Rapt Therapeutics ( NASDAQ: RAPT ) presented data from an ongoing phase 1/2 trial of FLX475 as monotherapy and in combination with Merck' ( MRK ) Keytruda (pembrolizumab) in patients with advanced cancer at ESMO IO Congress.
The company said that data showed a confirmed overall response rate of 31% (4/13 patients) in stage 1 of a phase 2 expansion group of patients with checkpoint-naïve non-small cell lung cancer (NSCLC), including two responses which are ongoing for over one year.
Ten out of the 13 patients had been previously treated with 1-3 or more prior therapies for advanced disease.
Of the 13 patients treated with 100 mg once-daily FLX475 and a standard regimen of Keytruda, eight patients had PD-L1 positive tumors (TPS ?1%), including two with PD-L1 high tumors (TPS ?50%), four patients had PD-L1 negative tumors (TPS <1%) and one patient’s PD-L1 status was unknown.
The confirmed response rate in the PD-L1 positive tumors was 38% (3/8 patients) and in the PD-L1 negative tumors was 25% (1/4 patients), the company added.
None of the four responders were PD-L1 high.
In a separate phase 2 expansion cohort of six patients with EBV+ NK/T cell lymphoma treated with FLX475 monotherapy, there were four responses, with two durable complete metabolic responses (CMR), one unconfirmed CMR and one unconfirmed partial metabolic response, according to the company.
Rapt noted that the safety profile for FLX475 was favorable, consistent with what has been previously seen in healthy people. There was no increased severity or frequency of adverse events in combination therapy compared to either FLX475 or Keytruda monotherapy.
"These data further support the antitumor activity for FLX475 with clear demonstration as a monotherapy and encouraging activity in a combination regimen with checkpoint inhibition," said Rapt President and CEO Brian Wong.
For further details see:
Rapt FLX475 shows antitumor activity in advanced lung cancer in phase 1/2 trial