Loxo Oncology Inc. (NASDAQ:LOXO) reported updated response data on Saturday at the American Society of Clinical Oncology meeting in Chicago from the Phase I LIBRETTO-001 trial evaluating its ret proto-oncogene (RET) inhibitor LOXO-292 to treat RET-altered cancers. LOXO-292 led to a confirmed overall response rate (ORR) of 74%, including 25 partial responses, in 34 evaluable patients with RET fusion-positive cancers.
In an abstract released ahead of ASCO, Loxo reported data from 32 evaluable patients showing that LOXO-292 led to an unconfirmed ORR of 69%, including an ORR of 65% in 26 non-small cell lung cancer (NSCLC) patients and 83% in six papillary thyroid cancer patients (see BioCentury Extra, May 17).
Newly released data at ASCO from 27 evaluable patients with RET fusion-positive NSCLC showed that LOXO-292 led to a confirmed ORR of 74%, including 20 partial responses, plus four cases of stable disease. In seven evaluable patients with RET fusion-positive thyroid or pancreatic cancer, LOXO-292 led to a confirmed ORR of 71%, including five partial responses, plus two cases of stable disease.
In 18 evaluable patients with RET-mutant medullary thyroid cancer (MTC), LOXO-292 led to a confirmed ORR of 33%, including one complete response and five partial responses, plus nine cases of stable disease.
As of an April 2 cutoff, the trial had enrolled 82 patients across eight LOXO-292 dose cohorts. Loxo said it is now enrolling patients in dose-expansion cohorts to receive LOXO-292 at a starting dose of 160 mg twice daily.