BOSTON ( TheStreet) -- New drugs from Pfizer ( PFE) and GlaxoSmithKline ( GSK) that precisely target genetic weaknesses in cancer were given spotlight treatment Wednesday night by the American Society of Clinical Oncology (ASCO) in a preview of its upcoming and closely followed annual meeting. ASCO officials also highlighted a mid-stage study of Johnson & Johnson's ( JNJ) Zytiga in early-stage (pre-surgical) prostate cancer patients. Later during the ASCO meeting, which starts in two weeks, J&J will present new Zytiga results from a phase III study in more advanced prostate cancer patients.
In all, ASCO released more than 4,500 research abstracts, or clinical summaries, of new cancer drug data Wednesday night in advance of its annual meeting. This year's ASCO meeting continues a trend toward exploiting new discoveries in the genetic makeup of cancer cells that allow drug makers to develop new therapies capable of directly targeting cancer at its weakest point. One such drug is Pfizer's Xalkori, which targets abnormalities in the ALK gene that cause cancer cells to develop and grow out of control. Xalkori and a companion diagnostic test for the ALK gene received FDA approval in August 2011 for the 5% of non-small cell lung cancer patients who have mutated ALK genes. Wednesday, researchers presented new data showing Xalkori stalls tumor growth, and in some cases, completely erases all signs of cancer, in children with select pediatric cancers. The study enrolled 70 children with advanced neuroblastoma, anaplastic large cell lymphoma (ALCL) and inflammatory myofibroblastic tumors (IMT) that was no longer responding to current treatments. Patients were treated with one of six different doses of Xalkori, administered as a pill twice daily. Eighty-eight percent (7/8) of patients with ALCL experienced a complete response, meaning they had no detectable disease. Responses have been durable, with patients remaining on Xalkori therapy with no return of their cancer for as long as 18 months. Abnormalities in the ALK gene are present in 80-95% of ALCL cases. Responses were also observed in patients with IMT and neuroblastoma. "It's remarkable that this targeted oral medication provided such a substantial benefit in these children with highly aggressive cancers, most of whom had already undergone every available therapy," said Dr. Yael Mosse of Children's Hospital of Philadelphia.