Abiraterone & Enzalutamide FAQs

 

a. When should a patient stop taking abiraterone and/or enzalutamide?

For patients with:

  • M1 disease
  • Relapsed previously radically treated disease
  • N+M0 disease not undergoing radical radiotherapy*

-> abiraterone acetate and enzalutamide should continue until biochemical, clinical and objective progressions have all been reported or other treatment for progressive disease is introduced

 

For patients with:

  • N0M0 disease
  • N+M0 disease undergoing radical radiotherapy

-> abiraterone acetate and enzalutamide should continue until the earliest of 2 years or all categories of disease progression as defined for M1 participants or other treatment is introduced

* For trial purposes the duration of treatment is determined by the intention at the time of randomisation.

 

b. My patient’s original staging has been revised, at randomisation they were staged as metastatic disease but it is now thought that they have locally advanced disease amendable to radical radiotherapy. Does this change the treatment duration?

For trial purposes the duration of therapy is determined by the intention at the time of randomisation. Therefore treatment with research abiraterone and enzalutamide may continue until all three types of progression have occurred. Radical prostate radiotherapy may be given concurrently with abiraterone and enzalutamide. Research treatment may also be paused and re-started providing the protocol criteria for stopping have not been met (all three types of progression or intention to commence an additional treatment for progressive disease).

 

c. Can we restart a patient on Abiraterone and/or Enzalutamide?

For patients for whom treatment was discontinued but who have not met the criteria for stopping, treatment can be re-introduced at any time if this is considered safe and in the patient’s best interest. If it is only possible to restart one of the treatments, STAMPEDE investigators may consider if this should be abiraterone, given that we now know of its positive effects and that we do not yet have data on enzalutamide alone in this setting.

 

d. When should safety bloods (serum potassium, liver function tests) be checked?

Regular monitoring of serum potassium is required whilst receiving research abiraterone. This should be 2-weekly in the first 12-weeks, then monthly until 12 months on treatment. For patients who have not experienced toxicity following 12 months of treatment this may be reduced to every 2 months, whilst receiving research abiraterone. Increased monitoring is required in patients experiencing toxicity.

 

e. When should we perform Blood Pressure Monitoring?

Regular monitoring of blood pressure is required whilst receiving research abiraterone. This should be monthly in the first year of treatment. If blood pressure is well controlled this may be reduced to every 2 months after 12 months. Patient-recorded BP diaries are encouraged; it is also possible for patients to have measurements obtained via their GP. Investigators should ensure representative values are obtained and recorded in the medical notes.

 

f. Do I have to stop research abiraterone and enzalutamide or can I dose reduce a patient experiencing toxicities?

The required action depends on the severity (grade) and specific toxicity. Dose reductions are encouraged for low grade toxicities. Guidance within protocol section 6.2.3 and 6.2.5 should be followed. Dose reductions and review of the prednisolone dose should be considered for all symptoms suggestive of mineralocorticoid excess (hypertension, hypokalaemia, peripheral oedema). Increasing the prednisolone dose from 5mg OD to BD should be tried.

Research abiraterone must be paused in the following circumstances:

  • Grade 3 or higher hypertension
  • Grade 2 hypokalaemia
  • Grade 2 increase in AST or ALT or increase in bilirubin >1.5 ULN

Research abiraterone must be permanently stopped in the following circumstances:

  • Grade 3 hypokalaemia associated with abiraterone
  • Grade 4 increase in AST or ALT or increase in bilirubin >10 ULN

Research enzalutamide must be permanently stopped in the following circumstance:

  • Participant experiences a seizure

 

 g. Where do I order abiraterone from?

Abiraterone for Arm G and Arm J are ordered through different distributors;

  • Arm G – CSM is the distributor. Please complete the order form and email to:

144-Abirateroneiis@csmondemand.com

  • Arm J – SHARP Clinical Services is the distributor. Please complete the order form and email to:

SCSUK-ShipmentRequests@sharpclinical.com

Please find the order form for each arm here:

http://www.stampedetrial.org/centres/essential-documents/pharmacy/

 

Have another question or looking for more information? Please visit the STAMPEDE Training Suite for the training slides detailing information on STAMPEDE.

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