Accelerating clinical development of HIV vaccine strategies: methodological challenges and considerations in constructing an optimised multi-arm phase I/II trial design

A Phase I trial of Non-invasive Ventilation and seizure prophylaxis with levetiracetam In Children with Cerebral Malaria Trial (NOVICE-M Trial)

Background

African children with cerebral malaria and seizures caused Plasmodium falciparum are at greater risk of poor outcomes including death and neurological sequelae. The agonal events are severe hypoventilation and respiratory arrest often triggered by seizures. We hypothesised that prophylactic anti-seizure medication (ASM) could avert 'spikes' of intracranial pressure during or following seizures and that adequate ventilation could be supported by biphasic Cuirass Ventilation (BCV) which requires no intubation.

Methods

A Phase I trial conducted in Kilifi, Kenya designed to provide data on safety, feasibility and preliminary data on seizure control using prophylactic ASM (levetiracetam) and BCV as non-invasive ventilatory support in children with cerebral malaria. Children aged 3 months to 12-years hospitalised with P falciparum malaria (positive rapid diagnostic test or a malaria slide), a Blantyre Coma Score ≤2 and a history of acute seizures in this illness are eligible for the trial. In a phased evaluation we will study i) BCV alone for respiratory support (n=10); ii) prophylactic LVT: 40mg/kg loading dose then 30mg/kg every 12 hours given via nasogastric tube for 72 hours (or until fully conscious) plus BCV support (n=10) and; iii) prophylactic LVT: 60mg/kg loading dose then 45mg/kg every 12 hours given via nasogastric tube for 72 hours (or until fully conscious) plus BCV support (n=10). Primary outcome measure: cumulative time with a clinically detected seizures or number of observed seizures over 36 hours. Secondary outcomes will be assessed by feasibility or ability to implement BCV, and recovery from coma within 36 hours. Safety endpoints include: aspiration during admission; death at 28 days and 180 days; and de-novo neurological impairments at 180 days.

Conclusions

This is a Phase I trial largely designed to test the feasibility, tolerability and safety of using non-invasive ventilatory support and LVT prophylaxis in cerebral malaria.

Registration

ISRCTN76942974 (5.02.2019); PACTR202112749708968 (20.12.2021).

T Cell Immunogenicity, Gene Expression Profile, and Safety of Four Heterologous Prime-Boost Combinations of HIV Vaccine Candidates in Healthy Volunteers: Results of the Randomized Multi-Arm Phase I/II ANRS VRI01 Trial

Heterologous prime-boost strategies are of interest for HIV vaccine development. The order of prime-boost components could be important for the induction of T cell responses. In this phase I/II multi-arm trial, three vaccine candidates were used as prime or boost: modified vaccinia Ankara (MVA) HIV-B (coding for Gag, Pol, Nef); HIV LIPO-5 (five lipopeptides from Gag, Pol, Nef); DNA GTU-MultiHIV B (coding for Rev, Nef, Tat, Gag, Env gp160 clade B). Healthy human volunteers (n = 92) were randomized to four groups: 1) MVA at weeks 0/8 + LIPO-5 at weeks 20/28 (M/L); 2) LIPO-5 at weeks 0/8 + MVA at weeks 20/28 (L/M); 3) DNA at weeks 0/4/12 + LIPO-5 at weeks 20/28 (G/L); 4) DNA at weeks 0/4/12 + MVA at weeks 20/28 (G/M). The frequency of IFN-γ-ELISPOT responders at week 30 was 33, 43, 0, and 74%, respectively. Only MVA-receiving groups were further analyzed (n = 62). Frequency of HIV-specific cytokine-positive (IFN-γ, IL-2, or TNF-α) CD4⁺ T cells increased significantly from week 0 to week 30 (median change of 0.06, 0.11, and 0.10% for M/L, L/M, and G/M, respectively), mainly after MVA vaccinations, and was sustained until week 52. HIV-specific CD8⁺ T cell responses increased significantly at week 30 in M/L and G/M (median change of 0.02 and 0.05%). Significant whole-blood gene expression changes were observed 2 wk after the first MVA injection, regardless of its use as prime or boost. An MVA gene signature was identified, including 86 genes mainly related to cell cycle pathways. Three prime-boost strategies led to CD4⁺ and CD8⁺ T cell responses and to a whole-blood gene expression signature primarily due to their MVA HIV-B component.

A Phase 2 Randomized Trial of Asleep versus Awake Subthalamic Nucleus Deep Brain Stimulation for Parkinson's Disease

OBJECTIVE

Asleep deep brain stimulation (DBS) for Parkinson's disease (PD) is being performed more frequently; however, motor outcomes and safety of asleep DBS have never been assessed in a prospective randomized trial.

METHODS

We conducted a prospective, randomized, noncomparative trial to assess the motor outcomes of asleep DBS. Leads were implanted in the subthalamic nucleus (STN) according to probabilistic stereotactic coordinates with a surgical robot under O-arm© imaging guidance under either general anesthesia without microelectrode recordings (MER) (20 patients, asleep group) or local anesthesia with MER and clinical testing (9 patients, awake group).

RESULTS

The mean motor improvement rates on the Unified Parkinson's Disease Rating Scale Part III (UPDRS-3) between OFF and ON stimulation without medication were 52.3% (95% CI: 45.4-59.2%) in the asleep group and 47.0% (95% CI: 23.8-70.2%) in the awake group, 6 months after surgery. Except for a subcutaneous hematoma, we did not observe any complications related to the surgery. Three patients (33%) in the awake group and 8 in the asleep group (40%) had at least one side effect potentially linked with neurostimulation.

CONCLUSIONS

Owing to its randomized design, our study supports the hypothesis that motor outcomes after asleep STN-DBS in PD may be noninferior to the standard awake procedure.

A Bayesian adaptive phase I/II platform trial design for pediatric immunotherapy trials

Immunotherapy is the most promising new cancer treatment for various pediatric tumors and has resulted in an unprecedented surge in the number of novel immunotherapeutic treatments that need to be evaluated in clinical trials. Most phase I/II trial designs have been developed for evaluating only one candidate treatment at a time, and are thus not optimal for this task. To address these issues, we propose a Bayesian phase I/II platform trial design, which accounts for the unique features of immunotherapy, thereby allowing investigators to continuously screen a large number of immunotherapeutic treatments in an efficient and seamless manner. The elicited numerical utility is adopted to account for the risk-benefit trade-off and to quantify the desirability of the dose. During the trial, inefficacious or overly toxic treatments are adaptively dropped from the trial and the promising treatments are graduated from the trial to the next stage of development. Once an experimental treatment is dropped or graduated, the next available new treatment can be immediately added and tested. Extensive simulation studies have demonstrated the desirable operating characteristics of the proposed design.

Willingness to Participate in Hypothetical HIV Vaccine Trial and Associated Factors among People Who Inject Drugs in Dar es Salaam, Tanzania

This study is aimed at assessing the willingness to participate in the HIV vaccine trials and the associated factors among people who inject drugs (PWIDs) in Tanzania. Information about the willingness to participate and the associated factors was collected using interviewer-administered questionnaires at the medication treatment for opioid use disorder (MOUD) clinic in Dar es Salaam. Data analysis was performed using the IBM SPSS Statistic 20. The mean age of respondents was 36.7, and the standard deviation (SD) was ±7.2. The majority of respondents (68%) had primary education, and a high proportion of them were single (61.5%). More than one-third (37.9%) shared needles and syringes. Most (87.3%) had more than three sexual partners, and almost half (51.4%) did not use condoms during sexual intercourse with nonregular partners. About 63% had knowledge of HIV transmission while 27% had heard about HIV vaccine trials. Generally, 76% of the respondents expressed willingness to participate in future HIV vaccine trials regardless of prior knowledge of HIV vaccine trials. Willingness to participate in HIV vaccine trials was not associated with education level, people living with, knowledge about HIV transmission, awareness of HIV vaccine trials, sharing of syringe/needles, and number of sexual partners. Only older age (OR = 1.6, 95%CI = 1.01, 2.6) and condom use (OR = 0.49, 95%CI = 0.26, 0.97) showed an association with willingness. However, after performing logistic regression with factors at p value ≤ 0.2 to ascertain the other factors on the effects of age, condom use, education level, and sharing of needles/syringes, the results were not statistically significant. Although participants reported a high willingness to participate in hypothetical HIV vaccine trials, no definitive conclusion can be drawn about the associated factors. Further studies with intensive educational programs are needed to investigate the factors on willingness to participate in actual HIV vaccine trials among PWIDs.

Multi-arm, multi-stage randomised controlled trials for evaluating therapeutic HIV cure interventions

The evaluation of immune-based approaches to achieve an antiretroviral therapy free remission of HIV infection requires proven efficacy through antiretroviral therapy interruption placebo-controlled trials. This approach is not without risk to participants and innovative trial designs need to be developed that minimise the number of participants treated with placebo and ineffective candidates. Multi-arm, multi-stage (MAMS) trial designs can be used in this context to accelerate the development of an immune-based therapeutic agent for HIV cure. Issues related to implementing a MAMS design within the planned EHVA T01 trial are considered here. EHVA T01 is a multicentre, MAMS, double-blind, phase 1 and 2 trial that aims to evaluate the effect of immune interventions on viral control in HIV-1 infected participants following analytic treatment interruption. The application of a MAMS design increases the likelihood that the EHVA T01 trial will identify a successful treatment and minimises the number of participants undergoing analytical treatment interruptions who have been treated with futile agents. The use of a MAMS design is a promising strategy to evaluate complex immune-based approaches aimed at curing HIV-infection, particularly relevant to the pipeline with multiple agents requiring examination.

A Bayesian design for phase I cancer therapeutic vaccine trials

Phase I clinical trials are the first step in drug development to test a new drug or drug combination on humans. Typical designs of Phase I trials use toxicity as the primary endpoint and aim to find the maximum tolerable dosage. However, these designs are poorly applicable for the development of cancer therapeutic vaccines because the expected safety concerns for these vaccines are not as much as cytotoxic agents. The primary objectives of a cancer therapeutic vaccine phase I trial thus often include determining whether the vaccine shows biologic activity and the minimum dose necessary to achieve a full immune or even clinical response. In this paper, we propose a new Bayesian phase I trial design that allows simultaneous evaluation of safety and immunogenicity outcomes. We demonstrate the proposed clinical trial design by both a numeric study and a therapeutic human papillomavirus vaccine trial.

Development of an epitope-based HIV-1 vaccine strategy from HIV-1 lipopeptide to dendritic-based vaccines

INTRODUCTION

Development of a safe, effective and globally affordable Human Immunodeficiency Virus strain 1 (HIV-1) vaccine offers the best hope for future control of the HIV-1 pandemic. However, with the exception of the recent RV144 trial, which elicited a modest level of protection against infection, no vaccine candidate has shown efficacy in preventing HIV-1 infection or in controlling virus replication in humans. There is also a great need for a successful immunotherapeutic vaccine since combination antiretroviral therapy (cART) does not eliminate the reservoir of HIV-infected cells. But to date, no vaccine candidate has proven to significantly alter the natural history of an individual with HIV-1 infection. Areas covered: For over 25 years, the ANRS (France Recherche Nord&Sud Sida-HIV hépatites) has been committed to an original program combining basic science and clinical research developing an epitope-based vaccine strategy to induce a multiepitopic cellular response against HIV-1. This review describes the evolution of concepts, based on strategies using HIV-1 lipopeptides towards the use of dendritic cell (DC) manipulation. Expert commentary: Understanding the crucial role of DCs in immune responses allowed moving from the non-specific administration of HIV-1 sequences with lipopeptides to DC-based vaccines. These DC-targeting strategies should improve HIV-1 vaccine efficacy.

Recent developments in clinical trial designs for HIV vaccine research

HIV vaccine strategies are expected to be a crucial component for controlling the HIV epidemic. Despite the large spectrum of potential candidate vaccines for both prophylactic and therapeutic use, the overall development process of an efficacious HIV vaccine strategy is lengthy. The design of clinical trials and the progression of a candidate strategy through the different clinical development stages remain methodologically challenging, mainly due to the lack of validated correlates of protection. In this review, we describe recent advances in clinical trial designs to increase the efficiency of the clinical development of candidate HIV vaccine strategies. The methodological aspects of the designs for early- (phase I and II) and later -stage (phase IIB and III) development are discussed, taking into account the specificities of both prophylactic and therapeutic HIV vaccine development.

HIV-1 prophylactic vaccines: state of the art

The quest for an effective HIV-1 vaccine began early in the course of the HIV pandemic. Over time, the paradigm has evolved from B cell- towards T cell-based vaccines. Results from initial Phase II/III trials have been disappointing; however, while modest, the unexpected results of the Phase II/III RV144 trial in Thailand have re-energised the field. Indeed a clear correlation was demonstrated in this trial between protection and immunological biomarkers, namely non-neutralising antibodies against the V1V2 region. Recent data obtained from cohorts of recently HIV-1-infected individuals have enabled exploration of the role of neutralising antibodies and their potential use in HIV-1 prevention. Results from non-human primate models using a cytomegalovirus vector have also shown the potential for a prophylactic HIV vaccine to induce effective T cell responses. Finally, the development of new vaccine vectors and trial strategies has also allowed progress in the field. Therefore, HIV-1 vaccine research remains a dynamic field that has also been stimulated by the recent positive results of pre-exposure prophylaxis strategies with antiretrovirals.