Purpose:

The RET proto-oncogene encodes a receptor tyrosine kinase that is activated by gene fusion in 1%–2% of non–small cell lung cancers (NSCLC) and rarely in other cancer types. Selpercatinib is a highly selective RET kinase inhibitor that has recently been approved by the FDA in lung and thyroid cancers with activating RET gene fusions and mutations. Molecular mechanisms of acquired resistance to selpercatinib are poorly understood.

Patients and Methods:

We studied patients treated on the first-in-human clinical trial of selpercatinib (NCT03157129) who were found to have MET amplification associated with resistance to selpercatinib. We validated MET activation as a targetable mediator of resistance to RET-directed therapy, and combined selpercatinib with the MET/ALK/ROS1 inhibitor crizotinib in a series of single patient protocols (SPP).

Results:

MET amplification was identified in posttreatment biopsies in 4 patients with RET fusion–positive NSCLC treated with selpercatinib. In at least one case, MET amplification was clearly evident prior to therapy with selpercatinib. We demonstrate that increased MET expression in RET fusion–positive tumor cells causes resistance to selpercatinib, and this can be overcome by combining selpercatinib with crizotinib. Using SPPs, selpercatinib with crizotinib were given together generating anecdotal evidence of clinical activity and tolerability, with one response lasting 10 months.

Conclusions:

Through the use of SPPs, we were able to offer combination therapy targeting MET-amplified resistance identified on the first-in-human study of selpercatinib. These data suggest that MET dependence is a recurring and potentially targetable mechanism of resistance to selective RET inhibition in advanced NSCLC.

Translational Relevance

Molecular mechanisms of acquired resistance to selpercatinib, a highly selective and potent RET kinase inhibitor, are poorly understood. We identified MET amplification as a recurrent mechanism of resistance to targeted therapy in patients with non–small cell lung cancer (NSCLC) treated with selpercatinib. We show that MET amplification is sufficient to cause selpercatinib resistance in vitro, and that the addition of the MET/ALK/ROS1 inhibitor crizotinib can rescue this phenotype. We then utilize a series of single-patient protocols to treat these patients with combination therapy, and this combination treatment showed clinical activity, with one response lasting 10 months. These data suggest that MET dependence is a recurring and potentially targetable mechanism of resistance to selective RET inhibition in advanced NSCLC. Prospective clinical trials are needed to validate these findings and to identify effective combination therapies to treat acquired resistance to selpercatinib.

Combination targeted therapy represents a compelling strategy for overcoming drug resistance in metastatic cancer. However, the clinical development of combination approaches has been challenging due to toxicity from combining two agents and the need for appropriate patient selection. While several combination therapies are approved (e.g., MEK inhibition with BRAF inhibition in BRAF-mutant melanoma; CDK4/6 inhibition with endocrine therapy in ER+ breast cancer; refs. 1–4), no drug combination has yet met the standard of regulatory approval for effective treatment of resistance to targeted kinase inhibitors (TKI) in genotype-selected patients. Because resistance to targeted TKIs is universal, effective strategies to overcome acquired resistance are key to prolonging clinical benefit. To that end, combination approaches remain a compelling investigational strategy in oncogene-dependent non–small cell lung cancer (NSCLC) with several clinical trials ongoing (5–8).

The RET proto-oncogene encodes a receptor tyrosine kinase which is activated by gene fusion in 1%–2% of NSCLC and rarely in many other tumor types. RET gene fusions are bona fide cancer drivers and they display the key characteristics of oncogene addiction preclinically (9). Selpercatinib is a highly selective and potent anti-RET TKIs which has recently reported durable responses in lung and thyroid cancers, and these responses were maintained regardless of the specific RET alteration or prior TKI use, and also in the setting of the RET V804 “gatekeeper” mutation (10). Selpercatinib was recently approved by the FDA for use in these cancers. Mechanisms of acquired resistance to treatment with selective RET inhibitors are not well understood. While a secondary mutation in the RET kinase domain has recently been reported (11), activation of bypass tracts, such as MET amplification, also represent a recurring mechanism of resistance to driver genotypes in NSCLC (12, 13). Here we piloted combination therapy to target MET amplification detected in 4 patients with RET-positive NSCLC (of a total 79 patients with NSCLC enrolled at all three sites) with resistance to selpercatinib. This was made possible through the use of multiple single-patient protocols (SPP) which allowed for the quick delivery of potentially effective combination therapy to patients with clear unmet clinical need.

Analysis of resistance to selpercatinib

Patients were included in this analysis if they had received selpercatinib (LOXO-292) for RET-positive NSCLC on the first-in-human study of selpercatinib (NCT03157128) and exhibited evidence of MET amplification following drug resistance. All patients provided written informed consent wherever necessary. Genomic analysis of tumor and plasma cfDNA was performed independently at each participating site. All specimens were studied at each participating institution with independent review board (IRB) approval and were analyzed in accordance with the Declaration of Helsinki.

Preclinical RET-dependent models

RET fusion–positive human bronchioepithelial (HBEC-RET) cell lines expressing a CCDC6-RET fusion were engineered to overexpress MET and a patient-derived organoid was also established. These models were subsequently studied to investigate the role of MET in selpercatinib resistance (see Supplementary Methods).

SPPs of selpercatinib and crizotinib

Each SPP was sponsored by LOXO and drafted in collaboration between LOXO and the site primary investigator. Each protocol enrolled a single patient after review by the FDA and approval by the site IRB. Dosing was individualized per patient and dose escalation was permitted as tolerated up to the established tolerable dose for each drug. Patients initiated combination therapy directly after demonstrating resistance to prior targeted therapy (Table 1; Supplementary Fig. S1).

Table 1.

Disease course and treatment history summary.

Case 1Case 2Case 3Case 4
Clinical presentation 36 yo former smoker (18 py), multiple prior lines of therapy, recent alectinib 48 yo former light smoker (<1 py) s/p first-line pembrolizumab 69 yo never-smoker, second-line 61 yo never-smoker, s/p first-line pembrolizmab 
Pretreatment genotype EML4-RET fusion on plasma NGS, prior MET CNG KIF5B-RET fusion on tumor NGS KIF5B-RET fusion on tumor NGS, also high MET amplification KIF5B-RET fusion on tumor NGS, also MET CNG 
Treatment duration on selpercatinib monotherapy and dosing 6.5 months (40 mg BID → 160 mg BID) 11 months (20 mg BID → 80 mg BID) 3 months (80 mg BID) 6 months (160 mg BID → 120 mg BID) 
Treatment duration on selpercatinib and crizotinib and dosing 3.5 months (80 mg BID → 160 mg BID; 250 mg QD → BID) 10 months (160 mg BID; 250 mg BID) 4 months (80 mg BID → 160 mg BID; 250 mg BID) 4 months (160 mg BID; 250 mg BID) 
Outcome of combination therapy Mixed response Durable response Brief response Brief response 
Adverse events Nausea Lower extremity edema, reflux Myocardial infarction (not attributed to study drugs) Severe colitis (not attributed to study drugs) 
Case 1Case 2Case 3Case 4
Clinical presentation 36 yo former smoker (18 py), multiple prior lines of therapy, recent alectinib 48 yo former light smoker (<1 py) s/p first-line pembrolizumab 69 yo never-smoker, second-line 61 yo never-smoker, s/p first-line pembrolizmab 
Pretreatment genotype EML4-RET fusion on plasma NGS, prior MET CNG KIF5B-RET fusion on tumor NGS KIF5B-RET fusion on tumor NGS, also high MET amplification KIF5B-RET fusion on tumor NGS, also MET CNG 
Treatment duration on selpercatinib monotherapy and dosing 6.5 months (40 mg BID → 160 mg BID) 11 months (20 mg BID → 80 mg BID) 3 months (80 mg BID) 6 months (160 mg BID → 120 mg BID) 
Treatment duration on selpercatinib and crizotinib and dosing 3.5 months (80 mg BID → 160 mg BID; 250 mg QD → BID) 10 months (160 mg BID; 250 mg BID) 4 months (80 mg BID → 160 mg BID; 250 mg BID) 4 months (160 mg BID; 250 mg BID) 
Outcome of combination therapy Mixed response Durable response Brief response Brief response 
Adverse events Nausea Lower extremity edema, reflux Myocardial infarction (not attributed to study drugs) Severe colitis (not attributed to study drugs) 

Abbreviations: BID, twice a day; py, pack years; yo, year old.

MET-dependent resistance to selpercatinib in patients with advanced NSCLC

Case 1

The first patient was a 36-year-old female former smoker with stage IV NSCLC metastatic to bone, heavily pretreated. Molecular testing identified a RET rearrangement by break-apart FISH (83% of cells) as well as MET copy-number gain (CNG) by FISH (6 copies). She initiated treatment with alectinib, an ALK TKI with some degree of anti-RET activity preclinically (14), and progressed in less than 2 months. Next-generation sequencing (NGS) analysis of plasma circulating cell-free tumor DNA (cfDNA) then identified an EML4-RET fusion (AF 14%; ref. 15). She started treatment with selpercatinib and experienced a clinical response (decreased tumor-related pain and anorexia) with radiographic tumor reduction on imaging (−21% decrease in tumor burden after 16 weeks, Fig. 1A; Table 1). She progressed after 4.5 months with growth of liver metastases and a new skin nodule on the neck. Biopsy of the skin nodule revealed metastatic adenocarcinoma and molecular analysis by NGS reidentified the EML4-RET fusion as well as increased MET copy number (56 copies; Fig. 1B). Given ongoing clinical benefit, she continued on selpercatinib postprogression for a total treatment time of 6.5 months.

Figure 1.

MET amplification identified in RET fusion–positive lung cancers treated with a selective RET inhibitor. A, Patient 1 had a symptomatic response to selpercatinib with radiographic tumor reduction on imaging (−21% decrease in tumor burden) after 16 weeks, but eventually developed resistance to drug. B, Tumor NGS at time of resistance showed, in addition to the original EML4-RET fusion, high amplification of MET (56 copies). C and D, In patient 4, NGS showed MET amplification in the posttreatment sample (T2), with lower level gain below threshold for amplification in the pretreatment biopsy (T1). E, The presence of MET overexpression (right) was confirmed with MET IHC both pretreatment (top) and at time of resistance (bottom).

Figure 1.

MET amplification identified in RET fusion–positive lung cancers treated with a selective RET inhibitor. A, Patient 1 had a symptomatic response to selpercatinib with radiographic tumor reduction on imaging (−21% decrease in tumor burden) after 16 weeks, but eventually developed resistance to drug. B, Tumor NGS at time of resistance showed, in addition to the original EML4-RET fusion, high amplification of MET (56 copies). C and D, In patient 4, NGS showed MET amplification in the posttreatment sample (T2), with lower level gain below threshold for amplification in the pretreatment biopsy (T1). E, The presence of MET overexpression (right) was confirmed with MET IHC both pretreatment (top) and at time of resistance (bottom).

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Case 2

The second patient was a 48-year-old male former light smoker with stage IV PD-L1–positive NSCLC that harbored a KIF5B-RET fusion identified on tumor NGS. After progression on first-line pembrolizumab, he initiated selpercatinib and achieved a partial response after 3 months of therapy (best response of 49% decrease in target lesions; Table 1). He eventually developed disease progression after 11 months on selpercatinib. NGS analysis of paired pretreatment and postprogression tumor samples identified acquired MET amplification (9 copies) completely absent from the pretreatment sample.

Case 3

The third patient was a 69-year-old Asian male nonsmoker diagnosed with stage IV NSCLC, and after developing a solitary brain metastasis he underwent craniotomy. Tumor NGS (Foundation One) identified a KIF5B-RET fusion and MET amplification (18 copies) in brain. He initiated treatment with selpercatinib which resulted in shrinkage of pulmonary nodules and improvement in clinical symptoms, but he also developed a new left adrenal nodule, indicating disease progression. RNA sequencing was performed on the previously resected brain metastasis (Illumina TST-170) which confirmed high-level MET mRNA expression. He then initiated crizotinib monotherapy given his MET gene amplification and overexpression, and he again demonstrated a mixed response, with decrease in size of the left adrenal nodule but growth of a right adrenal nodule and left hilar adenopathy; he remained on crizotinib for 3 months.

Case 4

The fourth patient was a 61-year-old woman, never smoker, with stage IV lung adenocarcinoma metastatic to brain, PD-L1 positive. After progression on first-line pembrolizumab, tumor NGS identified a KIF5B-RET fusion and selpercatinib was initiated. The patient had a best response of stable disease (1% increase in the sum of tumor diameters at 6 weeks) but subsequently progressed after 6 months and discontinued treatment. NGS analysis of posttreatment tumor showed MET amplification (fold change 2.1), while the pretreatment biopsy showed low-level MET CNG without frank amplification (Fig. 1C and D). By FISH, the posttreatment biopsy showed MET amplification (66% of cells) while the pretreatment biopsy noted MET polysomy (3–6 copies) in 78% of cells. The presence of MET overexpression was subsequently confirmed by IHC at both time points (Fig. 1E).

MET overexpression causes acquired resistance to selpercatinib preclinically and may be overcome by combining selpercatinib with the MET inhibitor crizotinib

To determine the potential effect of MET overexpression on sensitivity of RET fusion–positive tumor cells to selpercatinib, we overexpressed MET in HBEC-RET. HBEC-RET cells were designed to express a CCDC6-RET fusion cDNA and are sensitive to RET inhibitors (Fig. 2A and B). HBEC-RET+MET cells were far less sensitive to selpercatinib (Fig. 2C and D; IC50 = 10.92 μmol/L) compared with the isogenic control cells (IC50 = 0.09 μmol/L), with a more than a 100-fold shift in the IC50 values for growth inhibition in the presence of MET overexpression, suggesting that overexpression of MET drives resistance to selective RET inhibition.

Figure 2.

MET amplification drives resistance to selpercatinib and responds to MET inhibition in RET fusion–positive models. A and B,RET fusion confirmed by RT-PCR using primers targeting CCDC6 (exon 1, forward) and RET (exon 12, reverse), and MET expression was confirmed by qPCR. C, Cells were treated with the indicated concentrations of selpercatinib for 96 hours, and then the relative number of cells was determined using proliferation dye. D, Viability data were analyzed, and estimated IC50 values with the 95% confidence interval are shown. HBEC, human bronchiolar epithelial cells. EV, empty vector. E, Patient-derived organoid from KIF5B-RET fusion–positive NSCLC (Case 2) shows MET gain by both IHC and FISH. F and G, Cell viability of dissociated cells from cultured organoids treated with either selpercatinib (0.3 μmol/L) or crizotinib (1 μmol/L) has little effect, but the combination is cytotoxic. H, Selpercatinib alone blocked RET activity whereas pAKT and pERK were retained, while combination treatment successfully led to inactivation of both AKT and ERK.

Figure 2.

MET amplification drives resistance to selpercatinib and responds to MET inhibition in RET fusion–positive models. A and B,RET fusion confirmed by RT-PCR using primers targeting CCDC6 (exon 1, forward) and RET (exon 12, reverse), and MET expression was confirmed by qPCR. C, Cells were treated with the indicated concentrations of selpercatinib for 96 hours, and then the relative number of cells was determined using proliferation dye. D, Viability data were analyzed, and estimated IC50 values with the 95% confidence interval are shown. HBEC, human bronchiolar epithelial cells. EV, empty vector. E, Patient-derived organoid from KIF5B-RET fusion–positive NSCLC (Case 2) shows MET gain by both IHC and FISH. F and G, Cell viability of dissociated cells from cultured organoids treated with either selpercatinib (0.3 μmol/L) or crizotinib (1 μmol/L) has little effect, but the combination is cytotoxic. H, Selpercatinib alone blocked RET activity whereas pAKT and pERK were retained, while combination treatment successfully led to inactivation of both AKT and ERK.

Close modal

In addition, we derived an organoid culture from tumor cells isolated from pleural fluid of the patient described in Case 2. Analysis of the organoid by MET FISH confirmed high-level MET amplification, and IHC confirmed high-level MET protein expression, consistent with the post-selpercatinib NGS analyses (Fig. 2E). In vitro treatment with selpercatinib or crizotinib monotherapy was ineffective, but combined treatment with selpercatinib and crizotinib showed a cytotoxic effect (Fig. 2F and G). As expected, only combined treatment resulted in decreased phospho-RET and phospho-MET levels concomitantly (Fig. 2H). Selpercatinib alone blocked RET activity whereas the activity of AKT and ERK were retained possibly demonstrating a mechanism of resistance in this patient. Interestingly, crizotinib alone inhibited MET and AKT signaling but not pERK (Fig. 2H). Finally, the combination treatment successfully led to inactivation of both ERK and AKT, suggesting a potential mechanism for the utility of this drug combination in this RET fusion/MET amplification patient. These data demonstrate that MET amplification causes resistance to selpercatinib in patients with RET fusion–positive NSCLC, which can be overcome preclinically by combined treatment with selpercatinib and crizotinib.

Combination treatment with selpercatinib and crizotinib overcomes MET-dependent resistance in patients

We were motivated by the high selectivity and clean safety profile of selpercatinib and by the known feasibility of adding crizotinib to other targeted TKIs in other biomarker-selected subsets of patients with NSCLC. Therefore, we treated the above 4 patients with the combination of selpercatinib and crizotinib, each using an FDA-allowed, IRB-approved SPP.

Case 1 (patient with minor response to selpercatinib, MET CNG before treatment and high MET amplification after treatment) started treatment at one-half the recommended phase II (RP2D) of selpercatinib (80 mg twice a day) and one-half the approved dose of crizotinib (250 mg everyday). After tolerating these doses for 4 weeks, the patient was escalated sequentially until reaching RP2D/approved doses of 160 mg twice a day/250 mg twice a day of selpercatinib and crizotinib, respectively. Treatment was tolerated with only mild nausea. Real-time pharmacokinetic analysis indicated selpercatinib exposure remained consistent with the patient's exposure during selpercatinib monotherapy, while crizotinib exposure remained consistent with published exposures when used as monotherapy (Supplementary Fig. S2A). She experienced clinical improvement in bone pain after 1 month of combination therapy; however, scans after 2.5 months revealed a mixed response with improvement in liver metastases but progressive pulmonary disease. Because of ongoing improvement in bone pain, she continued on study therapy for a total of 3.5 months before dying of her cancer.

Case 2 (patient with partial response to selpercatinib lasting 11 months and acquired MET amplification) initiated treatment with the combination of selpercatinib and crizotinib, and pharmacokinetic analyses revealed the expected levels of each drug when used as monotherapy (Supplementary Fig. S2B). The patient experienced a clinical and radiographic tumor response to combination treatment, with resolution of shortness of breath and maximal tumor diameter reduction of −38%. He responded for 10 months before discontinuing treatment for progression in the lungs and increase in ascites (Fig. 3A). He tolerated treatment well, with adverse events (AE) of lower extremity edema, possibly related to crizotinib, and reflux. NGS of a resistance biopsy showed persistence of the RET fusion but loss of the MET gene amplification (Fig. 3B). Notably, the only other alteration detected was the ATM splice variant [c.8988–1G>C (splice)].

Figure 3.

Response to selective dual RET inhibition and RET inhibition. A, In patient 2, combination treatment yielded a clinical and radiological response, until he eventually developed disease progression. B, NGS showing acquired amplification of MET at time of resistance to selpercatinib, then at time of resistance the loss of the MET amplification but with continued presence of RET fusion. C, Patient 4 pretreatment (top) and on-treatment (bottom) imaging showing a partial response at 4 weeks to selpercatinib and crizotinib.

Figure 3.

Response to selective dual RET inhibition and RET inhibition. A, In patient 2, combination treatment yielded a clinical and radiological response, until he eventually developed disease progression. B, NGS showing acquired amplification of MET at time of resistance to selpercatinib, then at time of resistance the loss of the MET amplification but with continued presence of RET fusion. C, Patient 4 pretreatment (top) and on-treatment (bottom) imaging showing a partial response at 4 weeks to selpercatinib and crizotinib.

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Case 3 (patient with mixed response on selpercatinib followed by mixed response on crizotinib, with pretreatment MET amplification) continued treatment with crizotinib while restarting treatment with selpercatinib at 80 mg twice a day which was subsequently dose escalated. He experienced a partial response by RECIST 1.1 (maximum tumor reduction −42% below baseline) after 1.5 months of combination therapy; he died unexpectedly of an unrelated cardiac event after 4 months. Combination treatment was otherwise well tolerated without AEs.

Case 4 (patient with best response of stable disease on selpercatinib, with pretreatment MET CNG and posttreatment MET amplification) initiated treatment at the full doses of selpercatinib at 160 mg twice a day and crizotinib at 250 mg twice a day. A brisk partial response (−40%) was achieved at 4 weeks (Fig. 3C) with disease regression in a left lung mass and a left chest wall mass. Although the patient tolerated combination treatment well without drug-related AEs, she developed colitis (determined by the investigator to be unrelated to treatment) that ultimately required treatment interruption and surgery, and she elected to transition to hospice care.

We describe MET amplification as a targetable mechanism of resistance to selpercatinib in RET-rearranged NSCLC. As greater number of patients develop resistance to selpercatinib, it will be important to systematically quantify the prevalence of MET amplification and other potentially targetable resistance mechanisms, such as the secondary RET mutation that was recently described (11). We do note that there are 79 patients with NSCLC enrolled at our three centers, which does offer the reader a rough estimate of the rarity of this type of resistance. While the level of MET gene amplification clearly increased during selpercatinib monotherapy, in 3 of 4 cases, some degree of MET gain was already present prior to exposure to selpercatinib. This is reminiscent of EGFR-mutant NSCLC, in which rare clones with high-level MET amplification may be detected at baseline, prior to EGFR inhibitor therapy (16, 17). It is notable that a recent early-phase EGFR-mutant/MET-amplified NSCLC trial showed an ORR of 44% to osimertinib (EFGR-TKI) and savolitinib (MET-TKI; ref. 8).

While the median progression-free survival has been reported at 18 months for selpercatinib in RET-positive NSCLC (18), our patients in contrast had an unusually short benefit from selpercatinib. The cause of this modest PFS benefit is unknown, but this may be due to some degree of MET amplification present at baseline in these patients or may be related to the aggressive nature of the MET oncogene (19). In addition, these brief responses may be due to the presence of additional driver mutations, either through heterogeneity of resistance to selpercatinib at distinct metastatic sites, or by means of additional subclonal drivers not detected on NGS.

To better understand the clinical effect of this combination, prospective efforts will be needed to study combination therapy with selpercatinib plus MET inhibition. In addition, treatment tolerability is difficulty to assess in individual SPPs—while these patients did not complain of intolerable toxicity while under treatment, 1 patient died of an apparently unrelated cardiac event, and a second patient experienced severe colitis. Both of these AEs were thought to be unrelated to this drug combination, but the potential toxicities of such drug combinations will need to be studied in future prospective cohorts of patients with appropriate performance status and comorbidities. Finally, we are hopeful that the use of newer, more specific MET inhibitors including capmatinib (refs. 7, 20; which is FDA approved) and tepotinib (21) in combination with selpercatinib may result in increased efficacy and better tolerability of this drug combination.

In these SPPs, the expeditious delivery of a potentially effective combination therapy to patients with high unmet clinical need was enabled by the availability of an approved second agent, the willingness of the sponsor to permit early use of combination therapy with an investigational therapy still being studied in a first-in-human trial, and the rapid review and allowance of each SPP by the FDA and by local IRBs. Our experience provides further evidence for the importance of robust, multi-cancer gene panel–based molecular analysis in patients with resistance to targeted therapies to enable the identification of potentially targetable acquired resistance mechanisms in a time frame that can help each patient. These cases provide evidence for the feasibility of this approach, and this may enable other potentially effective combination therapies with a clear biologic rationale to be offered immediately to individual patients without alternative treatment options, while also providing clinical proof of concept that may be validated in subsequent, prospective clinical trials.

E.Y. Rosen reports grants from Bayer (research funding) outside the submitted work. M.L. Johnson reports grants and other from Loxo/Lilly (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI and payment to institution for consulting services performed by M.L. Johnson) during the conduct of the study; grants and other from AbbVie (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), AstraZeneca (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Atreca (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Boehringer Ingelheim (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Calithera Biosciences (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Lilly (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), EMD Serono (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Genentech/Roche (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), GlaxoSmithKline (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Gritstone Oncology (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Guardant Health (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Incyte (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Janssen (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Loxo Oncology (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Merck (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Mirati Therapeutics (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Novartis (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Pfizer (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Sanofi (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), WindMIL (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Ribon Therapeutics (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI and payment to institution for consulting services performed by M.L. Johnson); grants from Acerta (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Adaptimmune (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Apexigen (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Array BioPharma (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), BeiGene (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), BerGenBio (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Checkpoint Therapeutics (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Corvus Pharmaceuticals (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), CytomX (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Daiichi Sankyo (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Dynavax (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Genmab (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Genocea Biosciences (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Hengrui Therapeutics (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Immunocore (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Jounce Therapeutics (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Kadmon Pharmaceuticals (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Lycera (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Neovia Oncology (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), OncoMed Pharmaceuticals (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Regeneron Pharmaceuticals (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Seven and Eight Biopharmaceuticals (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Shattuck Labs (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Stem CentRx (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Syndax Pharmaceuticals (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Takeda Pharmaceuticals (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Tarveda (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), University of Michigan (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), TCR2 Therapeutics (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Arcus Biosciences (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), Amgen (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI), TMUNITY Therapeutics (payment to institution for conduct of clinical trial on which M.L. Johnson served as PI); other from Achilles Therapeutics, Association of Community Cancer Centers (payment to institution for consulting services performed by M.L. Johnson); personal fees from Astellas (consulting/advisory role for an immediate family member) and Otsuka (consulting/advisory role for an immediate family member) outside the submitted work. S.E. Clifford reports other from Foundation Medicine outside the submitted work. R. Somwar reports grants and nonfinancial support from Loxo Oncology (Loxo Oncology provided research funds as well as selpercatinib to conduct in vitro experiments) during the conduct of the study; grants from Helsinn Health Care (research grant), Elevation Oncology (research grant), and Merus (research) outside the submitted work. J.F. Kherani reports other from Loxo Oncology (employee of Loxo Oncology at Lilly) during the conduct of the study and other from Loxo Oncology (employee of Loxo Oncology at Lilly) outside the submitted work. B.C. Nair reports other from Loxo Oncology, Inc., a subsidiary of Eli Lilly and Company (full-time employment) during the conduct of the study. E.A. Olek reports other from Eli Lilly and Company (employee and stock grant) during the conduct of the study. K. Ebata reports other from Loxo Oncology, Inc., a subsidiary of Eli Lilly and Company (employment, stock) during the conduct of the study and other from Loxo Oncology, Inc., a subsidiary of Eli Lilly and Company (employment, stock) outside the submitted work. J.F. Hechtman reports personal fees from Illumina and grants from Eli Lilly outside the submitted work. B.T. Li reports grants and personal fees from Roche Genentech (consulting/advisory board and clinical trial funding), Guardant Health (consulting/advisory board and clinical research funding), and Hengrui Therapeutics (consulting/advisory board and clinical trial funding); personal fees from Thermo Fisher Scientific (consulting/advisory board) and Mersana Therapeutics (consulting/advisory board); grants from Lilly [clinical trial funding and advisory board (uncompensated)], AstraZeneca [clinical trial funding and advisory board (uncompensated)], Daiichi Sankyo (clinical trial funding), Amgen [clinical trial funding and advisory board (uncompensated)], Illumina (clinical trial funding), GRAIL (clinical trial funding), and BioMedValley Discoveries (clinical trial funding); grants and nonfinancial support from MORE Health (clinical research funding, academic travel support); nonfinancial support from Resolution Bioscience (academic travel support) and Jiangsu Hengrui Medicine (academic travel support); and other from Boehringer Ingelheim [advisory board (uncompensated)] outside the submitted work. In addition, B.T. Li has a patent for US62/685,057 issued (methods for detecting HER2 dimerization in patients with HER2-mutant lung cancers and predicting responsiveness to ado-trastuzumab emtansine) and a patent for US62/514,661 issued (predicting Cancer Treatment Outcome with T-DM1). L.M. Sholl reports personal fees from EMD Serono and grants from Roche/Genentech (to her institution) outside the submitted work. B.S. Taylor reports grants from Genentech, Inc and personal fees from Boehringer Ingelheim and Loxo Oncology at Lilly outside the submitted work. M. Ladanyi reports grants from LOXO Oncology and personal fees from Lilly Oncology outside the submitted work. P.A. Jänne reports personal fees from LOXO Oncology (consulting fees for drug development) and grants and personal fees from Eli Lilly and Company (consulting fees for drug development and sponsored research) during the conduct of the study; grants and personal fees from AstraZeneca (consulting fees for drug development and sponsored research), Boehringer Ingelheim (consulting fees for drug development and sponsored research), Daiichi Sankyo (consulting fees for drug development and sponsored research), Takeda Oncology (consulting fees for drug development and sponsored research), and PUMA (consulting fees for drug development and sponsored research); and personal fees from Pfizer (consulting fees for drug development), Roche/Genentech (consulting fees for drug development), Chugai (consulting fees for drug development), Ignyta (consulting fees for drug development), SFJ Pharmaceuticals (consulting fees for drug development), Araxes Pharmaceuticals (consulting fees for drug development), Voronoi (consulting fees for drug development), Biocartis (consulting fees for drug development), Novartis (consulting fees for drug development), Sanofi Oncology (consulting fees for drug development), Mirati Therapeutics (consulting fees for drug development), Transcenta (consulting fees for drug development), Silicon Therapeutics (consulting fees for drug development), Revolution Medicines (sponsored research), and Astellas Pharmaceuticals (sponsored research) outside the submitted work. In addition, P.A. Jänne has a patent for EGFR Mutations issued and licensed to Lab Corp (receives postmarketing royalties from DFCI owned patent licensed to Lab Corp). S.M. Rothenberg reports other from Loxo Oncology (employee, stock options) during the conduct of the study and other from Pfizer (employee, stock options) outside the submitted work. A. Drilon reports other from Loxo/Lilly (honoraria/advisory), Ignyta/Genentech/Roche (honoraria/advisory), and Blueprint Medicines (honoraria/advisory) during the conduct of the study; other from Bayer (honoraria/advisory), Takeda/Ariad/Millenium (honoraria/advisory), TP Therapeutics (honoraria/advisory), AstraZeneca (honoraria/advisory), Pfizer (honoraria/advisory), Helsinn (honoraria/advisory), Beigene (honoraria/advisory), BergenBio (honoraria/advisory), Hengrui Therapeutics (honoraria/advisory), Exelixis (honoraria/advisory), Tyra Biosciences (honoraria/advisory), Verastem (honoraria/advisory), MORE Health (honoraria/advisory), AbbVie (honoraria/advisory), 14ner/Elevation Oncology (honoraria/advisory), Remedica Ltd. (honoraria/advisory), ArcherDX (honoraria/advisory), Monopteros (honoraria/advisory), Novartis (honoraria/advisory), EMD Serono (honoraria/advisory), Melendi (honoraria/advisory), Exelixis (associated research to institution), GlaxoSmithKlein (associated research to institution), Teva (associated research to institution), Taiho (associated research to institution), and PharmaMar (associated research to institution) outside the submitted work; royalties from Wolters Kluwer; other from Merck (food/beverage), Puma (food/beverage), Merus (food/beverage), and Boehringer Ingelheim; and CME honoraria from Medscape, OncLive, PeerVoice, Physicians Education Resources, Targeted Oncology, Research to Practice, Axis, Peerview Institute, Paradigm Medical Communications, WebMD, and MJH Life Sciences. G.R. Oxnard reports personal fees and other from Foundation Medicine (employment) and Roche (equity) outside the submitted work. No disclosures were reported by the other authors.

E.Y. Rosen: Conceptualization, formal analysis, investigation, writing-original draft, writing-review and editing. M.L. Johnson: Conceptualization, formal analysis, supervision, writing-original draft. S.E. Clifford: Formal analysis, validation, investigation. R. Somwar: Investigation, visualization. J.F. Kherani: Resources, formal analysis, investigation, writing-original draft. J. Son: Formal analysis, validation, investigation, visualization, writing-original draft. A.A. Bertram: Investigation. M.A. Davare: Resources. E. Gladstone: Investigation. E.V. Ivanova: Investigation. D.N. Henry: Investigation. E.M. Kelley: Investigation. M. Lin: Investigation. M.S.D. Milan: Investigation. B.C. Nair: Investigation. E.A. Olek: Investigation. J.E. Scanlon: Investigation. M. Vojnic: Formal analysis, investigation. K. Ebata: Resources, writing-original draft, project administration. J.F. Hechtman: Resources, investigation. B.T. Li: Resources, investigation. L.M. Sholl: Formal analysis, validation. B.S. Taylor: Formal analysis, supervision. M. Ladanyi: Formal analysis, supervision, investigation. P.A. Jänne: Formal analysis, supervision, validation, investigation, writing-original draft. S.M. Rothenberg: Conceptualization, supervision, writing-original draft, project administration. A. Drilon: Conceptualization, resources, formal analysis, supervision, investigation, writing-original draft, writing-review and editing. G.R. Oxnard: Conceptualization, formal analysis, supervision, investigation, writing-original draft, writing-review and editing.

This work was supported by the NCI grants R01CA222823 (to P.A. Jänne) and R35CA220497 (to P.A. Jänne), NIH 2T32 CA009512–29A1 (to E.Y. Rosen), NIH Cancer Center Grant P30CA008748 to Memorial Sloan Kettering Cancer Center, and The Expect Miracles Foundation (to E.V. Ivanova) and Robert and Renée Belfer Foundation (to E.V. Ivanova).

The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

1.
Long
GV
,
Stroyakovskiy
D
,
Gogas
H
,
Levchenko
E
,
de Braud
F
,
Larkin
J
, et al
Combined BRAF and MEK inhibition versus BRAF inhibition alone in melanoma
.
N Engl J Med
2014
;
371
:
1877
88
.
2.
Flaherty
KT
,
Infante
JR
,
Daud
A
,
Gonzalez
R
,
Kefford
RF
,
Sosman
J
, et al
Combined BRAF and MEK inhibition in melanoma with BRAF V600 mutations
.
N Engl J Med
2012
;
367
:
1694
703
.
3.
Sherr
CJ
,
Beach
D
,
Shapiro
GI
. 
Targeting CDK4 and CDK6: from discovery to therapy
.
Cancer Discov
2016
;
6
:
353
67
.
4.
O'Leary
B
,
Finn
RS
,
Turner
NC
. 
Treating cancer with selective CDK4/6 inhibitors
.
Nat Rev Clin Oncol
2016
;
13
:
417
30
.
5.
Oxnard
GR
,
Hu
Y
,
Mileham
KF
,
Husain
H
,
Costa
DB
,
Tracy
P
, et al
Assessment of resistance mechanisms and clinical implications in patients with EGFR T790M-positive lung cancer and acquired resistance to osimertinib
.
JAMA Oncol
2018
;
4
:
1527
34
.
6.
Yu
HA
,
Arcila
ME
,
Rekhtman
N
,
Sima
CS
,
Zakowski
MF
,
Pao
W
, et al
Analysis of tumor specimens at the time of acquired resistance to EGFR-TKI therapy in 155 patients with EGFR-mutant lung cancers
.
Clin. Cancer Res
2013
;
19
:
2240
7
.
7.
Wu
YL
,
Zhang
L
,
Kim
D-W
,
Liu
X
,
Lee
DH
,
Chih-Hsin Yang
J
, et al
Phase Ib/II study of capmatinib (INC280) plus gefitinib after failure of epidermal growth factor receptor (EGFR) inhibitor therapy in patients with EGFR-mutated, MET factor-dysregulated non-small-cell lung cancer
.
J Clin Oncol
2018
;
36
:
3101
9
.
8.
Oxnard
GR
,
Yang
JC-H
,
Yu
H
,
Kim
S-W
,
Saka
H
,
Horn
L
, et al
TATTON: a multi-arm, phase Ib trial of osimertinib combined with selumetinib, savolitinib, or durvalumab in EGFR-mutant lung cancer
.
Ann Oncol
2020
;
31
:
507
16
.
9.
Mulligan
LM
. 
Progress and potential impact of RET kinase targeting in cancer
.
Expert Rev Proteomics
2016
;
13
:
631
3
.
10.
Subbiah
V
,
Velcheti
V
,
Tuch
BB
,
Ebata
K
,
Busaidy
NL
,
Cabanillas
ME
, et al
Selective RET kinase inhibition for patients with RET-altered cancers
.
Ann Oncol
2018
;
29
:
1869
76
.
11.
Solomon
BJ
,
Tan
L
,
Lin
JJ
,
Wong
SQ
,
Hollizeck
S
,
Ebata
K
, et al
RET solvent front mutations mediate acquired resistance to selective RET inhibition in RET-driven malignancies
.
J Thorac Oncol
2020
;
15
:
541
9
.
12.
Turke
AB
,
Zejnullahu
K
,
Wu
Yi-L
,
Song
Y
,
Dias-Santagata
D
,
Lifshits
E
, et al
Preexistence and clonal selection of MET amplification in EGFR mutant NSCLC
.
Cancer Cell
2010
;
17
:
77
88
.
13.
Dagogo-Jack
I
,
Yoda
S
,
Lennerz
JK
,
Langenbucher
A
,
Lin
JJ
,
Rooney
MM
, et al
MET alterations are a recurring and actionable resistance mechanism in ALK-positive lung cancer
.
Clin Cancer Res
2020
;
26
:
2535
45
.
14.
Lin
JJ
,
Kennedy
E
,
Sequist
LV
,
Brastianos
PK
,
Goodwin
KE
,
Stevens
S
, et al
Clinical activity of alectinib in advanced RET-rearranged non-small cell lung cancer
.
J Thorac Oncol
2016
;
11
:
2027
32
.
15.
Supplee
JG
,
Milan
MSD
,
Lim
LP
,
Potts
KT
,
Sholl
LM
,
Oxnard
GR
, et al
Sensitivity of next-generation sequencing assays detecting oncogenic fusions in plasma cell-free DNA
.
Lung Cancer
2019
;
134
:
96
9
.
16.
Scagliotti
G
,
Moro-Sibilot
D
,
Kollmeier
J
,
Favaretto
A
,
Cho
EK
,
Grosch
H
, et al
A randomized-controlled phase 2 study of the MET antibody emibetuzumab in combination with erlotinib as first-line treatment for EGFR mutation–positive NSCLC patients
.
J Thorac Oncol
2020
;
15
:
80
90
.
17.
Cappuzzo
F
,
Jänne
PA
,
Skokan
M
,
Finocchiaro
G
,
Rossi
E
,
Ligorio
C
, et al
MET increased gene copy number and primary resistance to gefitinib therapy in non-small-cell lung cancer patients
.
Ann Oncol
2009
;
20
:
298
304
.
18.
Drilon
A
,
Oxnard
G
,
Wirth
L
,
Besse
B
,
Gautschi
O
,
Tan
SWD
, et al
PL02.08 registrational results of LIBRETTO-001: a phase 1/2 trial of LOXO-292 in patients with RET fusion-positive lung cancers
.
J Thorac Oncol
2019
;
14
:
S6
S7
.
19.
Tong
JH
,
Yeung
SF
,
Chan
AWH
,
Chung
LY
,
Chau
SL
,
Lung
RWM
, et al
MET amplification and exon 14 splice site mutation define unique molecular subgroups of non-small cell lung carcinoma with poor prognosis
.
Clin Cancer Res
2016
;
22
:
3048
56
.
20.
Baltschukat
S
,
Engstler
BS
,
Huang
A
,
Hao
H-X
,
Tam
A
,
Wang
HQ
, et al
Capmatinib (INC280) is active against models of non–small cell lung cancer and other cancer types with defined mechanisms of MET activation
.
Clin Cancer Res
2019
;
25
:
3164
75
.
21.
Paik
PK
,
Felip
E
,
Veillon
R
,
Sakai
H
,
Cortot
AB
,
Garassino
MC
, et al
Tepotinib in non–small-cell lung cancer with MET exon 14 skipping mutations
.
N Engl J Med
2020
;
383
:
931
43
.