Preclinical Development

Actimab-C, Colorectal cancer, metastatic: API has been working collaboratively with the owner of rights to an anti-A33 mAb that targets metastatic colon cancer, to co-develop that mAb labeled with Ac-225.  MSKCC has expressed interest in commencing a clinical trial under a Physician IND.  Preclinical work with an A33 mAb – Ac-225 construct has shown acceptable toxicity profiles and encouraging proof of principal efficacy in mouse models, with complete elimination of metastatic disease in a number of animals.  The mAb has already been in clinical trials in its native form and coupled with beta emitting isotopes.  API has prepared a number of strategic documents with the owner of the antibody rights and is evaluating further development and collaboration strategies.

Actimab-P, Prostate cancer, metastatic: API has also collaborated with MSKCC and a commercial third party on development of an Ac-225 labeled mAb highly specific for prostate cells.  Preclinical mouse models have demonstrated encouraging proof of principal results in prostate cancer mouse models.  In addition to being expressed by prostate cancer cells, PSMA, the target antigen for this antibody, is also expressed by tumor vasculature, but not by normal vasculature.  This represents a potential point of entry into the antiangiogenesis market.  There is an ongoing open trial for radioisotopes labeled with this antibody and an Ac-225 labeled mAb could be included in that trial via an amendment to the existing IND.  Such an amendment would contain a new Protocol and other data based on additional labeling work that is planned.  API has had discussion with the antibody owner and is currently evaluating approaches for a collaboration proposal to the owner of antibody rights.

AA-A225 for Antiangiogenesis: In earlier stages of preclinical work, API’s key development partner and investor MSKCC has been developing another antiangiogenesis mAb coupled with Ac-225.  This construct could potentially be useful for treating most if not all metastatic solid cancers and has shown an excellent safety and efficacy profile in vivo in mouse models.  The mAb rights are owned by a third party and API intends to commence discussions with that party to explore opportunities for cooperation once further feasibility studies at MSKCC are completed.