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John W Melson
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P2.04 - Immuno-oncology (ID 167)
- Event: WCLC 2019
- Type: Poster Viewing in the Exhibit Hall
- Track: Immuno-oncology
- Presentations: 1
- Moderators:
- Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall
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P2.04-75 - Overall Survival by IDO1 and PD-L1 Expression in NSCLC Patients Receiving an Immune Checkpoint Inhibitor (ICI) (ID 1952)
10:15 - 18:15 | Author(s): John W Melson
- Abstract
Background
Although preliminary data suggest that differential expression of the immunoregulatory enzyme indoleamine-2,3-dioxygenase 1 (IDO1) may modulate clinical response to agents that target the PD-1/PD-L1 axis, little is known about the predictive value of measuring concomitant expression of both markers for patients receiving immune checkpoint inhibitor (ICI) therapy for non-small cell lung cancer (NSCLC).
Method
We identified patients with stage IV NSCLC who received at least one dose of an ICI alone or in combination with chemotherapy (CTX) at our institution between 2014 and 2018. Immunohistochemistry (IHC) for IDO1 (HPA023072, Sigma Prestige) and PD-L1 (SP142, Abcam) was performed on FFPE tissue. PD-L1 was scored as <1 %, 1-50%, or >50%, and IDO1 was scored as <1% or >1%. Median overall survival (OS) was calculated using proportional hazards model and groups were compared using log-rank test.
Result
65 eligible patients were identified. PD-L1 IHC failed in 1 patient. Patient characteristics and IHC results are detailed in Table 1. Patients with IDO1 expression had a numerically longer median OS (37.8 vs. 17.7 months, p=0.16), which was maintained regardless of PDL1 positivity. This effect was more pronounced in the ICI alone cohort (median OS of 34.4 mo vs. 17.7 mo, p=0.0995) than in the CTX+ICI cohort (p=0.92). There was no difference in OS when evaluating IDO and PDL1 expression in 4 subgroups (IDO1+/PD-L1+, +/-, -/+, -/-) using PD-L1 cutoffs of ≥1% (p=0.50) or ≥50% (p=0.49).
Table 1:
ConclusionCharacteristic - n, (%)
ICI Alone Cohort
n = 48 (73.8%)
ICI + CTX Cohort
n = 17 (26.2%)
Patient Demographics
Age (median in years)
63.5
59
Female Gender
22 (45.8)
9 (52.9)
Former/Current Smoking
44 (91.7)
14 (82.4)
EGFR Mutation
3 (6.3)
0 (0)
Line of Treatment
1st line
6 (12.5)
15 (88.2)
≥2nd line
42 (87.5)
2 (11.8)
IHC Results
PD-L1 IHC
0%
9 (19.1)
9 (53.0)
1-49%
25 (53.2)
5 (29.4)
≥50%
13 (27.7)
3 (17.6)
IDO1 IHC
0%
23 (47.9)
11 (64.7)
≥1%
25 (52.1)
6 (35.3)
PD-L1/IDO1
<50% / 0%
20 (41.7)
10 (58.8)
<50% / ≥1%
15 (31.2)
4 (23.5)
≥50% / 0%
3 (6.3)
1 (5.9)
≥50% / ≥1%
10 (20.8)
2 (11.8)
In this retrospective study of NSCLC patients receiving an ICI, our results suggest IDO positivity may be predictive of improved OS. Our ability to detect a statistically significant difference may have been limited by small sample size, particularly in the ICI+CTX cohort. Further studies examining the predictive role of IDO1 IHC would be useful to identify patients most likely to benefit from PD-1 or IDO1 inhibition.
