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Vol. 2, 483-491, March 1996 Clinical Cancer Research 483
3 The abbreviation used is: HMG-CoA, 3-hydroxy-3-methylglutaryl co-
enzyme A.
Phase I Study of Lovastatin, an Inhibitor of the Mevalonate
Pathway, in Patients with Cancer
Alain Thibault,” 2 Dvorit Samid,2
Anne C. Tompkins, William D. Figg,
Michael R. Cooper,2 Raymond J. Hohl,
Jane Trepel, Bertrand Liang, Nicholas Patronas,
David J. Venzon, Eddie Reed,
and Charles E Myers2Clinical Pharmacology Branch IA. T.. D. S., A. C. T.. M. R. C..
W. D. F., J. T., B. L.. E. R., C. E. M.] and Biometrics Section[D. J. V.�. National Cancer Institute and Neuro-RadiologyDepartment. Warren Magnussen Clinical Center IN. P.].NIH, Bethesda, Maryland 20892-1576. and Divisions of
Hematology-Oncology and Clinical Pharmacology, University of
Iowa College of Medicine, Iowa City, Iowa 52242 [R. J. H.]
ABSTRACTLovastatin, an inhibitor of the enzyme 3-hydroxy-3-
methylglutaryl-coenzyme A reductase (the major regulatory
enzyme of the mevalonate pathway of cholesterol synthesis),
displays antitumor activity in experimental models. We
therefore conducted a Phase I trial to characterize the tol-
erability of lovastatin administered at progressively higher
doses to cancer patients. From January 1992 to July 1994, 88
patients with solid tumors (median age, 57 ± 14 years) were
treated p.o. with 7-day courses of lovastatin given monthly
at doses ranging from 2 to 45 mg/kg/day. The inhibitory
effects of lovastatin were monitored through serum concen-
trations of cholesterol and ubiquinone, two end products of
the mevalonate pathway. Concentrations of lovastatin and
its active metabolites were also determined, by bioassay, in
the serum of selected patients. Cyclical treatment with by-
astatin markedly inhibited the mevabonate pathway, evi-
denced by reductions in both cholesterol and ubiquinone
concentrations, by up to 43 and 49% of pretreatment values,
respectively. The effect was transient, however, and its mag-
nitude appeared to be dose independent. Drug concentra-
tions reached up to 3.9 �LM and were in the range associated
with antiproliferative activity in vitro. Myopathy was the
dose-limiting toxicity. Other toxicities included nausea, di-
arrhea, and fatigue. Treatment with ubiquinone was associ-
ated with reversal of bovastatin-induced myopathy, and itsprophylactic administration prevented the development of
this toxicity in a cohort of 56 patients. One minor response
was documented in a patient with recurrent high-grade
glioma. Lovastatin given p.o. at a dose of 25 mg/kg daily for
Received S/I 8/95; revised 9/25/95; accepted I 1/21/95.
I To whom requests for reprints should be addressed. at University of
Virginia Health Sciences Center, Division of Hematology-Oncology,
Jordan Hall. P. 0. Box 513, Charlottesville, VA 22908.2 Present address: Cancer Center, University of Virginia Health Sci-ences Center. Charlottesville. VA 22908.
7 consecutive days is well tolerated. The occurrence of my-
opathy, the dose-limiting toxicity, can be prevented by
ubiquinone supplementation. To improve on the transient
inhibitory activity of this dosing regimen on the mevalonate
pathway, alternative schedules based on uninterrupted ad-
ministration of bovastatin should also be studied.
INTRODUCTIONThe role of lipid metabolism in cancer was initially inves-
tigated in the 1950s by Fumagalli et al. (1) who observed that
neoplastic cells synthesize large quantities of cholesterol from
precursors such as acetate and mevalonate. They concluded that
this ‘ ‘high rate of cholesterol synthesis may provide a useful
basis for testing whether tumor growth can be inhibited by
impairing its sterol synthesis’ ‘ ( 1 ). Twenty years later, Maltese
(2) demonstrated that the activity of HMG-CoA3 reductase, the
major regulatory enzyme of de novo cholesterol synthesis, was
increased in neoplastic tissue. This enzyme catalyzes the for-
mation of mevalonate, which is also the precursor of isoprenoid
moieties that are incorporated into or linked to several mole-
cules essential for cell growth and replication. The latter include
ubiquinone (an isoprenylated benzoquinone involved in the mi-
tochondrial electron transfer chain), dolichol, haem A, isopentyl
transfer RNA, and several proteins involved in signal transduc-
tion (Fig. 1 ; for review, see Ref. 3). The scope of these obser-
vations was later broadened when it was shown that inhibition
of HMG-CoA reductase by lovastatin selectively inhibited tu-
mor growth in vitro and in animal models of hepatocellular.
pancreatic, and central nervous system tumors (4-7). These
studies demonstrated that growth arrest was associated with
marked inhibition of isoprenoid synthesis and could be achieved
with minimal toxicity to the tumor-bearing animals, including
the absence of myelosuppression.
These findings suggested that inhibition of the mevalonate
pathway by lovastatin, a fungal antibiotic used in the treatment
of hypercholesterolemia (8), may offer a novel approach to the
treatment of cancer. We therefore designed a Phase I study to
determine the maximum tolerated dose of bovastatin when ad-
ministered at progressively higher doses to patients with cancer.
The study rationale was to attempt to achieve in patients drug
concentrations associated with the experimental antiprolifera-
tive activity. It was supported by animal toxicology studies
which indicated that much higher doses of lovastatin than are
currently recommended for the treatment of hypercholesterol-
emia (up to 80 mg/day, or 1 mg/kg/day) could be administered
for short periods of time and be well tolerated (9). This infor-
mation led us to administer lovastatin in cycles, to allow for
recovery from acute drug-induced toxicity, while preserving the
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Acetyl CoA
IAcetoacetyl CoA
3 Hydroxy-3 Methyl Glutaryl CoA
HMG-CoA reductase 1- LOVASTATIN
IFarnesyl-PP
ISqualene
I
I
484 Phase I Study of Lovastatin
II
Mevalonate
IMevabonate-PP
IIsopentenyl-PP
I. isopentenyl t-RNA
Geranyl-PP
Desmosterol
Geranylgeranyl-PP
. haem A
. farnesylated proteins
. side chain of ubiquinone
. geranylgeranylated proteins
. dolichol
Cholesterol
Fig. 1 Outline of the mevalonate pathway. The rate-limiting step is catalyzed by HMG-CoA reductase and inhibited by lovastatin. End productsinclude cholesterol, a cell membrane component; ubiquinone, an electron carrier of the respiratory chain; and isoprenoid moieties, required for the
posttranslational processing of proteins involved in intracellular signaling.
potential for drug activity. The secondary objectives of the trial
were to quantitate the pharmacological effects of high-dose
lovastatin in humans and to evaluate the clinical efficacy of
ubiquinone supplementation in the prevention of lovastatin-
induced rhabdomyolysis, since there is evidence that ubiquinone
depletion may play a role in the pathophysiology of this side
effect(lO, 11).
PATIENTS AND METHODS
Patient Population
Adults with a histological diagnosis of cancer confirmed by
the Pathology Department of the NIH Clinical Center were
eligible for this Phase I trial. Other inclusion criteria included:
Eastern Cooperative Oncology Group performance status of 2 or
better, ability to take p.o. medication, hemoglobin concentration
>9.0 mg/dl, platelet count > 100,000/mm3, absolute granulo-
cyte count > 1 ,500/mm3, normal prothrombin time and activated
partial thromboplastin time, serum alanine transferase concen-
trations less than twice the upper limit of normal, total bilirubin
within the normal range, and and serum creatinine concentration
of 2.0 mg/dl or less. Patients were ineligible if they had exten-
sive (>50%) liver replacement by tumor or if they had not
recovered from the toxicities of previous radiation or chemo-
therapy, or if they had received such therapy within a 4-week
period. Patients had to have failed standard therapy for their
disease or harbor a disease for which no acceptable therapy is
known. For example, patients with prostate cancer were re-
quired to have disease progression despite total androgen block-
ade therapy (hormone-independent prostate cancer) and subse-
quent cessation of flutarnide therapy. Patients with primary
central nervous system tumors had to have undergone maxi-
mally tolerated surgery followed by radiation therapy. Previous
treatment with adjuvant or palliative chemotherapy was not
required, nor did it constitute an exclusion criterion. No other
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Clinical Cancer Research 485
form of antitumor therapy was allowed during the study period.
Patients taking anticonvulsants and corticosteroids were main-
tamed on the same therapy. The dosage of anticonvulsants was
modified according to symptoms and plasma concentrations.
The dose of corticosteroids was kept identical to preprotocol
conditions or decreased as a function of clinical improvement.
All patients or their proxy signed an informed consent document
in compliance with the rules of the National Cancer Institute’s
Institutional Review Board.
Initial Clinical Evaluation
Each patient underwent a complete history and physical
examination along with an assessment of the performance sta-
tus. Pretreatment laboratory investigations included a hemogram
with leukocyte differential and platelet count, standard serum
biochemistry and coagulation studies, urinalysis, tumor markers
relevant to the tumor type, total and high-density lipoprotein
cholesterol, triglycerides, ubiquinone, chest X-ray, and electro-
cardiogram. Radiological studies appropriate to the disease type
and location were obtained within 4 weeks of entering protocol.
Treatment
Preclinical toxicology and pharmacology, available in the
mouse, rat, rabbit, and dog (9), demonstrated linear pharmaco-
kinetics in every species and indicated that doses up to 200
mg/kg/day would yield drug concentrations in the range of 2-20
p.M. Although the maximum tolerated dose and organ toxicity
differed among species, progressive anorexia and death devel-
oped after 9-14 days of uninterrupted drug administration to
rabbits (the most sensitive species) and was associated with
sustained drug concentrations of 20-25 JiM. In contrast, circu-
lating concentrations of 2-4 �i.M were well tolerated for months
in all animal models. For the purposes of this Phase I study,
intermittent drug administration, starting at a dose of 2 mg/kg/
day, was therefore predicted to be well tolerated.
Lovastatin (Mevacor; Merck, West Point, PA) was admin-
istered p.o. following a four times a day schedule, for 7 con-
secutive days, in monthly cycles. The trial was initially con-
ducted over seven dose levels, ranging from 2 to 45 mg/kg/day
(2, 4, 6, 8, 10, 25, and 45 mg). The initial dose level was twice
the dose currently recommended for prolonged administration in
humans and was chosen based on the preclinical information
and unpublished safety data made available by the manufac-
turer. The large dose increments of the last two dose levels were
arbitrarily chosen based on the paucity of toxicity episodes at
the first five dose levels. At least three new patients were treated
at each dose level. The first cycle of therapy was administered
in the outpatient clinic of the Clinical Pharmacology Branch,
National Cancer Institute. Patients then returned home and were
subsequently seen monthly. Compliance with the p.o. regimen
was monitored through pill count and weekly telephone inter-
views. In the absence of disease progression or severe (grade 3
or greater) drug-induced toxicity, treatment cycles were re-
peated every 4 weeks. The dose of lovastatin could be increased
for a given patient from one cycle to the next, according to the
dose escalation schedule, provided the preceding cycle had been
well tolerated in that patient and shown to be safe in at least
three new patients. The occurrence ofdose-limiting myopathy at
45 mg/kg/day prompted us to return to the 25-mg/kg/day dose
level and subsequently characterize the 30- and 35-mg/kg/day
dose levels. In a second part of the trial, lovastatin was given at
four dose levels (30, 35, 40, and 45 mg/kg/day) while coadmin-
istering ubiquinone (Vitaline Corporation, Ashland, OR) p.o.
(240 mg daily, in four divided doses, given at the same time as
lovastatin) to prevent lovastatin-induced myotoxicity. Supple-
mentation started 7 days before the initiation of bovastatin and
continued for as long as the patient remained on protocol. Other
hypolipidemic drugs (niacin, fibric acid derivatives, and other
HMG-CoA reductase inhibitors) were not concurrently admin-
istered.
Biochemical Measurements
Frequency of Laboratory Evaluation. Initially, the co-
hort of patients treated with lovastatin alone had blood drawn on
days 0, 1 . 3, 5, 8, and 28 of each cycle of therapy. Additional
blood was obtained from most patients on days 15 and 21 . The
cohort treated with lovastatin in combination with ubiquinone
was monitored on the day ubiquinone supplementation began
(day -7), on the day treatment with lovastatin began (day 1),
and subsequently on days 3, 5, 8, 15, 21, and 28. As a rule, blood
samples were obtained prior to the administration of the morn-
ing dose of lovastatin.
Measurement of Pharmacological Parameters. The
following biochemical effects of lovastatin therapy were mon-
itored: (a) inhibition of cholesterol synthesis, by measuring
serum total and high-density lipoprotein cholesterol; (b) inhibi-
tion of the synthesis of isoprenylated end products of the me-
valonate pathway, by measuring serum ubiquinone concentra-
tions; and (c) circulating concentrations of lovastatin and its
metabolites.
Measurements of Ubiquinone Concentrations in Blood.
Serum ubiquinone concentrations were assayed by normal phase
high-performance liquid chromatography according to a method
previously described by Abe et a!. ( 12). The assay was linear
between 0.08 and 10.67 �.g/ml (r� = 0.995 + 0.009, mean ±
SD; n = 12 standard curves), with a coefficient of variation
< 17%. The lower limit of quantification was 0.08 p.g/ml.
Measurements of Lovastatin Concentrations in Blood.
Serum concentrations of lovastatin and its metabolites, which
are also responsible for inhibition of HMG-CoA reductase in
vivo, were measured indirectly and retrospectively from serum
samples collected for other monitoring purposes. The method
used was a standardized bioassay which quantitates the total
inhibitory activity of a patient’s serum (referred to as drug
concentrations, in this report) against a microsomal suspension
of HMG-CoA reductase (13). The lower limit of quantification
was 0.03 �M.
Assessment of Toxicity
The laboratory evaluation of toxicity was implemented by
weekly hemograms with leukocyte differential and platelet
count, electrolytes, blood urea nitrogen, creatinine, albumin, and
total protein. Since myopathy and elevations of hepatic
transaminases have been recognized in 0.2-2% of patients tak-
ing lovastatin for the treatment of hypercholesterolemia (14),
patients were specifically monitored for the possible occurrence
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486 Phase I Study of Lovastatin
of these events with measurements of hepatic aminotransferases,
bilirubin (total and direct), alkaline phosphatase, lactate dehy-
drogenase, creatine phosphokinase with isoenzyme fraction, and
aldobase. Urinalysis and urine dipstick for myoglobin (positive
hemoglobin reaction) were also performed. Toxicity was graded
according to the National Cancer Institute Common Toxicity
Criteria. Since no standard criterion exists for the grading of
musculoskeletal toxicity, the following scale was used: myalgias
for <2 days without elevations of serum creatine phosphokinase
represented grade 1 toxicity; myalgias of >2 days duration or
elevations of serum creatine phosphokinase to < 10 times the
upper limit of normal defined grade 2 toxicity; and muscle pain,
falls, or weakness sufficient to prevent the performance of daily
activities and/or elevations of serum creatine phosphokinase
concentrations to 10 times the upper limit of normal or above
were defined as grade 3 toxicity. If, at any dose level, one
patient developed grade 3 toxicity or above, additional patients
were entered at that dose level until at least six patients had been
treated. Dose escalation was stopped once grade 3 or higher
toxicity developed in two of the six patients. The next lower
dose of lovastatin was defined as the maximum tolerated dose
and at least three additional patients were treated at this lower
dose to confirm its safety.
Assessment of Response
The response status of malignancies was determined
monthly, prior to each cycle of therapy, using conventional
anatomical criteria (15). For patients with prostate cancer, the
criteria from the National Prostate Cancer Project ( 16) and
published criteria for decline in prostate-specific antigen were
used ( 1 7, 1 8). A technetium bone scan was obtained every 3
months if initially positive or in the presence of new bone
symptoms. The assessment of patients with gliomas is compli-
cated by the variability in tumor-associated edema and its re-
sponse to steroid therapy, and technical factors which preclude
using the intensity of gadolinium enhancement on magnetic
resonance imaging to determine tumor response. In these pa-
tients, special attention was therefore paid to changes in perfor-
mance status and steroid requirements, which were assessed at
each visit. Complete response was defined as complete disap-
pearance of lesions on magnetic resonance imaging (assessment
performed in two different planes) and weaning from steroids.
Partial and minor responses were defined by conventional ana-
tomical criteria, absence of deterioration in performance status,
and stable or decreased corticosteroids requirements. Progres-
sive disease was defined by either anatomical criteria, deterio-
ration in performance status, or the need to increase steroid
doses to maintain function. Disease stabilization was defined as
the absence of a significant (more than 25%) increase or de-
crease in tumor size while the patient maintained or improved
performance status compared to pretreatment level. Disease
stabilization in these patients had to be maintained for at least 3
months to be considered significant.
Statistical Methods
Trend analysis of cholesterol change and lovastatin dose
was performed using the Spearman rank correlation method
( I 9). Changes from pretherapy ubiquinone concentrations to
Table 1 Demographic and treatment characteristic s of the study
population
Characteristic n
Median age, 57 ± 14Performance status (Eastern Cooperative
Oncology Group scale)Grade 0 21
Grade I 53Grade 2 14
Previous therapySurgery 44Radiation 54Chemotherapy 67Hormonotherapy 46
Tumor typeProstate (hormone independent) 38
Primary central nervous system 24
Astrocytoma 12
Glioblastoma 8Anaplastic oligodendroglioma 2
Others 2Breast 7Colorectal 4Ovary 4Sarcoma 3
Lung 2
Others 6
nadirs while receiving lovastatin were assessed with the Wil-
coxon signed rank test (19). Cholesterol declines in the two
patient groups (one supplemented with ubiquinone, the other
not) were compared using the Wilcoxon rank sum test (19).
Least-squares linear regression was used to test for trends in
circulating drug concentrations, which were logarithmically
transformed before analysis. The distributions of toxicities
across grade and dose level were compared using the Cochran-
Armitage test (20). SAS (Version 6.04; SAS Institute, Cary,
NC) and StatXact (Version 2.04a; Cytel Software Corp., Cam-
bridge, MA) statistical packages were used for all analyses.
RESULTSPatient Characteristics. Eighty-eight Caucasian pa-
tients (63 men and 25 women) entered the trial from January
1992 to July 1994. The demographic and treatment character-
istics of the study population are shown in Table 1 . All patients
(other than prostate and brain cancer patients) had failed at least
one course of chemotherapy with doxorubicin and/or cyclophos-
phamide (breast cancer and sarcoma), cisplatin or Taxol (ovar-
ian cancer), and 5-fluorouracil (colon cancer). Patients with
primary brain tumors and hormone-independent prostate cancer
made up the two largest cohorts of the trial (39 and 24 patients,
respectively).
Pharmacological Parameters. A total of 200 cycles of
therapy was administered over 13 dose levels (Table 2). Forty-
five patients received only one cycle of lovastatin, and 43 were
given more than one (occasionally administered at different
doses since dose escalation was allowed in 16 patients). To
simplify the analysis, therefore, only data from the first cycle of
therapy for each treated patient has been used to characterize the
pharmacological effects of lovastatin. All cycles of therapy were
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80
70
. 60
.� 50
�- 40
30
20
10
“ Numbers in parentheses. number of patients escalating from
lower dose level.
2 4 6 8 10 25 30 35 45
Lovastatin dose(mg/kg/day)
Fig. 2 Pharmacological effects of lovastatin. Percentage of decline in
serum concentrations of cholesterol (�) and ubiquinone (�) as a func-
tion of bovastatin dose (mean). Ubiquinone concentrations were deter-
mined only in patients treated at the 25-mg/kg/day dose level or higher.
Bars, SE.
Clinical Cancer Research 487
Table 2 Distribution of patien ts and number of cy des per dose level
Lovastatin dose Patients” Cycles
(mg/kg/day) (n) (n)
2 4 8
4 5(1) 7
6 4(1) 7
8 3 3
10 4 7
25 13(2) 23
30 8 18
35 12(1) 22
45 6 6
30 with ubiquinone 3 6
35 with ubiquinone 1 1 (2) 2040 with ubiquinone 20 (8) 30
45 with ubiquinone 22 (10) 43
included, however, in the analysis of toxicity and antitumor
activity.
Over the range of lovastatin doses administered without
ubiquinone supplementation, cholesterol concentrations de-
dined by 23-43% (nadir, mean ± SE: 143 ± 38 mg/dl; base-
line: 220 ± 56 mg/dl; normal range: 180-230 mg/dl; Fig. 2).
There was no direct correlation between the dose of lovastatin
and the magnitude of the declines. Cholesterol concentrations
rapidly declined during lovastatin administration. The time to
reach the nadir ranged from 7 to 1 1 days after starting therapy
and also appeared to be dose independent. In all patients, the
declines were not sustained once treatment was discontinued
and were completely resolved prior to the initiation of the next
cycle of therapy (Fig. 3).
Serum concentrations of ubiquinone were measured in 24
patients treated at the 25-mg/kg dose level and above. The
declines in this isoprenylated end product of the mevalonate
pathway ranged from 36 to 49% and were independent of the
dose administered (P = 0.72, Spearman’s rank correlation test).
The mean baseline and nadir ubiquinone concentrations mea-
sured before and after 7 days of lovastatin therapy were 0.94 ±
0.47 �.tg/ml and 0.55 ± 0.28 p.g/ml, respectively (Table 3).
Similar to the changes noted in cholesterol concentration, the
declines in ubiquinone were not sustained after stopping lovas-
tatin.
In the second part of the trial, ubiquinone supplementation
was started 7 days before the beginning of lovastatin and con-
tinued until the patient was taken off protocol. The administra-
tion of ubiquinone over 1 week had no effect on the circulating
concentrations of cholesterol. The magnitude of the decline in
cholesterol concentrations following the administration of by-
astatin was not different from those achieved in the first part of
the trial (P = 0.79, Wilcoxon’s rank sum test) and remained
dose independent.
Oral ubiquinone supplementation for a week resulted in a
3-fold increase in serum concentrations (Table 3) from baseline
concentrations of 1 .23 ± 0.78 p.g/ml to 4.58 ± 3.20 �i.g/ml
(mean ± SD, n = 27). Following the administration of lovas-
tatin for 7 days, ubiquinone concentrations decreased on average
by 49% (to 1.88 ± 0.97 p.g/rnl, P = 0.001, Wilcoxon’s signed
rank test) but still exceeded baseline measurements.
Serum HMG-CoA Reductase Inhibitory Activity. The
bioactivity of lovastatin and its metabolites was retrospectively
measured in 40 patients treated at the 4-mg/kg dose level and
above, with lovastatin alone or in combination with ubiquinone.
A total of 149 samples was analyzed. The range of HMG-CoA
reductase bioactivity achieved during the 7-day period of by-
astatin administration was assessed in 1 19 samples. Thirty ad-
ditional samples obtained from patients treated with more than
one cycle of therapy were analyzed to document the presence or
absence of drug activity at various time intervals after the
cessation of lovastatin. Peak bioactivity was reached within 4 h
in all patients and ranged from 0. 10 to 3.92 fiM (mean ± SD,
2.32 ± 1 .27 �.LM). Marked interpatient variability and no direct
relationship to the dose administered were noted (by least-
squares linear regression). Trough activity at the 25-mg/kg dose
level and above averaged 0.28 ± 0.09 p.M. Drug activity in
patients treated with lovastatin and ubiquinone did not differ
from those measured in patients treated with lovastatin alone. In
four patients treated with more than six cycles of therapy, no
drug activity was detected 1 week after completing lovastatin
administration.
Toxicity. Sixty patients (68%) experienced a total of 128
episodes of clinical toxicity. As can be seen from Table 4, the
incidence and severity of toxicity increased markedly once the
25-mg/kg dose level was reached. In the cohort of patients
treated with lovastatin alone (n 32 patients; 104 cycles of
therapy), grade 1 and 2 toxicity encompassed 92% of the epi-
sodes. Gastrointestinal dysfunction was the most commonly
recognized toxicity, comprising 56% of all episodes. The most
severe clinical toxicity was related to the musculoskeletal sys-
tern and manifested primarily as myalgias and muscle weakness.
No musculoskeletal toxicity was recognized at doses <25 mg/
kg/day. At higher doses, however, no direct correlation could be
established between the incidence of myotoxicity and the dose
of lovastatin administered (P = 0.24, Cochran-Armitage test).
In one patient with high-grade glioma treated with lovas-
tatin alone at a dose of 35-mg/kg/day and whose course is
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350’
300’
250’
200’
150�
100
-0--- patient 1
. patient 2-- a- patient 3
-“�-,“�--‘..“,‘ patient 4
�: patient 5
0
-U- I
5 10
Cycle Days
15 20 25 30
488 Phase I Study of Lovastatin
illC0
C00�C �00iOE
0
0
U)U)
0-CC-)
Fig. 3 Time course of cholesterol decline after bovastatin treatment. Lovastatin induced declines in serum cholesterol concentrations in five
representative patients treated for 7 days at the 25-45-mg/kg/day dose levels (horizontal bar). Notice the recovery in cholesterol concentrations by
the end of each treatment cycle.
Table 3 Serum ubiqu inone concentration s in patients treated wit h lovastatin alone or in combination with ubiquinone
Lovastatin dose
(mg/kg/day) n
Ubiquinone concentration (pg/mi)
Baseline Postubiquinone Postbovastatin
25 5 0.87 ± 0.36 0.49 ± 0.30
30 6 0.89 ± 0.50 0.64 ± 0.4935 10 1.01 ± 0.58 0.53 ± 0.1545 3 0.94 ± 0.60 0.49 ± 0.21
30 with ubiquinone 3 1.31 ± 1.21 3.50 ± 1.34 1.70 ± 0.6035 with ubiquinone 7 0.83 ± 0.16 5.16 ± 4.21 2.03 ± 1.47
40 with ubiquinone 9 1.46 ± 0.57 4.98 ± 2.88 1.93 ± 0.674swithubiquinone 8 1.28 ± 1.1 1 2.83 ± 1.34 1.68 ± 0.91
summarized in Fig. 4, the onset of myopathy occurred after the
sixth treatment cycle, simulating disease progression. The max-
imum severity of this patient’s symptoms was associated with a
low serum concentration of ubiquinone (0.33 pg/ml). Magnetic
resonance imaging of the brain at that time revealed no increase
in tumor volume. The patient’s symptoms resolved almost corn-
pletely 48 h after p.o. supplementation of ubiquinone (60 mg,
p.o., four times daily), at which time serum concentrations of
ubiquinone had increased 9-fold to 3.0 pg/mb. The patient was
subsequently maintained on p.o. ubiquinone and tolerated addi-
tional cycles of lovastatin with no recurrence of symptoms nor
radiological evidence of disease progression for 3 additional
months. Whether intracellular accumulation of lovastatin may
have underlied the occurrence of this toxicity remains specula-
tive at this time. In this patient with advanced brain cancer,
however, the administration of dexamethasone, a synthetic glu-
cocorticoid with known myopathic effects, is a confounding
factor that must be taken into consideration. With the exception
of this case, analysis of the toxicity patterns failed to disclose
any correlation between occurrence and cumulative lovastatin
dose.
Elevations in serum hepatic aminotransferases and creatine
phosphokinase concentrations above the upper limit of the nor-
mal range (alanine aminotransferase, 45 units/liter; aspartate
aminotransferase, 42 units/liter) were the most common labora-
tory toxicities recognized in 23% of the evaluable cycles. Of
note, no elevation of grade 3 severity or higher was noted. The
peak concentrations of these enzymes correlated with the max-
imum intensity of symptoms and occurred between days 7 and
10 in most patients.
To prevent rnyotoxicity and improve the tolerability of
lovastatin, ubiquinone was prophylactically administered to a
second cohort of patients. Fifty-six patients were treated with
bovastatin at doses of 30 mg/kg/day or more and received p.o.
ubiquinone prophylaxis; 27 (98%) patients experienced grade 1
or 2 toxicity and 1 patient experienced grade 3 nausea (2%). One
death occurred secondary to disease progression and was unre-
bated to treatment. Nausea and diarrhea were the most common
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Table 4 Toxicity: Major types and frequency per dose level
n Toxicity
Frequency grade
I 2 3 4
4
5
4
3
4
13
8
12
6
30
35
45
0000000
00
000
2
0
2
0000
000000
0000000000000
00
40
45
20
22
10 4
0000
0
0
0
0
000
00
Clinical Cancer Research 489
Lovastatin dose(mg/kg/day)
A. Lovastatin alone
2
468
1025
B. Ubiquinone supplementation
30 3
35 11
NauseaDiarrheaAbdominal pain
ConstipationConstipation
MyalgiasMuscle weaknessNausea/vomiting
DiarrheaSkin rashOthersDiarrheaFatigueMyalgias
Muscle weaknessNausea/vomiting
Diarrhea
FatigueOthersMyalgiasMuscle weaknessNausea/vomiting
Diarrhea
Fatigue
Myalgias
TrushMyalgiasMuscle weaknessNausea/vomiting
Diarrhea
OthersMyalgiasMuscle weaknessNausea/vomiting
DiarrheaConstipationOthersMyalgiasMuscle weaknessNausea/vomitingDiarrhea
ConstipationOthers
02
04
2
4
4
04
2
4
0
5
2
44
2
4
4
964
3
7
63
3
4
62
00000
0000
000
000000
6
00
0
0
000
000
0
0000
00
0
000000
0
000
000000000000
0
00
0
gastrointestinal toxicities. The administration of ubiquinone
alone for a week was not associated with toxicity. Ubiquinone
prophylaxis did not decrease the incidence of musculoskeletal
toxicity, but significantly reduced its severity (P = 0.01 1, Co-
chran Armitage test), which was limited to grade 1 ( 15/17, 88%)
and 2 (2/17, 12%). The maximum tolerated dose for the com-
bination regimen was not reached.
Response to Treatment. Evidence of antitumor activity
was documented in one patient with an anaplastic astrocytoma
that was progressing after surgical resection, radiation therapy,
and two cycles of carmustine. The patient was treated with
lovastatin at the 30- and 35-mg/kg/day dose levels and achieved
a minor response (45% reduction in tumor size) that was main-
tamed for 8 months. No activity was documented in the cohort
of patients with hormone-independent prostate cancer.
DISCUSSION
Lovastatin is a prodrug which yields several metabolites
that are responsible for the inhibition of HMG-CoA reductase in
vivo. Incompletely absorbed from the gastrointestinal tract, lo-
vastatin undergoes extensive first-pass metabolism in the liver,
Research. on February 23, 2020. © 1996 American Association for Cancerclincancerres.aacrjournals.org Downloaded from
C2 C3 C4 CS C6
* * * + *
25 50 75 100 125 150 175
490 Phase I Study of Lovastatin
C
0
aCe
C0-
oE
a,;0
0�
.�
E
a(I)
Time(days)
Fig. 4 Lovastatin-induced myopathy: changes in serum concentrations
of ubiquinone and response to p.o. supplementation. Time course of
bovastatin-induced changes in serum ubiquinone concentrations in a
patient who developed myopathy after several cycles (C) of lovastatin
therapy. Notice the transient inhibitory effect of lovastatin (documented
after cycles 2 and 3) and the rapid increase in ubiquinone concentrations
after p.o. supplementation (horizontal bar).
the main site of its therapeutic activity as a hypocholesterolemic
drug. Several studies have characterized the human pharmaco-
kinetics of lovastatin given at doses not exceeding 2 mg/kg
(21-24). Plasma concentrations of active lovastatin inhibitors
increase linearly following single doses ranging from 60 to 120
mg. Prolonged administration at the maximum recommended
dose (80 mg/day) results in steady-state concentrations of active
lovastatin inhibitors ranging from 0. 15 to 0.3 pM. The pharma-
cological effects of low-dose lovastatin in hypercholesterolemic
patients are better described (24). In these patients, maximum
reduction appears to be dose-related (in the order of 30-40% in
patients treated with 80 mg/day) and occurs within 4-6 weeks
of initiating therapy.
That high doses of lovastatin may be more effective at
inhibiting the mevalonate pathway than currently recommended
doses is suggested by the observation that comparable declines
in cholesterol concentrations occurred more rapidly in our study
(7-10 days) than has been reported with conventional doses. On
the other hand, although marked interpatient variability was
noted, neither the magnitude of the inhibitory effect nor the
circulating drug concentrations correlated directly with the dose
administered. Similarly, the incidence of myotoxicity was inde-
pendent of the dose once 25 mg/kg lovastatin or more were
administered. These findings, which led us to interrupt dose
escalation at the 45-mg/kg level, are possibly accounted for by
saturation of drug absorption at the higher dose levels or by the
short duration of drug administration, which may have pre-
vented larger, dose-dependent effects from taking place.
Several cases point to the depletion of ubiquinone as an
important pathophysiobogical mechanism responsible for lovas-
tatin-induced muscle damage (1 1 ). Our experience establishes
that this type of myopathy can be treated and prevented with p.o.
ubiquinone supplementation. Moreover, we could not identify
an antagonistic effect from ubiquinone in the patients who had
appeared to benefit from lovastatin, which is consistent with
laboratory data (5). Since it did not interfere with the cholester-
ol-lowering effect of lovastatin, ubiquinone may also prove
useful in the management of hypercholesterolemic patients un-
able to tolerate lovastatin’s most serious side effect.
The drug concentrations measured in this Phase I trial
(0. 1-3.9 pM) were comparable to those found to be active
against glioma cells in vitro (0.2-2.0 prvi; Refs. 5 and 7) and
provide a rationale to further study this approach in patients with
high-grade gliomas. Several limiting factors, however, must be
taken into consideration. Although it is not known at present
whether potential antitumor activity would result from the sys-
temic inhibitory effect of lovastatin on the mevalonate pathway
or by the actual drug concentrations in the cerebrospinal fluid or
brain parenchyma, the presence of a relatively intact blood-brain
barrier at the periphery of malignant gliomas represents a for-
midable obstacle to delivering a highly protein-bound drug such
as lovastatin to the actively dividing tumor cells. In addition, the
reversible inhibitory effect of lovastatin and its impact on p0-
tential antitumor activity must not be overlooked. Intermittent
administration of the drug is associated with normalization of
cholesterol and ubiquinone concentrations after treatment is
stopped, and by the absence of detectable lovastatin concentra-
tions as early as I week after drug administration. These find-
ings suggest that a temporary blockade of HMG-CoA reductase
activity is taking place, which would not be expected to result in
sustained biological activity. In this perspective, it is possible
that sustained inhibition of the mevalonate pathway by uninter-
rupted administration of lovastatin may yield improved clinical
results.
In the context of isoprenylation inhibition as an anticancer
approach, peptidic inhibitors of farnesyl transferase, the enzyme
responsible for the isoprenylation of numerous proteins in mam-
malian cells (25), must be mentioned. The therapeutic goal has
been to improve upon the specificity of isoprenylation inhibition
by targeting the ras oncogene in particular. Currently, however,
technical limitations related to the intracellular delivery of these
compounds remain to be solved (26), while their antiprolifera-
tive activity may actually be independent of the ras prenylation
status of the tumor (27).
We conclude that the administration of lovastatin at a dose
of 25 mg/kg daily for 7 consecutive days is well tolerated by
cancer patients, and that high-grade gliomas represent a reason-
able target for Phase II clinical trials. Alternative treatment
schedules aimed at achieving sustained inhibition of mevalonate
synthesis should be investigated.
ACKNOWLEDGMENTSWe thank Natalie McCall and Anne Schleifer for their laboratory
assistance, as well as Nancy Chen for her help in preparing the manu-
script.
Research. on February 23, 2020. © 1996 American Association for Cancerclincancerres.aacrjournals.org Downloaded from
Clinical Cancer Research 491
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1996;2:483-491. Clin Cancer Res A Thibault, D Samid, A C Tompkins, et al. pathway, in patients with cancer.Phase I study of lovastatin, an inhibitor of the mevalonate
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