Clinical Trial Details
— Status: Active, not recruiting
Administrative data
NCT number |
NCT04121195 |
Other study ID # |
DERIVE |
Secondary ID |
|
Status |
Active, not recruiting |
Phase |
Phase 2/Phase 3
|
First received |
|
Last updated |
|
Start date |
October 30, 2020 |
Est. completion date |
August 20, 2023 |
Study information
Verified date |
August 2022 |
Source |
University of Liverpool |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Interventional
|
Clinical Trial Summary
The standard treatment for TB consists of rifampicin (RIF) as part of the regimen. However,
due to drug-drug interactions (DDI), the bioavailability of PIs is greatly reduced when
co-administered with RIF necessitating use of higher doses of the PI to overcome this effect.
However, the potential effect of this increased dose on the DDI with bPIs is uncertain.
Though some data has been collected that shows safe use of higher doses of LPV to overcome
the DDI with standard doses of RIF in HIV-infected individuals, no substantive data has been
collected on ATV to correctly adjust its dose when co-administered with RIF-based TB
treatment.
Physiologically-based pharmacokinetic (PBPK) modelling was developed to understand ATV and
RIF DDIs, and identified potential dosing strategies to overcome this challenge in adults and
special populations under workpackage 1 of the VirTUAL consortium. From this work, it is
anticipated that the dose of ATV/r should be increased from 300/100 once daily to 300/100mg
twice daily in order to overcome the interaction with rifampicin and attain therapeutic
plasma concentrations.
This dose escalation trial aims to:
1. Evaluate the steady state plasma and intracellular PK of ATV/r, when administered in
adjusted (PBPK model-predicted) doses concurrently with RIF
2. Evaluate the safety and tolerability / acceptability of the adjusted dose of ATV/r that
provides the therapeutic concentration when co-administered with RIF.
3. Evaluate the concentration of dolutegravir (DTG) and RIF when co-administered and
explore the potential DDI with ATV/r
Description:
Background and Justification
Both HIV and TB can successfully be managed using the currently available medications with
the latter being curable. However, due to the detrimental drug-drug interaction (DDI) between
RIF and the bPIs, there is a challenge in the management of the two conditions concurrently
in persons who need both classes of drugs. RIF is a strong inducer of the hepatic enzyme
cytochrome P450 (CYP) 34A which metabolizes several agents including the PI drugs thereby
reducing their bioavailability. While rifabutin, an alternative rifamycin is associated with
less DDI with bPI and maybe a better alternative to RIF in such circumstances, its cost,
toxicity and lack of co-formulated preparations renders it to be a less likely sustainable
option especially in LRS.
Though data published in 2008 showed a high incidence of adverse events when higher adjusted
doses of LPV/r were used to overcome the DDI effect with RIF among healthy volunteers, data
in 2012 among HIV-infected adults treated with adjusted doses of LPV/r co-administered with
RIF-based TB treatment showed the drug was well tolerated with no significant adverse events.
The major difference is that the 2012 study was conducted among HIV infected patients, that
were already on normal doses of LPV/r and RIF at the time of enrolment who underwent PI dose
escalation unlike the 2008 study among healthy volunteers who received the RIF and shortly
after higher than normal doses of LPV/r in short succession with no step-wise phase to allow
compensation. Similarly to LPV, ATV is affected by the inducing effect of RIF on the drug
metabolizing enzyme cytochrome P450 (CYP) 34A, thereby significantly reducing its
bioavailability to sub-therapeutic levels when co-administered in standard doses with RIF.
Several studies exploring the interaction between ATV/r and RIF have reached similar
conclusions to the experience with LPV/r and RIF: A study in healthy volunteers given RIF
first, then ATV/r first at standard dose with proposed dose escalation was halted when the
first three participants developed hepatotoxicity. It was noted that the pre-induction of
giving RIF first could have caused this problem. This argument is supported by a study
conducted by Burger and colleagues where participants were first given ATV/r before the
addition of RIF and where no hepatotoxicity occurred; in that study, the dose escalation
evaluated was insufficient to overcome the interaction, but concluded that further evaluation
was safe and appropriate. Similarly, Acosta and colleagues concluded that increased unboosted
ATV was safe for co-administration with RIF, but that higher doses are required to overcome
the DDI. No studies have yet evaluated this interaction in HIV-infected individuals.
It is notable that all of the currently available PIs have been associated with transient and
usually asymptomatic elevations in serum aminotransferase levels, and ATV has been associated
with mild-to-moderate elevations in indirect and total bilirubin concentration. All studied
PIs are rare causes of clinically apparent, acute liver injury. The protease inhibitors are
heterogeneous molecules with little structural similarity, most of which are peptide-like and
resemble the short peptide that is cleaved by the viral protease; for this reason, the
patterns of liver toxicity will differ between drugs of this class.
A recent study seeking to evaluate an increased dose of the bPI ritonavir boosted darunavir
(DRV/r) in combination with rifampicin resulted in rates of hepatotoxicity which necessitated
the trial to be halted on the advice of the IDSMB (CROI 2019 Abstract 81). These trial
participants had been stable on treatment with LPV/r and were transitioned to DRV/r for the
trial; the alteration in liver enzymes became apparent early on, and may have resulted in
part from the change in bPI administered to the patient.
For the reasons detailed in the paragraphs above in consideration of the previous studies
investigating either LPV/r, ATV/r or DRV/r in conjunction with RIF, we have chosen the study
population of healthy HIV-infected patients who are already stable on treatment with standard
dose of ATV/r, and who will have RIF introduced at a time when they will be at equilibrium as
regards the ATV/r. Continuation on ATV/r at standard dose together with RIF for a two week
period will enable a further equilibrium to have been established prior to escalation of the
bPI dose. Both of these considerations may reduce the likelihood of hepatotoxicity, although
frequent monitoring of safety bloods will be undertaken.
RIF also affects the bioavailability of DTG, however, this is effectively overcome by
administering DTG twice daily as opposed to the standard once-a-day dose; the elevated dose
of DTG has not been associated with concerns relating to liver toxicity.
As part of the VirTUAL consortium, physiologically-Based Pharmacokinetic (PBPK) modelling was
done at the University of Liverpool to characterize bPI and RIF DDIs. Dosing strategies were
identified / predicted to overcome the DDI between bPI and RIF that informed the ATV doses
that shall be used in this trial to predict the most appropriate dose of ATV given with a
standard dose RIF. From this work, it is predicted that increasing the dose of boosted ATV
from ATV/r 300/100mg once daily to 300/100mg twice daily will achieve sufficient plasma
concentrations when ATV/r is to be given in combination with RIF. The PBPK model utilised for
this prediction was developed considering a mathematical description of the molecular and
physiological processes underpinning the distribution of ATV/r and RIF. Experimental and
clinical data were integrated into a computational framework developed using MATLAB and
Simbiology and validated following international guidelines.
The RIF induction potential on Phase I enzyme and transporters expression, the RIF inhibitory
effect on uptake transporters and the RTV inhibitory effect on CYP3A4 were all mathematically
described for the simulation of the DDI. The PBPK model was qualified considering available
clinical data for CYP3A4 probe (midazolam) and ATV ± RTV alone at different doses (400mg q.d
unboosted, 300/100 mg q.d boosted) or in combination with RIF as previously described. The
qualification was based on the calculation of the absolute average fold error (AAFE) and root
mean squared error (RMSE) where appropriate. AAFE is a useful parameter to assess over or
under-prediction of the model, values closer to 1 indicates a closer similarity with observed
values. RMSE calculates the error between the predicted value and the observed value. RMSE is
particularly sensitive to outliers and values closer to zero indicate a reliable prediction.
The model was assumed to be qualified if the simulated values were within 2-fold of the mean
reported values, AAFE <2 and RMSE <1 as per convention for the approach. Dose adjustment to
overcome the effect of RIF on ATV/r was simulated considering available formulations with the
overall of achieving ATV exposure comparable to established regimens (e.g. 300/100mg q.d)
without RIF.
This study therefore aims to evaluate the steady state of the PBPK modelled adjusted doses of
ATV given in different doses in HIV-1 infected adults on second line therapy with suppressed
viral load so as to determine the most appropriate dose to be used concurrently with RIF. The
study will evaluate baseline ATV/r concentrations in participants who have been treated with
this agent for many months, then evaluate the impact of the addition of RIF, before
evaluating ATV/r at the full modelled dose (300/100 twice daily) with a final step to
consider the impact of increased doses of RIF (from standard dosing of 600 mg once daily to
1200 mg once daily).