Table 3.

Summary of investigator-assessed clinical efficacy parameters

Parameter	All Patients (n = 24)
Best overall response, n (%)
Complete response (CR)	12 (50%)
Partial response (PR)	5 (21%)
Stable disease (SD)	4 (17%)
Progressive disease (PD)	2 (8%)
Clinical progressive disease (CPD)a	1 (4%)
Median treatment duration, months (range)b	8 (2 – 24)
Median duration of response, months (range)c	11 (0.4 – 34)
Clinical benefit rate (CBR), n (%)d	14 (58%)
Objective response rate (ORR), n (%)e	17 (71%)
Disease control rate (DCR), n (%)f	21 (88%)
Median follow-up time, months (range)	15 (3 – 34)
Median PFS, months	20.3
6 month PFS rate, n (%)g	15 (63%)
Progressive disease (PD)h	12 (50%)
On treatmenti	10 (42%)
Median time to progression, months (range)	4 (1 – 10)
Off treatmentj	2 (8%)
Median time to progression, months (range)	15 (9 – 20)
Survival rate	75%

Abbreviations: CR, complete response; PR, partial response; SD, stable disease; PD, progressive disease; CPD, clinical progressive disease; CBR, clinical benefit rate; ORR, objective response rate; DCR, disease control rate; PFS, progression free survival.

^aProgression without a scan (physician diagnosed progression based on symptoms prior to scan).

^bDefined as time between first ATRA dose and last treatment dose (pembrolizumab or ATRA).

^cDefined as measured from the time at which CR or PR criteria are first met until the first date of PD.

^dDefined as the proportion of patients demonstrating CR, PR, or SD for a minimum of four months from date of first CR, PR, or SD.

^ePatients who achieved a best overall response of CR or PR.

^fPatients who achieved a best overall response of CR, PR, or SD.

^gPatients without progression at six months from the date of the first treatment.

^hPatients diagnosed with PD or CPD.

ⁱPatients who progressed while on treatment.

^jPatients who progressed after coming off treatment.

Response to therapy was assessed based on RECIST v1.1 criteria.