Primaquine double dose for seven days is inferior to single dose treatment for fourteen days in preventing P. vivax relapses in Suriname

Stephen G.S. Vreden, Malti R. Adhin, Jeetendra Kumar Jitan, M. Sigrid Mac Donald Ottevanger, Gustavo Bretas

P. Vivax treatment

Study question:

Is PQ double dose for 7 days as effective as 14 day standard dose?

Study Design

En-blocque randomization in 2 groups Patients recruited from:

Kwamala Samutu, Amerindian Village in the south-west of Suriname

Paramaribo Malaria Center Group 1: 0.25mg/kg/day (15mg/day for 14

days) Group 2: 0.5mg/kg/day (30mg/day) for 7

days Follow up for at least 6 months

Study Design Inclusion Criteria

Confirmed P.vivax (History of) fever

Exclusion Criteria

History of anti-malarial use in previous 2 weeks

Severe malaria Other severe disease Intolerance to anti-

malarial drugs Positive pregnancy test Known positive G6PD-

deficiency status

Study Design (2)

At day 0, 14, and thereafter monthly follow up: Clinical evaluation Bloodsmear and dried bloodspot Binax NOW® (only at day 0, and at

recurring parasitaemia)

Baseline characteristics of patientsGroup 1

(14 days)Group 2(7 days)

P-value

Number patients 28 34

Sexe M/F 17/11 24/10 0.414

Age (years) Mean (SD) Median Range

19.8 (11.2)21

2 to 43

31 (12.8)32

1 to 51

0.001

Weight (Kg) Mean (SD) Range Median

50.8 (21.3)11 to 83

58

64.2 (16.1)8.5 to 100

64

0.011

P < 0.05 indicates significant differences between variables in Students’s t test and Pearson’s chi-square

Enrolment, exclusion and relapse frequency Group 1

(14 days)Group 2(7 days)

TotalP-

value

No. patients enrolled

33 51 84

No. patients evaluable#

28 34 62

Average follow-up 10.1

months7.8 months 0.015

Average time of recurring parasitaemia

3.8 months 4.1 months 0.832

Recurring parasitaemia

4(14.3%) 13(38.2%) 17 (27.4%) 0.035

# Patients excluded due to loss to follow up, protocol violation or other (in both groups 1 recurrent parasitaemia at month 1)

Relapse rate

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 2 4 6 8 10 12 14

Time (months)

14 DAYS 7 DAYS

Pro

po

rtio

n r

elap

se f

ree

Kaplan Meier survival analysis of P. vivax relapses in patients treated with primaquine single dose for 14 days or double dose for 7 days

Results

Higher incidence of recurrent parasitaemia in group 2 (38.2%; p <0.05)

14.3% relapse rate in group 1 suggests possible tolerance to PQ

2 recurrent parasitaemias in month 1 possible CQ tolerance

No difference in time of relapse

Conclusion

PQ 0.5mg/kg/day for 7 days is inferior to standard regimen (0.25mg/kg/day for 14 days) of PQ therapy in Suriname

Discussion

Small study population (n = 62) in this trial

Possibly a 1mg/kg/day PQ (60mg/day) regimen for 7 days should be investigated.

Because several patients traveled to endemic regions during the study, relapse could not be distinguished from reinfection

Recent studies on primaquine short regimen

Krudsoord, S., Tangpukdee, N., Wilairatana, P., Phophak, N., Baird, J. K., Brittenham, G. M., and Looareesuwan, S., 2008. High-dose Primaquine Regimens against Relapse of Plasmodium vivax Malaria. Am J Trop Med Hyg 78 (5): 736-740.

Nguyen Van Hoang Dao, Bui Tri Cuong, and Nguyen Dang Ngoa, 1-24-2007. Vivax malaria preliminary observations following a shorter course of treatment with artesunate plus primaquine. Trans R Soc Trop Med Hyg 101: 534-539.

Both studies showed high efficacy of primaquine for seven days in doses of 30 mg and 22.5 mg respectively,…………….BUT

Recent studies on primaquine short regimen, c’td.

Follow up in both studies was a mere 28 days, which may not be adequate to detect relapses.

Our relapses occurred at an average of 4 months.

Recrudescence in P. falciparum

Genes with areas of well known genetic variety are: MSP1 MSP2 GLURP

RECURRENT PARASITAEMIA IN P. vivax

Pv msp 1-F2 coding for merozoite surface protein 1

Pv msp3α coding for merozoite surface protein 3

Recurrent parasitaemia in P.vivax

Identical patterns: reflecting the same genotype for the

tested gene region, suggesting relapse.

Difference in size and/or restriction pattern: may suggest a new infection, but a relapse

with a different genotype is also possible

PROCEDURE Samples:

dag 0 & recurring: spotting of two drops of blood on filter paper (Whatman 3MM). .

Extraction of DNA:Plasmodium DNA extracted from both filters (Saponin-Chelex).

DNA Amplificatie:Both DNA samples : For both genes a master and an additional nested PCR

Repeatnumber Analysis: separation of DNA fragments by electrophoresis (horizontal/vertical agarose).

SNP Analyse: Restriction analysis (AluI, HhaI, MnlI) and separation on polyacrylamide slabgels.

Repeatnumber

10 15 14a

AB A C

Pv MSP1F2 SIZE _

+

4 5 6 7 8 9

RESTRICTIE ANALYSE AluI Pv MSP1F2

PPQ code Datum afname Relapse DNA master F2 nested F2 Alu Mnl Typemaster MSP3

nested MSP3

Alu Hha I Type Opmerkingen CONCLUSIES

1 2 16-Oct-2006 D0 OK OK A b 2 Ab2 OK A b 2 Ab2 M2 = D0

2 2a 18-Dec-06 M 2 OK OK A b 2 Ab2 OK A b 2 Ab2

3 15 10-Nov-2006 D0 OK OK A c 2 Ac2 OK B c 3 Bc3 M2 = D0

4 15a 30-Jan-07 M 2 OK OK A c 2 Ac2 OK B c 3 Bc3

5 28 18-Jan-2007 D0 OK OK C r 17 Cr17 OK C j 7 Cj7 M4 = D0 Possible RECRUDESCENCE:

6 28a 22-May-07 M 4 OK OK C r 17 Cr17 OK C j 7 Cj7 Beide samples vertonen gelijke infectie:

7 51 24-Sep-07 D0 OK OK A b 2 Ab2 OK C i 9 Ci9 M2 = D0 2, 15, 28, 51, 58, 44, 63

8 51a 5-Dec-2007 M 2 OK OK A b 2 Ab2 OK C i 9 Ci9

9 58 30-Oct-2007 D0 OK OK A c 2 Ac2 OK A a 1 Aa1 M7 = D0

10 58a 20-May-2008 M 7 OK OK A c 2 Ac2 OK A a 1 Aa1

11 44 3-Jul-2007 D0 OK OK C t 16 Ct16 no - - - M4 = D0 (1 gene)

12 44a 12-Nov-2007 M 4 OK OK C t 16 Ct16 OK C i 9 Ci9

13 63 21-Dec-2007 D0 OK OK C r 16 Cr16 no - - - - M3 = D0 (1 gene)

14 63a 25-Mar-08 M 3 OK OK C r 16 Cr16 no - - - -

15 8 1-Nov-2006 D0 OK OK A bc 2 Ac2/Ab2 OK B c 3 Bc3 mixed infection In een of beide samples een mixed infection;

16 8a 11-Jan-07 M 2 OK OK A c 2 Ac2 OK BA cb 32 Bc3/Ab2 same mix zelfde genotype wel in beide samples

17 14 10-Nov-2006 D0 OK OK C q 16 Cq16 OK BC ci 39 Bc3/Ci9 mixed infection 8, 14, 52

18 14a 15-Feb-07 M 3 OK OK C q 16 Cq16 OK C i 9 Ci9 M3 = 1 van de 2 van D0

19 52 27-Sep-2007 D0 OK OK A bc 2 Ab2/Ac2 OK B c 3 Bc3 mixed infection MSP-1F2

20 52a 3-Nov-07 M 1 OK OK A b 2 Ab2 OK B c 3 Bc3 M1 = 1 van de 2 van D0

21 36 12-Apr-2007 D0 OK OK C w 20 Cw20 OK C g 7 Cg7 D0 ≠ M2

22 36a 27-Jun-07 M 2 OK OK C v 19 Cv19 OK C g 7 Cg7 [one gene MSP1-F2]

23 17 20-Nov-2006 D0 OK OK C r 16 Cr16 OK C i 9 Ci9 D0 ≠ M2

24 17a 29-Jan-07 M 2 OK OK C s 15 Cs15 OK C k 10 Ck10 [both genes] Possible RE INFECTION

25 21 19-Dec-2006 D0 OK OK C t 17 Ct17 OK B d 4 Bd4 D0 ≠ M6 Verschillend genotype

26 21a 7-Jun-07 M 6 OK OK C s 15 Cs15 OK B e 5 Be5 [both genes] 17, 21, 22, 35, 36 , 60

27 35 11-Apr-2007 D0 OK OK C s 17 Cs17 OK C h 8 Ch8 D0 ≠ M2

28 35a 4-Jul-07 M 2 OK OK C x 21 Cx21 OK A b 2 Ab2 [both genes]

29 22 3-Jan-2007 D0 OK OK A b 2 Ab2 OK B c 3 Bc3 D0 ≠ M11

30 22a 18-Dec-2007 M 11 OK OK A b 17 Ab17 OK B d 4 Bd4 [both genes]

31 60 21-Nov-07 D0 OK OK AC bt 2 Ab2/Ct OK A b 2 Ab2 D0 ≠ M1

32 60a 4-Jan-2008 M 1 OK OK C w 17 Cw17 OK C l 11 Cl11 [both genes]/evt mix

33 16 17-Nov-2006 D0 OK no - - - - no - - - -

34 16a 6-Jun-07 M 7 OK OK AC t+ 18 At18/C OK A b 2 Ab2 GEEN UITSPRAAK

34

MWI RESULTS P. VIVAX RECRUDESCENCE PPQ TRIAL [aug 2008]

CharacteristicGroup 1

(14 days)

Group 2

(7days)

Total

No. relapses 4 13 17

same/mixed genotype 3 (75%) 6 (46.2%) 9 (52.9%)

different genotype 0 (0%) 5 (38.5%) 5 (29.4%)

data missing/insufficient 1 (25%) 2 (15.4%) 3 (17.6%)

p = 0.26 when comparing same/mixed genotype to different genotype of both groups using Fisher’s exact test

Genotyping results

Conclusions/Discussion

PQ 0.5mg/kg/day for 7 days is inferior to standard regimen (0.25mg/kg/day for 14 days) of PQ therapy in Suriname

In this study genotyping did not supply extra evidence for the inferiority of the 7 day regimen.

The study would be more convincing in an area where reinfection could be excluded (infections from same geographical area!).

Questions?