Clinical Pharmacology, ASPHO Flashcards
Gray =?
amount of radiation depositining 1 joule of energy into 1 kg
benefit of proton radiation?
Plateau dose distribution‐ deposit 90‐100% of dose at the point they
stop in tissue (Bragg peak); avoids exit dose
dose of TBI? waht does it do? (2)
12‐15Gy in 8‐12 fractions • Eliminate residual cancer cells • Make space in bone marrow compartment • Immune suppression
what is teh gross tumour volume?
volume occpied by tumor at diagnosis
what is the clincial target volume?
• Includes gross tumor volume (GTV) and sites of suspected occult disease and involved adjacent lymph nodes
what is the planning target volume?
Planning Target Volume (PTV)
• Includes CTV including surrounding geometric area accounting for variability in set up,
breathing and motion during treatment
• PTV is not the same as photons for protons
• PTV is same as CTV for brachytherapy
3 sources of radiation for therapy?
photons, protons, gamma rays
3 types of IV radiotherpay?
Systemic Delivery (IV) Radiotherapy (Radiopharmaceuticals)
• Radio‐Iodine (RAI, 131Iodine) Gamma and Beta particles, Thyroid cancer
• 131I‐Meta‐iodobenylguanidine (131I‐MIBG): delivers beta particles via neuroendocrine
transporter to Neuroblastoma or Pheochormocytoma
• 177Lu‐ DOTO‐TATE: Beta emitting, somatostatin receptor positive GI neuroendocrine
tumors (Peptide Receptor Radiouclotide Therapy, PRRT)
which familiy of drug met enzymes is responseible for 70-80% of all phase drug metabolism (activate/deactivate)? which specific enzyme is most commonly used?
cytochrome p450; cyp3a
which enzyme is mutated in people who have increased sensitivity to 6MP?
Thiopurine Methyl Transferase (TPMT), seen in 1/300
which enzume is mutatied in gilberts disease?
• UDP‐glucuronosyl‐transferase 1A1
3 ways to overcome blood brain barrier for CNS disease?
- High‐dose chemotherapy
• Methotrexate, cytarabine - Identifying drugs which penetrate the BBB based on
lipophilicity, molecular weight, degree of ionization, plasma
concentration of free drug (protein binding)
• nitrosoureas, thiotepa, topotecan - Disruption of the blood‐brain barrier
• Osmotic, radiation, vasoactive compounds, - Regional Chemotherapy
• Intra‐carotid chemotherapy (cisplatin, methotrexate)
• Intrathecal injection (methotrexate, cytarabine)
• Intra‐tumoral (carmustine)
• Convection Enhanced Delivery
IT chemo dosing based on? exception?
- Intrathecal (IT) chemotherapy dose is based on age
* IT MTX dosing based on BSA, children < 18 months had higher rate of isolated CNS
what is the goldie-coldman hypothesis? 3 points
• Cancer cells mutate and become resistance to therapy at a rate that
depends on the cancer’s inherent genetic instability
• Probability that a cancer contains a resistant clone is dependent on the
mutation rate and size of the tumor
• Even when tumor burden is low there is likely to be at least one drug
resistant clone
main principle of chemo #1: give combo therapy: what does this mean? eg?
Concurrent administration of multiple anticancer drugs with non‐overlapping
mechanism of action and non‐overlapping toxicity profiles…Acute Lymphoblastic Leukemia: transient response rates of 60% with single agents
(MTX, MP, Prednisone, VCR, Dauno, or L‐ASP); 3‐4 drug combination induction
regimens produce durable response rate of 95%
main principel of chemo #2: adjuvant therapy: what is this?
Administration of chemotherapy when disease burden is
minimal but risk of recurrence is high (Goldie‐Coldman Hypothesis)
• Continuation of system therapy after local control in localized cancer
• Osteosarcoma: Improved 3 y EFS when chemotherapy administered after complete resection of
localized tumor (20% surgery alone vs 65% surgery + chemotherapy) Eilber et al J Clin Oncol 1987;5:21‐6
• Maintenance Therapy
• ALL: Methotrexate, 6‐Mercopatopurine
• RMS: vinorelbine + cyclophosphamide.
Regarding adjuvant therapy, what is neoadj therapy? benefits (2)
Neoadjuvant Setting: Administration of systemic chemotherapy prior to
definitive local control
• Reduce tumor burden at the primary site prior to definitive local therapy
(surgery/radiation)
• Control disease not amenable to local therapy (metastases)
• Assess the sensitivity of the tumor to chemotherapy by measuring tumor response
chemo pirnicple #3: dose intensity: what does this pertain to? eg?
Maximize the Dose Rate of chemotherapy
• Highest possible dose at the shortest tolerable interval
• Calculated by normalizing the dose rate (mg/m2/week) for a drug and
comparing to the dose rate of a reference drug or prior regimen.
• Examples:
• Interval Compression improved EFS in localized EWS
• Dose intensity of 4 drug induction in NBL correlates with response and survival
• Children with ALL have improved survival with standard dose vs half dose MTX and MP in
maintenance.
give 4 alkylating agnets
cyclophos ifofos cisplatin busulfan melphalan temozolamide
give 2antimetabolities
TG
MP
give 7 common toxicities of chemo
SHAM MAN skin reactions hepatotox alopecia mucositis myelosupp allergic rxn n/v
unique tox of anthras?
cardiotox
unique tox fo cyclo, ifos?
hemorrhagic cystitis
unqiue tox of alkaloids, cisplatin?
peirpheral neuropathy
unique tox of aparaginse?
coagulopathy
unique tox of cisplatin?
ototox
unique tox of cisplatingand mtx?
nephrotox
unique tox of mtx?
leucoencephalopahty
how to attenuate myelosupp? (3)
G-CSF
stem cell re-infusion
individualized dosing
how to attenuate n/v
antiemetics
how to attenuate heomrrhagic cysitis?
mesna
how to attenuate nephrotox from cisplatin?
hyperteonic saline
how to attenuate cardiotox from anthras?
dexrazoxane
how to attenuate myelosupp/mucositis from mtx? (2)
Leucovorin
Carboxypeptidase
vesicant= compound that causes severe skin/eye mucosal pain and irritaiton…give 5 high chemos with high vesicant potential
think DMV= super irritating
Dauno, doxo, dactino….mitotoxin c…VBL, VCR, vinorelbine
how do alkylating agents work?
• Damage to the DNA template (alkyl adducts)
induces apoptosis
• For bifunctional alkylators (nitrogen
mustards), damage results from the formation
of crosslinks (inter‐strand, intra‐strand, DNA‐
protein)
are alkylators dependent on cell cycle?
no
give 5 alkylating agents
ifos cyclophos cisplatin carboplatin busulfan temozolamide thiotepa melphalan lomustine
give 3 alkylating agents that are pro-drugs
Cyclophosphamide
Ifosfamide
Dacarbazine
Temozolomide
in what 4 ways in cisplatin worse than carbo?
periopheral neuropathy, n/v, nephrotox, ototox
in what 2 ways is carboplatin worse than cisplatin?
myelosupp, hypersens
what do audiograms show in cisplatin-related ototox?
Bilateral High
Frequency (Hz > 4000) hearing
loss (dB)
plateau then decreases high in the x-axis
what compound can help with ototox in some groups?
Sodium Thiosulfate
how does cyclophos –> nephrotox?
- Direct tubular effect–> water retention
- hemorrhagic cystitis due to acrolein= metabolite
how does ifos–> GU tox?
- prox tubular damage, ricketts in younger children
- decreased GFR
- distal tubular damage with RTA
- hemorrahgic cystitis due to acrolein= metabolite
how does mesna work?
chelates acrolein metabolite in the bladder
other than GU tox, another organ tox secondary to ifosfamide? how can you tx this?
neurotox (esp with aprepritant)…tx iwth methylene blue
list 4 alkylating agents
busulfan carmustine= BCNU cisplatin ifosfamide cyclophosphamide
late effects of alkylators? 4
- gonadal atrophy (high dose busulfan)
- pulmonary fibrosis (busulfan, carmustine)
- renal dysfunction(cisplatin, ifosfamide)
- ototox (cisplatin)
- secondayr cancers
mtx mech?
inhibits dihydrofolate reductase
antimetabolites are cell cycle specific?
yes, specific to S phase
folate analog?
mtx
purine analog?
6MP, 6TG, fludarabine, clofarabine, cladribine, melarabine=Ara-G
pyrimidine analogs?
Ara-C, gemcitabine, fluorouracil
all anti-metabolites are ___
pro-drugs
4 frequent toxicities of antimetabolities?
myelosupp, hepatotox, mucositis, nausea, vomiting, neurotox, rash, dermatitis, pulm tox
specfici tox of HD mtx?
nephrotox
specific tox of gemcitabine?
radiation recall
specific tox of 6TG?
VOD
specific tox of fludarabine?
immunosupp
specific tox of cladribine?
immunosupp
specific tox of ara-c?
flu-like sx
other than ara-c, another drug with AE= flu-like sx?
gemcitabine
neurotox secondary to mtx? (2) resolution?
acute encephalopathy (5-14 days later) with HD– resolution in 1-7 days; 10-50% recur….chronic encephalopathy= permanent
cytarabine neutotox?
acute cerebellar syndrome…onset 3-8 days days…resolves in 1 week, but 30% have rseidual defect
nelarabine neutotx?
somnolence, seizures, guillain-barre-like weakness, paresthesia…gradually reversible
fludarabine neurotox?
progress leukoencephalopahty, can be fatal
what is the MAX mtx infusion duration?
42 hours…must start leucovorin within this timeframe!!
4 ways to maange nephrotox from HD Mtx?
- Hydration and alkalination of urine
- increase leucovorin/give more often
- dialysis
- glucarpidase=carboxypeptidase
how does glucarpidase work?
cleaves mtx into DAMPA and glutamic acid
allopurinol’s effect on 6MP? if giving both at same time do what?
allopurinol inhibits xanthine oxidase, which is responsibilie for metabolism of PO 6mp (not iV)–> 6mp becomes more bioavailable…if giving both, decresae 6MP dose by 75%!
give 3 drugs that interact with mtx–> decreased secretion of mtx
salicylates, pencillin, NSAIDs, ciproflox
topoisomerase 1 does what? 2 does wht?
–> single strand DNA breaks? ….2–> double stand DNA breaks
3 classes of topoisomerase inhibitors?
anthracyclines, epipodophyllotoxins, camptothecins, anthracednediones, phenoxazones
give 3 anthracyclines
doxo, dauno, idarubicin
give 2 epipodophyllotoxins
etoposide, teniposide
mitxantrone= what type of chemo?
anthracenedione= topoisomerase 2 inhibitor
dactinomycin= what type of chemo?
phenoxazone= topoisomerase 2 inhibitor
topotecan and irinotecan = what type of chemo?
camptothecins…= topoisomeraise ONE inhibitors
give 2 antitumour antibiotics
anthracyclines, dactinomycin
how to tx irinotecan induced diarrhea iwthin 8 hours of starting?
atropine
how to tx irinotecan diarrhea after 8 hours?
loperimide, octreotide
how to prevent irinotecan diarreha? how does this work?
cefixime; decreases glucuronidase producing bacteria in the gut
give 4 tubulin binding agents
vincristine, vinblastine, vinorelbine, paclitaxel, docetaxel
4 specific AEs of vcr?
- peripheral nueroptahy (loss of DTRs, numbness)
- CN involvement (double vision)
- SIADH
- autonomic neuorpathy= constipation
3 drugs that reduce clearance of vinca alkaloids?
fluconazole, cipro, grapefruit juice
3 drugs taht increase clearance of vinca alkaloids?
st johns wort, phenobarb, rifampin
5 AEs of steroids?
AVN, htn, diabetes, immunouppression, growth failiure, centripedal obesity
tox assoicated with bleomycin
interstitial pneumonitis, alopecia, reynaud, hyperpigemntation of skin and nails
goals of phase 1 trial?
establish safe dose, establish tox profile, establish pharmacology
population used in phase 1 trials?
relapsed cancer, <25 pts
phase 2 trial goal?
determine response to a certain drug
populaiton for phase 2 trial?
relapased cancer pts
goal of phase 3 trail?
efficacy (benefit) of drug, with endpoint being survival
population in phase 3 trial?
untreated cancer pts
3 AEs of Aresnic trioxide?
prolonged QTc, leukocytosis, APL differentation syndrome
3 AEs of ATRA?
differentation syndrome, venous thrombosis, pseudotumour cerebri
3 AEs of imatinib?
increased transaminases, n/v, fatigue
2AEs of crizotinib?
hepatotox, AKI
NTRK fusion (NTRK-ETV6) seen in which tumours?
congential mesoblastic neprhoma, infantile fibrosarcoma
give an NTRK inhibitor
larotrectinib
give an inhibitor of dna methylation
azacitidine
give an immune hceckpoint inhibitor and an AE of it
nivolumab, pleural effusion
give 3 MABs used to treat cancer, the cancer they treat, mech, and AE
- avastin=bevacizumab; LGG; blocks angiogenesiss via VEGF inhibition; hypertesnion
- rituximab; PTLD and b-cell lymphoma; inhibits CD20-> depletes normal b-cells–> hypogammaglobulinemia
- dintuximab, NBL, anti-GD2–> antibody dependent cell mediated toxicity; neuropathic pain
AE of gemtuzumab?
infusion-related reaction, myelosupp
AE of inotuzumab?
infusion-related reaction, myelosupp, VOD
AE of brentuximab?
neutropenia, neuropathy