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, coramitug (PRX004) for the potential treatment of ATTR amyloidosis, and BMS-986446/PRX005 and PRX012 for the potential treatment of Alzheimer’s disease.

Phase 3 AFFIRM-AL Study
for AL Amyloidosis

Birtamimab is a humanized monoclonal antibody being developed for the potential treatment of patients with Mayo Stage IV AL amyloidosis. The confirmatory Phase 3 registration enabling AFFIRM-AL study (NCT04973137) evaluating the efficacy and safety of birtamimab in patients with Mayo Stage IV AL amyloidosis is ongoing under a Special Protocol Assessment (SPA) agreement with the FDA.

Phase 2 PASADENA Studies
for Parkinson’s Disease

Prasinezumab is a humanized monoclonal antibody being developed for the potential treatment of Parkinson’s disease, and is the focus of a worldwide collaboration between Prothena and Roche. The Phase 2b PADOVA study (NCT04777331) evaluating the efficacy and safety of prasinezumab in patients with early Parkinson’s disease is ongoing. Also, the open label extension portion of the Phase 2 PASADENA study (NCT03100149) evaluating prasinezumab in participants with early Parkinson’s disease is ongoing. Both studies are being conducted by our partners at Roche.

FOR ATTR Amyloidosis

Coramitug (PRX004) is a humanized monoclonal antibody being developed for the potential treatment of ATTR amyloidosis. The Phase 1 study (NCT03336580) is complete. Novo Nordisk has acquired Prothena’s coramitug (PRX004) and is conducting the ongoing Phase 2 study (NCT05442047) in patients with ATTR cardiomyopathy. More information on the acquisition can be found here.


BMS-986446/PRX005, a potential best-in-class antibody for the treatment of AD that specifically targets a key epitope within the microtubule binding region (MTBR) of tau, a protein implicated in the causal human biology of AD. BMS-986446 is part of a Global Neuroscience Research and Development Collaboration with Bristol Myers Squibb. Bristol Myers Squibb reported that Phase 1 data supports rapidly moving BMS-986446 into a Phase 2 clinical trial in first half 2024.


PRX012 is a next-generation monoclonal antibody being developed for the potential treatment of Alzheimer’s disease. The Phase 1 study with PRX012 is ongoing.

Expanded Access Policy

Prothena is committed to developing safe and effective therapies for patients through thoughtful and efficient drug development. Consistent with this commitment, Prothena conducts clinical trials to generate safety and efficacy data required for regulatory approval to make our medicines available broadly to patients as quickly as possible. Prothena believes that enrollment in these clinical trials should be the first and most preferable route for patients to access investigational treatments.

Patients facing serious or life-threatening illnesses who are ineligible or unable to participate in a clinical trial and may not have options for alternative therapies, including investigational therapies in trials being conducted by other sponsors, may consider expanded access programs for unapproved therapies. 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 to provide expanded access for a given investigational drug outside of a clinical trial:

  • 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 expanded access?
  • Is there enough evidence of the investigational drug’s safety and effectiveness to allow an assessment of whether its potential benefits justify the potential risks before providing the investigational drug to 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?
A man and a woman smiling as they think about the possibilities of prothena's clinical trials

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 on a case-by-case basis in a fair and equitable manner and respond to the physician who makes the request. During this process, we will need to ensure that:

  • The patient suffers from a serious or immediately life-threatening disease or condition.
  • 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 potential benefits and risks of providing the investigational drug to the patient and found that the potential benefit outweighs the risk.
  • The patient is unable to participate in or does not qualify for any ongoing or planned clinical trials.
  • The patient has exhausted other therapies that may help him/her.
  • Any other pertinent medical criteria for access to the investigational product, as established by the Prothena clinically or medically responsible individual.

The above are general requirements, and specific requirements will be applied for a given investigational drug or clinical program if and when Prothena initiates an expanded access program.
Note that investigational drugs have not yet been approved or cleared by regulatory authorities and regulatory authorities have not found these products to be safe and effective for their specific use. Furthermore, investigational drugs may, or may not, be effective in the treatment of the applicable condition, and use of such investigational drugs may cause unexpected serious side effects.
– Patients should consult with their treating physician about their eligibility to enroll in any of Prothena’s clinical trials. To get more details about Prothena’s clinical trials, please visit the “Clinical Trials” page on Prothena’s website or on If you are a physician who has questions about Prothena’s investigational therapies, please contact us at
– The publication of this policy by Prothena is not a guarantee of access to any specific investigational drug by any individual patient. Prothena may revise this expanded access policy at any time.