ART drug resistance mutations Implications for TDF use Phyllis Kanki and Beth Chaplin Harvard PEPFAR Harvard School of Public Health.

ART drug resistance mutations

Implications for TDF use

Phyllis Kanki and Beth Chaplin

Harvard PEPFAR

Harvard School of Public Health

• Drug resistance to current d4t or ZDV based regimens?– Implications for TDF in alternative or second

line regimens

• What do we know about drug resistance to TDF as first line regimens?– HIV subtype issues

• Preliminary data on TDF resistance (K65R) transmission potential

• Baseline and toxicity issues with TDF

K65RMutation of Lysine to Arginine in Codon 65 of the reverse transcriptase.

It was first identified in response to TDF; only drug resistance mutation for TDF

It confers resistance to TDF and also causes cross resistance to other NRTIs (ABC, ddI, FTC, 3TC) except zidovudine.

In subtype B virus it is uncommon in patients who are not on a regimen containing TDF

Drug resistance in d4t or AZT based first line regimens

“Options for 2nd line ART regimens whose initial regimen of d4T+3TC+NVP fails”

• 92-95% of mulit-drug resistance to NRTIs and NNRTIs (89% M184V)

• TAMs (37%), K65R (6%), Q151M (8%)

(Sungkanuparph et al, CID 2007:44-447)

• 194 Nigerian patients on a regimen of d4T-3TC-NVP/EFV in virologic failure

• Virologic failure defined as VL >2000 copies/ml with history of 6 month regular drug pickup.

• 10/194 (5.2%) had the K65R mutation

Preliminary data on drug resistance mutations in Nigerian patients on

non-TDF regimens

Possible Implications:

•Drug resistance to TDF (K65R) observed in non-TDF based regimens was not predicted.

• Coupled with M184V will effectively limit options for alternative or second line regimens.

What do we know about drug resistance to TDF as first line

regimens?

Regimen total from Pharmacy with DispenseNo = 1, and from

patients that are naïve

Number with VL during this time

period

Mean Viral Load

Median Viral Load

Number with VL during this time period

Mean Viral Load

Median Viral Load

TDF-FTC-NVP/EFV n = 1092 n = 610 21,811 200 n = 439 11,556 200(or Truvada-NVP/EFV)

d4T-3TC-NVP/EFV n = 1076 n = 682 8,256 200 n = 810 9,090 200

AZT-3TC-NVP/EFV n = 2242 n = 1500 13,516 200 n = 1147 15,258 200

Viral Load at 4.5 to 9 months Viral Load at 10 to 15 months

RegimenPatients Median VL Patients Median VL

TDF+3TC/ZDV+NVP or EFV 620 <400 439 <400 TDF/FTC+NVP or EFV

d4T+3TC+NVP or EFV 682 <400 810 <400

ZDV+3TC+ NVP or EFV 1500 <400 1147 <400

<9 month VL 10 to 15 months VL

No significant difference in efficacy measured by viral suppression

• Preliminary data from Nigeria:-Evaluated drug resistance in patients initiating TDF first line regimens in virologic failure

-4 of 10 TDF virologic failures had K65R

-K65R was accompanied by multi-drug resistance mutations including M184V and TAMS

What do we know about drug resistance to TDF as first line

regimens?

What do we know about drug resistance to TDF as first line

regimens?Duration of ART Subtype Drug Resistance Mutations

1 14.8 CRF 02 K065R, T069N, K103N, Y181C, M184I,M230L2 5.6 CRF 02 K065R, Y181C, M184I, M184V, M230L3 5.5 G K065R, K101E, M184V, G190A4 5.5 G K065R, K101E, M184V, G190A5 2.5 CRF 026 11.8 CRF 02 M184V, Y188L

7 22.3 CRF 02D067N, K070R, A098G, K103N, M184V,K219Q, K219E

8 31.1 CRF 02A062V, T069N, T069D, T069A, A098G, K103N,Q151M, Y181C, M184V, T215Y

9 42.9 CRF 06

M041L, D067N, T069D, K070R, V075M, K101E,V118I, Y181C, M184V, G190A, L210W, T215F, K219Q

10 47.1 G K103N, Y181C, M184V, T215F

Which mutations are the first to appear?

0

1

2

3

4

5

K103NY181C M184VV106IV90I A98G

G190AV179E Y181C

# of

pat

ient

s w

ith th

is m

utat

ion

Patients with only one mutation

NNRTIs: NVP EFV

NRTIs: 3TC d4T ZDV

“Early” and “Late” NNRTI Mutations

0%

5%

10%

15%

20%

25%

30%

35%

40%

Y181C K103N A098G G190A K101E V108I V090I V179E V106I

1 NNRTI Mutation 2 NNRTI Mutations 3 NNRTI Mutations

earlymutation

mutations that seem to appear later in the course of resistance

Implications:

• Use of TDF in first line may lead to high rates of resistance (K65R)

• TDF resistance mutations would occur late

• Therefore, AZT could still be employed in alternative and second line regimens

• Botswana : Increased In vitro resistance to TDF in subtype C virus (Wainburg et al)

• Nigeria: Genotype data

-Subtype CRF 02 increased development of resistance to TDF

- Subtype 06 decreased development of

resistance to TDF

What do we know about drug resistance to TDF as first line regimens?

HIV subtype issues

Emergence of Resistance to Tenofovir (TDF) in Subtype C Compared to Other Subtypes in Vitro

Subtype Weeks of selection

7 12 20–25 35–40

C (BG-05) wt K65R K65R K65R

C (Mole 18) wt K65R K65R K65R

C (BG-15) wt K65R, A62V K65R, A62V K65R, A62V

C (4742) wt K65R K65R, M41L K65R, M41L

B (n=4) wt wt wt wt

AE (n=2) wt wt wt wt

A (n=2) wt wt wt wt

G (n=1) wt wt wt wt

HIV-2 wt wt wt wt

12-23 AIDS 20:F9-F13,2006

LUTHLagos State

N = 47

NIMRLagos State

N = 58

68MilitaryLagos State

N = 43

JUTHPlateau State

N = 123

UMTHBorno State

N = 31

UCHOyo State

N = 39

G

CRF06

A

CRF13F2

REC D

CRF02

CRF02

G

CRF06CRF11 A

REC

CRF02

G

A

CRF06

REC

CRF02G

CRF06

AF2 REC

CRF02G

CRF06

REC

CRF02G

CRF06REC

K65R by subtypeSubtype K65R %

Subtype G 3/87 3.4%

CRF_02 A/G 7/76 9.2%

CRF_06 0/9 0%

Frequency of Mutations Associated with NRTI ResistanceGrouped by Subtype

M41L E44D D67N K70R V118I L210W T215YF K219QEMulti-nRTI

Resistance

Didanosine L74VK65R

Tenofovir K65R

Lamivudine K65R M184VI

Emtricitabine K65R M184VI

Zidovudine M41L E44D D67N K70R V118I L210W T215YF K219QE

K65RStavudine M41L E44D D67N K70R V118I L210W T215YF K219QE

Abacavir Y115F M184VK65R L74V

Multi-NRTIResistance

151 ComplexA62V V75I F77L F116Y Q151M

Multi-NRTIResistance

Ins. ComplexM41L A62V 69ins K70R L210W T215YF K219QE

A62V2/875/760/9

V75I9/875/760/9

F77L3/875/760/9

F116Y2/873/760/9

Q151M3/875/760/9

Subtype:GCRF02CRF06

M41L14/876/764/9

E44D3/871/760/9

K65R3/877/760/9

D67N18/8710/765/9

K70R25/8711/764/9

L74V2/870/760/9

Y115F2/872/760/9

V118I 6/872/761/9

M184V72/8765/767/9

L210W4/873/761/9

T215F11/8713/763/9

K219Q12/876/763/9

Subtype:GCRF02CRF06

T215Y13/8714/760/9

M184I2/873/761/9

K219E6/874/760/9

Implications:

• HIV subtype may influence (increase) development of K65R

• More studies need to evaluate potential impact of geographic (subtype) implications for TDF use

• However, even with K65R subtype differences - AZT could still be employed in alternative and second line regimens

• Preliminary data from Nigeria:

- Clustering of TDF resistance (K65R)

-3 possible cases of TDF resistance(K65R) - where

resistance seen prior to ART

Preliminary data on TDF resistance (K65R) transmission potential

K65RT69delV75IF77L

Q151MK219R

--NNRTIs

K65RT69delV75IF77L

Q151MK219R

--NNRTIs

d4T-3TC-NVP AZT-TDF-LPV/r

Responsive to a regimen of Kaletra (LPV/r), AZT and TDF

G

K65RQ151M

--NNRTIs

K65RV75IF77L

Y115FF116YQ151M

--NNRTIs

K65RV75IF77L

F116YQ151M

--NNRTIs

d4T-3TC-NVP AZT-TDF-LPV/r

This patient may represent a case of transmitted resistance.

CRF02

Another case of transmitted resistance?

K65RF116YQ151MM184V

--NNRTIs

K65RT69IF77L

F116YQ151MM184V

--NNRTIs

AZT-3TC-NVP

AZT-3TC-TDF-LPV/r

CRF02

Surveying for possible cases of transmitted resistance...

• Surveillance is needed to evaluate possibility of transmission of drug resistant viruses

• TDF-first line regimens might have reduced efficacy in the face of transmitted resistant virus (K65R) but we need much more data

• In our small numbers patients still responded to TDF-second line even with the drugs resistance mutations (K65R)

Implications:

Baseline and toxicity issues with TDF

• Reports of renal dysfunction in TDF-treated patients raise concerns about the potential for nephrotoxicity despite its excellent safety profile in clinical trials; particularly in patients with other risk factors for renal dysfunction, or deranged baseline renal function.

Baseline and toxicity issues with TDF

Preliminary data from Nigeria:

• Baseline chemistries suggest that abnormal renal function will be low -- TDF could be used in the majority of patients.

• Serum CR and creatinine clearance compromised in patients on TDF- regimens

Laboratory values at baseline (n= 25,747)

17%

4%3%

0%

2%

4%

6%

8%

10%

12%

14%

16%

18%

20%

No. Patientsw/Hb ≤ 8 g/dL

No. Patientsw/ALT ≥ 120

IU/L

No. Patientsw/Creatinine ≥

260 mmol/L

TEMPORAL CHANGES IN RENAL FUNCTION ASSOCIATED WITH THE USE OF TENOFOVIR DISOPROXIL FUMARATE (TDF) IN HIV-

INFECTED NIGERIAN ADULTSAgbaji O1, Agaba P1, Sule H1, Ojoh R1, Audu E1, Sani M1, Akintunde L1, Taiwo B2, Idoko J1, Murphy R²

Kanki P3

1AIDS Prevention Initiative in Nigeria Plus, Jos University Teaching Hospital, Jos, Nigeria; 2Division of Infectious Diseases, Northwestern School of Medicine, Chicago, IL, USA;

3Harvard School of Public Health Boston, MA, USA.

•Clinical/laboratory data for 84 on TDF-regimen and 102 on other NRTI regimens evaluated at 12 months

•Creatinine clearance (CLcr) estimated using the Cockcroft-Gault equation.

•Changes in serum creatinine and CLcr from baseline for each patient were compared between the TDF-treated patients and those in the non-TDF NRTI group.

•Multivariate analysis to control for other factors.

Results

• Serum creatinine increased by 23% (97.8 ± 25.9) and 3% (89.0 ± 26.2) in the TDF and non-TDF NRTI arms, at 48 weeks (p=0.02).

• Greater mean decrease in CLcr reduction from baseline in TDF (14.7 ± 44.4 ml/L) versus the non-TDF NRTI (10.4 ± 37.7 ml/L) arm at 48 weeks (p=0.001).

•In multivariate analyses, variables predictive of reduced CLcr were TDF use (p=0.005), age (p=0.002) and male gender (p=0.004).

• TDF-regimens associated with a small, but statistically significant renal compromise compared with non-TDF- regimens.

• CLcr however remained within normal range.

• Assessment of renal function prior to initiation of tenofovir therapy is recommended for all patients.

• Therefore, frequent monitoring of renal function may not be necessary in patients with baseline normal renal function.

Implications:

Future Directions

•Are second line therapies containing tenofovir effective

over the long-term for resistant (K65R) patients?

- How do failure rates compare to patients with other

mutation patterns?

- Does TDF in a 2nd line regimen impact efficacy?

• Testing partners where available and examining cases of

transmitted resistance.

P. KankiB. Chaplin R. MurphyJ-L SankaléS. MeloniA-Dieng SarrS. CalvesJ. HosseiniW. OdutoluP. OkonkwoE. EkongT. JolayemiJ. SamuelsS. OchigboP. AkandeB. AlukoB. TaiwoK. ScarsiK. Hurt

J. IdokoO. IdigbeI. Adewole D. OIaleyeC. OkanyS. AkanmuS. OgunsolaW. GashauM. GarbatiR. NkadoD. OwujekweH. MuktarS. GarkoJ. Abah

Harvard PEPFAR

R. MarlinkT. GaolatheJ. Mukhema N. NdwapiP.J. BurnsP. MwalaK. MukendiJ. PuvimanasingheM. MineC. BussmannM. EssexV. Novitsky

M. Wainburg