Clinical Trials

At Prothena, every step we take to heal, cure and prevent disease, we take in collaboration with the patients and their families who generously participate in clinical studies.

Our current clinical programs include birtamimab for the potential treatment of AL amyloidosis, prasinezumab for the potential treatment of Parkinson’s disease, PRX004 for the potential treatment of ATTR amyloidosis and PRX005 for the potential treatment of Alzheimer’s disease.

Birtamimab Phase 3
AFFIRM-AL Study for
AL Amyloidosis

Birtamimab is a humanized monoclonal antibody under investigation for the treatment of AL amyloidosis in patients categorized as Mayo Stage IV. The confirmatory Phase 3 registration enabling AFFIRM-AL study evaluating the efficacy and safety of birtamimab in Mayo Stage IV patients with AL amyloidosis has initiated under a Special Protocol Assessment agreement with the U.S. Food and Drug Administration (FDA).

Prasinezumab Phase 2 PASADENA Study for Parkinson’s Disease

Prasinezumab is a humanized monoclonal antibody under investigation for the treatment of Parkinson’s disease, and is the focus of a worldwide collaboration between Prothena and Roche. The Phase 2b PADOVA study evaluating the efficacy and safety of prasinezumab in patients with early Parkinson’s disease has initiated. The Phase 2 PASADENA study evaluating prasinezumab in participants with early Parkinson’s disease is ongoing. Both studies are being conducted by our partners at Roche.

PRX004 Phase 1 Study for
ATTR Amyloidosis

PRX004 is a humanized monoclonal antibody under investigation for the treatment of ATTR amyloidosis. The Phase 1 study is complete. Novo Nordisk has acquired Prothena’s Phase 2 ready antibody PRX004. More information on the acquisition can be found here.


PRX005 is a humanized monoclonal antibody under investigation for the treatment of Alzheimer’s disease and is the first target in a collaboration with Bristol Myers Squibb. The Phase 1 study with PRX005 has initiated.

Expanded Access Policy

Prothena is committed to developing safe and effective therapies for patients through thoughtful and efficient drug development. We support the need for expanded access programs and our goal is to provide access to study drugs at the appropriate time and in the correct context for patients with life-threatening diseases.

We consider a number of factors when determining whether or not to support expanded access for a given investigational drug:

  • Will it jeopardize the ongoing development work that Prothena is conducting to bring a therapeutic to market as quickly as possible and to as many patients as possible?
  • Is there adequate drug supply for both the clinical development program (current and future trials) and broad expanded access? To be equitable, the company should endeavor to provide study drug to all qualified expanded access patients if it provides study drug to any one patient.
  • Is there enough evidence to assess that the drug will be safe and effective so that it can be provided to a significant number of patients in an environment that is less controlled than a sponsored clinical trial?
  • Can expanded access be offered in accordance with local laws and regulatory requirements?
  • To meet regulatory requirements, will the safety data be adequately provided to Prothena by a local physician outside of a sponsored clinical trial?

Prothena has determined, after assessing these considerations, that expanded access cannot currently be offered for any of our investigational drugs. We periodically re-evaluate this policy and its application to our study drugs.

If and when we provide expanded access for a particular investigational drug, we will review each individual request and respond to the physician who makes the request. During this process, we will need to ensure that:

  • Granting access will not interfere with current clinical trials or regulatory filings.
  • The request is made through a clinician expert in the therapeutic area who has weighed the benefit and risk of providing the investigational drug to the patient.
  • The patient does not qualify for any ongoing or planned clinical trials.
  • The patient has exhausted other therapies that may help him/her.

The above are general requirements, and specific requirements will be generated for a given investigational drug or clinical program if and when Prothena initiates an expanded access program. If you have questions about Prothena’s Expanded Access Policy, please contact us at