Isis announces preliminary data from ISIS-STAT3 Phase 1 study on cancer

Isis Pharmaceuticals, Inc. (NASDAQ: ISIS) announced that preliminary data from the Phase 1 study of ISIS-STAT3_Rx in patients with cancer were presented today at the Oligonucleotide Therapeutics Society in Boston.  Interim results of the initial dose escalation study in patients with cancer showed that ISIS-STAT3_Rx treatment resulted in clear responses in patients with advanced cancer who were refractory to prior chemotherapy treatment, with an acceptable safety profile.  Based on these results, Isis has initiated a Phase 2 study in focused patient populations with advanced cancer.

"STAT3 expression has been shown to be associated with the growth, invasiveness and metastases of many types of cancer making it an attractive target.  However, STAT3 has proven to be a difficult target to inhibit safely with small molecule drugs, making ISIS-STAT3_Rx even more interesting," said David S. Hong, M.D., associate professor, department of investigational cancer therapeutics at the University of Texas MD Anderson Cancer Center.  "Patients with advanced cancer have often failed multiple therapies and have no other chemotherapeutic options.  For these patients there is a desperate need for new therapies that can halt their disease progression.  The clinical responses observed to date suggest that inhibition of STAT3 could provide benefit to some of these patients.   The early data on ISIS-STAT3_Rx is impressive because it suggests that this drug can produce responses in patients with advanced cancer who have failed to respond to other therapies."

ISIS-STAT3_Rx is the first drug in Isis' pipeline that incorporates Isis' Generation 2.5 chemistry, which was developed to increase potency of antisense drugs thereby creating opportunities for drugs like ISIS-STAT3_Rx to be effective in more difficult to treat cancers.  The Phase 1 study evaluated ISIS-STAT3_Rx in patients with solid tumors and lymphoma who have relapsed or were refractory to multiple chemotherapy regimens.  The Phase 2 study will evaluate the safety and efficacy of ISIS-STAT3_Rx in focused patient populations with advanced cancers that have been linked to STAT3 who have failed all other treatment options.  The endpoints for the study include measurements of anti-tumor activity, STAT3 protein levels in tumor biopsies, STAT3-related biomarkers, and safety.  Efficacy will be evaluated across different types of cancer and correlated with genetic sequencing from patient tumor biopsies. 

"We believe that the significant improvements in potency we have observed in our preclinical cancer studies with our Generation 2.5 chemistry should translate into an effective anti-tumor agent that is broadly applicable to many different types of cancer.  The important role that STAT3 plays in tumor survival and growth made it a great target to evaluate our Generation 2.5 platform in patients," said Brett Monia, Ph.D., senior vice president, antisense drug discovery at Isis.  "We are very pleased and encouraged with the safety and efficacy observed in our Phase 1 study of ISIS-STAT3_Rx.  The promising data generated in our Phase 1 study has enabled us to accelerate our development plans and move into a Phase 2 study earlier than originally anticipated." 

ISIS-STAT3_Rx is designed to inhibit the production of signal transducer and activator of transcription 3 (STAT3), a protein critical for tumor cell growth and survival.  Because STAT3 is overexpressed in numerous types of cancer, ISIS-STAT3_Rx has the potential to be broadly useful for both solid and liquid tumors.  ISIS-STAT3_Rx has been shown to reduce STAT3 levels in preclinical tumor models and produce anti-tumor activity.  Inhibition of STAT3 has also been shown to block the induction of tumor-associated cytokines involved in the progression of cancer, such as IL-6, IL-1, TGFb, and IL-10, which could serve as important biomarkers in clinical studies.