Algorithmic selection of
therapeutic cancer vaccines
Alex Rubinsteyn
January 31st, 2018
UM CS Pizza Seminar
OpenVax @ Mount Sinai
● www.openvax.org
● Focus: personalized cancer vaccines
○ Machine learning for immunology
○ Cancer genomics
● Started: January 1st, 2018
● Enthusiastically translational research
● Open source software: github.com/openvax
Cancer Immunotherapy
What is cancer?
Immune system kills (most) cancer cells
Three E’s of cancer immunity, Ian York (2007)
Immune avoidance a hallmark of cancer
Hallmarks of
Cancer: The Next
Generation
(2011)
Don’t get eaten
by immune cells
Cancer immunotherapy
● Traditional treatments: focus on killing cancer cells directly
● Immunotherapy: get the immune system to kill the cancer
● Why is the immune system allowing cancer to spread?
○ Cancer cells inhibiting immune cells
■ Block the inhibitory signals!
○ Immune cells unable to recognize cancer as non-self
■ Teach the immune system what to kill
Flavors of cancer immunotherapy
Checkpoint blockade Cellular therapies Vaccines
Disinhibit CD8+ T-cells,
antigens responsible for
tumor clearance unknown.
Success stories:
● CTLA-4 (ipi)
● PD-1 (pembro, nivo)
● PD-L1 ( atezo)
Ex-vivo expansion of
patient T-cells after
receptor engineering
and/or selection.
Success stories:
● CD19 CAR T-cells for
B-cell malignancies
Therapeutic vaccines
against tumor antigens.
Significant interest in
personalized “neo-antigen”
vaccines.
Success stories:
● ???
● Hints of efficacy in
neoantigen vaccine trials
Immunotherapy vs. Chemotherapy
Nivolumab in Previously
Untreated Melanoma…
(Robert NEJM 2015)
Therapeutic Cancer Vaccines
What’s in a therapeutic cancer vaccine?
● Tumor antigen
○ What should immune system look for?
● Adjuvant
○ Something the immune system already responds to as
dangerous
○ Examples: double-stranded RNA, mineral oil, dead
bacteria
● Objective: get the immune system to learn that the antigen is
bad and cells which have it should be killed
Tumor-specific antigens
● Don’t occur in normal
cells
○ most commonly:
mutated proteins
● Unlikely to be shared
between patients
● Called “neo-antigens”
Getting Personal with Neoantigen-Based Therapeutic Cancer Vaccines
Typical personalized cancer vaccine
pipeline
● Sequence DNA from tumor and
patient
○ Identify tumor-specific
mutations
● Sequence RNA from tumor
○ Which mutations are being
produced into proteins?
● Predict which mutations can be
seen by immune system Computational genomics tools for dissecting tumour–immune cell interactions
Murine Experiment
Checkpoint blockade cancer immunotherapy targets tumour-specific mutant antigens, Gubin et al. (2014)
● Taconic 129S6 mice
● MCA-T3 sarcoma cell line
● “mLama4” & “mAlg8” are
predicted neoantigens
● Long peptide vaccine +
Poly(I:C) adjuvant
More Mouse Evidence
Mutated neo-antigens as targets for individualized cancer immunotherapy (Figure 3.18), Vormehr (2016)
● BALB/c mice
● CT26 colon cell line
● mRNA vaccine
● Two groups of 5
epitopes (#2 works)
○ Individual
epitopes don’t
work
Cathy Wu & Pat Ott’s trial @ DFCI
● 6 (stage III & IV) melanoma patients
● Up to 20 mutated peptides per vaccine
● Adjuvant: Poly-ICLC
DFCI Trial: Tumor Control
Of six vaccinated patients, four had no recurrence
at 25 months after vaccination, while two with
recurrent disease were subsequently treated with
anti-PD-1 (anti-programmed cell death-1) therapy
and experienced complete tumour regression, with
expansion of the repertoire of neoantigen-specific T
cells.
Genome Sequencing
DNA Sequencing
NextSeq 500 in Mount Sinai’s Sequencing Core
● Human genome ~= 3
billion nucleotides
○ Longest
chromosome ~=
250M nucleotides
● Split DNA into tiny
fragments
● Read billions of short
sequences
Alignment to Reference Genome
● Where did each short DNA “read” sequence come from?
Detecting Mutations
Categories of
mutations
Mutated neo-antigens as targets for individualized cancer immunotherapy, Mathias Vohrmer
● Easy to detect
○ Substitutions (e.g. C -> G)
○ Small insertions / deletions
(~10 nucleotides)
● Hard
○ Larger indels
○ Inversions
○ Gene fusions
Immune Predictions
T cell surveillance
Yewdell, J.W., Reits, E. & Neefjes, J., 2003. Nature Reviews Immunology
● Proteins cleaved by proteasome
● Some of the resulting peptides
loaded onto MHC to be
presented on cell surface
● T cells perform surveillance of
these peptide/MHC complexes
● Abnormal (non-self) displayed
peptides lead to a cytotoxic T cell
response
24
MHC
● Thousands of MHC alleles in
human population
● Each allele capable of binding a
distinct set of peptides
● Objective: Predict whether an
MHC allele will bind a given
peptide
25
Holland, C.J., Cole, D.K. & Godkin, A., 2013. Frontiers in Immunology
Immune Epitope Database (IEDB)
● Public dataset of B and T cell
epitopes and related data curated
from the literature
● Includes >200,000 in vitro binding
affinity measurements of purified
MHC/peptides, which is the core
training data for MHC ligand
prediction tools
Linear models perform reasonably well
● Binding motifs (Sette 1989)
● Position specific scoring
matrices (Parker 1994)
● Ignore dependencies between
positions
Bjoern Peters
Neural networks do better:
NetMHCpan (2007)
● Standard tool to predict peptide/MHC binding affinity given: peptide
sequence and binding groove residues of MHC allele
PGV001: Safety and Immunogenicity
of Personalized Genomic Vaccine
(Phase I Clinical Trial at Mount Sinai)
Nina Bhardwaj
PGV-001 Trial
● H&N, NSCLC, Breast, Ovarian, Urothelial, SCC, MM
● Patients w/o evidence of residual or metastatic disease
● Vaccine:
○ 10 peptides (~25 amino acids)
○ Adjuvant: Poly-ICLC
○ 10 intracutaneous injections over 6 months
● Peptide selection:
○ Phase cancer mutations with germline variants using RNA reads
○ Add multiple MHC I binding predictions overlapping same mutation
○ Ranking: expression * MHC I affinity
Neoantigen
Selection
Pipeline for
PGV-001
Trial Status
● Open & enrolling
● 1 H&N patient treated
● 1 MM patient with manufactured peptides, will begin
treatment soon
● 4 patients with DNA/RNA sequencing data
New Trials in 2018
● PGV for Glioblastoma
○ + Novocure’s TTfields
○ PI: Adelia Hormigo
● PGV for Bladder Cancer
○ + ⍺PD-1
○ PI: Matt Galsky
Open Source Software
Open Source Tools Developed for PGV
Available at github.com/openvax
varcode Python interface for VCFs, variant effect prediction
isovar Determine mutant coding sequence from RNA-seq
vaxrank Vaccine peptide selection (including manufacturability)
epidisco Turn-key workflow to generate vaccine peptide report from FASTQ inputs (runs
all bioinformatics tools)
ketrew Workflow engine used to run tools on Google Cloud, AWS, and traditional HPC
mhctools Standard interface to pMHC binding predictors
pyensembl Python interface to Ensembl reference genome annotations
GGCGACTGTCCGGCTTTGAGCCAGGTGCCTC
Intron
Isovar: Phasing and Transcript Selection
TGTCCGGCT
ACTTGTCATGGCGACTGTCCGGCT
TGGCGACTGTCCAGCT
CGACTGTCCAGCT
TGTCATGGCGACTGTCCAGCT
Somatic mutation Germline mut.
RNA Read 1
RNA Read 2
RNA Read 3
RNA Read 5
RNA Read 4
TTGAGCCAGGAGCCTC
TTGAGCCA
TTGAGCCAGGAGCCTC
TTGTGCCAGGAGCCTC
TTGTGCCAGGA
Exon 1 Exon 2
Selected coding sequence includes germline mutation:
Vaxrank: Vaccine Peptide Selection
vaxrank
--vcf mutect.vcf
--vcf strelka.vcf
--bam tumor-rna.bam
--vaccine-peptide-length 25
--mhc-predictor netmhcpan
--mhc-alleles-file
alleles.txt
Startup Landscape
Funding for Personalized Cancer Vaccines
$161M
$195M
$270M
$1.2B
Thanks!

Data Science Salon: Machine Learning for Personalized Cancer Vaccines

  • 1.
    Algorithmic selection of therapeuticcancer vaccines Alex Rubinsteyn January 31st, 2018 UM CS Pizza Seminar
  • 2.
    OpenVax @ MountSinai ● www.openvax.org ● Focus: personalized cancer vaccines ○ Machine learning for immunology ○ Cancer genomics ● Started: January 1st, 2018 ● Enthusiastically translational research ● Open source software: github.com/openvax
  • 3.
  • 4.
  • 5.
    Immune system kills(most) cancer cells Three E’s of cancer immunity, Ian York (2007)
  • 6.
    Immune avoidance ahallmark of cancer Hallmarks of Cancer: The Next Generation (2011) Don’t get eaten by immune cells
  • 7.
    Cancer immunotherapy ● Traditionaltreatments: focus on killing cancer cells directly ● Immunotherapy: get the immune system to kill the cancer ● Why is the immune system allowing cancer to spread? ○ Cancer cells inhibiting immune cells ■ Block the inhibitory signals! ○ Immune cells unable to recognize cancer as non-self ■ Teach the immune system what to kill
  • 8.
    Flavors of cancerimmunotherapy Checkpoint blockade Cellular therapies Vaccines Disinhibit CD8+ T-cells, antigens responsible for tumor clearance unknown. Success stories: ● CTLA-4 (ipi) ● PD-1 (pembro, nivo) ● PD-L1 ( atezo) Ex-vivo expansion of patient T-cells after receptor engineering and/or selection. Success stories: ● CD19 CAR T-cells for B-cell malignancies Therapeutic vaccines against tumor antigens. Significant interest in personalized “neo-antigen” vaccines. Success stories: ● ??? ● Hints of efficacy in neoantigen vaccine trials
  • 9.
    Immunotherapy vs. Chemotherapy Nivolumabin Previously Untreated Melanoma… (Robert NEJM 2015)
  • 10.
  • 11.
    What’s in atherapeutic cancer vaccine? ● Tumor antigen ○ What should immune system look for? ● Adjuvant ○ Something the immune system already responds to as dangerous ○ Examples: double-stranded RNA, mineral oil, dead bacteria ● Objective: get the immune system to learn that the antigen is bad and cells which have it should be killed
  • 12.
    Tumor-specific antigens ● Don’toccur in normal cells ○ most commonly: mutated proteins ● Unlikely to be shared between patients ● Called “neo-antigens” Getting Personal with Neoantigen-Based Therapeutic Cancer Vaccines
  • 13.
    Typical personalized cancervaccine pipeline ● Sequence DNA from tumor and patient ○ Identify tumor-specific mutations ● Sequence RNA from tumor ○ Which mutations are being produced into proteins? ● Predict which mutations can be seen by immune system Computational genomics tools for dissecting tumour–immune cell interactions
  • 14.
    Murine Experiment Checkpoint blockadecancer immunotherapy targets tumour-specific mutant antigens, Gubin et al. (2014) ● Taconic 129S6 mice ● MCA-T3 sarcoma cell line ● “mLama4” & “mAlg8” are predicted neoantigens ● Long peptide vaccine + Poly(I:C) adjuvant
  • 15.
    More Mouse Evidence Mutatedneo-antigens as targets for individualized cancer immunotherapy (Figure 3.18), Vormehr (2016) ● BALB/c mice ● CT26 colon cell line ● mRNA vaccine ● Two groups of 5 epitopes (#2 works) ○ Individual epitopes don’t work
  • 16.
    Cathy Wu &Pat Ott’s trial @ DFCI ● 6 (stage III & IV) melanoma patients ● Up to 20 mutated peptides per vaccine ● Adjuvant: Poly-ICLC
  • 17.
    DFCI Trial: TumorControl Of six vaccinated patients, four had no recurrence at 25 months after vaccination, while two with recurrent disease were subsequently treated with anti-PD-1 (anti-programmed cell death-1) therapy and experienced complete tumour regression, with expansion of the repertoire of neoantigen-specific T cells.
  • 18.
  • 19.
    DNA Sequencing NextSeq 500in Mount Sinai’s Sequencing Core ● Human genome ~= 3 billion nucleotides ○ Longest chromosome ~= 250M nucleotides ● Split DNA into tiny fragments ● Read billions of short sequences
  • 20.
    Alignment to ReferenceGenome ● Where did each short DNA “read” sequence come from?
  • 21.
  • 22.
    Categories of mutations Mutated neo-antigensas targets for individualized cancer immunotherapy, Mathias Vohrmer ● Easy to detect ○ Substitutions (e.g. C -> G) ○ Small insertions / deletions (~10 nucleotides) ● Hard ○ Larger indels ○ Inversions ○ Gene fusions
  • 23.
  • 24.
    T cell surveillance Yewdell,J.W., Reits, E. & Neefjes, J., 2003. Nature Reviews Immunology ● Proteins cleaved by proteasome ● Some of the resulting peptides loaded onto MHC to be presented on cell surface ● T cells perform surveillance of these peptide/MHC complexes ● Abnormal (non-self) displayed peptides lead to a cytotoxic T cell response 24
  • 25.
    MHC ● Thousands ofMHC alleles in human population ● Each allele capable of binding a distinct set of peptides ● Objective: Predict whether an MHC allele will bind a given peptide 25 Holland, C.J., Cole, D.K. & Godkin, A., 2013. Frontiers in Immunology
  • 26.
    Immune Epitope Database(IEDB) ● Public dataset of B and T cell epitopes and related data curated from the literature ● Includes >200,000 in vitro binding affinity measurements of purified MHC/peptides, which is the core training data for MHC ligand prediction tools
  • 27.
    Linear models performreasonably well ● Binding motifs (Sette 1989) ● Position specific scoring matrices (Parker 1994) ● Ignore dependencies between positions Bjoern Peters
  • 28.
    Neural networks dobetter: NetMHCpan (2007) ● Standard tool to predict peptide/MHC binding affinity given: peptide sequence and binding groove residues of MHC allele
  • 29.
    PGV001: Safety andImmunogenicity of Personalized Genomic Vaccine (Phase I Clinical Trial at Mount Sinai) Nina Bhardwaj
  • 30.
    PGV-001 Trial ● H&N,NSCLC, Breast, Ovarian, Urothelial, SCC, MM ● Patients w/o evidence of residual or metastatic disease ● Vaccine: ○ 10 peptides (~25 amino acids) ○ Adjuvant: Poly-ICLC ○ 10 intracutaneous injections over 6 months ● Peptide selection: ○ Phase cancer mutations with germline variants using RNA reads ○ Add multiple MHC I binding predictions overlapping same mutation ○ Ranking: expression * MHC I affinity
  • 31.
  • 32.
    Trial Status ● Open& enrolling ● 1 H&N patient treated ● 1 MM patient with manufactured peptides, will begin treatment soon ● 4 patients with DNA/RNA sequencing data
  • 33.
    New Trials in2018 ● PGV for Glioblastoma ○ + Novocure’s TTfields ○ PI: Adelia Hormigo ● PGV for Bladder Cancer ○ + ⍺PD-1 ○ PI: Matt Galsky
  • 34.
  • 35.
    Open Source ToolsDeveloped for PGV Available at github.com/openvax varcode Python interface for VCFs, variant effect prediction isovar Determine mutant coding sequence from RNA-seq vaxrank Vaccine peptide selection (including manufacturability) epidisco Turn-key workflow to generate vaccine peptide report from FASTQ inputs (runs all bioinformatics tools) ketrew Workflow engine used to run tools on Google Cloud, AWS, and traditional HPC mhctools Standard interface to pMHC binding predictors pyensembl Python interface to Ensembl reference genome annotations
  • 36.
    GGCGACTGTCCGGCTTTGAGCCAGGTGCCTC Intron Isovar: Phasing andTranscript Selection TGTCCGGCT ACTTGTCATGGCGACTGTCCGGCT TGGCGACTGTCCAGCT CGACTGTCCAGCT TGTCATGGCGACTGTCCAGCT Somatic mutation Germline mut. RNA Read 1 RNA Read 2 RNA Read 3 RNA Read 5 RNA Read 4 TTGAGCCAGGAGCCTC TTGAGCCA TTGAGCCAGGAGCCTC TTGTGCCAGGAGCCTC TTGTGCCAGGA Exon 1 Exon 2 Selected coding sequence includes germline mutation:
  • 37.
    Vaxrank: Vaccine PeptideSelection vaxrank --vcf mutect.vcf --vcf strelka.vcf --bam tumor-rna.bam --vaccine-peptide-length 25 --mhc-predictor netmhcpan --mhc-alleles-file alleles.txt
  • 38.
  • 39.
    Funding for PersonalizedCancer Vaccines $161M $195M $270M $1.2B
  • 40.