Glactone Pharma has generated new exciting data demonstrating that the STAT3 inhibitor GPA500 reduces immunosuppressive markers on treatment resistant prostate cancer cells and that activation of the oncogenic STAT3 pathway is a mechanism of treatment resistance. The results will be published as an abstract at the annual meeting for ASCO (American Society of Clinical Oncology). With GPA500 as a lead, Glactone Pharma has developed novel proprietary STAT3 inhibitors with improved drug like properties.

The scientific abstract “Reduction in PD-L1 expression by STAT3 inhibition with GPA500 in enzalutamide-resistant prostate cancer” will be published in conjuncture with the 2015 ASCO annual meeting (J Clin Oncol 33, 2015 (suppl; abstr e16075)).

The data are the result of an ongoing collaboration between Glactone Pharma and the group of Professor Amina Zoubeidi at the world-renowned Vancouver Prostate Center in Canada. The study provides pre-clinical proof that targeting the STAT3 pathway using the small molecule inhibitor GPA500 can target multiple resistance mechanisms in prostate cancer cells resistant to the anti-androgen drug enzalutamide. GPA500 mediated STAT3 inhibition reduces the expression of cellmarkers that lead to immunesuppression (PD-L1). Furthermore it is shown that GPA500 reduces cell proliferation and viability of these anti-androgen resistant cells and that targeting STAT3 may provide an effective method to treat patients who are resistant to the novel anti-androgen therapies.

ASCO’s Annual Meeting is held in Chicago, on May 29 – June 2.

Cancer and Immunotherapy
Unleashing the body’s own immune system against tumours, so called immunotherapy, is one of the most promising treatment strategies in modern cancer treatment. However, some cancers like prostate cancer respond poorly to existing immunotherapies due to strongly immunosuppressive tumour mechanisms. It is believed that blocking these mechanisms will increase the response to immunotherapies thereby enabling more patients to be treated with immunotherapy. In preclinical models, it has been shown that the STAT3 pathway is involved in tumour induced immunosuppression and that targeting STAT3 will reverse these effects.

GPA500 and STAT3
GPA500 is a small molecule inhibitor of the transcription factor STAT3 with a unique mechanism of action. GPA500 directly inhibits STAT3 and reduces the proliferation of prostate cancer cells in vivo and in vitro. With GPA500 as a lead, Glactone Pharma has developed novel proprietary STAT3 inhibitors with improved drug like properties.

Glactone Pharma
Glactone Pharma is a biopharmaceutical company within PULS, a unique Swedish development company in life sciences, and is based on ground-breaking science from the University of Lund. Glactone Pharma has developed a pipeline of novel potential drugs that target the STAT3 transcription factor for the treatment of castration resistant prostate cancer (CRPC) and other cancers. STAT3 is involved in tumor mediated immune suppression (Immune Oncology) and resistance to androgen inhibition therapy making it an ideal target in combination treatments.,

The Vancouver Prostate Center (VPC)
VPC has a track record of success that has earned it a reputation as one of the world’s most respected cancer facilities. It is a National Centre of Excellence and a designated Centre of Excellence for Commercialization and Research.

For more information please contact:

Jan Törnell, Chairman of the Board, Glactone Pharma, +46 (0)70 676 00 08 or

Martin Johansson, CEO, Glactone Pharma, +1 705 768 0603 or

P.U.L.S. (Partners för Utvecklingsinvesteringar inom Life Sciences) is a unique development company within life sciences. PULS invests in novel projects and turns life science projects into attractive business opportunities for the life science industry. PULS has started nine project companies and exited three, of which one is listed. PULS is headquartered in Helsingborg, Sweden. PULS current projects are: AcuCort, Adenovir Pharma, Glactone Pharma, Laccure och