Last reviewed 2026-05-31 · How we verify

Apirazin (CHLORTHENOXAZINE)

Phase 2 active Small molecule ✓ Verified May 2026

Apirazin (generic name: CHLORTHENOXAZINE) is a drug. It is currently in Phase 2 development.

Apirazin works by inhibiting the activity of PARP1, a protein that plays a key role in DNA repair and cell death.

Apirazin is a small molecule with the synonyms AP 67, AP-67, APIRAZIN, CHLORTHENOXAZIN(E), CHLORTHENOXAZINE, and CLORTENOXAZINA.

Likelihood of approval

13.3% vs 15.3% industry baseline

If approved by FDA: likely 2031–2034

Steps remaining: Phase 3 → NDA/BLA submission

Confidence: Medium

Why this estimate

Baseline phase 2 → approval rate +15.3pp
Industry-wide phase 2 drugs reach approval ~15.3% of the time (BIO/Informa 2023 industry benchmark across all therapeutic areas).
Oncology Phase 2 attrition -2.0pp
Oncology drugs have higher Phase 2-to-Phase 3 attrition than average — many fail to show OS benefit in larger studies.

Predicted approval windows by jurisdiction (conditional on FDA approval)

Regulator	Country	Likely year	Lag vs FDA
FDA	US	2031–2034	—
EMA	EU	2032–2035	+0.7 yr
MHRA	GB	2032–2035	+0.7 yr
Health Canada	CA	2032–2036	+0.9 yr
TGA	AU	2032–2036	+1.2 yr
PMDA	JP	2032–2036	+1.5 yr
NMPA	CN	2033–2037	+2.3 yr
MFDS	KR	2032–2036	+1.4 yr
CDSCO	IN	2032–2037	+1.8 yr
ANVISA	BR	2033–2037	+2.3 yr

Hover any row for the lag rationale. Lag estimates are reduced when the drug has FDA Breakthrough or EMA PRIME designation (sponsors file globally in parallel).

Estimate based on the BIO/Informa industry phase transition rates plus per-drug modifiers for therapeutic area, sponsor type, FDA designations, mechanism, and trial design. Per-jurisdiction lags from Tufts CSDD international approval studies. Not investment, clinical or regulatory advice. Methodology: /methodology#likelihood.

At a glance

Generic name	CHLORTHENOXAZINE
Target	Poly [ADP-ribose] polymerase 1
Modality	Small molecule
Therapeutic area	Oncology
Phase	Phase 2

Mechanism of action

Think of PARP1 like a repair crew that fixes damaged DNA. When PARP1 is inhibited, the repair crew can't fix the damage, which can lead to cell death. This can be beneficial in treating certain types of cancer, but it also means that healthy cells may be more susceptible to damage.

Approved indications

No approved indications tracked.

Common side effects

No common side effects on file.

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

Apirazin CI brief — competitive landscape report
Apirazin updates RSS · CI watch RSS

Frequently asked questions about Apirazin

What is Apirazin?

Apirazin (CHLORTHENOXAZINE) is a Small molecule drug.

How does Apirazin work?

Apirazin works by inhibiting the activity of PARP1, a protein that plays a key role in DNA repair and cell death.

What is the generic name of Apirazin?

CHLORTHENOXAZINE is the generic (nonproprietary) name of Apirazin.

What development phase is Apirazin in?

Apirazin is in Phase 2.

What does Apirazin target?

Apirazin targets Poly [ADP-ribose] polymerase 1.

Target: All drugs targeting Poly [ADP-ribose] polymerase 1
Therapeutic area: All drugs in Oncology

Primary sources · FDA · ClinicalTrials.gov · EMA · SEC EDGAR · ChEMBL · Wikidata · full sourcing