Title: How can ART observational cohorts and randomized clinical trials inform policy and practice
1How can ART observational cohorts and randomized
clinical trials inform policy and practice?
- Praphan Phanuphak, M.D., Ph.D.
- Thai Red Cross AIDS Research Centre, Bangkok
IAS 2005
2Strengths of randomized controlled trials (RCT)
- Random allocation minimizes selection bias
confounding. All confounders are evenly
distributed between the groups being compared. - Thus, RCT is the gold standard since the results
are most reliable especially if the results can
be duplicated by another RCT.
3Rating scheme for clinical practice
recommendations
- Category Definition
- Strength of recommendation
- A Strong should always be offered
- B Moderate should usually be offered
- C Optional
- D Should usually not be offered
- E Should never be offered
- Quality of evidence for recommendation
- I At least one randomized trial with
clinical results - II Clinical trials with laboratory results
- III Expert opinion
- Dybul M et al, Guidelines for using ARVMMWR
2002
4Strengths of RCT (II)
- Results can be obtained relatively short.
- HIV diseases are relatively urgent. It is a
dead or live situation such as AZT monotherapy
could double the life span of AIDS patients in
1990 or an infected vs. uninfected situation such
as the use of AZT in preventing mother-to-child
transmission (ACTG 076)
5HIV observational cohorts
- Multicenter AIDS Cohort Study (MACS)
- French Hospital Database on HIV (FHDH)
- Swiss Cohort
- EuroSIDA
- Australian HIV Observational Database (AHOD)
- TREAT Asia HIV Observational Database (TAHOD),
etc, etc.
6How the HIV observational cohorts being used?
- Predict disease progression
- Monitor trends in HIV disease outcomes
- - Too sad a story, we are treating physician,
not horoscopist! - Monitor trends in HIV treatment
- -Do we try to be in the norms?
- Assess association between HIV treatment and
disease outcomes - -Dont we all know?
7How the HIV observational cohorts being used (2)?
- Compare different populations
- -Can Asians be compared to Caucasians?
- Monitor long-term efficacy long-term
side-effects - -Can also be learned by clinical experience
post-marketing surveillance - See whether knowledge from clinical trials can be
applied in clinical practice - -It depends on how convincing the results are and
its feasibility
8How the HIV observational cohorts being used (3)?
- Assess effectiveness of particular ARV
combinations some agreement such as - -ZDV monotherapy could have a short-term
benefit - -Graham et al, Lancet 1991338265
- -Moore et al, NEJM 19913241412
- -Vella et al, JAMA 19922671232
- -Lundgren et al, JAMA 19942711088
- - Double nucleosides was better than
monotherapy - -Graham et al, Ann Intern Med
19961241031 - -Phillips et al, JAIDS 199717239
- Do we really need these information?
- And sometimes it can be misleading!!
9Results from some observational cohorts can be
misleading
- Phillips et al, AIDS 1999 132075-82.
- Compared progression to AIDS death between RCT
(Delta, ACTG175, CPCRA 007, ACTG320) and 3
cohorts (EuroSIDA, FHDH, Swiss) all agree except
FHDH which showed higher risk of progression on
triple therapy as compared to double nucleosides
(RR 1.20, 95CI 1.01-1.44) while ACTG320 results
showed a RR of 0.50, 95CI 0.33-0.76. The reason
was due to those who received triple therapy in
FHDH were more advanced patients.
10Weakness of observational cohorts
- Selection bias
- Information (observation, classification,
measurement) bias - Confounding bias known unknown
- By chance? what p value? adequate power?
- Causal association?
- At the end, critical clinicians will always ask
about the experimental evidence, i.e., randomized
control trials
11Statisticians magic
- Observational cohorts open the door for
experienced statisticians to use various magic
statistical methods to prove or disprove their
hypotheses such as Weibull proportional hazards
model, parametric survival model, log-logistic,
lognormal, generalized gamma and gompertz
distributions, etc. - Do any practitioners or policy makers really
understand these techniques?
Thus, should one believe or not believe?
12Translation of RCT results into practice policy
- Practice of experts or general internist Who is
more difficult to convince? - Practice in resource-limited settings not very
many options!! - Policy guidelines IAS/USA, DHHS, WHO
- Government policy how committed?
- Policy of funding agencies always thinking
about the best buy for their money, example
Mwanza trial
13For practicing physician
- Results from reliable (investigators,
institutions, journals, carefully planned
methodology analysis, p value lt0.00..) and
sizable (Ngt100) RCT, particularly double-blinded
and confirmed by at least another group of
investigators - Recommended in treatment guidelines by
professional or reliable organizations, not
necessarily government - Observational cohorts are nice to learn but will
believe only if can be confirmed by RCT, e.g.,
D/C cotrimoxazole prophylaxis after CD4 rise.
14For policy makers (government funding agencies)
- For a good government policy on treatment
guidelines should be based on the best reliable
data, i.e., RCT results because public money will
be used - For a bad government wait for long term efficacy
safety data, i.e., data from long term
observational cohorts so that they dont have to
spend money early
15For policy guidelines makers
- IAS/USA, DHHS other developed country
guidelines based on the most solid evidence (AI,
AII, BII) - Developing country guidelines the minimum
standards, adjusted on affordability and
willingness to pay (by the government) - WHO guidelines minimum standards and applicable
to all resource-limited countries, no distinction
between low vs. medium income developing
countries
16Examples of translating RCT results into practice
policy
- HAART is better than double NUCs
- (ZDV/3TC vs. ZDV/3TC/IDV Hammer et al, NEJM
1997 337725, -
Gulick et al, NEJM 1997 337734) - Half-dose d4T is as good as full-dose d4T (ddI)
- (Ruxrungtham et al, AIDS 2000 14 1375)
- NNRTI is as good as or better than PI
- (EFV vs. IDV Staszewski et al, NEJM 1999
3411665) - (EFV vs. ATV Squires et al, JAIDS 2004 361011)
- LPV/r is better than 1st generation PI
- (LPV vs. NLV Walmsley et al, NEJM 2002
3462039) - ATV does not cause dyslipidemia as compared to
other PIs - (ATV vs. NLV Murphy et al, AIDS 2003 172603,
Wood et al, JAIDS 2004 36684) - PMTCT regimens (ACTG 076, HIVNET 012)
17Moving clinical trials to the South
- Plenty of examples of good clinical trials from
the South HIV-NAT (Bangkok), Chennai (India),
South Africa, Argentina, Brazil - Knowledge, skill, patient population, need and
willingness are there. - Infrastructure local funding may not be optimal
but can be strengthened, not starting from
scratch. - But not many trials from the South. Why how can
we improve it?
18Rationales of doing clinical trials in the South
- Enormous number of naïve patients HIV-infected
pregnant women for PMTCT pediatric trials - Recruitment is rapid, adherence, tolerance
retention are much better than the trials in the
North. - Personnel laboratory costs are lower.
- A way to sensitize academicians, government NGO
in the country in the region for research ARV
use - Opportunity for research on top of the ongoing
services provided by PEPFAR, GFATM - Equal gain for the collaborating institutions
from the North - What we dont need is a token or a Saint from
the North.
19What type of clinical trials that are appropriate
for the South?
- When to start ARV in children (CD4 lt15 vs.
15-25) and in TB co-infected patients (2-8 wks
vs. gt8 wks in CD4 lt200) - Drug interaction studies (RFM NVP 400 vs. 600
mg, EFV 600 vs. 800 mg) - Reduced dose regimens to save cost and reduce
side-effects, e.g., ZDV 200 mg vs. 300 mg bid,
d4T 20 vs. 30 vs. 40 mg bid in BWgt60 kg, IDV 400/
600/ 800 mg boosted with RTV 100 mg bid, ATV
200/r OD
20What type of clinical trials that are appropriate
for the South (2)?
- Equivalence study of generic drugs in countries
where only few can afford brand name drugs - Regimens that one knows that it is safe but
contra-indicated such as EFV in 2nd-3rd
trimesters or NVP in pregnancy - PMTCT regimens such as ZDV/3TC/TDF vs. ZDV/3TC/PI
- STI to reduce cost side-effects
21Structured treatment interruptions
- Treatment interruption is common in real life.
- STI is proposed to guide safe treatment
interruption - Dybul et al were strong advocates for 1 week on,
1 week off STI - Both of 2 small cohorts (8-10) showed no rebound
viremia in any patients for as long as 72 weeks - PNAS 2001 9815161 (4/10 on NNRTI, 6 PI)
- JID 2004 1891974 (ddI/3TC/EFV OD)
221 week on, 1 week off STI was proved ineffective
by RCT
- Ananworanich et al, AIDS 2003 17F33 (Staccato
study, planned N600 randomized in continued
treatment arm, CD4-guided arm and
1-week-on-1-week- off arm). Scheduled preliminary
safety analysis showed 53 (19/36) virologic
failure (i.e., 2 consecutive VLgt500 copies/ml) in
wk-on-off arm, as compared to 2/37 in continuous
arm (plt0.001) and 0/39 in CD4-guided arm. Thus,
wk-on-off arm was terminated. Most (11/19) who
failed were on d4T/ddI/SQV/r (1600/100 OD).
23Obstacles of doing trials in the South
- Less pharmaceutical interest because not being
the market or uncertainty about the quality of
the trials - Certain limitations from funding agencies such as
grant cannot be used for ARV, needles, generic
drugs - Too much paper work site preparation
- Limitations on boundaries, territories
networking for international collaboration
24Conclusions
- RCT is most reliable to establish treatment
efficacy. - Its researchers innovation, not
epidemiologists imagination. - It can be accomplished rapidly and can be adopted
rapidly by policy maker practitioner. - Moving clinical trials to the South is
compelling. - Observational cohorts are fun data collection and
analysis to prove or disprove things. - If disprove, then another RCT, i.e.,
RCT is the ultimate goal. Then, why to
bother about observational cohorts?