The purpose of this study is to determine whether a new catheter is safe and effective in treating malignant pleural effusions.

Inclusion Criteria:

1. Subject is ≥ 18 years old.

2. Subject has a symptomatic malignant pleural effusion requiring intervention. For an effusion to be defined as malignant, at least one of the following must be true:

   • There is histocytological confirmation of pleural malignancy
   • The effusion is an exudate (as per Light's criteria) in the context of histocytologically proven malignancy elsewhere, with no other clear cause for fluid identified

3. Subject has a history of at least one ipsilateral pleural effusion causing dyspnoea that responded to thoracentesis where the lung expanded and the dyspnoea was relieved.

4. Subject is willing and able to provide written informed consent.

5. Subject is willing and able to meet all study requirements, including attending follow-up visits or receiving trial-related telephone calls.

6. There is sufficient fluid on thoracic ultrasound to allow safe insertion of an indwelling pleural catheter

7. Negative pregnancy test if appropriate

Exclusion Criteria:

1. Subject has significant trapped lung (>20%), or a proximal bronchial obstruction which is likely to lead to trapped lung.
2. Subject has a Karnofsky score of less than 50, or a WHO/ECOG performance status of 3* or more.
3. Subject is pregnant, planning to become pregnant, or is lactating.
4. Subject has a history of empyema.
5. Subject has a history of chylothorax.
6. Subject has an uncorrected coagulopathy.
7. Subject is allergic to device materials.
8. Subject has evidence, in the opinion of the Chief Investigator, of either on-going systemic or pleural infection.
9. Subject has had a lobectomy or pneumonectomy on the side of the effusion.
10. Subject has undergone a previous attempt at pleurodesis which has failed.
11. Subject has previously been diagnosed with a serious immunodeficiency disorder.
12. Subject has bilateral pleural effusions, with both being at least moderate in size (greater than 1/3 of the hemithorax on chest x-ray).
13. Subject has evidence of fluid loculation such that attempts at pleurodesis are likely to be futile.
14. Subject has a mediastinal shift of ≥2cm toward the side of the effusion.
15. Subject is receiving concurrent intrapleural chemotherapy or radiation therapy to the ipsilateral chest.
16. Subject has any clinical condition, diagnosis, or social circumstance that, in the opinion of the Chief Investigator, would mean participation in the study would be contraindicated.
17. Subject has no access to a telephone
18. No details of blood values (full blood count, clotting screen, urea and electrolytes, liver function) from within the last 10 days * Patients who have a performance status of 3 may be considered for the trial if the removal of their fluid would likely improve their performance score by 1 or more.