• Assessment of long term safety and tolerability of Sativex and GW-2000-02 in subjects with cancer related pain by monitoring the number, frequency and type of adverse events reported by subjects. [ Time Frame: 7-10 days after Visit 1 and then every four weeks ] [ Designated as safety issue: Yes ]
  

• Laboratory parameters pre and post-treatment [ Time Frame: Every four weeks ] [ Designated as safety issue: No ]
  
• Use of rescue medication [ Time Frame: 7-10 days after Visit 1 and then every four weeks ] [ Designated as safety issue: No ]
  
• Use of maintenance analgesic medication [ Time Frame: 7-10 days after Visit 1 and then every four weeks ] [ Designated as safety issue: No ]
  
• Pain severity 0-10 NRS [ Time Frame: 7-10 days after Visit 1 and then every four weeks ] [ Designated as safety issue: No ]
  
• Health 0-10 NRS [ Time Frame: 7-10 days after Visit 1 and then every four weeks ] [ Designated as safety issue: No ]
  
• EORTC quality of life questionnaire [ Time Frame: 7-10 days after Visit 1 and then every four weeks ] [ Designated as safety issue: No ]
  
• Brief Pain Inventory Short Form [ Time Frame: 7-10 days after Visit 1 and then every four weeks ] [ Designated as safety issue: No ]
  

Subjects who have previously participated in GWCA0101, a two week (two days baseline and two weeks treatment period), multicentre, double blind, randomised, placebo controlled, parallel group study to evaluate the efficacy of Sativex® and GW-2000-02 in subjects with cancer-related pain are screened, and if eligible begin dosing with open-label Sativex®. They are allowed to self-titrate their study medication to symptom resolution or maximum tolerated/allowable dose of 130 mg THC and 120 mg CBD and have the opportunity to request a change from Sativex® to GW-2000-02 if they or the investigator consider their response less than optimal. Subjects are reviewed for tolerability and evidence of clinical benefit at 7-10 days after Visit 1 and then every four weeks. Continuation within the study is conditional on satisfactory reports of tolerability, efficacy and dosing regime.

Inclusion Criteria:

• Willing and eligible to continue into the extension study from GWCA0101.
• Complied adequately with the study requirements, as detailed in GWCA0101.
• In the investigator's opinion able to undertake and comply with all of the study requirements (it is understood that progress of the disease may accelerate and affect this ability).
• Willing and able to read, consider and understand the subject information and consent form and to give written informed consent in compliance with the Declaration of Helsinki1.
• Willing to allow their own general practitioner, and consultant if appropriate, to be informed of study participation.
• Willing for their name to be notified to the Home Office for participation in the trial.

Exclusion Criteria:

• Have not participated in GWCA0101.
• Have not complied adequately with the study requirements, as detailed in GWCA0101.
• Experienced an unacceptable AE, whilst participating in GWCA0101.
• Known or suspected to have had an adverse reaction to cannabinoids causing psychosis or other severe psychiatric illness.
• History of any type of schizophrenia, any other psychotic illness, a serious personality disorder, or other significant psychiatric illness other than depression associated with their chronic pain and/or in response to the underlying condition.
• Currently taking levodopa (Sinemet®, Sinemet plus®, Levodopa®, L-dopa®, Madopar®, Benserazide®).
• Has a serious cardiovascular disorder, including angina, uncontrolled hypertension, or an uncontrolled symptomatic cardiac arrhythmia.
• Has significant renal or hepatic impairment, which in the opinion of the investigator, are unsuitable for treatment with IMP.
• History of epilepsy.
• Female subjects of child bearing potential and male subjects whose partner is of child bearing potential, unless willing to ensure that they or their partner use effective contraception during the study and for three months thereafter.
• If female, are pregnant or lactating, or are planning pregnancy during the course of the study and for three months thereafter.
• Have oral cavity cancers or whose previous treatments had included radiotherapy to the floor of the mouth.
• In the opinion of the investigator, are unsuitable to participate in the study for any other reason, not mentioned in the inclusion and exclusion criteria.