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.
[email protected] (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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