Immunotherapy in gastrointestinal stromal tumors: Current landscape and future horizons

Table 1 summarizes the results of clinical trials evaluating various immunotherapeutic approaches in gastrointestinal stromal tumors

Ref.	Treatment	Phase	Number of patients	ORR (%)	Median PFS	Median OS	Discussion
Chen et al[5], 2012	Peg-IFNa2b + Imatinib	II	8	100%	NR (> 3 years)	NR	New PR achieved after reintroduction of Peg-IFNa2b in a patient who progressed on imatinib maintenance therapy
D’Angelo et al[6], 2017	Dasatinib + Ipilimumab	Ib	20	53.8% (by Choi criteria)	2.8 months	13.5 months	7/13 evaluable GISTs had PR by Choi criteria
Toulmonde et al[7], 2018	Pembrolizumab + Cyclophosphamide	II	9	0%	6 months PFS: 11%	-	63% of GISTs showed high IDO expression
Singh et al[8], 2019	Nivolumab +/- Ipilimumab	II	N: 15, N + I: 12	N: 0%, N + I: 8.3%	N: 8.57 weeks, N + I: 9.1 weeks	N:9.1 months, N + I: 12.1 months	Responses and disease control observed, drugs well tolerated
Chen et al[9], 2020	Nivolumab +/- Ipilimumab	II	N: 9, N + I: 9	N: 0%, N + I: 0%	N: 1.5 months, N + I: 2.9 months	-	No confirmed responses in GIST
NCT05152472[10]	Imatinib + Atezolizumab vs Imatinib alone	II	110 (planned)	Ongoing	Ongoing	Ongoing	Trial ongoing to assess PFS improvement with combination therapy
NCT03609424[10]	PDR001 + Imatinib	I/II	39	Not reported	Not reported	Not reported	Not reported

Peg-IFNa2b: Pegylated interferon alpha-2b; PFS: Progression-free survival; OS: Overall survival; ORR: Objective response rate; PR: Partial response; NR: Not reached; IDO: Indoleamine 2,3-dioxygenase; N: Nivolumab; I: Ipilimumab.