Regulatory Decision Summary for Panhematin

Acute intermittent porphyria (AIP) is a rare and serious genetic disease with a partial deficiency of the enzyme porphobilinogen deaminase (PBGD). Currently, there are no approved drug products for the treatment of AIP in Canada. Panhematin fulfills this unmet medical need.

This New Drug Submission (NDS) was based on publications in the literature and included one Phase 3 compassionate-use study, 5 open-label studies, 19 publications of case reports and an observational study. A total of 372 patients were treated with hemin for acute attacks of porphyria in the studies. The majority of the patients were female. The publications did not include any placebo-controlled or active-controlled studies with Panhematin. In addition, the definition of clinical response varied between the studies and the evaluation of clinical response was mainly subjective.

Overall, there is substantial evidence of clinical efficacy on the amelioration of recurrent attacks of the disease, including improvement of symptoms and reduction in pain. In addition, all patients in the 5 open-label studies experienced a chemical response in urinary enzymes. The drug was generally well tolerated.

A challenge for this review was the fact that the clinical evidence was from the literature and post-marketing experience, so some of information could not be verified. For example, the actual amount of drug given to patients in the published studies that were done in the 1970s and 80s was not available. The reported clinical response varied between studies. The impact on the efficacy of Panhematin of patients receiving other treatments at the same time was uncertain. And finally, the safety data provided in the submission were limited. These limitations have been reflected in the product monograph.

Nevertheless, this review found that the benefits of Panhematin for the amelioration of recurrent attacks of acute intermittent porphyria outweighed the risks.

An assessment of the Risk Management Plan (RMP) for Panhematin did note deficiencies that require the company to revise the document. A revised RMP is to be submitted to the MHPD within 90 days of market authorization by the BGTD. In addition, the sponsor was asked to provide a copy of educational material, the Dear Health Care Professional letter regarding new label claims, and dose recommendations within the revised RMP.