I'll analyze the freedom-to-operate landscape for your HER2-directed ADC. Let me start by orienting myself in the corpus.
{
"n_families": 14,
"targets": {
"CLDN18.2": {
"modalities": [
"Antibody-drug conjugate",
"Naked monoclonal antibody"
],
"n_families": 6
},
"HER2": {
"modalities": [
"Antibody-drug conjugate",
"Naked monoclonal antibody"
],
"n_families": 4
},
"DLL3": {
"modalities": [
"Antibody-drug conjugate",
"T-cell engager (bispecific)"
],
"n_families": 4
}
},
"assignees": [
"AbbVie / Stemcentrx",
"Amgen",
"Astellas Pharma",
"Boehringer Ingelheim",
"Byondis",
"Daiichi Sankyo",
"Ganymed Pharmaceuticals",
"Ganymed Pharmaceuticals / Astellas",
"Genentech",
"Harbour BioMed",
"ImmunoGen",
"Keymed Biosciences",
"LaNova Medicines",
"Sotio Biotech"
],
"jurisdictions": [
"CN",
"US",
"WO"
]
}Let me search the HER2 families and the relevant payload/linker technology.
{
"count": 4,
"families": [
{
"publication_number": "US10973920B2",
"jurisdiction": "US",
"assignee": "Daiichi Sankyo",
"title": "Anti-HER2 antibody-drug conjugate with an exatecan-derivative payload",
"target": "HER2",
"modality": "Antibody-drug conjugate",
"priority_date": "2014-09-30",
"expiry": "2035-09-30",
"legal_status": "GRANTED",
"claim_types": [
"composition"
],
"keywords": [
"HER2",
"ADC",
"deruxtecan",
"DXd",
"exatecan",
"GGFG linker",
"topoisomerase",
"high DAR",
"composition of matter"
]
},
{
"publication_number": "US7575748B1",
"jurisdiction": "US",
"assignee": "Genentech",
"title": "Humanized anti-HER2 antibodies",
"target": "HER2",
"modality": "Naked monoclonal antibody",
"priority_date": "1998-08-27",
"expiry": "2019-08-27",
"legal_status": "EXPIRED",
"claim_types": [
"composition"
],
"keywords": [
"HER2",
"trastuzumab",
"naked antibody",
"humanized",
"expired",
"extracellular domain",
"composition of matter"
]
},
{
"publication_number": "WO2020196474A1",
"jurisdiction": "WO",
"assignee": "Byondis",
"title": "Anti-HER2 antibody-drug conjugate with a duocarmycin payload",
"target": "HER2",
"modality": "Antibody-drug conjugate",
"priority_date": "2019-03-26",
"expiry": "2040-03-26",
"legal_status": "PENDING",
"claim_types": [
"composition"
],
"keywords": [
"HER2",
"ADC",
"duocarmycin",
"vc linker",
"cleavable linker",
"pending",
"alternative payload"
]
},
{
"publication_number": "US9968687B2",
"jurisdiction": "US",
"assignee": "ImmunoGen",
"title": "Anti-HER2 maytansinoid conjugate (T-DM1 class)",
"target": "HER2",
"modality": "Antibody-drug conjugate",
"priority_date": "2010-02-24",
"expiry": "2031-02-24",
"legal_status": "GRANTED",
"claim_types": [
"composition",
"method"
],
"keywords": [
"HER2",
"ADC",
"T-DM1",
"maytansinoid",
"DM1",
"SMCC",
"non-cleavable linker",
"composition of matter"
]
}
]
}{
"count": 2,
"families": [
{
"publication_number": "CN114106192A",
"jurisdiction": "CN",
"assignee": "Keymed Biosciences",
"title": "Anti-claudin18.2 antibody conjugated to a topoisomerase-I inhibitor payload",
"target": "CLDN18.2",
"modality": "Antibody-drug conjugate",
"priority_date": "2020-09-30",
"expiry": "2040-09-30",
"legal_status": "PENDING",
"claim_types": [
"composition"
],
"keywords": [
"CLDN18.2",
"ADC",
"topoisomerase",
"exatecan",
"DXd",
"cleavable linker",
"pending",
"China"
]
},
{
"publication_number": "US10973920B2",
"jurisdiction": "US",
"assignee": "Daiichi Sankyo",
"title": "Anti-HER2 antibody-drug conjugate with an exatecan-derivative payload",
"target": "HER2",
"modality": "Antibody-drug conjugate",
"priority_date": "2014-09-30",
"expiry": "2035-09-30",
"legal_status": "GRANTED",
"claim_types": [
"composition"
],
"keywords": [
"HER2",
"ADC",
"deruxtecan",
"DXd",
"exatecan",
"GGFG linker",
"topoisomerase",
"high DAR",
"composition of matter"
]
}
]
}{
"count": 1,
"families": [
{
"publication_number": "US10973920B2",
"jurisdiction": "US",
"assignee": "Daiichi Sankyo",
"title": "Anti-HER2 antibody-drug conjugate with an exatecan-derivative payload",
"target": "HER2",
"modality": "Antibody-drug conjugate",
"priority_date": "2014-09-30",
"expiry": "2035-09-30",
"legal_status": "GRANTED",
"claim_types": [
"composition"
],
"keywords": [
"HER2",
"ADC",
"deruxtecan",
"DXd",
"exatecan",
"GGFG linker",
"topoisomerase",
"high DAR",
"composition of matter"
]
}
]
}{
"count": 2,
"families": [
{
"publication_number": "CN114106192A",
"jurisdiction": "CN",
"assignee": "Keymed Biosciences",
"title": "Anti-claudin18.2 antibody conjugated to a topoisomerase-I inhibitor payload",
"target": "CLDN18.2",
"modality": "Antibody-drug conjugate",
"priority_date": "2020-09-30",
"expiry": "2040-09-30",
"legal_status": "PENDING",
"claim_types": [
"composition"
],
"keywords": [
"CLDN18.2",
"ADC",
"topoisomerase",
"exatecan",
"DXd",
"cleavable linker",
"pending",
"China"
]
},
{
"publication_number": "US10973920B2",
"jurisdiction": "US",
"assignee": "Daiichi Sankyo",
"title": "Anti-HER2 antibody-drug conjugate with an exatecan-derivative payload",
"target": "HER2",
"modality": "Antibody-drug conjugate",
"priority_date": "2014-09-30",
"expiry": "2035-09-30",
"legal_status": "GRANTED",
"claim_types": [
"composition"
],
"keywords": [
"HER2",
"ADC",
"deruxtecan",
"DXd",
"exatecan",
"GGFG linker",
"topoisomerase",
"high DAR",
"composition of matter"
]
}
]
}The Daiichi Sankyo family (US10973920B2) is the centerpiece — it directly reads on your described product (this is trastuzumab deruxtecan / Enhertu chemistry). Let me read the actual claims of the most relevant families to assess scope.
{
"publication_number": "US10973920B2",
"title": "Anti-HER2 antibody-drug conjugate with an exatecan-derivative payload",
"legal_status": "GRANTED",
"independent_claims": [
{
"claim_no": 1,
"claim_type": "composition",
"text": "An antibody-drug conjugate wherein an anti-HER2 antibody is conjugated through a maleimide-GGFG peptide linker to a DX-8951 (exatecan) derivative topoisomerase-I inhibitor, at a drug-to-antibody ratio of about 7 to 8."
},
{
"claim_no": 12,
"claim_type": "composition",
"text": "The drug-linker intermediate of the conjugate of claim 1, comprising the GGFG tetrapeptide spacer and self-immolative aminomethyl group."
}
]
}{
"publication_number": "CN114106192A",
"title": "Anti-claudin18.2 antibody conjugated to a topoisomerase-I inhibitor payload",
"legal_status": "PENDING",
"independent_claims": [
{
"claim_no": 1,
"claim_type": "composition",
"text": "An antibody-drug conjugate comprising an anti-CLDN18.2 antibody covalently linked via a tetrapeptide-based cleavable linker to an exatecan-derivative topoisomerase-I inhibitor payload."
}
]
}{
"publication_number": "US7575748B1",
"title": "Humanized anti-HER2 antibodies",
"legal_status": "EXPIRED",
"independent_claims": [
{
"claim_no": 1,
"claim_type": "composition",
"text": "A humanized antibody that binds the extracellular domain of human HER2/neu, comprising the trastuzumab heavy- and light-chain variable regions."
}
]
}{
"publication_number": "WO2020196474A1",
"title": "Anti-HER2 antibody-drug conjugate with a duocarmycin payload",
"legal_status": "PENDING",
"independent_claims": [
{
"claim_no": 1,
"claim_type": "composition",
"text": "An antibody-drug conjugate comprising an anti-HER2 antibody, a cleavable valine-citrulline linker, and a seco-duocarmycin-hydroxybenzamide-azaindole (duocarmycin) payload."
}
]
}{
"publication_number": "US9968687B2",
"title": "Anti-HER2 maytansinoid conjugate (T-DM1 class)",
"legal_status": "GRANTED",
"independent_claims": [
{
"claim_no": 1,
"claim_type": "composition",
"text": "An immunoconjugate comprising trastuzumab linked via a non-cleavable SMCC linker to the maytansinoid DM1."
},
{
"claim_no": 8,
"claim_type": "method",
"text": "A method of treating HER2-positive metastatic breast cancer that has progressed on trastuzumab and a taxane, comprising administering the immunoconjugate of claim 1."
}
]
}Let me get the full record on the Daiichi family to check for any HER2-low method claims or additional details that bear on the indication.
{
"publication_number": "US10973920B2",
"jurisdiction": "US",
"assignee": "Daiichi Sankyo",
"priority_date": "2014-09-30",
"expiry": "2035-09-30",
"legal_status": "GRANTED",
"title": "Anti-HER2 antibody-drug conjugate with an exatecan-derivative payload",
"target": "HER2",
"modality": "Antibody-drug conjugate",
"independent_claims": [
{
"claim_no": 1,
"claim_type": "composition",
"text": "An antibody-drug conjugate wherein an anti-HER2 antibody is conjugated through a maleimide-GGFG peptide linker to a DX-8951 (exatecan) derivative topoisomerase-I inhibitor, at a drug-to-antibody ratio of about 7 to 8."
},
{
"claim_no": 12,
"claim_type": "composition",
"text": "The drug-linker intermediate of the conjugate of claim 1, comprising the GGFG tetrapeptide spacer and self-immolative aminomethyl group."
}
],
"keywords": [
"HER2",
"ADC",
"deruxtecan",
"DXd",
"exatecan",
"GGFG linker",
"topoisomerase",
"high DAR",
"composition of matter"
]
}{
"count": 0,
"families": []
}I now have a complete picture of the FTO landscape. Here is my assessment.
Your proposed product is essentially trastuzumab deruxtecan (Enhertu) chemistry. As designed, it falls squarely within a granted, in-force composition-of-matter claim owned by Daiichi Sankyo. FTO is not clear — you have a hard blocking position on the core composition, and meaningful design-arounds require moving off the exatecan/GGFG/high-DAR combination.
| Attribute | Detail |
|---|---|
| Status | GRANTED / in force |
| Priority | 2014-09-30 |
| Expiry | 2035-09-30 (no PTE/SPC modeled here) |
| Claim 1 | Anti-HER2 antibody + maleimide-GGFG peptide linker + DX-8951 (exatecan) derivative topo-I inhibitor at DAR ~7–8 |
| Claim 12 | The drug-linker intermediate (GGFG tetrapeptide + self-immolative aminomethyl) |
Element-by-element read against your product:
Conclusion: Literal infringement of claim 1 if your DAR is in the 7–8 range. This is a genuine blocking patent through September 2035. The indication (HER2-low) is irrelevant — claim 1 is a pure composition claim; it does not matter what cancer you treat. Note: no HER2-low method claim exists in this corpus, but you cannot reach the method-of-use design-around because making/selling the composition itself infringes.
| Family | Assignee | Status | Why it doesn't block you |
|---|---|---|---|
| US7575748B1 | Genentech | EXPIRED (2019) | The trastuzumab humanized-antibody composition claim is expired. You are free to use the trastuzumab antibody scaffold itself — the antibody is no longer a barrier. The barrier is the conjugate. |
| US9968687B2 (T-DM1) | ImmunoGen | Granted, but non-overlapping | Claims a non-cleavable SMCC linker + maytansinoid DM1. Different linker chemistry and different payload class — does not read on a GGFG/exatecan ADC. Its method claim is limited to HER2-positive post-trastuzumab/taxane, also not implicated. Expires 2031. |
The expiry of the Genentech antibody patent is the key positive: the binder is free; only the payload+linker+DAR combination is encumbered.
| Family | Assignee | Status | Relevance |
|---|---|---|---|
| WO2020196474A1 | Byondis | PENDING | HER2 ADC but duocarmycin payload + vc linker — a competing design-around archetype, not a blocker against you. Confirms the duocarmycin route is being staked out by others. |
| CN114106192A | Keymed | PENDING (CN) | Anti-CLDN18.2 + tetrapeptide linker + exatecan/DXd. Different target, so no overlap on a HER2 product. BUT note its claim 1 is drafted to a tetrapeptide-based cleavable linker + exatecan payload generically — watch its prosecution; relevant only if you ever extend the platform to CLDN18.2. CN-only jurisdiction. |
Claim 1's three pillars are (a) exatecan-derivative payload, (b) GGFG linker, (c) DAR ~7–8. Defeating any one element avoids literal infringement, but watch doctrine of equivalents.
Strongest design-arounds (change the payload class — cleanest escape):
1. Switch payload chemistry entirely — e.g., the duocarmycin route (cf. Byondis WO2020196474A1) or a maytansinoid/auristatin. This exits "exatecan-derivative topo-I" and is the most defensible. Caveat: you then need FTO against those families (Byondis pending; ImmunoGen for maytansinoids).
Moderate (keep topo-I MoA but engineer off the literal claim — higher DoE risk):
2. Non-exatecan topo-I payload — a camptothecin/SN-38-type or a structurally distinct topo-I warhead that is not a "DX-8951/exatecan derivative." Preserves the topo-I mechanism and bystander effect attractive for HER2-low, but DoE risk is highest here because the patentee will argue equivalence of topo-I exatecan-likes.
3. Replace the GGFG tetrapeptide linker — e.g., a different cleavable peptide (val-cit, val-ala) or a glycosidase/disulfide-cleavable chemistry, dropping the self-immolative aminomethyl of claim 12. Reduces overlap on both claim 1 (linker) and claim 12 (intermediate). Strongest if combined with a non-maleimide conjugation handle.
Weakest (do not rely on alone):
4. DAR engineering — moving to a homogeneous DAR ~2–4 technically exits "about 7–8." This is brittle: "about" invites a DoE argument, and a high-DAR topo-I bystander payload is much of what makes the product work for HER2-low. Use only as a secondary differentiator, never the sole basis.
Procedural levers:
5. Geographic strategy — confirm whether the Daiichi family is granted/in-force in each target jurisdiction; FTO is country-by-country. The exatecan-topo-I CLDN18.2 art is CN-pending, indicating active CN filing activity in this space.
6. License — given a literal in-force composition claim through 2035, an in-license from Daiichi Sankyo is the realistic path if you want to keep the exact exatecan/GGFG/high-DAR design (which is what makes Enhertu effective in HER2-low).
7. Validity challenge — assess prior art against the 2014 priority date if a design-around isn't commercially viable; not modeled in this corpus.
| Family | Assignee | Status | Verdict for your product |
|---|---|---|---|
| US10973920B2 | Daiichi Sankyo | Granted, expires 2035 | BLOCKING — literal read on Ab+GGFG+exatecan+DAR7-8 |
| US7575748B1 | Genentech | Expired 2019 | Clear — trastuzumab scaffold free to use |
| US9968687B2 | ImmunoGen | Granted, 2031 | Not blocking — different (SMCC/maytansinoid) chemistry |
| WO2020196474A1 | Byondis | Pending | Not blocking — duocarmycin; a design-around template |
| CN114106192A | Keymed | Pending (CN) | Not blocking (CLDN18.2 target); monitor if platform extends |
Recommendation: As specified, your candidate is blocked by US10973920B2 until 2035. To obtain FTO you should either (1) license from Daiichi Sankyo, or (2) re-engineer the payload class (most robust — e.g., off topo-I entirely, or to a clearly non-exatecan warhead) ideally combined with a non-GGFG cleavable linker, rather than relying on DAR adjustment alone. The HER2-low indication itself raises no method-claim barrier in this corpus — the obstacle is entirely the composition.
Caveats: this analysis covers only the 14-family corpus provided; no PTE/SPC term extensions, foreign counterparts outside US/WO/CN, or pending continuations are reflected. Confirm jurisdiction-by-jurisdiction status and obtain formal patent-counsel opinion before clearance.
I now have a complete picture of the FTO landscape. Here is my assessment.
Your proposed product is essentially trastuzumab deruxtecan (Enhertu) chemistry. As designed, it falls squarely within a granted, in-force composition-of-matter claim owned by Daiichi Sankyo. FTO is not clear — you have a hard blocking position on the core composition, and meaningful design-arounds require moving off the exatecan/GGFG/high-DAR combination.
| Attribute | Detail |
|---|---|
| Status | GRANTED / in force |
| Priority | 2014-09-30 |
| Expiry | 2035-09-30 (no PTE/SPC modeled here) |
| Claim 1 | Anti-HER2 antibody + maleimide-GGFG peptide linker + DX-8951 (exatecan) derivative topo-I inhibitor at DAR ~7–8 |
| Claim 12 | The drug-linker intermediate (GGFG tetrapeptide + self-immolative aminomethyl) |
Element-by-element read against your product:
Conclusion: Literal infringement of claim 1 if your DAR is in the 7–8 range. This is a genuine blocking patent through September 2035. The indication (HER2-low) is irrelevant — claim 1 is a pure composition claim; it does not matter what cancer you treat. Note: no HER2-low method claim exists in this corpus, but you cannot reach the method-of-use design-around because making/selling the composition itself infringes.
| Family | Assignee | Status | Why it doesn't block you |
|---|---|---|---|
| US7575748B1 | Genentech | EXPIRED (2019) | The trastuzumab humanized-antibody composition claim is expired. You are free to use the trastuzumab antibody scaffold itself — the antibody is no longer a barrier. The barrier is the conjugate. |
| US9968687B2 (T-DM1) | ImmunoGen | Granted, but non-overlapping | Claims a non-cleavable SMCC linker + maytansinoid DM1. Different linker chemistry and different payload class — does not read on a GGFG/exatecan ADC. Its method claim is limited to HER2-positive post-trastuzumab/taxane, also not implicated. Expires 2031. |
The expiry of the Genentech antibody patent is the key positive: the binder is free; only the payload+linker+DAR combination is encumbered.
| Family | Assignee | Status | Relevance |
|---|---|---|---|
| WO2020196474A1 | Byondis | PENDING | HER2 ADC but duocarmycin payload + vc linker — a competing design-around archetype, not a blocker against you. Confirms the duocarmycin route is being staked out by others. |
| CN114106192A | Keymed | PENDING (CN) | Anti-CLDN18.2 + tetrapeptide linker + exatecan/DXd. Different target, so no overlap on a HER2 product. BUT note its claim 1 is drafted to a tetrapeptide-based cleavable linker + exatecan payload generically — watch its prosecution; relevant only if you ever extend the platform to CLDN18.2. CN-only jurisdiction. |
Claim 1's three pillars are (a) exatecan-derivative payload, (b) GGFG linker, (c) DAR ~7–8. Defeating any one element avoids literal infringement, but watch doctrine of equivalents.
Strongest design-arounds (change the payload class — cleanest escape):
1. Switch payload chemistry entirely — e.g., the duocarmycin route (cf. Byondis WO2020196474A1) or a maytansinoid/auristatin. This exits "exatecan-derivative topo-I" and is the most defensible. Caveat: you then need FTO against those families (Byondis pending; ImmunoGen for maytansinoids).
Moderate (keep topo-I MoA but engineer off the literal claim — higher DoE risk):
2. Non-exatecan topo-I payload — a camptothecin/SN-38-type or a structurally distinct topo-I warhead that is not a "DX-8951/exatecan derivative." Preserves the topo-I mechanism and bystander effect attractive for HER2-low, but DoE risk is highest here because the patentee will argue equivalence of topo-I exatecan-likes.
3. Replace the GGFG tetrapeptide linker — e.g., a different cleavable peptide (val-cit, val-ala) or a glycosidase/disulfide-cleavable chemistry, dropping the self-immolative aminomethyl of claim 12. Reduces overlap on both claim 1 (linker) and claim 12 (intermediate). Strongest if combined with a non-maleimide conjugation handle.
Weakest (do not rely on alone):
4. DAR engineering — moving to a homogeneous DAR ~2–4 technically exits "about 7–8." This is brittle: "about" invites a DoE argument, and a high-DAR topo-I bystander payload is much of what makes the product work for HER2-low. Use only as a secondary differentiator, never the sole basis.
Procedural levers:
5. Geographic strategy — confirm whether the Daiichi family is granted/in-force in each target jurisdiction; FTO is country-by-country. The exatecan-topo-I CLDN18.2 art is CN-pending, indicating active CN filing activity in this space.
6. License — given a literal in-force composition claim through 2035, an in-license from Daiichi Sankyo is the realistic path if you want to keep the exact exatecan/GGFG/high-DAR design (which is what makes Enhertu effective in HER2-low).
7. Validity challenge — assess prior art against the 2014 priority date if a design-around isn't commercially viable; not modeled in this corpus.
| Family | Assignee | Status | Verdict for your product |
|---|---|---|---|
| US10973920B2 | Daiichi Sankyo | Granted, expires 2035 | BLOCKING — literal read on Ab+GGFG+exatecan+DAR7-8 |
| US7575748B1 | Genentech | Expired 2019 | Clear — trastuzumab scaffold free to use |
| US9968687B2 | ImmunoGen | Granted, 2031 | Not blocking — different (SMCC/maytansinoid) chemistry |
| WO2020196474A1 | Byondis | Pending | Not blocking — duocarmycin; a design-around template |
| CN114106192A | Keymed | Pending (CN) | Not blocking (CLDN18.2 target); monitor if platform extends |
Recommendation: As specified, your candidate is blocked by US10973920B2 until 2035. To obtain FTO you should either (1) license from Daiichi Sankyo, or (2) re-engineer the payload class (most robust — e.g., off topo-I entirely, or to a clearly non-exatecan warhead) ideally combined with a non-GGFG cleavable linker, rather than relying on DAR adjustment alone. The HER2-low indication itself raises no method-claim barrier in this corpus — the obstacle is entirely the composition.
Caveats: this analysis covers only the 14-family corpus provided; no PTE/SPC term extensions, foreign counterparts outside US/WO/CN, or pending continuations are reflected. Confirm jurisdiction-by-jurisdiction status and obtain formal patent-counsel opinion before clearance.
Heuristic reference over the curated corpus for target=HER2, modality=Antibody-drug conjugate. Families in scope: 4 ({'GRANTED': 2, 'PENDING': 1, 'EXPIRED': 1}). BLOCKING = granted composition-of-matter on the same target+modality and not expired; WATCH = pending or method-only; CLEARABLE = expired. This is illustrative reasoning over a teaching snapshot, NOT legal advice.
| Publication # | Assignee | Legal status | Expiry | Claim type(s) | FTO relevance |
|---|---|---|---|---|---|
| US10973920B2 | Daiichi Sankyo | GRANTED | 2035-09-30 | composition | BLOCKING (granted composition-of-matter) |
| WO2020196474A1 | Byondis | PENDING | 2040-03-26 | composition | WATCH (pending — claims not yet fixed) |
| US9968687B2 | ImmunoGen | GRANTED | 2031-02-24 | composition, method | BLOCKING (granted composition-of-matter) |
| US7575748B1 | Genentech | EXPIRED | 2019-08-27 | composition | CLEARABLE (expired) |
| OVERALL FTO VERDICT (heuristic) | BLOCKED — 2 granted composition-of-matter family(ies) read on the proposed product; need a licence or a design-around. |