#HVAD2018 in Thailand. The VARG & the Armed Forces Research Institute of Medical Sciences – Celebrating Partnerships!

The half-day event commemorated not only HVAD but also the 25th anniversary of AFRIMS. About 120 people attended the meeting. They were CAB members from 5 CABs, research teams from 6 institutes and officers from MoPH and HIV vaccine development sub-committee. The event was opened by the USA Ambassador to Thailand, Glyn Davies, the Deputy Minister of the MoPH, and the Surgeon General of the Thai Army Medical Department. This was followed by Dr. Suwat Chariyalertsak, one of the co-PIs of HPTN 052, iPrEX, and the cabotegravir long-acting PrEP. He talked about the history of HIV prevention since the first reported case in 1981 up to the present which included HIV prevention methods such as PEP, PMTC, RV144, iPrEX, TasP, and the on-going HIV prevention trials. He concluded that there is still a need for HIV vaccine.

VARG member Udom Likhitwonnawut spoke next and used the AVAC/IAVI model demonstrating the impact of an HIV vaccine. Using a slide from Professor Glenda Gray that shows the UNAIDS Investment Framework Enhanced Model and projections of the potential impact of an HIV vaccine. Udom also talked about Dr. Anthony Fauci’s presentation at the 2017 IAS Conference in Paris that showed that the eradication of AIDS is unlikely without vaccine. Ending with action items and advocacy points for the Thai government to consider which centred on work needed to better understand who the target populations for a potential vaccine are, how to integrate an HIV vaccine with other prevention options and model options that analyse an HIV vaccine as an anchor instead of condom as anchor as it is now. A historical account of RV144 was also shared that provided context and grounding for Dr Vasan’s presentation.

Dr. Sandya Vasan from AFRIMS provided background information on HIV vaccine trials after RV144: RV 305 (late booster), RV 306 (early booster) and RV 328 (AIDSVAX alone). The presentation was an update on the status of the trials. What was interesting is that the retention of these trials were very high – more than 90% on all three even with the late booster which enrolled participants from RV 144 which had a lag time about 6-8 years. Dr. Eugene Kroon from SEARCH program of the AIDS Research Centre of the Thai Red Cross talked about the optional clinical procedures of the after RV 144 trials and why they do them. The procedures included mucosal samples and procedures to collect them such as cervical biopsy, rectal swap and sigmoid biopsy, leukapheresis, bone marrow aspiration. He talked about the rates that people consented to these (bone marrow aspiration about 55% and leukapheresis is more than 90%). Dr. Kroon also talked about the safety of these procedures which are quite safe and carried out by specialists at one of the best hospitals in Thailand (and the Thai Red Cross is a part of the hospital/- medical school complex).

Dr. Punnee Pitisuttithum from the Vaccine Trial Centre, Mahidol University who is the co-PI of RV 144 and VAX 003, and Janssen’s Ad26 trial (the phase 1/2 trial) presented next. She explained the main component of the immune system – the immunoglobulin and its component (IgG, IgA, IgM….) andthe structure of gp120 protein on the HIV envelop and different regions of the protein that are targets of the immunoglobulin. This was followed by the results of the RV 144 follow-on studies – which looked at vaccine induced immune response (AIDSVAX does this while Alvac didn’t and the immune responses of both vaccines used together are similar to AIDSVAX alone – hence it is AIDSVAX that makes RV 144 effective). She also showed that AIDSVAX induced more response with AE subtype and not so well with B subtype which might explain why the VAX 003 and another trial that used AIDSVAX in USA didn’t work. She also showed that late booster (of RV 144 regiment) activated more CD4 and CD8 responses and makes the cells more susceptible to HIV infection while the early booster doesn’t do that.

The last two presentations were updates on the MSM cohort for the upcoming HIV prevention for MSM and the HVTN 702 and 705 by the chief of Retrovirology Department, Dr. Robert O’ Connell. The last presentation was on a therapeutic HIV vaccine by Dr. Donn Colby from SEARCH, the AIDS Research Centre of the Thai Red Cross. His presentation was focused on using the Ad26 vaccine for therapeutic purposes and showed that there will be analytical treatment interruptions after the participants receive the vaccine. There are no results from this study (RV 405) yet.