Last reviewed 2026-04-20 · How we verify

Arsobal (MELARSOPROL)

Phase 3 active Small molecule

Arsobal (generic name: MELARSOPROL) is a melarsoprol drug. It is currently in Phase 3 development for African trypanosomiasis.

Arsobal works by inhibiting the enzyme dihydrofolate reductase in the parasite, disrupting its ability to synthesize DNA and ultimately leading to its death.

Arsobal (Melarsoprol) is a melarsoprol-based small molecule drug developed by Rhône-Poulenc, currently owned by Sanofi. It is used to treat African trypanosomiasis, a parasitic disease caused by the protozoan Trypanosoma brucei. The commercial status of Arsobal is not explicitly stated, but it is likely patented. Key safety considerations include potential neurotoxicity and allergic reactions. It is essential to monitor patients for these adverse effects.

Likelihood of approval

58.3% vs 58.3% industry baseline

If approved by FDA: likely 2028–2030

Steps remaining: NDA/BLA submission

Confidence: High

Why this estimate

Baseline phase 3 → approval rate +58.3pp
Industry-wide phase 3 drugs reach approval ~58.3% of the time (BIO/Informa 2023 industry benchmark across all therapeutic areas).

Predicted approval windows by jurisdiction (conditional on FDA approval)

Regulator	Country	Likely year	Lag vs FDA
FDA	US	2028–2030	—
EMA	EU	2029–2031	+0.7 yr
MHRA	GB	2029–2031	+0.7 yr
Health Canada	CA	2029–2032	+0.9 yr
TGA	AU	2029–2032	+1.2 yr
PMDA	JP	2029–2032	+1.5 yr
NMPA	CN	2030–2033	+2.3 yr
MFDS	KR	2029–2032	+1.4 yr
CDSCO	IN	2029–2033	+1.8 yr
ANVISA	BR	2030–2033	+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	MELARSOPROL
Drug class	melarsoprol
Modality	Small molecule
Therapeutic area	Other
Phase	Phase 3

Mechanism of action

Imagine your body's cells are like factories that make new parts. The parasite's cells are like factories that make new copies of themselves. Arsobal stops the parasite's factories from making new parts, which eventually kills the parasite.

Approved indications

African trypanosomiasis

Common side effects

No common side effects on file.

Key clinical trials

Randomized Clinical Trial of Three Drug Combinations for Late-Stage Gambiense Human African Trypanosomiasis (PHASE3)

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

Source	Used for
ClinicalTrials.gov	Trial enrolment, design, endpoints, results

Competitive intelligence

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

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

Frequently asked questions about Arsobal

What is Arsobal?

Arsobal (MELARSOPROL) is a melarsoprol drug, indicated for African trypanosomiasis.

How does Arsobal work?

Arsobal works by inhibiting the enzyme dihydrofolate reductase in the parasite, disrupting its ability to synthesize DNA and ultimately leading to its death.

What is Arsobal used for?

Arsobal is indicated for African trypanosomiasis.

What is the generic name of Arsobal?

MELARSOPROL is the generic (nonproprietary) name of Arsobal.

What drug class is Arsobal in?

Arsobal belongs to the melarsoprol class. See all melarsoprol drugs at /class/melarsoprol.

What development phase is Arsobal in?

Arsobal is in Phase 3.

Drug class: All melarsoprol drugs
Therapeutic area: All drugs in Other
Indication: Drugs for African trypanosomiasis

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