Background: Blockade of PD-1/PD-L1 pathways enhances anti-leukemic responses in pre-clinical studies. PD1 inhibition alone had limited clinical activity in AML. CLTA4 inhibition demonstrated encouraging single-agent CR's in postASCT patients (pts), especially for extra-medullary (EMD) relapses (Davis M et al, NEJM 2016). AZA+Nivo up-regulated CTLA4 on bone marrow (BM) CD8 cells in both responders (R) and non-responders (NR) on treatment (Daver N, et al, Cancer Discovery 2019), suggesting a triplet of AZA+Nivo+Ipi may abrogate PD-1 mediated resistance.

Methods: Pts were eligible for the AZA+Nivo (cohort 1, n=59) if they had R/R AML, ECOG ≤ 2, and adequate organ function. This cohort has completed enrollment.

A cohort of AZA+Nivo+Ipi was opened (cohort 2), with the same eligibility criteria. Ipi 1mg/kg Q6 weeks was added to the established AZA+Nivo schedule and found to be safe in a lead-in dose cohort.

Results: Cohort 1 (59 R/R AML) pts were treated with Aza+Nivo (Daver et al., Cancer Discovery 2019). CR/CRi and OS were superior to contemporary historic HMA-based clinical trial controls at MDACC (Table 1). Pts with low pretherapy BM blasts (<20% BM blasts) and early salvage (salvage 1) had encouraging median (med) OS 11 months (mos), indicating progressive T-cell exhaustion with multiple relapses. Importantly, on 40-parametric CYTOF assessment, Rs to AZA+Nivo had a higher frequency of pre-therapy BMA CD3+ and CD8+ cells compared with NRs (optimal CD3+ cutoff 13.2%: ORR 56% versus 23%), suggesting pre-existing BM T-cell infiltration may be a pre-requisite of response to PD1 based therapies, as PD1 inhibitors have limited ability to mobilize peripheral T-cells (Fig 1A). The pre-therapy BM CD4 polyfunctional strength index (PSI) defined as percentage of polyfunctional cells in the sample, multiplied by the intensities of the secreted cytokines, assessed by single cell cytokine analysis was dramatically different between Rs and NRs (P=0.03). Single-cell RNA-seq on 113,394 BM cells collected longitudinally from 8 pts (3R, 2 stable disease (SD), 3NR) demonstrated that deletion 7/7q, LSC signature enrichment, and activated metabolic/oxidative pathways, were associated with resistance to AZA+Nivo (Abbas H et al, ASH 2020). Importantly, AZA+Nivo induced novel and expanded T cell clonotypes, almost exclusively in Rs.

Cohort 2 (36 R/R AML) pts were treated with Aza+Nivo+Ipi, with med age 67 years (25-83), secondary AML (50%), ELN unfavorable cytogenetics (67%), TP53 (36%), med salvage 2 (range, 1-3), and prior HMA based therapies in 67%. All 36 pts are evaluable. Per ELN 2017, CR/CRi was noted in 7 (19%) and PR in 1 (3%). Five (14%) pts had durable stable disease (SD) (defined as absence of CR, CRi, PR; with SD on treatment for ≥6 months), and 23 (64%) were NRs (Table 1). Interestingly, 4 pts with EMD were enrolled and 3 had CR/PR [med DOR 8 (5-13) mos]. The 4- and 8-week mortalities were 0 and 6%, respectively. Grade 3/4 immune toxicities noted in 8 pts (19%), including rash, pneumonitis, colitis, pyrexia. One pt required ICU stay, but no deaths attributed to immune toxicity. Other grade ≥2 toxicities were as expected for R/R AML population and were mostly infections/febrile neutropenia. Converse to AZA+Nivo, on CYTOF, R did not have a higher frequency of pre-therapy BM CD8+ infiltration, but did have progressive BM CD8+ infiltration on therapy, compared with NRs, demonstrating that Ipi (unlike Nivo) may be able to mobilize peripheral T-cells to the BM (Fig 1B). Expansion of a cluster of antigen experienced CD8+ T cells was associated with response (Fig 1B).

In all salvage the med OS with Aza+Ipi+Nivo versus Aza+Nivo versus contemporary HMA-controls in R/R AML, were 7.6, 5.9, and 4.6 mos, respectively (P=0.01) (Fig 1C). The 1-year OS in R/R AML pts with AZA+Nivo+Ipi was 25%. The med OS with Aza+Ipi+Nivo was comparable to med OS 6-8 mos reported with HMA+VEN salvage in numerous studies.

Conclusion: The OS with Aza+Nivo+Ipi was modestly improved over AZA+Nivo and HMA-controls in R/R AML. Single-cell cytokine profiling and single-cell RNA-seq from Aza+Nivo showed striking pre- and on-treatment differences among R and NR not only in T-cell fitness and clonality, but also in the tumor microenvironment. Ipi may be uniquely able to mobilize peripheral T-cell to BM and EMD. This underappreciated immune diversity suggests a critical need for biomarker-based trials (as we are doing with molecular therapies) for immunotherapies in AML.

Disclosures

Daver:Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Trovagene: Research Funding; Fate Therapeutics: Research Funding; ImmunoGen: Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Jazz: Consultancy, Membership on an entity's Board of Directors or advisory committees; Trillium: Consultancy, Membership on an entity's Board of Directors or advisory committees; Syndax: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees; Agios: Consultancy, Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharm: Research Funding; Servier: Research Funding; Genentech: Research Funding; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novimmune: Research Funding; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Garcia-Manero:Merck: Research Funding; Onconova: Research Funding; Novartis: Research Funding; Jazz Pharmaceuticals: Consultancy; Helsinn Therapeutics: Consultancy, Honoraria, Research Funding; H3 Biomedicine: Research Funding; AbbVie: Honoraria, Research Funding; Acceleron Pharmaceuticals: Consultancy, Honoraria; Amphivena Therapeutics: Research Funding; Astex Pharmaceuticals: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Konopleva:Eli Lilly: Research Funding; Rafael Pharmaceutical: Research Funding; Genentech: Consultancy, Research Funding; Stemline Therapeutics: Consultancy, Research Funding; Agios: Research Funding; Cellectis: Research Funding; Calithera: Research Funding; AstraZeneca: Research Funding; Ascentage: Research Funding; Reata Pharmaceutical Inc.;: Patents & Royalties: patents and royalties with patent US 7,795,305 B2 on CDDO-compounds and combination therapies, licensed to Reata Pharmaceutical; Sanofi: Research Funding; Kisoji: Consultancy; Amgen: Consultancy; F. Hoffmann La-Roche: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; Ablynx: Research Funding; Forty-Seven: Consultancy, Research Funding. Kadia:Pulmotec: Research Funding; Astellas: Research Funding; Cellenkos: Research Funding; Amgen: Research Funding; Genentech: Honoraria, Research Funding; BMS: Honoraria, Research Funding; Cyclacel: Research Funding; JAZZ: Honoraria, Research Funding; Celgene: Research Funding; Incyte: Research Funding; Astra Zeneca: Research Funding; Ascentage: Research Funding; Pfizer: Honoraria, Research Funding; Novartis: Honoraria; Abbvie: Honoraria, Research Funding. DiNardo:AbbVie: Consultancy, Honoraria, Research Funding; Takeda: Honoraria; Agios: Consultancy, Honoraria, Research Funding; Daiichi Sankyo: Consultancy, Honoraria, Research Funding; Calithera: Research Funding; Jazz: Honoraria; MedImmune: Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Syros: Honoraria; Notable Labs: Membership on an entity's Board of Directors or advisory committees; ImmuneOnc: Honoraria; Novartis: Consultancy. Borthakur:Abbvie: Research Funding; Novartis: Research Funding; Incyte: Research Funding; PTC Therapeutics: Research Funding; Curio Science LLC: Consultancy; FTC Therapeutics: Consultancy; Argenx: Consultancy; PTC Therapeutics: Consultancy; BioLine Rx: Consultancy; BioTherix: Consultancy; Nkarta Therapeutics: Consultancy; Treadwell Therapeutics: Consultancy; Oncoceutics: Research Funding; Xbiotech USA: Research Funding; Polaris: Research Funding; AstraZeneca: Research Funding; BMS: Research Funding; BioLine Rx: Research Funding; Cyclacel: Research Funding; GSK: Research Funding; Jannsen: Research Funding. Pemmaraju:AbbVie: Honoraria, Research Funding; Daiichi Sankyo: Research Funding; Stemline Therapeutics: Honoraria, Research Funding; DAVA Oncology: Honoraria; Incyte Corporation: Honoraria; Celgene: Honoraria; Novartis: Honoraria, Research Funding; SagerStrong Foundation: Other: Grant Support; Plexxikon: Research Funding; LFB Biotechnologies: Honoraria; Blueprint Medicines: Honoraria; Samus Therapeutics: Research Funding; Affymetrix: Other: Grant Support, Research Funding; Pacylex Pharmaceuticals: Consultancy; MustangBio: Honoraria; Roche Diagnostics: Honoraria; Cellectis: Research Funding. Jabbour:Takeda: Other: Advisory role, Research Funding; Adaptive Biotechnologies: Other: Advisory role, Research Funding; Pfizer: Other: Advisory role, Research Funding; BMS: Other: Advisory role, Research Funding; Amgen: Other: Advisory role, Research Funding; AbbVie: Other: Advisory role, Research Funding; Genentech: Other: Advisory role, Research Funding. Sasaki:Novartis: Consultancy, Research Funding; Otsuka: Honoraria; Pfizer Japan: Consultancy; Daiichi Sankyo: Consultancy. Yilmaz:Pint Pharma: Honoraria; Pfizer: Research Funding; Daicho Sankyo: Research Funding. Issa:Syndax: Research Funding; Celegene: Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees. Short:AstraZeneca: Consultancy; Amgen: Honoraria; Astellas: Research Funding; Takeda Oncology: Consultancy, Honoraria, Research Funding. Andreeff:Amgen: Research Funding; Centre for Drug Research & Development; Cancer UK; NCI-CTEP; German Research Council; Leukemia Lymphoma Foundation (LLS); NCI-RDCRN (Rare Disease Clin Network); CLL Founcdation; BioLineRx; SentiBio; Aptose Biosciences, Inc: Membership on an entity's Board of Directors or advisory committees; Daiichi-Sankyo; Breast Cancer Research Foundation; CPRIT; NIH/NCI; Amgen; AstraZeneca: Research Funding; Daiichi-Sankyo; Jazz Pharmaceuticals; Celgene; Amgen; AstraZeneca; 6 Dimensions Capital: Consultancy. Cortes:Novartis: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Sun Pharma: Research Funding; BioPath Holdings: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Telios: Research Funding; Astellas: Research Funding; Amphivena Therapeutics: Research Funding; Arog: Research Funding; BiolineRx: Consultancy, Research Funding; Bristol-Myers Squibb: Research Funding; Daiichi Sankyo: Consultancy, Research Funding; Jazz Pharmaceuticals: Consultancy, Research Funding; Immunogen: Research Funding; Merus: Research Funding. Ravandi:Jazz Pharmaceuticals: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria, Research Funding; Astellas: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria; Macrogenics: Research Funding; Orsenix: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria; Xencor: Consultancy, Honoraria, Research Funding. Allison:BioAlta: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Apricity Health: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Achelois: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Codiak BioSciences: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Dragonfly Therapeutics: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Forty-Seven Inc.: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Hummingbird: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; ImaginAB: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Jounce Therapeutics: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; Lava Therapeutics: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Lytix Biopharma: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Marker Therapeutics: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Polaris: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; BioNTech: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees. Kantarjian:Cyclacel: Research Funding; BMS: Research Funding; Takeda: Honoraria; Agios: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; Astex: Research Funding; AbbVie: Honoraria, Research Funding; Jazz Pharma: Research Funding; Amgen: Honoraria, Research Funding; Daiichi-Sankyo: Research Funding; Actinium: Honoraria, Membership on an entity's Board of Directors or advisory committees; Immunogen: Research Funding; Novartis: Research Funding; Ariad: Research Funding. Sharma:Achelois: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Apricity Health: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; BioAlta: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Codiak BioSciences: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Constellation: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Dragonfly Therapeutics: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Forty-Seven Inc.: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Hummingbird: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; ImaginAb: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Jounce Therapeutics: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; Lava Therapeutics: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Lytix Biopharma: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Marker Therapeutics: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Oncolytics: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Infinity Pharma: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; BioNTech: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Glympse: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Polaris: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees.

OffLabel Disclosure:

Nivolumab and Ipilimumab based combinations for AML, will be discussed. These agents do not have an on label indication for AML at this time.

Author notes

*

Asterisk with author names denotes non-ASH members.