Surgical Neurolog

Neoplasm

Institutional experience with chloroquine as an adjuvant to the

therapy for glioblastoma multiforme

Eduardo Briceno, MD, Alejandra Calderon, MD, Julio Sotelo, MD4

Departments of Neuroimmunology and Neurooncology, National Institute of Neurology and Neurosurgery of Mexico, Mexico City 14269, Mexico

Received 9 May 2006; accepted 23 August 2006

www.surgicalneurology-online.com

Abstract Background: Results of the current therapy for GBM are dismal; the mean survival time of patients

0090-3019/$ – see fro

doi:10.1016/j.surneu.2

Abbreviations: CI,

OR, odds ratio.

4 Corresponding

surgery of Mexico, In

E-mail address: js

is approximately 1 year—and it has been so for several decades. In preliminary studies, we have

observed a potentiating therapeutic effect when chloroquine was added to the conventional treatment

of GBM.

Methods: Over the last 5 years, 41 patients with GBM received chloroquine as an optional adjuvant

administered concurrently with conventional surgery, chemotherapy, and radiotherapy. These

patients did not participate in our previous studies on chloroquine administration and were studied

retrospectively; 82 contemporary patients with GBM who did not receive chloroquine were included

in this analysis as control subjects. The end point observed was time of survival after surgery.

Results: Survival time in patients treated with chloroquine was 25 F 3.4 months, as compared with

that of 11.4 F 1.3 months in control subjects (P = .000; OR = 0.4; 95% CI = 0.26-0.6); the

difference remained significant after regression analysis for possible clinical confounders.

Conclusions: In agreement with our recent reports, chloroquine exerts a strong adjuvant effect when

added to the conventional treatment of GBM. In this large cohort of unselected patients with GBM

who were treated with chloroquine, the median survival time doubled as compared with that of

control subjects.

D 2007 Elsevier Inc. All rights reserved.

Keywords: Glioblastoma multiforme; Malignant glioma; Chloroquine; Cancer therapy; Radiosensitization

1. Introduction

Recent studies made in our institute showed a relevant

adjuvant effect on the therapy for GBM when chloroquine

was added to the conventional scheme of surgery, radio-

therapy, and chemotherapy. Two trials, an initial open-label

study followed by a double-blind placebo-controlled study,

showed similar results; the median survival time of the

patients treated with chloroquine doubled as compared with

that of control subjects [1,19]. Patients included in both

trials were selected following strict inclusion criteria;

however, several other patients with GBM who were not

nt matter D 2007 Elsevier Inc. All rights reserved.

006.08.080

confidence interval; GBM, glioblastoma multiforme;

author. National Institute of Neurology and Neuro-

surgents Sur 3877, Mexico City 14269, Mexico.

otelo@servidor.unam.mx (J. Sotelo).

included in those trials were offered the treatment with

chloroquine as an option to be taken in addition to the

conventional treatment. Over the last years, several patients

with GBM have received the additional treatment with

chloroquine. These patients, including all those with GBM

treated with chloroquine but who were not included in the

2 studies already reported [1,19], are the subject of the

present report; contemporary patients with GBM who did

not receive chloroquine but were treated with the conven-

tional standard therapy were included as control subjects.

2. Patients and methods

One hundred twenty-three patients with GBM were

included in the present retrospective analysis; of them,

41 received chloroquine and 82 contemporary patients who

did not receive chloroquine but were treated identically were

y 67 (2007) 388–391

Table 1

Demographic and clinical characteristics of the patients with GBM and

control subjects

Chloroquine-treated

patients (n = 41)

Control subjects

(n = 82)

Age (y; mean F SE) 45 F 2 47 F 2

Male/female ratio 29:12 50:32

Evolution of symptoms

before diagnosis (mo)

5 F 1 3 F 1

Bihemispheric tumoral

extension (%)

5 9

Complete surgical

resection (%)

25 9

Partial surgical resection (%) 75 91

Karnofsky scale score

1 mo after surgery

86 F 19 84 F 12

Time free of tumoral

growth after surgery (mo)

14.9 F 2.2 8.3 F 0.8

Mean survival (mo) 25 F 3.4 11.4 F 1.3

E. Briceno et al. / Surgical Neurology 67 (2007) 388–391 389

included as control subjects. The selection criteria for in-

clusion in this analysis were survival of more than 6 weeks

after extensive surgical ablation and histopathologic diag-

nosis of GBM on the tissue obtained during surgery as

confirmed by 2 or more neuropathologists. All patients

included in the chloroquine branch signed a letter of

informed consent on their acceptance to take chloroquine

in addition to the conventional therapy with surgery,

chemotherapy, and radiotherapy. The observation period in

all subjects included was at least 1 year after surgery. All

patients were treated by extensive surgery. Radiotherapy

was divided in 30 doses of 60 Gy, with the first dose

Fig. 1. Kaplan-Meier estimates of survival in the 123 patients with GBM who rec

alone (n = 82) and in those who received it with chloroquine as an adjuvant (n

administered 60 days after surgery. Chemotherapy with

carmustine consisted of 6 courses of 200 mg/m2 SC of body

weight, each administered every 8 weeks; the initial course

was given 3 months after surgery. Patients who were treated

with chloroquine took the drug for 12 to 18 months at a

daily dose of 150 mg starting on day 15 after their surgery.

The end point evaluated was survival after surgery.

3. Results

The demographic and clinical characteristics of the

patients with GBM who were treated with chloroquine

and those of the control subjects are shown in Table 1.

Bihemispheric extension of the tumor was more frequent in

the control subjects than in the patients (9% vs 5%). Report

by the neurosurgeon of complete ablation of the neoplasm at

the time of surgery was more frequent in patients who

received chloroquine therapy than in the control subjects

(25% vs 9%). Evolution of symptoms before diagnosis was

longer in the chloroquine-treated patients than in the control

subjects (mean F SE, 5 F 1 vs 3 F 1 months). Other

parameters were similar in both groups. The mean survival

time was 25 F 3.4 months (median = 18 months) for the

chloroquine-treated patients (95% CI = 18.4-31.7) and

was 11.4 F 1.3 months (median = 8 months) for the control

subjects (95% CI = 8.9-13.9). The difference in survival

time was statistically significant by the log rank test

(P = .000; Fig. 1; OR = 0.4; 95% CI = 0.26-0.6). This

difference remained significant after the Cox regression

analysis to control for possible clinical confounders:

P = .000 for bihemispheric extension, P = .03 for degree

eived the conventional treatment (surgery, chemotherapy, and radiotherapy)

= 41).

E. Briceno et al. / Surgical Neurology 67 (2007) 388–391390

of tumoral excitation by surgery, and P = .000 for time of

evolution of symptoms before diagnosis. Time free of

disease after surgery was 14.9 F 2.2 months (95%

CI = 10.5-19.3) for the chloroquine-treated patients and

was 8.3 F 0.8 months (95% CI = 6.9-9.9) for the control

subjects. Four patients in the chloroquine group and

7 control subjects had diabetes and/or arterial hypertension

(P = not significant).

4. Discussion

Chloroquine administered as an adjuvant in patients with

GBM was associated with a significant extension of

survival as compared with contemporary control subjects.

This large cohort of patients with GBM, although studied

retrospectively, adds to the incipient experience on the use

of chloroquine in the treatment of GBM. Sixty-five patients

have been treated with chloroquine in addition to the

conventional therapeutic approach for GBM in our insti-

tute; of them, 9 were included in a prospective open-label

and controlled initial study [1], 15 were included in a

double-blind placebo-controlled study [19], and 42 were

included in the present report. In all, the mean survival time

of the patients who received chloroquine (n = 65) was

27 months, as compared with 11 months in the control

subjects (n = 106).

Chloroquine interferes with several metabolic pathways

in eukaryotic cells; 2 main properties of chloroquine are

responsible for most intracellular actions: molecular inter-

calation of chloroquine into DNA and inhibition of

lysosomic enzymes, particularly phospholipase A2. Through

the strong intercalation of chloroquine into the molecules of

the DNA tumoral cells, dramatic configurational changes in

nucleic acids [19] that seem to render neoplastic cells more

susceptible to the cytotoxic effects of radiotherapy as well as

chemotherapy and less prone to mutagenesis [4,5,17] occur.

Through the inhibition of phospholipase A2, the cell release

of cytokines, particularly tumor necrosis factor, is dimin-

ished and various metabolic pathways are altered [12,19].

These 2 features could enhance the therapeutic effect of

radiotherapy and chemotherapy, as has been demonstrated

in cultured neoplastic cells [2,5,17]; in vitro, chloroquine

potentiates the cell-damaging effect of ionizing radiation on

neoplastic cells [10] and reverts chemoresistance to some

antineoplastic drugs [8]. Although radiotherapy seems to be

more effective than chemotherapy for malignant brain

tumors [22], the adjuvant effect of chloroquine could be

more intense as a radiosensitizer [2,14,21].

Our results suggest that chloroquine, as an adjuvant to

surgery, radiotherapy, and chemotherapy, could improve the

still-somber prognosis of GBM [3,6,7,11,20]. Larger

studies are necessary to define optimal doses and thera-

peutic schemes. Because chloroquine has a peculiar affinity

for leukocytes and melanocytes [2,9,13-16,18] as well as a

fair pharmacologic and toxicological profile, a trial on

neoplasias derived from these cells seems warranted.

Currently, we are studying the role of chloroquine as an

adjuvant in the treatment of patients with GBM treated by

conformal radiosurgery (Novalis, BrainLAB) and the

effects of increasing the dose of chloroquine (from 150 to

300 mg/d) on the specific days of radiotherapy and

chemotherapy administration.

Acknowledgments

This work was entirely supported by the National Institute

of Neurology and Neurosurgery of Mexico and the National

Council of Science and Technology of Mexico (Mexico City,

Mexico) (CONACYT grant no. SALUD-2003-C01-15). No

pharmaceutical company participated in any part of the study.

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