LOXO-305

Eli Lilly and Company · Phase 2 active Small molecule

LOXO-305 is a BTK inhibitor Small molecule drug developed by Eli Lilly and Company. It is currently in Phase 2 development for Relapsed or refractory mantle cell lymphoma, Relapsed or refractory marginal zone lymphoma. Also known as: LY3527727, Pirtobrutinib.

Selective Bruton's tyrosine kinase (BTK) inhibitor

Selective Bruton's tyrosine kinase (BTK) inhibitor Used for Relapsed or refractory mantle cell lymphoma, Relapsed or refractory marginal zone lymphoma.

Likelihood of approval

16.3% 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.
• Big-pharma sponsor +3.0pp
  Eli Lilly and Company is a top-20 pharma sponsor — historical approval rates run ~3pp above average due to scale, regulatory experience, and trial-design quality.

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	LOXO-305
Also known as	LY3527727, Pirtobrutinib
Sponsor	Eli Lilly and Company
Drug class	BTK inhibitor
Target	BTK
Modality	Small molecule
Therapeutic area	Oncology
Phase	Phase 2

Mechanism of action

LOXO-305 is a selective inhibitor of Bruton's tyrosine kinase (BTK), a key component of the B-cell receptor signaling complex. Inhibition of BTK has been shown to be effective in treating certain types of non-Hodgkin lymphoma.

Approved indications

• Relapsed or refractory mantle cell lymphoma
• Relapsed or refractory marginal zone lymphoma

Common side effects

• Neutropenia
• Thrombocytopenia
• Anemia
• Fatigue
• Diarrhea

Key clinical trials

• Phase II Study of Pirtobrutinib With Venetoclax In Relapsed-Refractory MCL (Mantle Cell Lymphoma) Patients (PHASE2)
• A Study of Pirtobrutinib (LOXO-305) Versus Ibrutinib in Participants With Chronic Lymphocytic Leukemia (CLL)/Small Lymphocytic Lymphoma (SLL) (PHASE3)
• Study of Oral LOXO-338 in Patients With Advanced Blood Cancers (PHASE1)
• A Study of (LY3527727) Pirtobrutinib in Participants With Previously Treated Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma or Non-Hodgkin Lymphoma (PHASE4)
• A Master Protocol to Evaluate the Long-Term Safety of (LY3527727) Pirtobrutinib (PHASE4)
• LV20.19 CAR T-Cells in Combination With Pirtobrutinib for Relapsed, Refractory B-cell Malignancies (PHASE1)
• Pirtobrutinib (LOXO-305) and Venetoclax for the Treatment of Patients With CLL or SLL Resistant to Covalent BTKi (PHASE2)
• Pirtobrutinib and Venetoclax With MRD Detection for Previously Untreated Chronic Lymphocytic Leukemia (PHASE2)

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:

• LOXO-305 CI brief — competitive landscape report
• LOXO-305 updates RSS · CI watch RSS
• Eli Lilly and Company portfolio CI

Frequently asked questions about LOXO-305

What is LOXO-305?

LOXO-305 is a BTK inhibitor drug developed by Eli Lilly and Company, indicated for Relapsed or refractory mantle cell lymphoma, Relapsed or refractory marginal zone lymphoma.

How does LOXO-305 work?

Selective Bruton's tyrosine kinase (BTK) inhibitor

What is LOXO-305 used for?

LOXO-305 is indicated for Relapsed or refractory mantle cell lymphoma, Relapsed or refractory marginal zone lymphoma.

Who makes LOXO-305?

LOXO-305 is developed by Eli Lilly and Company (see full Eli Lilly and Company pipeline at /company/eli-lilly).

Is LOXO-305 also known as anything else?

LOXO-305 is also known as LY3527727, Pirtobrutinib.

What drug class is LOXO-305 in?

LOXO-305 belongs to the BTK inhibitor class. See all BTK inhibitor drugs at /class/btk-inhibitor.

What development phase is LOXO-305 in?

LOXO-305 is in Phase 2.

What are the side effects of LOXO-305?

Common side effects of LOXO-305 include Neutropenia, Thrombocytopenia, Anemia, Fatigue, Diarrhea.

What does LOXO-305 target?

LOXO-305 targets BTK and is a BTK inhibitor.

Related

• Drug class: All BTK inhibitor drugs
• Target: All drugs targeting BTK
• Manufacturer: Eli Lilly and Company — full pipeline
• Therapeutic area: All drugs in Oncology
• Indication: Drugs for Relapsed or refractory mantle cell lymphoma
• Indication: Drugs for Relapsed or refractory marginal zone lymphoma
• Also known as: LY3527727, Pirtobrutinib