Tesaro Presents Initial Data From Phase1 Trial Of TSR-011 - Quick Facts

(RTTNews) - Tesaro Inc. (TSRO) presented initial data from a Phase 1 trial of TSR-011 at the European Cancer Congress in Amsterdam. TSR-011 is a potent inhibitor of both anaplastic lymphoma kinase or ALK and tropomyosin-related kinases or TRK.

The company stated that preliminary clinical activity has been observed in this study in one papillary thyroid carcinoma patient and one pancreatic cancer patient without ALK expression, and in three patients with ALK-positive non-small cell lung cancer or NCSLC who progressed following prior treatment with crizotinib.

According to the company, Of the three ALK-positive NSCLC patients who progressed on prior crizotinib treatment, one achieved a RECIST partial response after four weeks of treatment with TSR-011; one, with disease not evaluable by RECIST criteria, achieved an investigator-assessed partial response; and one has stable disease. Each of these three patients remains on study today. In addition, one patient with papillary thyroid carcinoma and one patient with pancreatic cancer each have long term stable disease following several cycles of TSR-011 treatment. Preliminary results after eight weeks of treatment with TSR-011 demonstrated disease control (partial responses plus stable disease) in 11 of 17 (65%) evaluable patients treated with TSR-011.

"We remain on track to move into Phase 2a by the end of this year, which will allow us to further evaluate the benefit/risk profile of TSR-011 in patients with cancers that are ALK-positive or have TRK rearrangements," said Dr. Mary Lynne Hedley, President of TESARO.

The company stated that Pharmacokinetic data demonstrated rapid absorption, predictable, dose proportional plasma concentrations following oral administration and an elimination half-life of 12 to 24 hours. TSR-011 was well tolerated at therapeutic dose levels, and no drug related Grade 4 or Grade 5 adverse events have been observed to date. The most frequently occurring dose limiting toxicities included ECG changes and dysaethesia, both of which were reversible.