# Olaparib In Metastatic Breast Cancer

Source: https://onco.cc/trials/nct03344965/  
OnCo record `nct03344965` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Olaparib showed activity in metastatic breast cancer with germline PALB2 or somatic BRCA alterations, but the somatic cohort missed its prespecified response target.

## Summary

The registry lists NCT03344965 as active not recruiting, last updated 2026-01-05. Enrolment is 114 planned participants, an estimate. Interventions: Olaparib. Primary measures include Objective Response Rate. No results are posted in the registry; this does not exclude separate publications. The 2026 expansion publication reports 54 participants: 24 germline PALB2 and 30 somatic BRCA1/2, with 42 ER-positive/HER2-negative, seven TNBC and five HER2-positive cancers. Germline PALB2 response was 75% (80% CI 60.2-86.3), median PFS 9.4 months (90% CI 8.3-13.1). Somatic BRCA response was 36.7% (80% CI 24.7-50.0), median PFS 5.5 months (90% CI 2.8-8.3), and failed the prespecified response target. This metastatic single-arm evidence does not establish an adjuvant somatic-BRCA indication.

## Fields

- Kind: Trial
- Status: active
- Last checked: 2026-10-06
- Registry id: NCT03344965
- Phase: 2
- Setting: A Phase 2 Study of Olaparib Monotherapy in Metastatic Breast Cancer Patients With Germline or Somatic Mutations in DNA Repair Genes (Olaparib Expanded)
- Sponsor: Beth Israel Deaconess Medical Center
- Outcomes: Objective response, germline PALB2 cohort (2026 expansion): Olaparib, germline PALB2 75%; Objective response, somatic BRCA1/2 cohort (2026 expansion): Olaparib, somatic BRCA1/2 36.7%

## Sources

- ClinicalTrials.gov NCT03344965: https://clinicaltrials.gov/study/NCT03344965
- TBCRC 048 expansion, 2026: https://doi.org/10.1200/JCO-25-02075

## Connected records

- cancers: [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/)
- targets: [PARP](https://onco.cc/targets/parp/)
- drugs: [Olaparib](https://onco.cc/drugs/olaparib/)

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