Urgent action is needed to improve access to the antifungal
drug flucytosine, say investigators, following the presentation of the results
of a trial showing that treatment containing flucytosine is superior to any
other form of treatment in reducing the risk of death from cryptococcal
meningitis in people with very advanced HIV disease.
The findings open up the possibility of more widespread treatment for cryptococcal meningitis, one of the major causes of death in people with HIV in sub-Saharan Africa.
The study also found that one week of treatment with
amphotericin B combined with either flucytosine or fluconazole was just as
effective as the gold standard regimen of two weeks of amphotericin B and
flucytosine, and that if amphotericin B infusion treatment is not possible, an
oral regimen of fluconazole and flucytosine is just as effective as the gold
standard.
The results of the Advancing
Cryptococcal Meningitis Treatment for Africa (ACTA) study were presented on
Monday at the 9th International AIDS Society Conference on HIV
Science (IAS 2017) in Paris, France. The study was sponsored by the United Kingdom’s Medical
Research Council and the French Agency for Research on AIDS and Viral Hepatitis
(ANRS).
The findings open up the possibility of more widespread
treatment for cryptococcal meningitis, one of the major causes of death in
people with HIV in sub-Saharan Africa. UNITAID, the international drug purchase
fund for HIV, TB and malaria, is set to investigate how it can help to make
flucytosine more widely available, said Sile Molloy of St George’s, University
of London, speaking at a press conference this morning.
Cryptococcal meningitis may cause up to 15% of all
HIV-related deaths each year in lower- and middle-income countries
(181,000 deaths), according to a
recently published analysis. Cryptococcosis is a fungal infection caused by Cryptococcus neoformans that causes
life-threatening meningitis. The review, published in The Lancet Infectious Diseases, estimated that 6% of people living with
HIV with CD4 cell counts below 100 cells/mm3 are positive for
cryptococcal antigen, which strongly predicts the development of cryptococcal
meningitis.
Cryptococcal meningitis can be treated with antifungal
drugs: amphotericin B, fluconazole or flucytosine. A two-week course of
treatment with amphotericin B and flucytosine is considered to be the gold
standard. Amphotericin B must be administered by infusion in hospital and
flucytosine is largely unavailable in Africa and Asia. Flucytosine is not registered
in South Africa, where a previous product registration lapsed in 1996, nor in
any other African country, and only one generic form of the drug is available.
Rapid advice guidelines issued by the World Health
Organization in 2011 proposed several alternative regimens but these have never
been compared in a large randomised clinical trial. The ACTA trial was designed
to compare several regimens which might prove sustainable and effective in
sub-Saharan Africa:
- Oral: fluconazole (1200mg/day) plus flucytosine (100mg/kg/day) for 2
weeks.
- 1-week: Amphotericin B (1mg/kg/d), plus fluconazole (1200mg/day), or
flucytosine (100mg/kg/day) (ratio 1:1), for 7 days. Days 8-14, fluconazole
1200mg/day.
- 2-weeks: Amphotericin B (1mg/kg/d) plus fluconazole (1200mg/day), or
flucytosine (100mg/kg/day) (ratio 1:1), for 14 days.
All participants received fluconazole 800mg/day until starting
antiretroviral treatment at around day 28 of the study, when the dose was
reduced to 400mg until week 10, and then to a maintenance dose of 200mg/day.
Participants were followed for ten weeks in all.
One-week
dosing of amphotericin B may be just as effective as two-week dosing, animal
studies suggest, but may result in less toxicity. Preliminary studies show that
high-dose fluconazole and flucytosine clears cryptococcus just as quickly as
amphotericin B.
The ACTA study
recruited 721 people in Cameroon, Malawi, Tanzania and Zambia between 2013 and
2016. All study participants had been diagnosed with a first episode of
cryptococcal meningitis. The median CD4 cell count of study participants was 25 cells/mm3. Approximately one in five already had severe symptoms and around one in three were in need of interventions such as lumbar puncture to relieve pressure on the brain caused by the infection. The need for intervention to reduce pressure indicates a poor prognosis.
The primary
study outcome was a comparison of mortality after two weeks of treatment.
The final intent-to-treat analysis covered 678 study
participants. The study showed:
- No significant difference in mortality at 2
weeks or 10 weeks between the three treatment strategies, although there was
a trend towards fewer deaths in the all-oral treatment arm.
- Faster clearance of cryptococcus from the cerebrospinal fluid
with the all-oral regimen compared to the 2-week amphotericin B regimen (p < 0.001).
- Substantially fewer blood transfusions to treat
anaemia induced by amphotericin B in the all-oral arm and the 1-week arm when compared
to the 2-week arm.
- Significantly lower mortality at 10 weeks when
amphotericin B was combined with flucytosine rather than fluconazole in the
1-week arm (p = 0.002).
- After 10 weeks of follow-up, the lowest
all-cause mortality was observed in the 1-week amphotericin B & flucytosine
arm (24 vs 38% in the 2-week amphotericin B & flucytosine arm, hazard
ratio 0.56, 95% CI: 0.35-0.91).
The study investigators recommend that centres in
sub-Saharan Africa should use the 1-week amphotericin B and flucytosine regimen
if possible, and the 1-week fluconazole and flucytosine regimen if the use of
amphotericin B is not possible. They say that adoption of the new regimens
could save tens of thousands of lives each year if flucytosine can be made available
in Africa.