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Lyfgenia: what flexibility did regulators accept, and why?

lovotibeglogene autotemcel · HBB T87Q (LVV, ex vivo HSC)
Flexibility accepted
CarcinogenicityAcceptedBeyond the letter
No traditional carcinogenicity studies; insertional mutagenesis assessed by in vitro immortalization assay and integration site analysis
Why: Acceptable based on the product type · Other reason
“Carcinogenicity Studies: No traditional carcinogenicity studies were conducted with lovo-cel which is acceptable based on the product type.”
✓ VerifiedFDA pharmacology/toxicology review, p. 26Source ↗
DARTAcceptedBeyond the letter
No developmental and reproductive toxicity studies
Why: No adverse findings in reproductive tissues of mice; not warranted given product characteristics and safety profile · Weight of evidence · Other reason
“Developmental and Reproductive Toxicology Studies: Per the applicant, developmental and reproductive toxicology studies were not conducted because there were no adverse findings in the male and female reproductive tissues of mice administered mBMCs transduced with BB305 LVV”
✓ VerifiedFDA pharmacology/toxicology review, p. 22Source ↗
“Carcinogenicity and developmental and reproductive toxicity studies were not conducted with LYFGENIA™. These studies are not warranted based on the product characteristics and safety profile.”
✓ VerifiedFDA pharmacology/toxicology review, p. 3Source ↗
Efficacy modelVerdict not stated
Proof-of-concept in SCD mice used a related vector (βA-T87Q LVV) encoding the same transgene, not BB305
Why: Related vector encodes the same transgene
“In vivo POC studies were also conducted using transgenic mouse models of SCD, where murine bone marrow cells (mBMCs) were transduced with the βA-T87Q LVV, a related vector encoding the same transgene, and showed expression of βA-T87Q and correction of the sickling phenotype through 3 months post-transplantation.”
✓ VerifiedFDA summary basis for approval, p. 11Source ↗

Same question, other gene therapies

Adstiladrin

nadofaragene firadenovec · IFN-alpha2b (adenovirus, intravesical)
No carcinogenicity studies with vector or novel excipient; weight-of-evidence assessment for a non-advanced cancer indication

Beqvez

fidanacogene elaparvovec · Factor IX
Definitive 3-month monkey GLP toxicity study used a closely related predecessor vector, not the clinical product

Casgevy

exagamglogene autotemcel · BCL11A enhancer (CRISPR-Cas9, ex vivo HSC)
No in vivo proof-of-concept study; no disease model for TDT or SCD, so engraftment and editing persistence studied in NSG xenotransplant mice

Elevidys

delandistrogene moxeparvovec · Micro-dystrophin
No developmental and reproductive toxicology studies

Fayuvi

rebisufligene etisparvovec · SGSH (AAV9)
No genotoxicity or carcinogenicity/tumorigenicity studies; weight-of-evidence risk assessment instead

Genglycos

pariglasgene brecaparvovec · G6PC (AAV8)
No carcinogenicity/tumorigenicity studies; justified by low integration risk of episomal AAV8 vector and literature

Glybera

alipogene tiparvovec · LPL (AAV1)
Toxicity evaluated in a single species (wild-type mice) only

Hemgenix

etranacogene dezaparvovec · Factor IX
Several toxicology studies used predecessor vector AMT-060 (wild-type hFIX) instead of the final product

Imlygic

talimogene laherparepvec · GM-CSF (oncolytic HSV-1)
No genotoxicity studies; non-integrating HSV-1 episome

Itvisma

onasemnogene abeparvovec (intrathecal) · SMN1 (AAV9, intrathecal)
No NOAEL in the pivotal intrathecal NHP study; DRG, spinal cord, nerve and brain findings at the clinical-equivalent dose

Kebilidi

eladocagene exuparvovec · AADC
No in vivo pharmacology studies with the product; in vitro human cell data plus published literature only

Kresladi

marnetegragene autotemcel · ITGB2 (LVV, ex vivo HSC)
Clinical product not tested; surrogate murine Lin- HSPCs transduced with the clinical vector used for definitive toxicology and biodistribution

Lenmeldy

atidarsagene autotemcel · ARSA (LVV, ex vivo HSC)
No reproductive and developmental toxicity studies

Luxturna

voretigene neparvovec · RPE65
No reproductive toxicity studies; gonadal biodistribution in dogs and primates used instead

Otarmeni

lunsotogene parvec · OTOF (AAV, intracochlear)
No genotoxicity or carcinogenicity/tumorigenicity studies; tumorigenicity risk to be assessed in a postmarketing study

Papzimeos

zopapogene imadenovec · HPV6/11 antigens (gorilla adenovirus)
Definitive repeat-dose toxicology study non-GLP, in wild-type mice only; murine antigen processing likely differs from human

Roctavian

valoctocogene roxaparvovec · Factor VIII
No carcinogenicity or tumorigenicity studies (nor safety pharmacology or DART studies)

Skysona

elivaldogene autotemcel · ABCD1 (LVV, ex vivo HSC)
Safety tested only in single-dose studies in immunodeficient myeloablated mice given healthy-donor transduced cells

Strimvelis

autologous CD34+ cells transduced with ADA (no INN) · ADA (gamma-retroviral, ex vivo HSC)
No tumorigenicity study: long-term engraftment of transduced cells in mice not achievable; risk assessed from clinical data and vector literature

Tudriqev

vusolimogene oderparepvec · GALV-GP + GM-CSF (oncolytic HSV-1)
Rat toxicology, biodistribution and DART studies used the murine surrogate mRP1 (murine GM-CSF); clinical product tested only in tumor-bearing mice

Vyjuvek

beremagene geperpavec · COL7A1 (HSV-1, topical)
Toxicity tested in a single species (mouse), chosen only on historical use

Waskyra

etuvetidigene autotemcel · WAS (LVV, ex vivo HSC)
Pharmacology and toxicology done with murine surrogate HSPCs transduced with the WAS vector in mice, not the human product

Zevaskyn

prademagene zamikeracel · COL7A1 (RV-modified keratinocyte sheets)
No carcinogenicity or tumorigenicity studies; insertional oncogenesis risk deferred to a long-term postmarketing safety study

Zolgensma

onasemnogene abeparvovec · SMN1
Pivotal toxicity in neonatal mice only; no adequate safety study in a species closer to human (NHP study non-GLP, low-dose pilot)

Zynteglo

betibeglogene autotemcel · HBB T87Q (LVV, ex vivo HSC)
No carcinogenicity studies; low risk of oncogenic transformation concluded from the available vector data

Summary across all 26 gene therapies →