have initial bad reactions
to the drug are often encouraged to find.

ways to try the therapy again. A new study
reports that gradually increasing the dose
may be the best way to 'rechallenge' with
TMP/SMX. This study compared dose escalation (starting small and gradually increasing to the full recommended dose) to
direct rechallenge (giving the full recommended dose again) in 191 people with
prior treatment-limiting reactions to TMP/
SMX. Results show that a six-day dose
escalation is the superior method for re-introducing TMP/SMX to those with previous bad reactions to the drug. This is an
important finding since 50% or more of
HIV-infected people have an initial reaction
to sulfa drugs, including TMP/SMX.
Finally, for those who simply cannot tolerate TMP/SMX, another study compared
atovaquone to dapsone, both non-sulfa
drugs, as alternatives for preventing PCP.
A total of 1057 people were followed for
an average of 2 years. The two compounds
were found to be equally effective in preventing PCP. The only difference between
the two groups was in the types of side
effects experienced. People receiving
atovaquone experienced more nausea and
diarrhea while those on dapsone experienced more rash.
IVIAC Prevention
A study of 131 people who had never taken
a protease inhibitor looked at the use of
clarithromycin in a reduced daily dose of
500 mg once, rather than twice, daily for
preventing MAC (Mycobacterium avium
Complex) in people with CD4+ cell counts
below 100. The study compared reduced
dose clarithromycin to rifabutin dosed at
the normal 300 mg a day, to no preventative therapy. Findings showed reduced dose
clarithromycin is as effective as rifabutin in
preventing MAC and improving survival.
Both therapies showed better survival rates
than no preventative therapy at all. Previous studies have shown that clarithromycin
at the full dose of 1000 mg day (500 mg
twice daily) is superior to rifabutin, however for people struggling with difficult
treatment regimens or limited financial resources, reduced dose clarithromycin may
be acceptable. Some researchers are concerned that the reduced dose of clanithromycin may lead to the organism becoming resistant to the drug which is generally preferred for treating MAC. How any
of this translates into the current era in
which almost everyone with MAC would
also be using HAART with a protease inhibitor, is uncertain.

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PI PERSPECTIVE NUIVBER 23 NOVEVIBER 1997