Are antiretroviral switch or simplification studies of benefit for patients?
The attitude of physicians, ethics
committees and medical journals to antiretroviral switch and simplification
studies needs to be radically reappraised, according to an article published in
Before approval, studies of this type must
show a clear potential advantage to patients and the risks and benefits need to
be explicitly outlined to participants during recruitment, state the authors.
They add that commercial advantage for a
pharmaceutical company is not a valid reason for approving a switch or
The recent SWITCHMRK studies (substitution
of raltegravir for lopinavir/ritonavir) and MONET trial (a simplification study
exploring darunavir/ritonavir monotherapy) are highlighted by the authors as
studies whose design and reporting failed to show any benefit to patients or
healthcare systems. Indeed, for some patients participation in the study led to
loss of virologic control.
Outcomes for patients taking HIV therapy in
the UK and similar countries are hugely impressive. The majority of patients
treated with antiretroviral drugs, regardless of their past treatment history
and resistance profile, have an undetectable viral load, the primary goal of
The safety and efficacy of antiretroviral
treatment is demonstrated in phase III clinical studies. In these studies, a
new drug is generally required to show virological superiority over either a
placebo or the current standard of care.
Because of the substantial improvements
seen in virological outcomes over the part 15 years, it is becoming
increasingly difficult to recruit patients to clinical trials.
One solution has been to evaluate new drugs
and treatment strategies in individuals whose existing therapy is effective and
suppressing viral load. Many of these studies involve switching treatment to see
if a new drug is non-inferior to an existing therapy, or if it leads to the
simplification of treatment.
Switching studies have intended to show the
non-inferiority of a new drug (no more than 10% to 12% worse than the existing
therapy). If non-inferiority is proved, then the secondary end-points of these
studies, such as the impact of the switch on quality of life and side-effects,
can be of great interest.
Treatment simplification studies should
also show that a new therapy if non-inferior to the pre-existing therapy.
Simplification of treatment can include the replacement of two or three drugs
with a co-formulation of these agents to reduce pill burden, or the cessation
of one drug without the introduction of a new therapy.
There are undoubted benefits from switching
or simplifying treatment. These can include reduced pill burden, greater
tolerability and lower cost. However, there are also potential disadvantages.
For instance, an effective and tolerable treatment may be abandoned.
Moreover, it has become clear that neither
switching nor simplifying treatment reduces the risk of virological failure. Nor
does a non-inferior finding in a study show that new agents or strategies are
as potent as existing drugs. This can only be demonstrated in patients starting
HIV therapy for the first time.
According to the Declaration of Helsinki,
the benefits of a clinical trial should outweigh the potential risks.
“A switch or simplification study…with a
primary end point of continued virological suppression and with no clinically
useful impact on toxicity, costs, or quality of life cannot have any benefit to
the participant,” write the authors. However, they found that 42% of HIV switch
or simplification studies registered on Clinical-Trials.org “had virological
non-inferiority as the primary end point.”
Rather, they believe that a particular
disadvantage of a current treatment should be an explicit and well-defined
entry criteria for the study. “Good examples of this approach are trials that
evaluated the ability of drug switching to reverse objectively defined
lipoatrophy and efavirenz-related central nervous symptoms.”
Moreover, the authors emphasise that the
possible potential disadvantages of the switch should be “measured, analysed
Patients must therefore be informed about
the potential advantages and disadvantages and which is the primary focus of
the study. If cost is the main focus, then the consent form must make it clear
that the patient is not expected to derive any benefit from the study.
The authors also question whether some
laboratory improvements reported as a benefit of a treatment switch are really of
any clinical relevance. For instance, they suggest that reductions in
cholesterol levels are likely only to be of meaningful benefit for patients
with cardiovascular risk factors. “No lipid switch study specifically enrolled
patients with elevated cardiovascular risk,” note the authors.
Ethics committees should only approve
studies if they are “convinced the potential gain is both clearly anticipated
and clinically relevant to all participants and confident that patients are not
likely to be at risk of virological failure,” write the investigators. “Trials
that primarily benefit as pharmaceutical company should not be contemplated or
In terms of design, switch studies should
be double-blind and have subjective end points. Any large switch study with a
primary focus on toxicity should be preceded by a smaller pilot study. The
virological efficacy of therapy should be assessed in trials involving
treatment-naïve patients, not in switch studies.
Journal editors are asked by the authors to
consider making it compulsory to submit patient information and consent forms
with manuscripts reporting the findings of switch and simplification research.
They would enable editors to “determine whether patients were fully informed
about the risks and benefits of a trial, all risks and benefits were reported,
and the principles of the Helsinki Declaration were upheld.”
Switching HIV treatment can be appropriate,
conclude the authors, but it is essential to determine the full risks and benefits
before and to communicate these to patients.
“The diminishing antiretroviral drug
pipeline suggests greater care will need to be given in coming years to
extending the benefits of existing drugs for what is likely to remain lifelong