Adstiladrin
nadofaragene firadenovec
Species
MonkeyRat
Longest study
22 wk (derived)
Genotox
Not conducted Not conducted
Carcinogenicity
Not conducted Not conducted
Repro
Not conducted Not conducted
First dose
Not conducted Not stated publicly
Speciesopen answer page →
Species
Cynomolgus monkey for rAd-IFN/Syn3 GLP tox; rat and monkey for excipient Syn3
“Rat and cynomolgus monkey have been used as the toxicology species for Syn3NODA and cynomolgus monkeys were used for the toxicological assessment of rAd-IFN/Syn3NODA.”
Why that species
Monkey shows systemic vector exposure after intravesical dosing (unlike rodents), a worst-case model; permissiveness not otherwise discussed
“As a toxicological species, monkeys may be a worst-case model, since systemic toxicity of rAd-IFN will be of very limited relevance to the clinical situation.”
Surrogate molecule
No surrogate; clinical rAd-IFN/Syn3 tested intravesically in monkeys (human IFN-alpha2b transgene)
“Safety was assessed in cynomolgus monkeys receiving intravesical administration of rAd”
Species: general tox
Cynomolgus monkey for rAd-IFN/Syn3; rat and cynomolgus monkey for the Syn3 excipient
“Rat and cynomolgus monkey have been used as the toxicology species for Syn3NODA and cynomolgus monkeys were used for the toxicological assessment of rAd-IFN/Syn3NODA.”
Species: DART
Not conducted (not warranted: product characteristics, toxicology results, patient population)
“Carcinogenicity and reproductive and developmental toxicity studies were not performed for rAd-IFN/Syn3. These studies are not warranted based on the product characteristics, results from the toxicology studies, and target patient population.”
Species: carcinogenicity
Not conducted (not warranted: product characteristics, toxicology results, patient population)
“Carcinogenicity and reproductive and developmental toxicity studies were not performed for rAd-IFN/Syn3. These studies are not warranted based on the product characteristics, results from the toxicology studies, and target patient population.”
Surrogate used in
No surrogate used; clinical rAd-IFN/Syn3 given intravesically to cynomolgus monkeys
“Rat and cynomolgus monkey have been used as the toxicology species for Syn3NODA and cynomolgus monkeys were used for the toxicological assessment of rAd-IFN/Syn3NODA.”
Study lengthopen answer page →
Longest pivotal study
22 (derived from the dosing and observation schedule)
“dose levels of 2.5 x 1011 vp/animal (1x1011 vg rAd-IFN/mL in 1 mg/mL Syn3), 1.25 x 1013 vp/animal (5x1011 vg rAd-IFN/mL in 1 mg/mL Syn3), Syn3 alone (1mg/mL), or placebo control on Days 1 and 91, followed by a two month observation period”
Pivotal GLP studies
GLP monkey intravesical study: 2 doses (Days 1 and 91) of rAd-IFN/Syn3 at 2.5e11 or 1.25e13 vp/animal, Syn3 alone, placebo; 2-month observation
“on Days 1 and 91, followed by a two month observation period in a GLP toxicology study.”
Route in tox
Intravesical (clinical route); IV for Syn3 excipient
“studies involving the intravesical (the intended clinical route of administration) and intravenous (IV) routes of administration in rats and cynomolgus monkeys have been conducted.”
Skipped studiesopen answer page →
Genotoxicity
Not conducted for rAd-IFN; conducted for excipient Syn3 only (Ames and chromosome aberration, negative)
“Safety pharmacology, pharmacokinetics, toxicology, and genotoxicity studies were also conducted for the exicipient Syn3.”
Carcinogenicity
Not conducted (not warranted by product characteristics, tox results, target population)
“Carcinogenicity and reproductive and developmental toxicity studies were not performed for rAd”
Reproductive & developmental
Not conducted (not warranted by product characteristics, tox results, target population)
“Carcinogenicity and reproductive and developmental toxicity studies were not performed for rAd”
Safety pharmacology
No dedicated vector study; excipient Syn3 in vitro hERG and in vivo CNS/CV/respiratory studies showed no risk up to 5 mg/kg
“Safety pharmacology studies do not indicate a risk for Syn3NODA in the in vivo studies evaluating CNS, cardiovascular and respiratory systems up to a concentration of 5 mg/kg.”
Genotox: Ames
Excipient Syn3: Ames negative
“The genotoxicity of Syn3NODA was evaluated in vitro in an Ames test for bacterial mutagenicity and in a chromosome aberration study in human lymphocytes for potential for clastogenicity. Overall, these studies indicate that Syn3NODA is not genotoxic in vitro.”
Genotox: in vitro mammalian
Excipient Syn3: chromosome aberration assay in human lymphocytes negative
“The genotoxicity of Syn3NODA was evaluated in vitro in an Ames test for bacterial mutagenicity and in a chromosome aberration study in human lymphocytes for potential for clastogenicity. Overall, these studies indicate that Syn3NODA is not genotoxic in vitro.”
Genotox: in vivo
Excipient Syn3: rat bone marrow micronucleus negative up to 25 mg/kg/day
“In the main study, male rats (n=5/group) dosed up to 25 mg/kg/day did not show an increase in the mean frequency of micronucleated polychromatic erythrocytes in bone marrow compared to control animals.”
Carcinogenicity model
Not conducted
“No carcinogenicity studies were conducted with Adstiladrin.”
Carcinogenicity timing
Not conducted: not warranted (product characteristics, toxicology results, target population)
“Carcinogenicity and reproductive and developmental toxicity studies were not performed for rAd-IFN/Syn3. These studies are not warranted based on the product characteristics, results from the toxicology studies, and target patient population.”
hERG / QT
Excipient Syn3: no hERG tail-current effect up to 4.53 µM (GLP); hERG inhibition not expected clinically
“In a GLP compliant hERG test for SYN3NODA, 4.53 µM (nominally 10 µM) is considered the highest tested concentration of Syn3NODA with no statistically significant effect on hERG tail current, thereby confirming that hERG inhibition by SYN3NODA will not occur upon clinical treatment.”
First doseopen answer page →
First-in-human starting dose
Not stated in public reviews
Why it's blank
The public FDA and EMA reviews of Adstiladrin don't say how the first human dose was chosen. That rationale is in the IND, which is confidential, so it is missing for most approved products.
How it's usually set for gene therapies
FDA expects preclinical proof-of-concept and toxicology studies to identify active dose levels and support the choice of starting dose and escalation. The 2013 guidance gives no numeric formula or scaling rule for the starting dose.
“Selection of potential starting dose level, dose-escalation schedule, and dosing regimen for clinical trials.”
✓ VerifiedFDA 2013: Preclinical Assessment of Investigational Cellular and Gene Therapy…, p. 7Source ↗
This product's starting point
NOAEL / key findings: Local NOAEL not set (urinary tract changes at all doses, reversible); highest non-severely toxic dose 1.25e13 vp rAd-IFN with 25 mg Syn3; bladder/ureter/urethra inflammation (EMA assessment report, p. 37)
NOAEL / key findings
Local NOAEL not set (urinary tract changes at all doses, reversible); highest non-severely toxic dose 1.25e13 vp rAd-IFN with 25 mg Syn3; bladder/ureter/urethra inflammation
“25 mg Syn3NODA and 1.25x1013 vp rAd-IFN could be considered the highest non-severely toxic dose.”
Risksopen answer page →
Immune & cytokine safety
Neutralizing anti-adenovirus and anti-IFNa2b antibodies in most high-dose monkeys, persisting through observation period
“Development of neutralizing antibodies to the adenovirus and anti-IFNα2b antibodies occurred in the majority of animals in the high dose group and to a lesser extent in the low dose group”
Biodistribution & persistence
Vector DNA in bladder (Days 8, 98); blood within 24 h; urine 2-3 days; low levels in liver, kidney, gonads; none in reproductive tissue at end
“Biodistribution analysis indicated the presence of rAd-IFN DNA in the bladder on Days 8 and 98.”
Modality-specific risk
Local urothelial toxicity of intravesical vector/Syn3 (inflammation, ulceration, fibrosis); anti-vector immunity; limited systemic spread
“Findings in the urinary bladder included mononuclear cell infiltration, inflammation, cytoplasmic vacuolation, urothelial hyperplasia, ulceration, and chronic inflammation”
Anti-drug antibodies: animals
Monkeys: neutralizing anti-adenovirus and anti-IFNα2b antibodies in most high-dose and fewer low-dose animals, persisting through observation
“Development of neutralizing antibodies to the adenovirus and anti-IFNα2b antibodies occurred in the majority of animals in the high dose group and to a lesser extent in the low dose group, and antibody titers remained detectable throughout the entire observation period.”
Anti-drug antibodies: patients
Anti-adenovirus type 5 and anti-IFNα2b antibodies with no apparent impact on safety or efficacy
“The immune responses against ADSTILADRIN (anti-adenovirus type 5 antibody and anti-IFNα2b antibody) did not have apparent impact on the safety and efficacy of ADSTILADRIN.”
Label warnings
- Risk of Muscle Invasive or Metastatic Bladder Cancer with Delayed Cystectomy
- Risk of Disseminated Adenovirus Infection
Secondary malignancyInfections
US prescribing information, Warnings and PrecautionsDailyMed ↗
Tox packageopen answer page →
Before first-in-human
First-in-human: where
US: all clinical studies, including first-in-human in patients with BCG-unresponsive NMIBC, conducted in the US
“It is acceptable that all clinical studies with nadofaragene firadenovec were conducted in the US (Table 1)”
Repeat-dose tox before first-in-human
Not stated in public reviews
Not reported in the public reviews. Reviewers summarise selectively, so this usually means it wasn't discussed publicly, not that it wasn't studied.
First-in-human starting dose
Not stated in public reviews
Why it's blank
The public FDA and EMA reviews of Adstiladrin don't say how the first human dose was chosen. That rationale is in the IND, which is confidential, so it is missing for most approved products.
How it's usually set for gene therapies
FDA expects preclinical proof-of-concept and toxicology studies to identify active dose levels and support the choice of starting dose and escalation. The 2013 guidance gives no numeric formula or scaling rule for the starting dose.
“Selection of potential starting dose level, dose-escalation schedule, and dosing regimen for clinical trials.”
✓ VerifiedFDA 2013: Preclinical Assessment of Investigational Cellular and Gene Therapy…, p. 7Source ↗
This product's starting point
NOAEL / key findings: Local NOAEL not set (urinary tract changes at all doses, reversible); highest non-severely toxic dose 1.25e13 vp rAd-IFN with 25 mg Syn3; bladder/ureter/urethra inflammation (EMA assessment report, p. 37)
Longest repeat-dose systemic studies
Longest repeat-dose study and recovery
Cynomolgus monkey intravesical GLP study, doses on Days 1 and 91, with 2-month recovery
“control on Days 1 and 91, followed by a two month observation period in a GLP toxicology study.”
Pivotal GLP studies
GLP monkey intravesical study: 2 doses (Days 1 and 91) of rAd-IFN/Syn3 at 2.5e11 or 1.25e13 vp/animal, Syn3 alone, placebo; 2-month observation
“on Days 1 and 91, followed by a two month observation period in a GLP toxicology study.”
DART package
Species: DART
Not conducted (not warranted: product characteristics, toxicology results, patient population)
“Carcinogenicity and reproductive and developmental toxicity studies were not performed for rAd-IFN/Syn3. These studies are not warranted based on the product characteristics, results from the toxicology studies, and target patient population.”
Reproductive & developmental
Not conducted (not warranted by product characteristics, tox results, target population)
“Carcinogenicity and reproductive and developmental toxicity studies were not performed for rAd”
PPND / ePPND: when
Not conducted: DART not warranted (product characteristics, toxicology results, target population)
“Carcinogenicity and reproductive and developmental toxicity studies were not performed for rAd-IFN/Syn3. These studies are not warranted based on the product characteristics, results from the toxicology studies, and target patient population.”
Carcinogenicity
Species: carcinogenicity
Not conducted (not warranted: product characteristics, toxicology results, patient population)
“Carcinogenicity and reproductive and developmental toxicity studies were not performed for rAd-IFN/Syn3. These studies are not warranted based on the product characteristics, results from the toxicology studies, and target patient population.”
Carcinogenicity model
Not conducted
“No carcinogenicity studies were conducted with Adstiladrin.”
Carcinogenicity timing
Not conducted: not warranted (product characteristics, toxicology results, target population)
“Carcinogenicity and reproductive and developmental toxicity studies were not performed for rAd-IFN/Syn3. These studies are not warranted based on the product characteristics, results from the toxicology studies, and target patient population.”
Safety marginopen answer page →
Safety margin at NOAEL
Monkey-to-human local exposure multiple (dose-based) 3.11x for nadofaragene firadenovec, 1.87x for Syn3
“The local exposure multiples between monkeys and humans are low with 3.11 for nadofaragene firadenovec and 1.87 for Syn3NODA based on dose.”
NOAEL / key findings
Local NOAEL not set (urinary tract changes at all doses, reversible); highest non-severely toxic dose 1.25e13 vp rAd-IFN with 25 mg Syn3; bladder/ureter/urethra inflammation
“25 mg Syn3NODA and 1.25x1013 vp rAd-IFN could be considered the highest non-severely toxic dose.”
Efficacy evidenceopen answer page →
Efficacy evidence
Orthotopic mouse model of human bladder cancer: anti-tumor activity after intravesical rAd-IFN/Syn3
“Intravesical administration of rAd-IFN with the excipient Syn3 was evaluated in an orthotopic mouse model of human bladder cancer . Anti-tumor activity was observed following intravesical administration of rAd-IFN/Syn3 at 1x1010 viral particles/mouse (rAd-IFN concentration of 1x1011 vp/ml in 1 mg/mL Syn3).”
Why that model
Immunodeficient mice required to host human bladder cancer cell xenografts
“The mice were immunocompromised which does not represent the clinical situation reliably, however this is inherent to the use of human bladder cancers cells for the xenograft.”
Reviewer's view of the efficacy data
EMA: in vivo data provide proof-of-concept against bladder cancer xenografts and support dose and Syn3 concentration
“The in vivo pharmacodynamic data provide proof-of-concept for treatment of bladder cancer xenografts by intravesical rAd-IFN/Syn3NODA. Furthermore, the in vivo studies support the choice for the dose of 1x1011 as well as the choice for use of 1 mg/mL Syn3NODA.”
Flexibilityopen answer page →
Flexibility accepted
CarcinogenicityAcceptedBeyond the letter
No carcinogenicity studies with vector or novel excipient; weight-of-evidence assessment for a non-advanced cancer indication
Why: Limited exposure due to dosing once per three months and low systemic levels of excipient and vector reduce carcinogenicity risk · Weight of evidence · Pharmacology or kinetics
“As the proposed indication (high grade Bacillus Calmette-Guerin unresponsive non-muscle invasive bladder cancer) is not an advanced cancer indication, the omission of carcinogenicity evaluation needed to be supported with a weight-of-evidence (WoE) approach for both the vector and the novel excipient.”
“In summary, the limited exposure due to dosing frequency (not chronic, but once per three months) together with the low systemic levels of Syn3NODA and rAd-IFN/IFNα2b reduce the risk for potential carcinogenicity/tumorigenicity.”
DARTAcceptedBeyond the letter
No reproductive and developmental toxicity studies with vector or excipient Syn3
Why: Transient vector DNA in gonads; intravesical route precludes standard studies; infrequent dosing and limited systemic exposure · Pharmacology or kinetics · Weight of evidence
“Developmental and Reproductive Toxicity studies were not conducted using rAd-IFN/Syn3 or Syn3 alone based on the transient rAd-IFN DNA levels detected in the gonads in the biodistribution analysis of rAd-IFN/Syn3”
“The omission of these studies was not considered significant, given the clinical route of administration and inability to conduct standard studies by this route, and the infrequent dosing and anticipated limited systemic exposure.”
GenotoxicityAcceptedBeyond the letter
No genotoxicity assessment of the adenoviral vector; justified with literature on adenoviral integration
Why: Literature on adenoviral integration in treated patients; new bladder tumours more likely reflect natural course of disease · Human data · Weight of evidence
“Absence of genotoxicity assessment of rAd-IFN was justified with literature information on the potential for adenoviral integration in the host genome from (bladder) cells of NMIBC patients treated with Adstiladrin (after treatment with BCG).”
“However, any new bladder tumour in clinical practice will more likely reflect the natural course of NMIBC rather than insertional mutagenesis.”
BiodistributionCriticised but acceptedBeyond the letter
Vector biodistribution in monkey limited to bladder, liver, kidney and gonads; no full tissue analysis
Why: Impact of limited systemic vector exposure on patient safety anticipated to be low · Pharmacology or kinetics
“In a GLP cynomolgus monkey study, tissue distribution of rAd-IFN was studied following intravesical administration, but only for bladder, liver, kidney and gonad tissue. A full tissue analysis of the presence and persistence of rAd-IFN has not been performed.”
“However, the impact of limited systemic exposure to this vector on patient safety is anticipated to be low.”
Safety marginVerdict not stated
Low local exposure multiples in monkey: 3.11 for vector and 1.87 for Syn3 (dose-based)
“The local exposure multiples between monkeys and humans are low with 3.11 for nadofaragene firadenovec and 1.87 for Syn3NODA based on dose. Effects seen in non-clinical monkey studies at a local level can therefore be of clinical relevance.”
Similar precedents
ImlygicGene therapy · talimogene laherparepvec · GM-CSF (oncolytic HSV-1)Rodent + dog or minipig · 12 wkTudriqevGene therapy · vusolimogene oderparepvec · GALV-GP + GM-CSF (oncolytic HSV-1)Rodent only · 26 wkBeqvezGene therapy · fidanacogene elaparvovec · Factor IXMonkey + rodent · 104 wkHemgenixGene therapy · etranacogene dezaparvovec · Factor IXMonkey + rodent · 26 wkRoctavianGene therapy · valoctocogene roxaparvovec · Factor VIIIMonkey + rodent · 26 wkAvastinAntibodies · bevacizumab · VEGF-AMonkey only · 26 wk