Transcript Reflexões e Contribuições à Farmacologia

Reflexões e Contribuições à
Farmacologia
Gilberto De Nucci
Desenvolvimento de um Medicamento
Testes Pré-clínicos
Dose (Conc)
Resposta clínica
População PK/PD
Grandes ensaios clínicos
Vigilância
pósmercado
Aumento escalonado
da dose
In vitro PK/PD
Animal PK/PD
Eficácia
Tolerância
Seleção da Dose
PK/PD em população
especiais
Testes em animais
Testes Clínicos (Humanas)
Fase 0
Fase I
Fase II
Vols sadios
Fase III
Vols sadios
Fase IV
Poucos pctes
Muitos pctes
População
We found that the methodological quality of the included studies
was poor. Issues such as randomization, masked treatment
allocation, blinded outcome assessment, and intention to treat
analyses, which are very important issues and are now generally
required in clinical studies, were especially neglected in these
Surprisingly, 1 study reported
a double-blind assessment of effectiveness.
animal experiments.
Ames Test (Salmonella typhimurium)
 Bacterial reverse mutation assays are widely used to evaluate the
mutagenic potential of chemicals, formulations, or extracts. The most
common assay involves the use of amino acid-requiring strains of Salmonella
typhimurium and is commonly referred to as the "Ames Test".
 In the absence of an external amino acid source (histidine for Salmonella),
the cells cannot grow to form colonies unless a reversion of the mutation
allows the synthesis of the amino acid to resume.
 Spontaneous reversions occur with each of the strains. However, some
compounds induce a mutagenic response and thereby increase the number of
revertant colonies substantially over the spontaneous reversion level.
The bacterial reverse mutation assay involves the
measurement of revertant colony frequencies that
are obtained when Salmonella strains are treated
in the presence and absence of a test article.
Positive and negative controls are included for
each strain tested. Metabolic activation using rat
liver S9 is included to mimic the in vivo activity of
the liver enzymes in transforming some promutagens to mutagens
São Paulo, 20 de setembro de 2000 n.606/00.
Antiinflamatório 100% brasileiro
Pesquisadores do ICB desenvolvem primeiro antiinflamatório totalmente
sintetizado no País. O novo medicamento, além de possuir boa atividade
farmacológica, apresenta grande capacidade muco-protetora.
The Best Model for Humans is Human — How to
Accelerate Early Drug Development Safely
Mark Seymour
Altern Lab Anim. 2009 Sep;37 Suppl 1:61-5.
Classificação de estudos
•
•
•
•
•
Aleatorizado (randomizado) ou não-aleatorizado.
Aberto, simples-cego, duplo-cego, triplo-cego.
Superioridade ou não-inferioridade
Paralelo, cruzado.
Controlado ou não-controlado.
Bíblia Sagrada
Bíblia Sagrada – Tradução da CNBB – 5° edição – pag 1109 (Daniel 1-2)
“Perhaps the most famous historical example of a
planned controlled, comparative, clinical trial is
from the eighteenth century: that where Lind (1753)
found oranges and lemons to be the most effective
of six dietary treatments for scurvy on board ships.”
- Textbook of Clinical Trials. 2004: p03.
In 2003 Graham Sutton searched HMS Salisbury’s
original papers, both the captain’s log and the separate
roll-call. “However the weekly roll-call shows at most
one or two, and usually none, as sick during this entire
voyage”.
“Lind was well aware that it was impractical to carry
citrus fruits on long sea voyages because (…) oranges
and lemons are liable to spoil. (…) Lind therefore
devised a system of almost boiling purified citrus juice,
so that 24 oranges or lemons were reduced to a few
ounces. (…) Lind’s rob (fruit syrup) was later shown
to be ineffective in preventing scurvy (now known
because he had boiled the heat-labile ascorbic acid).“ Nutr Rev. 2009 Jun;67(6):315-32.
Testes Clínicos
• Fase 0 – voluntários sadios (microdosagem) – não é regulatória
• Fase I – voluntários sadios
• Fase II – pacientes para prova conceitual
• Fase III – grande número de pacientes – estudos multicêntricos
• Fase IV – vigilância pós-mercado – pesquisa sobre novas
indicações
“Assumed to be stripped clean of human bias, the
masked (blind) RCT is accepted as the gold standard
and thus above scrutiny as a potential source of
systematic error ”
- J Clin Epidemiol. 2001
Jun;54(6):541-9.
J Clin Psychopharmacol. 1997 Oct;17(5):407-18.
J Clin Psychopharmacol. 1997 Oct;17(5):407-18.
Am J Psychiatry 2006; 163:185–194
Medicina baseada em evidência é considerada
como consenso nas diretrizes de tratamento
médico. Entretanto, isso pode ser válido se a
evidência for completa.
N Engl J Med 2008;358:252-60
Lancet. 1993 Feb 13;341(8842):418-22.
Control Clin Trials. 1997 Oct;18(5):431-44.
Kidney Stones
Treatment A
Treatment B
78% (273/350)
83% (289/350)
Kidney Stones
Large
Stones
Treatment A
Treatment B
Group 3
73% (192/263)
Group 4
69% (55/80)
Kidney Stones
Small
Stones
Treatment A
Treatment B
Group 1
93% (81/87)
Group 2
87% (234/270)
Kidney Stones
Treatment A
Treatment B
Small Stones
Group 1
93% (81/87)
Group 2
87% (234/270)
Large Stones
Group 3
73% (192/263)
Group 4
69% (55/80)
Both
78% (273/350)
83% (289/350)
J Clin Epidemiol. 1995 Jan;48(1):71-9.
Meta-analysis: statistical alchemy for the
21st century.
Feinstein AR.
The p-value for each study is > 0.20 but the p-value for
summary effect is <0.02
Introduction to Meta-Analysis – Fig 28.1
Impact of streptokinase on mortality (adapted from Lauet al., 1992)
Introduction to Meta-Analysis – Fig 2.1
Couto L.T; et al. Analysis of five streptokinase formulations using the euglobulin lysis test and the
plasminogen activation assay. Braz J Med Biol Res 2004;37:1889–1894.
Couto L.T; et al. Analysis of five streptokinase formulations using the euglobulin lysis test and the
plasminogen activation assay. Braz J Med Biol Res 2004;37:1889–1894.
Couto L.T; et al. Analysis of five streptokinase formulations using the euglobulin lysis test and the
plasminogen activation assay. Braz J Med Biol Res 2004;37:1889–1894.
Conclusion
These data show that the commercially
available clinical streptokinase formulations
vary significantly in their in vitro activity.
Whether these differences have clinical
implications needs to be investigated.
CONCLUSION:
There are wide variations in the activity, purity, and composition
of the available streptokinase preparations.
A methodological drawback of the work by Hermentin et al.9 (which the authors acknowledge) is
the assessment of only one sample per batch of SK, limiting the generalizability of the results.
Moreover, the authors have a direct interest in publicizing their findings, as the SK formulation
produced and distributed by their employer showed an exemplary profile in their analyses.
Despite these limits, the data by Hermentin et al.9 appear reliable, as they are supported
by another report, from an independent academic institution, using rigorous methods of
analysis, which also describes marked differences in the activity of five commercially
available SK formulations.10
•9. Hermentin P.; et al. Eur Heart J 2005;26:933–940.
•10. Couto LT.; et al. Braz J Med Biol Res 2004;37:1889–1894.
Int J STD AIDS. 1999 Jan;10(1):8-16.
Circumcision and HIV infection: review of the literature and meta-analysis.
Van Howe RS.
Source
Department of Pediatrics, Marshfield Clinic, Lakeland Center, USA. [email protected]
Abstract
Thirty-five articles and a number of abstracts have been published in the medical literature looking at the relationship
between male circumcision and HIV infection. Study designs have included geographical analysis, studies of high-risk
patients, partner studies and random population surveys. Most of the studies have been conducted in Africa. A metaanalysis was performed on the 29 published articles where data were available. When the raw data are combined, a man
with a circumcised penis is at greater risk of acquiring and transmitting HIV than a man with a non-circumcised penis
(odds ratio (OR)=1.06, 95% confidence interval (CI)=1.01-1.12). Based on the studies published to date, recommending
routine circumcision as a prophylactic measure to prevent HIV infection in Africa, or elsewhere, is scientifically
unfounded.
PIP:
This article reviews the literature on circumcision and HIV infection. Recent studies show raw figures suggesting
circumcised men to be at greater risk for HIV infection. Circumcised men have been found to also have more sexual
partners. Findings explain that circumcision may be responsible for the increased number of partners, and therefore, the
increased risk. In Africa, the use of dirty instruments and mass ritual events, including group circumcision, may increase
the number of young boys developing HIV infections. Based on the studies published in the scientific literature, it is
incorrect to assert that circumcision prevents HIV infection. Moreover, even if studies showing circumcision to be
beneficial are accurate, the risk from circumcision outweighs any small benefit it may have. Thus, promoting
circumcision as protection against HIV infection would lead to the belief that circumcised men are being protected from
contracting AIDS, which would result in increased HIV infections.
Int J STD AIDS. 2000 Mar;11(3):137-42.
Circumcision in men and the prevention of HIV infection: a 'meta-analysis' revisited.
O'Farrell N, Egger M.
Source
Department of Genitourinary Medicine, Milne Clinic, Bristol Royal Infirmary, UK.
Abstract
There is debate on the role of male circumcision in HIV transmission. Most case-control and cohort studies from Africa have shown an
association between a lack of circumcision and an increased risk of HIV infection in men. The evidence is conflicting, however, with crosssectional surveys from Tanzania and Rwanda either showing no relationship or an association in the opposite direction. A recent review and
meta-analysis of the literature concluded that the risk of HIV infection was lower in uncircumcised men (combined odds ratio 0.94, 95%
confidence interval 0.89 to 0.99). However, the analysis was performed by simply pooling the data from 33 diverse studies, which is an
inappropriate method for combining studies. We re-analysed the data, stratifying by study, and found that an intact foreskin was associated
with an increased risk of HIV infection: combined odds ratio 1.43 (1.32 to 1.54) with a fixed effect model and 1.67 (1.25 to 2.24) with a
random effect model. There was significant between-study heterogeneity (P<0.0001) which was partly explained by stronger associations in
studies in high-risk groups. The results from this re-analysis thus support the contention that male circumcision may offer protection against
HIV infection, particularly in high-risk groups where genital ulcers and other STDs 'drive' the HIV epidemic. A systematic review is
required to clarify this issue. Such a review should be based on an extensive search for relevant studies, published and unpublished, and
should include a careful assessment of the design and methodological quality of studies. Much emphasis should be given to the exploration
of possible sources of heterogeneity. In view of the continued high prevalence and incidence of HIV in many countries in sub-Saharan
Africa, the question of whether circumcision could contribute to prevent infections is of great importance, and a sound systematic review of
the available evidence should be performed without delay.
Comment on
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Circumcision and HIV infection: review of the literature and meta-analysis. [Int J STD AIDS. 1999]
Why Most Published Research Findings Are False
John P. A. Ioannidis
Summary
There is increasing concern that most current published research findings are false. The
probability that a research claim is true may depend on study power and bias, the number of other
studies on the same question, and, importantly, the ratio of true to no relationships among the
relationships probed in each scientific field. In this framework, a research finding is less likely to
be true when the studies conducted in a field are smaller; when effect sizes are smaller; when
there is a greater number and lesser preselection of tested relationships; where there is greater
flexibility in designs, definitions, outcomes, and analytical modes; when there is greater financial
and other interest and prejudice; and when more teams are involved in a scientific field in chase
of statistical significance. Simulations show that for most study designs and settings, it is more
likely for a research claim to be false than true. Moreover, for many current scientific fields,
claimed research findings may often be simply accurate measures of the prevailing bias. In this
essay, I discuss the implications of these problems for the conduct and interpretation of research.
Intention-to-Treat Analysis
Includes all randomized patients in the groups to which they
were randomly assigned, regardless of their adherence with
the entry criteria, regardless of the treatment they actually
received, and regardless of subsequent withdrawal from
treatment or deviation from the protocol
(Lloyd) Fisher et al., 1990
- Intention to treat analysis is a euphemism not to
include all events in all patients from randomised
until study completion.
- Intention to treat analysis leads to missing data,
which is one of the most catastrophic problems
facing clinical trials today.
- Missing data is a cancer growing on the clinical
trial community.
What is meant by intention to treat analysis? Survey of published
randomised controlled trials
Sally Hollis, Fiona Campbell
Abstract
Objectives To assess the methodological quality of intention to treat
analysis as reported in randomised controlled trials in four large medical
journals.
Conclusions The intention to treat approach is often inadequately
described and inadequately applied. Authors should explicitly
describe the handling of deviations from randomised allocation and
missing responses and discuss the potential effect of any missing
response. Readers should critically assess the validity of reported
intention to treat analyses.
BMJ 1999;319:670–4
Far better an approximate answer to the
right question, which is often vague, than
an exact answer to the wrong question,
which can always be made precise.
John W. Tukey (1962)
Fase I para moléculas sintéticas e biológicas
para o tratamento do câncer
Objetivos da Fase I
•
•
•
•
•
Farmacocinética
Tolerabilidade
Toxicidade
Escalonamento de dose para Fase II
Avaliar aspectos Farmacodinâmmicos
A phase I trial of the bombesin/gastrin-releasing peptide
(BN/GRP) antagonist RC3095 in patients with advanced solid
malignancies
G. Schwartsmann, L. P. DiLeone, M. Horowitz, D. Schunemann, A. Cancella, A. S.
Pereira, M. Richter, F. Souza, A. Brondani da Rocha, F. H. Souza, P. Pohlmann, G. De
Nucci.
Purpose: To determine the safety and feasibility of the administration of RC3095 by daily subcutaneous injections in patients with advanced and refractory
solid malignancies.
Methods: Twenty-five patients received RC-3095 once or twice-daily at doses
ranging from 8 to 96 ug/kg. Dose was escalated in groups of 3–5 patients per
dose level.
Invest New Drugs (2006) 24:403–412.
A dose-escalation phase I trial of nimotuzumab,
an antibody against the epidermal growth factor receptor, in
patients with advanced solid malignancies
Benoit You, Anthony Brade, Joao M. Magalhaes, Lillian L. Siu, Amit Oza, Sonya
Lovell, Lisa Wang, David W. Hedley, Leonardo V. Nicacio, Eric X. Chen.
Objective: The primary objective of the trial was to assess the pharmacodynamic effects of nimotuzumab in tumor and skin tissues. Hence, no dose
escalation above 800 mg was planned. This study did not aim at determining a
recommended dose for phase 2 trial.
Invest New Drugs (2011) 29:996–1003.
A dose-escalation phase I trial of nimotuzumab,
an antibody against the epidermal growth factor
receptor, in patients with advanced solid
malignancies
Eligibility: The 17 patients enrolled onto this study had histologically or
cytologically documented solid tumors either refractory to standard therapy or
for which no curative therapy exists.
Administration: Nimotuzumab was administered intravenously every week
over 30 min after administration of 50 mg of diphenhydramine on an
outpatient basis. Each cycle was defined as 6 weeks and treatment was
continued until disease progression, occurance of intolerable toxicity, or
patient’s withdrawal of consent. No routine antiemetic prophylaxis was
mandated.
Invest New Drugs (2011) 29:996–1003.
Invest New Drugs (2011) 29:996–1003.
Metabolism and disposition of imatinib mesylate
in healthy volunteers
Hans-Peter Gschwind, Ulrike Pfaar, Felix Waldmeier, Markus Zollinger, Claudia
Sayer, Peter Zbinden, Michael Hayes, Rolf Pokorny, Michael Seiberling, Monique BenAm, Bin Peng and Gerhard Gross
Purpose: To investigate the disposition and biotransformation of imatinib
mesylate in 4 male healthy volunteers after a single oral dose of 239 mg of 14Clabeled imatinib mesylate. Biological fluids were analyzed for total radioactivity,
imatinib, and its main metabolite CGP74588.
Int J Pharm Med (2006) 20:159-165.
Int J Pharm Med (2006) 20:159-165.
Int J Pharm Med (2006) 20:159-165.
Advantages of Microdosing
First of all, microdosing requires minute quantities of the drug for safety
testing. A microdose is so small that when administered to human subjects, it
is not intended to produce any pharmacologic action; hence, the risk of adverse
events is less.
A smaller toxicology package is required. As per the regulatory requirement,
animal studies, at least in one species, are required to establish microdose in
humans, but at a much reduced level. Further, if human screening of
compounds is done earlier in the drug development process, fewer animal
studies are required before Phase I clinical trials. Thus, further animal studies
can be avoided with compounds having unsuitable pharmacokinetic profiles.
Capecitabine
• Capecitabine is an adjuvant treatment for colon cancer and
for the treatment of metastatic breast cancer in patients
whose pathology did not improve during treatment with
other therapeutic agents.
• Capecitabine is a prodrug, and it is selectively activated by
tumor cells to its cytotoxic moiety, 5-fluorouracil, by
thymidine phosphorylase, which is generally expressed at
high levels in tumors.
Capecitabine
• Clinical and pharmacokinetics studies for capecitabine are
performed in patients with cancer.
• Standard dosing is 1,250 mg/m2 orally twice daily, morning
and evening, for 14 consecutive days in 3-week cycles.
• For an average healthy male volunteer weight (70 kg) and
height (170 cm) this would mean 2150 mg per dose (4300
mg per day). Corporal Area = 1,809 m2
Metabolic activation of capacitabine in humans
Reiner et al, 1998
Adverse effects
• Asthenia/ fatigue
• Diarrhea
• Lymphopenia
• Leukopenia
• Mucositis
• Nausea
• Neutropenia
• Thrombocytopenia
• Vomit
• Hand Foot Syndrome
April 10th, 2010
Committee of Ethics in Research approval the pilot study protocol
Item V- CER evaluation
The Committee of Ethics in Research of the Faculty of Medical Sciences of
UNICAMP, obeying the evaluations of the previously designated members for the
present case and attending all of dispositions of Resolutions 196/96 and
complementary, decided to approve without restrictions the Research Protocol,
the informed consent, as well as all the attached files included in the research
proposal.
June 6th 2011
2nd World Congress on Bioavailability
& Bioequivalence 2011 (BABE 2011)
Presentation of the results of the two pilot studies of
capecitabine on 16 healthy male volunteers
National Commission on Ethics in Research (CONEP)
August 10th 2011
CONEP had received from the National Agency of Sanitary Vigilance
(ANVISA) a note warning about the approval from the Committee of
Ethics in Research of clinical studies that violated the ethical concepts
of resolution CNS 196/96.
In response, CONEP released a note stating the following:
“Healthy individuals should not enroll on bioequivalence studies of
drugs with high toxic potential (chemotherapeutics); Studies with these
agents should only be performed on patients that may benefit from the
studied drug.”
- Evaluated the safety of a capecitabine bioequivalence study (150 mg tablet) using 8 healthy
male volunteers under fasting and non-fasting conditions.
- The study was initially conducted with an open, randomized, two-period crossover design
in a 2-week washout with fasted volunteers.
- After the fasted study a new protocol was submitted to the Ethics Committee to evaluate the
non-fasted study.
- The volunteers were selected for the study after having their health status previously
assessed by a clinical evaluation and laboratory tests .
- A single capecitabine tablet (150mg) was given in each interment.
- The drug was well tolerated by the volunteers, and they presented no adverse reactions. The
biochemical and hematological parameters presented no clinically relevant alterations.
- Results indicate that it is safe to perform capecitabine bioequivalence studies in healthy
male volunteers.
Technical Note 05/2012
Item 2 – Relative bioavailability/ bioequivalence studies with drugs present on attachment
I must respect the general measures described on this note as well as specific measures to
each drug described on the same attachment.
Item 3.1 – Based on the toxic potential of these drugs the investigators must decide on the
participation of patients or healthy volunteers, as well as the most adequate dose to use in
the study.
Attachment I – Drugs that must have bioavailability/ bioequivalence studies
conducted accordingly to this note
Capecitabine
Male volunteers
Study population
Oral dose
Female volunteers with definitive sterilization
150 mg
Technical Note 06/2012
Item 2 – Relative bioavailability/ bioequivalence studies with drugs present on
attachment I must be conducted on patients of the target population of the studied
drug; patients must be receiving treatment to a pathology to which the reference
drug is indicated. These studies must respect the technical aspects depicted on this
note.
Attachment I – Drugs that must have bioavailability/ bioequivalence studies
conducted on patients.
Azacitidine
Ganciclovir
Temozolomide
Chlorambucil
Goserelin
Testosterone
Clozapine
Leuprorelin
Topotecan
Doxorubicin
Melphalan
Triptorelin
Etoposide
Mercaptopurine
Vorinostat
Everolimus
Nabilone
Felbamate
Nilutamide
European Medicines Agency
December 13th, 2012
6.2.1. Phase I, single agent dose and schedule finding trials
– Non-clinical data and, when available, data from healthy volunteers
should be used to design the studies to be conducted in patients
– Based on preclinical tolerability and toxicology findings and the assumed
pharmacology of the compound, early trials may sometimes be
conducted in healthy volunteers.
Objective
To evaluate bioequivalence between two
formulations of capecitabine (test and
reference) in healthy male volunteers
Why evaluate on healthy volunteers?
Capecitabine is employed for the treatment of metastatic
cancer, therefore the prognosis of these patients is usually
reserved. To expose these critical patients to either ineffective
or toxic doses of the drug (due to unforeseen infra or suprabioavailability of the test formulation), to experimental
procedures such as internment, venous puncture and blood
collection to evaluate bioequivalence should be ethically reevaluated. Furthermore, studies performed in patients are with
therapeutic doses, using several tablets for each administration
(generally a combination of both 150 and 500 mg tablets), a
procedure that limits the discrimination between dosage
forms.
Methods
• The clinical protocols were approved by the university IRB.
• The studies were conducted using an open, randomized, two-period
(150 mg single administration of Xeloda; F. Hoffmann-La Roche Ltd.,
vs a test formulation) crossover design with a one-week washout
interval, in two groups, with food.
• All male subjects were negative for HIV, HCV and HBV. The
laboratory tests (biochemical and hematological parameters) were
performed on average three days after the first confinement, and 7
days after the second confinement.
Methods
• Subjects: Seventy-two healthy male volunteers were recruted
• Hematological
evaluation:
Hemoglobin,
Hematocrit,
Erythrocyte Count, VCM, HbCM, White Cell and Platelet
Count
• Biochemistry: Total Cholesterol, Triglycerides, Total
Proteins, Albumin, Uric Acid, Total Bilirubins (Direct and
Indirect), Alkaline Phosphatase, SGOT
(AST), SGPT
(ALT), Urea, Creatinine, Fasting Blood Glucose
• Physical exam and EKG.
Methods
• Dose: 150mg single-dose on each treatment with a one-week
washout period between treatments.
• Volunteers had a standardized breakfast 30 minutes before
drug administration.
• Blood samples were collected at 0:10, 0:15, 0:20, 0:30, 0:40,
0:50, 1:00, 1:10, 1:20, 1:30, 1:40, 1:50, 2:00, 2:30, 3:00, 3:30,
4:00, 5:00, 6:00 and 7:00h after drug administration
Determination of Capecitabine
• HPLC coupled to tandem mass spectrometry
• Deuterated capecitabine
Capecitabine
M.W. 359.93 g/mol
Capecitabine-d11
M.W. 371.08 g/mol
Results
• Three drop-outs due to time unavailability.
• The drug was well tolerated by the 69 volunteers
that concluded the study.
• One volunteer had a mild headache.
• Three individuals presented hypertriglyceridemia.
Results
•
To determinate if hypertriglyceridemia was due to capecitabine, plasma
samples remaining from the analitical study were evaluated for
triglycerides.
•
Two out of the 3 volunteers had hypertriglyceridemia before the first
and the second dose of capecitabine, and did not have significant
variation through out the treatment day.
•
The volunteer that had normal triglycerides before treatments only
presented mildly elevated levels (273 mg/dL) 8 days after the second
dose (discharge evaluation). It resolved without treatment, as evaluated
30 days after the last dose.
Conclusion
It is safe to perform capicetabine (150mg)
bioequivalence study in healthy male volunteers.
John Robert Vane
Oswaldo Vital Brazil
João Garcia Leme
Missed but not forgotten