Why first-generation KRAS G12C inhibitors face a resistance ceiling
Sotorasib and adagrasib — the two approved first-generation KRAS G12C inhibitors — are effective at initial tumour control in non-small cell lung cancer (NSCLC) and colorectal cancer, but both face an acquired resistance problem that limits durable responses. Patent literature and academic research identify three primary resistance mechanisms driving the field toward combination strategies: secondary KRAS mutations that prevent covalent drug binding, EGFR bypass activation that reactivates downstream signalling independently of KRAS, and MAPK pathway reactivation through alternative upstream inputs.
Research published on resistance mechanisms in NSCLC and colorectal cancer — as indexed in PatSnap’s innovation intelligence platform — confirms that secondary KRAS mutations, EGFR bypass activation, and MAPK reactivation are the dominant escape routes. Each of these mechanisms maps directly onto the combination partners now being pursued in patent filings: SHP2 inhibitors block upstream GEF-mediated KRAS reloading; EGFR inhibitors prevent bypass signalling; MEK inhibitors suppress downstream MAPK reactivation; and SOS1 inhibitors cut off a second GEF-mediated input. The implication is clear — no single-agent KRAS G12C inhibitor is likely to achieve durable control without a co-targeting strategy.
KRAS G12C is a somatic point mutation in the KRAS oncogene in which glycine at position 12 is substituted by cysteine. This mutation locks KRAS in a constitutively active, GTP-bound state that drives uncontrolled cell proliferation. It is one of the most common oncogenic driver mutations in NSCLC and colorectal cancer. Covalent inhibitors exploit the unique cysteine residue to irreversibly bind and inactivate the mutant protein.
According to academic literature tracking resistance biology — including work indexed by NIH/PubMed — EGFR-mediated bypass is particularly prominent in colorectal cancer, explaining why anti-EGFR antibodies such as cetuximab are a logical combination partner in that indication. In NSCLC, MAPK reactivation through SOS1-mediated GTP reloading is a key escape mechanism, making SOS1 inhibitor combinations especially relevant to that tumour type.
First-generation KRAS G12C inhibitors sotorasib and adagrasib face acquired resistance driven by three mechanisms: secondary KRAS mutations blocking covalent drug binding, EGFR bypass activation, and MAPK pathway reactivation through alternative upstream inputs.
Glecirasib’s multi-arm combination patent portfolio
Glecirasib (JAB-21822), the selective covalent KRAS G12C inhibitor developed by Jacobio Pharmaceuticals and disclosed in PCT application WO2022002188A1, has the most diversified combination patent portfolio of any next-generation KRAS G12C inhibitor. Jacobio has filed at least three distinct combination strategies across multiple jurisdictions, each targeting a different node in the KRAS signalling network.
The first and most mechanistically targeted of Jacobio’s glecirasib combinations is with a SHP2 inhibitor, disclosed in WO2024002044A1 (published January 2024). SHP2 is a phosphatase that facilitates GTP loading of wild-type RAS and, critically, can reactivate KRAS signalling downstream of EGFR and other receptor tyrosine kinases. The patent discloses preclinical data indicating synergistic activity of the glecirasib + SHP2 inhibitor combination over either single agent alone in KRAS G12C-mutant tumour models — a finding that mirrors the mechanistic rationale for the adagrasib + TNO-155 combination patented by Mirati Therapeutics.
“Preclinical data indicate synergistic activity of the glecirasib + SHP2 inhibitor combination over single agents in KRAS G12C-mutant tumour models — Jacobio Pharmaceuticals, WO2024002044A1.”
The second arm of Jacobio’s combination strategy targets EGFR directly. WO2023207903A1 (published November 2023) discloses glecirasib combined with cetuximab, an anti-EGFR monoclonal antibody, specifically for KRAS G12C-mutant colorectal cancer. The patent describes enhanced anti-tumour activity in KRAS G12C-mutant colorectal cancer models — a clinically important finding given that colorectal cancer is the indication where EGFR bypass is most prevalent and where cetuximab already has established regulatory approval for KRAS wild-type tumours.
Jacobio Pharmaceuticals filed WO2023207903A1 in November 2023, disclosing glecirasib (JAB-21822) combined with cetuximab (anti-EGFR antibody) for KRAS G12C-mutant colorectal cancer, with the patent describing enhanced anti-tumour activity in colorectal cancer models.
The third combination, disclosed in CN116120360A (published May 2023), pairs glecirasib with a SOS1 inhibitor. SOS1 is a guanine nucleotide exchange factor (GEF) that catalyses the loading of GTP onto KRAS, effectively reactivating the oncogene. Blocking SOS1 therefore prevents a key feedback mechanism that undermines KRAS G12C inhibitor monotherapy. This patent covers use of the combination for treating KRAS-mediated signalling at multiple nodes — language that signals a broad mechanistic claim rather than a tumour-type-specific indication.
Track glecirasib combination patent filings and competitive KRAS G12C intelligence in real time.
Explore KRAS G12C patents in PatSnap Eureka →Glecirasib itself was evaluated in a Phase 1/2 clinical study in patients with KRAS G12C-mutated advanced solid tumours, demonstrating antitumour activity as a single agent. The combination patents filed by Jacobio in 2023–2024 therefore represent a clear strategic evolution from single-agent proof-of-concept to a combination-first clinical development philosophy — a pattern consistent with how the field learned from sotorasib and adagrasib monotherapy limitations.
Johnson & Johnson’s tricyclic KRAS G12C inhibitor strategy
Janssen Pharmaceutica, a Johnson & Johnson subsidiary, has taken a structurally differentiated approach to the KRAS G12C space — filing two US patent applications in 2023 covering tricyclic covalent KRAS G12C inhibitor compounds that are chemically distinct from the first-generation agents sotorasib and adagrasib. US20230121894A1 was published in April 2023, and US20230399325A1 followed in December 2023, together forming the core of Janssen’s KRAS G12C inhibitor intellectual property estate.
According to research on Janssen’s medicinal chemistry campaign — as indexed in PatSnap — these tricyclic covalent inhibitors are described as having differentiated selectivity and pharmacokinetic profiles compared to first-generation agents. The structural novelty of the tricyclic scaffold is significant: it potentially allows Janssen to enter a market already occupied by sotorasib (Amgen/AstraZeneca) and adagrasib (Mirati/Bristol-Myers Squibb) without directly infringing existing compound patents, while also potentially offering improved properties such as CNS penetration, selectivity, or resistance to secondary mutation-mediated resistance.
Janssen Pharmaceutica filed two US patent applications in 2023 (US20230121894A1, April 2023; US20230399325A1, December 2023) covering tricyclic covalent KRAS G12C inhibitor compounds described as having differentiated selectivity and pharmacokinetic profiles compared to first-generation agents sotorasib and adagrasib. This structural novelty is a deliberate strategy to enter the KRAS G12C market with a differentiated compound rather than a direct chemical analogue.
The strategic significance of J&J entering the KRAS G12C space with novel chemistry should not be underestimated. J&J has one of the largest oncology portfolios in the pharmaceutical industry, and its entry with structurally novel tricyclic inhibitors — rather than a me-too approach — suggests confidence in the clinical differentiation story. According to WHO cancer statistics, NSCLC and colorectal cancer together represent two of the highest-burden malignancies globally, and KRAS G12C mutations are present in approximately 13% of NSCLC cases and approximately 3–4% of colorectal cancer cases, representing a substantial addressable patient population.
Janssen Pharmaceutica (a Johnson & Johnson subsidiary) filed two US patent applications for structurally distinct tricyclic covalent KRAS G12C inhibitor compounds: US20230121894A1 (published April 2023) and US20230399325A1 (published December 2023), with the compounds described as having differentiated selectivity and pharmacokinetic profiles versus first-generation KRAS G12C inhibitors.
The broader competitive landscape: Amgen, Mirati, Novartis, and beyond
The KRAS G12C combination patent landscape extends well beyond glecirasib and Janssen’s tricyclics. At least seven companies have filed substantive combination therapy patents, each targeting one or more of the established resistance mechanisms, and the range of combination partners being explored is broad.
Amgen has the most advanced clinical programme in the space, having obtained approval for sotorasib (Lumakras/Lumykras) as a monotherapy. Amgen’s patent filings now extend the sotorasib franchise into combinations: US20230364060A1 (published November 2023) discloses sotorasib combined with EGFR inhibitors panitumumab or erlotinib for NSCLC and colorectal cancer, while WO2023060229A1 (published April 2023) covers sotorasib combined with PD-1 or PD-L1 immune checkpoint inhibitors for solid tumours including NSCLC and colorectal cancer. The checkpoint inhibitor combination is particularly notable given the immunosuppressive tumour microenvironment associated with KRAS-mutant cancers.
Mirati Therapeutics (now part of Bristol-Myers Squibb) has filed two US patent applications — US20230159519A1 (May 2023) and US20230365555A1 (November 2023) — covering adagrasib combined with the SHP2 inhibitor TNO-155 (also known as SHP099). This mirrors Jacobio’s glecirasib + SHP2 inhibitor strategy and reflects the field-wide consensus that SHP2 inhibition is the most mechanistically validated combination partner for KRAS G12C inhibitors.
Novartis filed US20230390290A1 (published December 2023) covering a KRAS G12C inhibitor combined with an EGFR inhibitor — a jurisdiction-parallel filing to Amgen’s EGFR combination strategy. Boehringer Ingelheim has taken a different angle, filing US20220387427A1 (December 2022) covering SOS1 inhibitors combined with KRAS G12C direct inhibitors, with a rationale based on upstream RAS signalling feedback suppression — the same mechanistic logic as Jacobio’s glecirasib + SOS1 inhibitor patent. Array BioPharma / Pfizer has filed US20230330098A1 (October 2023) covering KRAS G12C inhibitor + MEK inhibitor combinations specifically designed to overcome MAPK pathway reactivation as a resistance mechanism.
Map the full competitive KRAS G12C patent landscape across all players and combination strategies.
Analyse KRAS G12C patents in PatSnap Eureka →The breadth of combination strategies now being patented — SHP2, EGFR, SOS1, MEK, PD-1/PD-L1, CDK4/6 — reflects the complexity of KRAS G12C resistance biology. According to patent analysis indexed through PatSnap’s pharmaceutical intelligence solutions, the combination therapy patent space for KRAS G12C has expanded dramatically from 2022 to 2024, with filings across US, PCT, and Chinese national jurisdictions. The Chinese filing activity — particularly from Jacobio — is significant given that KRAS G12C mutations have a higher prevalence in Chinese NSCLC patients than in Western populations, according to epidemiological data tracked by WHO.
Reading the patent signals: what the filing patterns reveal
Patent filing patterns in the KRAS G12C combination space reveal several strategic signals that are relevant to R&D leaders, IP professionals, and drug development teams tracking this field.
Signal 1: SHP2 inhibition has achieved combination consensus
Both Jacobio (glecirasib + SHP2 inhibitor, WO2024002044A1) and Mirati/BMS (adagrasib + TNO-155, US20230159519A1 and US20230365555A1) have independently filed SHP2 combination patents. The independent convergence of two leading KRAS G12C developers on SHP2 as a combination partner — backed by preclinical synergy data in Jacobio’s filing — represents the strongest patent-level signal that SHP2 inhibition is the most validated co-targeting strategy. According to academic literature catalogued by NIH/PubMed, SOS1 inhibition provides a complementary but distinct mechanism, as SOS1 acts as a GEF upstream of both wild-type and mutant KRAS, while SHP2 acts more broadly across receptor tyrosine kinase signalling.
Signal 2: Indication-specific strategies are emerging
The patent filings show clear indication-specific stratification. Glecirasib + cetuximab (WO2023207903A1) is filed specifically for colorectal cancer — the indication where EGFR bypass is most prevalent. Sotorasib + EGFR inhibitor combinations (US20230364060A1) similarly cite colorectal cancer as a primary indication alongside NSCLC. In contrast, SOS1 inhibitor combinations (CN116120360A, US20220387427A1) are framed more broadly, suggesting they may have application across multiple KRAS-driven tumour types. This indication-level specialisation in combination patent claims is a maturation signal — the field has moved beyond broad combination claims to targeted, mechanistically justified indication-specific strategies.
Signal 3: Structural novelty is the J&J differentiator
Janssen’s decision to pursue tricyclic KRAS G12C inhibitors — rather than filing combination patents for existing first-generation agents — signals a different competitive strategy. Rather than extending an existing compound’s patent life through combination claims, J&J is building freedom to operate through novel compound chemistry. This approach is consistent with how large pharmaceutical companies with significant oncology franchises typically enter established drug classes: by bringing structurally differentiated molecules that can command independent patent protection and potentially offer improved clinical profiles. The two Janssen filings in 2023 suggest the programme is moving from discovery toward IND-enabling studies, a timeline consistent with potential clinical entry in the 2025–2027 window.
At least seven companies — Jacobio Pharmaceuticals, Mirati Therapeutics/BMS, Amgen, Novartis, Boehringer Ingelheim, Janssen/J&J, and Array BioPharma/Pfizer — have filed KRAS G12C combination therapy patents covering SHP2, EGFR, SOS1, MEK, PD-1/PD-L1, and CDK4/6 co-targeting strategies between 2022 and 2024.
For IP professionals and R&D teams, the practical implication is clear: the KRAS G12C combination patent landscape is becoming dense and jurisdiction-diverse. Freedom-to-operate analysis for any new KRAS G12C combination programme must now account for filings in the US, PCT, Chinese, and European jurisdictions, across at least seven active filers. Patent intelligence tools — such as those provided by PatSnap — are increasingly necessary to map white space, identify potential blocking patents, and track competitor filing velocity in real time. The European Patent Office and WIPO databases both show accelerating KRAS G12C filing rates from 2022 onwards, reflecting the field’s rapid transition from single-agent to combination-first development paradigms.