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First-in-human starting dose
Not stated in public reviews
Why it's blank

The public FDA and EMA reviews of Padcev 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 ADCs

ADCs with cytotoxic payloads follow the S9 rules (1/10 STD10 or 1/6 HNSTD of the ADC, scaled by body surface area). For immune agonists, a MABEL-based start dose should be considered instead.

“For example, for cytotoxic payloads, the starting clinical dose can be determined using either 1/10th the Severely Toxic Dose (STD) in 10% of animals (STD10) in rodents or 1/6th the Highest Non- Severely Toxic Dose (HNSTD) in non-rodents, for the ADC based on body surface area, depending on which is the most appropriate and/or sensitive species.”
✓ VerifiedICH 2018: ICH S9 Guideline: Nonclinical Evaluation for Anticancer…, p. 15Source ↗
This product's starting point

NOAEL / key findings: Monkey HNSTD/MTD 3 mg/kg, rat MTD 5 mg/kg; skin, injection site, bone marrow, liver, eye, male reproductive organs (FDA multi-discipline review, p. 56)

Full method, every step sourced →

NOAEL / key findings
Monkey HNSTD/MTD 3 mg/kg, rat MTD 5 mg/kg; skin, injection site, bone marrow, liver, eye, male reproductive organs
“In the 4-week monkey study (# 20005664), AGS-22M6E systemic exposure at 3 mg/kg (MTD/HNSTD) was 2450 µg.hr/mL (Day 1) and 903 µg.hr/mL (Day 22).”
✓ VerifiedFDA multi-discipline review, p. 56Source ↗

Same question, other ADCs

Elahere

mirvetuximab soravtansine · FRα
Rationale not stated; FIH Study 0401 escalated from 0.15 mg/kg (TBW) to 7.0 mg/kg

Enhertu

fam-trastuzumab deruxtecan · HER2
1/12 HED of monkey HNSTD (0.8 mg/kg), also matching minimum effective trough concentration

Kadcyla

ado-trastuzumab emtansine · HER2
HNSTD-based: monkey HNSTD 10 mg/kg (q3w x4), below 1/10 rat severely toxic dose, used to set Phase I start

Zynlonta

loncastuximab tesirine · CD19
1/6 HNSTD in cynomolgus monkey cited as rationale for species choice; actual FIH calculation not detailed

Adcetris

brentuximab vedotin · CD30
Not stated in public reviews

Besponsa

inotuzumab ozogamicin · CD22
Not stated in public reviews

Datroway

datopotamab deruxtecan · Trop-2
Not stated in public reviews

Decnupaz

pivekimab sunirine · CD123
Not stated in public reviews

Emrelis

telisotuzumab vedotin · c-Met
Not stated in public reviews

Mylotarg

gemtuzumab ozogamicin · CD33
Not stated in public reviews

Polivy

polatuzumab vedotin · CD79b
Not stated in public reviews

Tivdak

tisotumab vedotin · Tissue factor
Not stated in public reviews

Trodelvy

sacituzumab govitecan · Trop-2
Not stated in public reviews

Summary across all 14 ADCs →