Abstracts Vol. 1 [International Conference on AIDS (11th: 1996: Vancouver, Canada)]

Mo.A.I 117- Mo.B.1I123

Monday, July 8, 1996

pM ddl were required to inhibit >95% the correspondent resistant viruses. However, in the
presence of Hydroxyurea, only 0.4 pM AZT or 2 pM ddl were required to achieve the
same level of inhibition.I The latter concentrations are readily achievable in patients treated
with routine dosages of AZT or ddl.
Conclusions: HIV I drug resistance is common to all drugs that directly target viral proteins.
Hydroxyurea inhibit s HIV I indirectly, by rtargeting one of the cellular proteins, which are less
prone to mutations than the v ial ones, and resistance to hydroxyurea has not been reported after 30years clniai experience. Combinrations of hydroxyurea and nucleoside analogs
leads to synergy, thus reducing viral replication and the potential onset of escape mutants.
Here we demonstrate that HIV- variants, resistant to either AZT or ddl, are significantly
more sensitive (25 -100 fold) 1to these drugs in the presence of hydroxyurea.This was
obtained by using low concentration of hydroxyurea together with concentrations of
AZ /ddl routinely achievable in vivo. Hydroxyurea appears therefore to be a primary candidate for HIV I therapy in combinations with nucleoside analogues before as welli as after
resistancre to the nucleoside anaogues has emerged.
FRANC O LO RI, Research Institute for Genetic and Human Therapy (RIGHT), 7965 Cessna
Ave. Galthersburg, MD, 20879, USA Tel: + 1 (301) 3302699; Fax [phone]
Mo.A.I I 17
IN VITRO RESISTANCE TO HIV IN PBMC CULTURES FROM RECENTLY INFECTED
PARTICIPANTS IN HIV VACCINE TRIALS IS CD8 DEPENDENT
Schwartz, David H, Arrango Jaramillo S, Castilo R, Sridharan G, Clements ML. The Johns
Hopkins School of Hygiene and Public Health, Baltimore, MD, U.S.A.
Objective: To longitudirnally assess the in vitro susceptibility or resistance of PBMCs from
recent seroconverters who had received two or more injections of HIV-I envelope based
vaccine products.
Methods: Indviduals who had participated in various Phase I or II trials of envelope based
I IV vaccrnes weore oired for subsequenit nfection (as determined by unequivocal WB,,and env + si, + LTR region proviral DNA PCR signal). Eight such individuals were identified
between 1992 and 1995, and spacing between negative anrid positive samples permitted an
estimate of< I yr betweern infection and in vitro testing for resistance/susceptibility as follows: I0 x 10f PBMC were stimulated with OKT 3 + IL-2 for 2 days, then split into cultures
icontaning 5 x 106 cells each. One culture was incubated I hr with HIV- I MN (3-4 TCID50
for these conditions) then washed. Both cultures were then replated in I ml day 2 supernatant+ I mri fresh medium (RPMI 1640, 10% FCS), and sampled every 3-4 days x 2 weeks
for p24 production. Cultures which turned positive invariably did so by day 10 and showed
increasing p24 concentrations despite being refed with 50% fresh medium with each samping.The 2 plarebo and 6 vaccine recipients donated 2-4 times in the first 2 months of
HIV+ status detection and I-3 more times over the next 10 months.
Results: Of the 40 samples cultured, 17 showed outgrowth of endogenous HIV by day 10
and thus were not readily assessed for exogenous virus resistance.The remaining 23 samples were negative for endogenous HIV growth and in 23/23 parallel cultures resisted HIVI MN challenge. Resistance was correlated with lower plasma viremia as determined by
Roche Armpicor HIV I RNA RT DNA PCR monitoring (p < 0.005). When analyzed by individual donor and product received, results showed that 2/2 placebo and 2/6 vaccine recipients cells were repeatedly resistant to endogenous and exogenous HIV CD8 depletions
were performed on 7 PBMC samples with resistant phenotype; endogenous HIV grew in 4
of these wells and added HIV IMN grew in another two. One CD8 depleted culture
remairned p24 negative even after addition of exogenous virus.
Conclusions: In vitro resistance or susceptibility to endogenous and/or exogenous HIV
becomes a stable phenotype within I year of infection and correlates with plasma viremia.
It appears to be mediated largely by CD8+ cells and may like viremia, be predictive of disease progression rate. Envelope based vaccines ttested to date do not appear to enhance in
vitro resistince.
David i. Schwartz, MD, PhD, Johns Hopkins University Center ftor immunization Research,
Hampton House/Roomn 125 624 N. Broadway B.rltimrore, MD 21205 Phone:[phone]
Fax: [phone]
Mo.B.I 120
HIV-I RNA IN PATIENTS RECEIVING ZIDOVUDINE + LAMIVUDINE AFTER LONG
TERM ZIDOVUDINE MONOTHERAPY
Costes C)livier, Lafeuil ide A., Pelepsno PI. Poggi C.*, Profizi N.,TLamalet C.*. > General
Hospital,Toulon; * Timone Hospital, Marseille, France
Objective: to measure the evolution of HIV- I viremia in patients treated with Zidovudine
(ZDV) monotherapy receiving in second line a combination with Lamivudine (3 TC).
Methods: 15 HIV- infected patients (I 3 males, 2 females) have been studied at that time in
this ongoing prospective study Inclusion crtena included ZDV monotherapy since at least 6
months and HIV I RNA titre > 10000 copies/ml. HIV I RNA was quantified in plasma at
baseline, week 2 and monthly thereafte-r with a PCR technique using an internal standard
(Amplicor Monitor Roche LDiagnostic Systems, Neuilly sur Seine, France)
Results: The mean duraton of ZDV was 44 months (range: 7-96) when 3 TC was added.
Mein HIV I RNA titre t baseline was 365475 copies/ml and mean CD4+ T cells count
152 x 106/L. A prompt decrease of HIV I RNA was seen in each case within 2 weeks after
initiation of 3 10C.This decrease was of 0.75 Logl0 in average after 2 months.With a mean
follow up of 3 days (60 330), plasma HIVI RNA ttres continued to decrease regularly
in 5 cases, increased in 8 cases without reaching pretreatment levels, and increased higher
than baseline wlues in 2 cases. The slope of the CD4+ T cells count was decreasing in 2
cases and stable in others during that time.
Conclusion: Addition of 3 TC n patents on lon term ZDV monotherapy produces a
tpd but tra soi'st decrease o50f HIV I repscation.This effect is of limited amplitude and
taration and not apablr to induce sgnficant increase in CD4+ T cells. Analysis of viral
mutations known to confer restance to ZDV and 3 TC is ongoing.
Docteur Olvier COSTES, Unite d infectiologie, H6pital Chalucet, F-83000 TOULON,
France.Tel: [phone] t; Fax: [phone]

Mo.B.I 121
A RANDOMIZED, DOUBLE-BLIND, DOSE-RANGING PHASE II EUROPEAN STUDY
OF THE SAFETY AND EFFICACY OF CHRONICALLY ADMINISTERED BUTANOYLCASTANOSPERMINE (MDL 28,574A) HIV-INFECTED PATIENTS.
Arasteh Keikawus-', Czerwinska R. I, Schlote F2, F:itkenheuo r G.3, Jessen H.. Moll A.2,
Gehring P4, Ulmer A.5, Hamedani P6, MCPherson M.6!Auguste ViktoritHospital, Berln
Germany; 2Berlin, Germany; 3Dept. I Int. Med. Unw. Coioer. Germany: Hospital
Dortmund, Germany; 5Stuttgart. Germany Hchst Mraon Roussel, Inc., Kansas ty USA
Study Drug: MDL 28,574A is a derivate of castanospermine, naturall y occu r nig plant alka
loid of the Australian chestnut. It is inhibiting the ctivity of iuosdase, ho tcell
enzyme, resulting in a diminished amount of gp 120 in the vir ervlope, whr cnay lead to
reduced infectivity of the HIV virus.
Objectives: Objectives of this clinical trial are the characterzation of safet y and efficacy of
fixed doses of MDL 28,574A alone and in combination with Zidovudine (ZDV), as well as
the examination of the demographic effects on the population phar'racoinetts and phar
mnacodynamics of MDL 28,574A alone and,in combination vwith ZDV.
Methods: The duration of the treatment is 24 weeks. I he study population of two separate
protocols respectively consists of different subgroups with CD4-count from 100 to 300
cell/ol, respectively from 301 to 500 cell/pl.The tudy population s further subdivided nto
five treatment arms, receiving 50(A), 50(B), I300(C), 400(D) m P113L 28,574A per day or
control (AZT or placebo) alone for 12 weeks. followed by comb nation with da ly dose of
600 mg AZT for the next 12 weeks.The planned entire part;cipation count is approximately 400.We will present the European data. Efficacy measure s are quantitative plasma HIV I
RNA assay, CD4-cell count, clinical assessment and plasma p24 ntiaen. Safety measures are
treatment emergent adverse events, laboratory e'sts, stool uaac teist, vaital signs, ECGs and
physical exams.
Results: The data are still blinded. Preliminary reults show ood to lrP p Ity5c tMrDL
28,574A. Side effects were few. Side effects are fc The o st 00 m on si de effect weres
flatulence and diar-hea with a predomnantely uild to moderate intensity. Only few paents
had to discontinue the study due to study drug related adverse events. Prelimrinary efficacy
measures show a good result for about one third of the pents, stable results for one third
and a rather poor result for another third of the patients

44
CL
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Arasteh, Keikawus; Auguste-Viktorna -Hospital, Rubensstrasse
Phone No..49.30.7903.2581/2609; Fax No..49.30.7903.200!

Berin, ( erm rr

Mo.B.I 122
STAVUDINE (d4T) - HIV I VIRAL LOAD AND CD4 POSITIVE CELL COUNT IN HIV+
INDIVIDUALS PRETREATED WITH ZIDOVUDINE.
Mauss S, Adams O*,Willers R**, Hiussinger D, Jblonowsk,e Hlmut. Dept. of Medicine.
*Dept. of Virology "*Computer Center, Univers ty of Duesseidorf Duesseldorf, oermany
Objective: To determine HIV I viral load and the course of CD4-positw (CD'4 +) cells in
HIVseropositive (HIV+) individuals treated with stavudine (d4T) utter prolonged pretreatment with zidovudine (ZDV).
Methods: HIV+ individuals with <350 CD4+ cells/pl and rcrIonths of ZDV prtreatment
were randomized in a double-blind d4T dose coiparison tr, 1 (20 m bid vs. 40 mg bid)
Blood samples of 16 study participants were col lected at one study site and an yzed for
CD4+ cell count and HIV I RNA in plasma (Ro(he, Basel, Swtzerland) at baseine, week 4,
I 6, 28, 40, and 52.
Results:The median CD4+ cell count at baseline was 239/.The median increase of
CD4+ cells was maximal at week 4 (+ 38/pil) and decreased subsequently (week I6:
+18/pl, week 28: +21/pI, week 40: 16/p1, week 52: 201pl).The median HIV I vral id at
baseline was 33746 copies/pl (4.53 log).The median decrease in,, w5 5c ad was r1~ir'ala t
week 4 (-0.23 Iog).Thereafter the viral load returned to baserIe (week i6: 0.07 log. week
28: 0.04 log, week 40: -0.04 log, week 52 0.08 o).
There was a significant inverse correlation between pretreatnent CD1+ cel count and
viral load at baseline (-0.65, p:-0.009), but not bet ween changes in i 1 lod,n-d changesi n
CD'4+ cell count during treatment with d4t
Conclusions: Antiretroviral treatment with d4T fer pro lon ad pretreatment wth ZDV
decreased HIV I viral load and increased CD4+ cell count, a though part of the patients
received the drug in a suboptimal dose.This change in surroe uarkers was comparatble
to the effect of ZDV in a predominantly ZDV nve -HIV- t ptient populaition reported
recently (Eron etoal. NEJM 1995;5 333: 6629). At,asetine the-e was a s1ron ve-sorrlation of HIV I viral load and CD4+ cell tstrs u tipng i tio retweer celusar
immunology and viral repication. However in this small sa mpl' size s,,e in antretroviral monotherapy no clear correlation could be demonstrated 'reta' e ichone C[_)4
cell count and HIV viral load under treatment.
Dr Helmut Jablonowski, Klinik fuer Gastroenterologic und Infstiro i, Usri rs t
Duesseldorf, Mooren str. 5,40225 Duesseldorf Tl.,19 12 I 18 7
FAX +49 121 I1 181 1-8752
Mo.B. I 123
DEFINED MANIPULATION OF MUTATIONAL PATHWAYS OFTHE HIV-I RT GENE WITH
THE NONNUCLEOSIDE REVERSETRANSCRIPTASE INHIBITOR (NNRTI) HBY 097
Kleimorg -Peter*,Winkler I.*, Rosner M. *. Kirsch R, Rubsamen- Wagmiann H.", Paessens
A.", RieB G.*. *Hoechst AG, Frankfurt; *Bayer AG, Wupper al, Germany
Objective: HBY 097 is a second generation NNRTI of HIV-I replication and is at present
undergoing phase 1/11 clinical trials. In vitro, HBY 097 causes the appearance of characteristic
RT G 190-aE viral variants, which are resistant to the drug but display a crippled RTpolymerase function and retarded growth properties.
Methods: We simulated alternative selective forces of HBY 097 by applyng different experimental protocols for the generation of resistance.
Results: A total of 20 H9 cell cultures infected with HIV- I MN were initially incubated in the
presence of the same drug concentration (0.001 p g/ml) in hal of the neages the quantity
of HBY 097 was raised by a factor of 4-5 with every subsequent passage (highest concen
tration: 20 pg/ml, group A).The remaining virus stra ns were processed by adding to the
culture media only 2-fold the amount of HBY 097 of the previous passage (highest concentration: 20 pg/ml, group B). Genotypic conmpanson of the resuling muta nts revealed two
distinct ways by which resistance to HBY 097 was achieved. Group A mutants preferentially

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