LTK mutations responsible for resistance to lorlatinib in non-small cell lung cancer harboring CLIP1-LTK fusion.

The CLIP1-LTK fusion was recently discovered as a novel oncogenic driver in non-small cell lung cancer (NSCLC). Lorlatinib, a third-generation ALK inhibitor, exhibited a dramatic clinical response in a NSCLC patient harboring CLIP1-LTK fusion. However, it is expected that acquired resistance will inevitably develop, particularly by LTK mutations, as observed in NSCLC induced by oncogenic tyrosine kinases treated with corresponding tyrosine kinase inhibitors (TKIs). In this study, we evaluate eight LTK mutations corresponding to ALK mutations that lead to on-target resistance to lorlatinib. All LTK mutations show resistance to lorlatinib with the L650F mutation being the highest. In vitro and in vivo analyses demonstrate that gilteritinib can overcome the L650F-mediated resistance to lorlatinib. In silico analysis suggests that introduction of the L650F mutation may attenuate lorlatinib-LTK binding. Our study provides preclinical evaluations of potential on-target resistance mutations to lorlatinib, and a novel strategy to overcome the resistance.

Mechanisms of Resistance to Tyrosine Kinase Inhibitors in ROS1 Fusion-Positive Nonsmall Cell Lung Cancer.

BACKGROUND: ROS1 fusion-positive (ROS1+) nonsmall cell lung cancer (NSCLC) patients are highly sensitive to tyrosine kinase inhibitor (TKI) treatments. However, acquired TKI resistance remains the major hurdle preventing patients from experiencing prolonged benefits. METHODS: 107 advanced or metastatic ROS1+ NSCLC patients who progressed on crizotinib and lorlatinib were recruited. Tissue and plasma samples were collected at baseline (N = 50), postcrizotinib (N = 91), and postlorlatinib (N = 21), which were all subject to the 139-gene targeted next-generation DNA sequencing. Molecular dynamics modeling was performed to investigate the effects of ROS1 mutations on binding to different TKIs. RESULTS: In patients with postcrizotinib and postlorlatinib samples, an accumulation of on- and off-target resistance alterations after multiple TKI treatments was observed. ROS1 G2032R and MET amplification were the most common on-target and off-target alterations, respectively. Patients with CD74-ROS1 and SLC34A2-ROS1 had longer progression-free survival (PFS) (P < 0.001) and higher rates of resistance mutations (on-target, P = 0.001; off-target, P = 0.077) than other ROS1 fusion variants following crizotinib treatment. Ten distinct on-target resistance mutations were detected after TKI therapies, of which 4 were previously unreported (ROS1 L2010M, G1957A, D1988N, L1982V). Molecular dynamics simulations showed that all 4 mutations were refractory to crizotinib, while G1957A, D1988N, and L1982V were potentially sensitive to lorlatinib and entrectinib. CONCLUSIONS: This study provided a comprehensive portrait of TKI-resistance mechanisms in ROS1+ NSCLC patients. Using in silico simulations of TKI activity, novel secondary mutations that may confer TKI resistance were identified and may support clinical therapeutic decision-making.

An Infant-Type Hemispheric Glioma With SOX5::ALK: A Novel Fusion.

Infant-type hemispheric glioma (IHG) is a rare pediatric brain tumor with variable response to chemotherapy and radiotherapy. Molecular insights into IHG can be useful in identifying potentially active targeted therapy. A male fetus was found to have congenital hydrocephalus at the gestational age of 37 weeks. Fetal MRI showed a 2.6 × 2.0-cm tumor located at the frontal horn of the left lateral ventricle, involving the left basal nuclei and thalamus. Tumor biopsy at the age of 2 days revealed an IHG consisting of spindle tumor cells with strong expression of GFAP and ALK. Targeted RNA sequencing detected a novel fusion gene of SOX5::ALK. After initial chemotherapy with cyclophosphamide, carboplatin, and etoposide for 2 cycles, the tumor size progressed markedly and the patient underwent a subtotal resection of brain tumor followed by treatment with lorlatinib, an ALK tyrosine kinase inhibitor with central nervous system (CNS) activity. After 3 months of treatment, reduction of tumor size was observed. After 14 months of treatment, partial response was achieved, and the infant had normal growth and development. In conclusion, we identified a case of congenital IHG with a novel SOX5::ALK fusion that had progressed after chemotherapy and showed partial response and clinical benefit after treatment with the CNS-active ALK inhibitor lorlatinib.

Successful application of lorlatinib in a 23-year-old patient with anaplastic lymphoma kinase (ALK)-positive lung cancer and multiple brain metastases.

BACKGROUND: Anaplastic lymphoma kinase (ALK)-positive lung cancer has a better long-term prognosis with ALK-inhibitor than other lung cancers. However, resistance to ALK-inhibitors and the control of metastases in the central nervous system (CNS) remain to be a challenge in the management of ALK-positive lung cancer. CASE: We present the case of a 23-year-old man who developed multiple brain metastases while receiving alectinib treatment for ALK-positive lung cancer. After 3 months of lorlatinib initiation, brain metastases disappeared, and complete response (CR) was maintained. CONCLUSION: While lorlatinib can be used as first line therapy, this drug may be considered as second line or later option for patients with multiple brain metastases if the patient has already been treated with other ALK-inhibitors since lorlatinib is thought to have good CNS penetration. This treatment option should be verified by further research.

Lorlatinib as a first-line treatment of adult patients with anaplastic lymphoma kinase-positive advanced non-small cell lung cancer: Α cost-effectiveness analysis in Greece.

OBJECTIVES: To evaluate the cost-effectiveness of lorlatinib compared to 1st generation anaplastic lymphoma kinase (ALK) TKI crizotinib, and 2nd generation TKIs alectinib and brigatinib, for previously untreated patients with ALK+ advanced Non-Small Cell Lung Cancer (aNSCLC). METHODS: A partitioned survival model was locally adapted from a Greek payer perspective over a lifetime horizon. Clinical, safety and utility data were extracted from literature. Direct medical costs reflecting the year 2023 were included in the analysis (€). Model outcomes were patients' life years (LYs), quality-adjusted life years (QALYs), total costs and incremental cost-effectiveness ratios (ICERs). RESULTS: Total cost per patient with lorlatinib, alectinib, crizotinib, and brigatinib was estimated to be €188,205, €183,343, €75,028, and €145,454 respectively. Lorlatinib appeared to yield more LYs and QALYs gained versus alectinib, crizotinib, and brigatinib. Hence, lorlatinib resulted in ICERs of €4,315 per LY gained and €4,422 per QALY gained compared to alectinib, €34,032 per LY gained and €48,256 per QALY gained versus crizotinib and €16,587 per LY gained and €26,271 per QALY gained compared to brigatinib. CONCLUSION: Lorlatinib provides substantial clinical benefit and appears to be a cost - effective treatment option compared to 1st and 2nd generation TKIs for previously untreated patients with ALK+ aNCSLC in Greece.

Dissecting the role of ALK double mutations in drug resistance to lorlatinib with in-depth theoretical modeling and analysis.

Anaplastic lymphoma kinase (ALK) is implicated in the genesis of multiple malignant tumors. Lorlatinib stands out as the most advanced and effective inhibitor currently used in the clinic for the treatment of ALK-positive non-small cell lung cancer. However, resistance to lorlatinib has inevitably manifested over time, with double/triple mutations of G1202, L1196, L1198, C1156 and I1171 frequently observed in clinical practice, and tumors regrow within a short time after treatment with lorlatinib. Therefore, elucidating the mechanism of resistance to lorlatinib is paramount in paving the way for innovative therapeutic strategies and the development of next-generation drugs. In this study, we leveraged multiple computational methodologies to delve into the resistance mechanisms of three specific double mutations of ALKG1202R/L1196M, ALKG1202R/L1198F and ALKI1171N/L1198F to lorlatinib. We analyzed these mechanisms through qualitative (PCA, DCCM) and quantitative (MM/GBSA, US) kinetic analyses. The qualitative analysis shows that these mutations exert minimal perturbations on the conformational dynamics of the structural domains of ALK. The energetic and structural assessments show that the van der Waals interactions, formed by the conserved residue Leu1256 within the ATP-binding site and the residues Glu1197 and Met1199 in the hinge domain with lorlatinib, play integral roles in the occurrence of drug resistance. Furthermore, the US simulation results elucidate that the pathways through which lorlatinib dissociates vary across mutant systems, and the distinct environments during the dissociation process culminate in diverse resistance mechanisms. Collectively, these insights provide important clues for the design of novel inhibitors to combat resistance.

In-depth Analysis of Lorlatinib-related neurocognitive Adverse Events in Patients With Non-small-cell Lung Cancer.

INTRODUCTION: Lorlatinib is a potent, brain penetrant, next-generation ALK/ROS1 TKI, with high response rates and durable responses, including the brain. However, a significant drawback is the manifestation of neurocognitive adverse events (NCAEs). Despite being generally low-grade in severity, these NCAEs can be physically and mentally disabling. Extensive neurocognitive testing in this group of patients is lacking; therefore we conducted this study. PATIENTS AND METHODS: This observational prospective study was conducted across 3 Dutch university hospitals. Patients with metastatic NSCLC with an ALK- or ROS1-rearrangement and having an indication to start lorlatinib in daily clinical practice were eligible. The primary endpoints were to identify changes in neurocognitive functioning, measured through neurocognitive assessment at intervals of 2 weeks and 2 months after starting lorlatinib, in comparison to baseline. As a secondary endpoint, the correlation between neurocognitive impairment and self-reported neurocognitive dysfunction was examined. RESULTS: Between June 2019 and October 2022, 22 patients were included. Among the various neurocognitive tests administered, only the Hopkins Verbal Learning Test-Revised parts b and c demonstrated a significant and clinically relevant decrease in scoring 2 weeks post initiation of lorlatinib (P = .036 and P = .003, respectively). However, these returned to baseline at the 2-month evaluation. The questionnaires did not result in significantly different outcomes over time. CONCLUSION: Lorlatinib treatment did not result in a sustained and significant decline within any of the specified neurocognitive domains.

Neoadjuvant Lorlatinib Induces Pathological Complete Response in Advanced ALK-Positive Lung Cancer: A Case Report.

BACKGROUND Chemotherapy has been the conventional treatment method for advanced non-small-cell lung cancer (NSCLC). Nevertheless, the identification and comprehension of oncogenic driver alterations have paved the way for targeted therapies, significantly enhancing patient outcomes. The management of locally advanced NSCLC that is positive for ALK presents a challenge due to the lack of reported randomized controlled trials. The efficacy of neoadjuvant and adjuvant targeted therapy in this context remains uncertain. CASE REPORT A 54-year-old man was diagnosed with stage IIIB (pT1N3M0) upper right lung adenocarcinoma carrying the EML4-ALK fusion gene. Clinically, the patient had multiple enlarged lymph nodes in the right hilum and mediastinum, with the largest measuring approximately 28×19 mm by CT scan and we found that the L4 lymph node was invaded by metastasis. Then, the patient received 1 cycle of chemotherapy with paclitaxel in combination with nedaplatin and subsequently received maintenance treatment involving lorlatinib. Two months later, clinical evaluations revealed progressive reduction of the lesions, especially the reduced size of the mediastinal lymph nodes. Therefore, the patient underwent thoracoscopic partial lobectomy and lymphadenectomy and achieved pathological complete response (pCR). After 3 months, a follow-up CT scan was similar to the first postoperative CT scan and no tumor was found. CONCLUSIONS This case demonstrates the potential advantage of lorlatinib as a neoadjuvant therapy in advanced ALK-positive NSCLC. It emphasizes the importance of identifying new therapeutic targets by next-generation sequencing (NGS) and implementing precise treatment strategies in clinical practice.

Second-trimester medical abortion after exposure to lorlatinib during early pregnancy, a case report.

Use of Lorlatinib, a third-generation tyrosine kinase inhibitor currently indicated in the treatment of non-small-cell lung cancer (NSCLC) with ALK or ROS1 gene fusion, is formally contra-indicated during pregnancy due to teratogenic effects observed during pre-clinical studies. We report the case of a 38-year-old woman with a ROS1-positive NSCLC, successfully treated with lorlatinib as second line therapy, who became pregnant while on treatment. Due to significant disease progression 12 weeks after lorlatinib stop and the great uncertainty on the pregnancy outcome, she finally decided to interrupt the pregnancy at 22 weeks of gestation. Echography and gross infant examination did not reveal any malformation. Pregnancies occurring under this kind of new oncologic treatment is expected to happen more frequently in the future. It seems therefore important to us to report any information on the topic to increase our level of knowledge and improve decision-making.

Podcast on Lorlatinib as a First-Line Treatment Option for Patients with ALK-Positive Metastatic NSCLC with Brain Metastasis.

Brain metastases are especially common in anaplastic lymphoma kinase (ALK)-positive non-small cell lung cancer (NSCLC), with a cumulative incidence of over 50% and associated with a poor prognosis, high symptom burden, and decreased quality of life. Lorlatinib is a brain-penetrant, third-generation ALK tyrosine kinase inhibitor (TKI), which has a high potency against resistance mutations seen with earlier generation ALK TKIs. In 2018, lorlatinib was granted accelerated approval in second- and third-line treatment for use in patients with ALK-positive metastatic NSCLC on the basis of phase 1/2 study results. This initial approval was expanded for first-line treatment of patients with ALK-positive metastatic NSCLC on the basis of the interim analysis of the phase 3 CROWN study showing longer progression-free survival, time to intracranial progression, duration of response, and objective response rate compared with crizotinib. This manuscript is a transcript of our podcast, in which we discuss the clinical significance of controlling the onset of brain metastases, considerations in selecting a first-line therapy option, efficacy and safety observed in patients with and without brain metastases, and rationales for using lorlatinib upfront versus reserving for a later line in therapy.

Lorlatinib Effectiveness and Quality-of-Life in Patients with ALK-Positive NSCLC Who Had Failed Second-Generation ALK Inhibitors: Canadian Real-World Experience.

Lorlatinib is the only targeted therapy approved in Canada to treat patients with anaplastic lymphoma kinase (ALK)-positive non-small cell lung cancer (NSCLC) whose tumor has progressed despite treatment with second-generation ALK tyrosine kinase inhibitor (TKI), a patient population with high unmet need and lack of publicly reimbursed targeted treatments in Canada. We prospectively examined the real-world effectiveness and impact of lorlatinib on quality-of-life in 59 lorlatinib-treated patients, characterized as: median age of 62.0 years; 47.5% were female; 32.2% had central nervous system metastases; 50.8% had 2+ prior ALK TKI lines; and alectinib was the most common ALK TKI (72.9%) administered before lorlatinib, including 44.1% who received first-line alectinib. With a median follow-up of 15.3 months (IQR: 6.2-19.2), median time-to-treatment discontinuation of lorlatinib was 15.3 months (95% CI: 7.9-not reached), with 54.2% (95% CI: 40.8-65.9%) of patients without treatment discontinuation at 12 months. At baseline, the mean health utility score (HUS) was 0.744 (SD: 0.200). At 3 months, patients receiving lorlatinib demonstrated a 0.069 (95% CI: 0.020-0.118; p = 0.007) average HUS increase over baseline; HUS was maintained at 6 and 12 months. Thus, patients with ALK-positive NSCLC post second-generation ALK TKI remained on lorlatinib for a meaningful duration of time while their quality-of-life was preserved.

Early Circulating Tumor DNA Dynamics and Efficacy of Lorlatinib in Patients With Treatment-Naive, Advanced, ALK-Positive NSCLC.

INTRODUCTION: Circulating tumor DNA (ctDNA) has been used as a biomarker for prognostication and response to treatment. Here, we evaluate ctDNA as a potential biomarker for response to lorlatinib, a third-generation ALK tyrosine kinase inhibitor in patients with treatment-naive, advanced, ALK-positive NSCLC in the ongoing phase 3 CROWN study (NCT03052608). METHODS: Molecular responses were calculated using mean variant allele frequency (VAF), longitudinal mean change in VAF (dVAF), and ratio to baseline. Efficacy assessments (progression-free survival [PFS] and objective response rate) were paired with individual patient ctDNA and analyzed for association. RESULTS: Compared with baseline, mean VAF at week 4 was decreased in both treatment arms. Considering all detected somatic variants, a reduction in dVAF (≤0) was associated with a longer PFS in the lorlatinib arm. The hazard ratio (HR) for a dVAF less than or equal to 0 versus more than 0 was 0.50 (95% confidence interval [CI]: 0.23-1.12) in the lorlatinib arm. A similar association was not observed for crizotinib (HR = 1.00, 95% CI: 0.49-2.03). Comparing molecular responders with nonresponders, patients treated with lorlatinib who had a molecular response had longer PFS (HR = 0.37, 95% CI: 0.16-0.85); patients treated with crizotinib who had a molecular response had similar PFS as those without a molecular response (HR = 1.48, 95% CI: 0.67-3.30). CONCLUSIONS: In patients with treatment-naive, advanced, ALK-positive NSCLC, early ctDNA dynamics predicted better outcome with lorlatinib but not with crizotinib. These results suggest that ctDNA may be used to monitor and potentially predict efficacy of lorlatinib treatment.

Safety and efficacy of lorlatinib against ALK-driven refractory or relapsed neuroblastoma.

We spotlight the promising preliminary findings reported by Goldsmith et al. of a phase 1 first-in-child study showcasing the safety and efficacy of lorlatinib against treatment-refractory or relapsed ALK-driven neuroblastoma.1.

Circulating tumor DNA reveals mechanisms of lorlatinib resistance in patients with relapsed/refractory ALK-driven neuroblastoma.

Activating point mutations in Anaplastic Lymphoma Kinase (ALK) have positioned ALK as the only mutated oncogene tractable for targeted therapy in neuroblastoma. Cells with these mutations respond to lorlatinib in pre-clinical studies, providing the rationale for a first-in-child Phase 1 trial (NCT03107988) in patients with ALK-driven neuroblastoma. To track evolutionary dynamics and heterogeneity of tumors, and to detect early emergence of lorlatinib resistance, we collected serial circulating tumor DNA samples from patients enrolled on this trial. Here we report the discovery of off-target resistance mutations in 11 patients (27%), predominantly in the RAS-MAPK pathway. We also identify newly acquired secondary compound ALK mutations in 6 (15%) patients, all acquired at disease progression. Functional cellular and biochemical assays and computational studies elucidate lorlatinib resistance mechanisms. Our results establish the clinical utility of serial circulating tumor DNA sampling to track response and progression and to discover acquired resistance mechanisms that can be leveraged to develop therapeutic strategies to overcome lorlatinib resistance.

From preclinical efficacy to 2022 (36.7 months median follow -up) updated CROWN trial, lorlatinib is the preferred 1st-line treatment of advanced ALK+ NSCLC.

Six ALK TKIs (crizotinib, ceritinib, alectinib, brigatinib, lorlatinib, ensartinib) have received first-line treatment indication of advanced ALK+ NSCLC in various countries. In Ba/F3 cells, lorlatinib achieved lowest IC50 among these 6 ALK TKIs against EML4-ALK variant 1 or 3. In 2022, 7 abstracts reported updated efficacy and safety data from CROWN. With a median follow-up time of 36.7 months, the 3-year progression-free survival (PFS) rate was 63.5% for lorlatinib-treated patients and the median PFS of lorlatinib still has not been reached. Importantly, post-lorlatinib treatment median PFS2 was 74.0% at 3-years. Lorlatinib-treated Asian patients achieved similar 3-year PFS rate as overall lorlatinib-treated patients. Median PFS was 33.3 months among lorlatinib-treated EML4-ALK v3 patients. CNS AE occurred fewer than 1 event per patient over the median follow-up time of 36.7 months and most resolved without intervention. Altogether these data affirm our belief that lorlatinib should be the treatment of choice of advanced ALK+ NSCLC.

Novel High-Throughput Microwell Spectrophotometric Assay for One-Step Determination of Lorlatinib, a Novel Potent Drug for the Treatment of Anaplastic Lymphoma Kinase (ALK)-Positive Non-Small Cell Lung Cancer.

Background and Objectives: Lorlatinib (LOR) belongs to the third-generation anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors. People who are diagnosed with ALK-positive metastatic and advanced non-small cell lung cancer (NSCLC) are eligible to get it as a first-line treatment option after it was given the approval by "the Food and Drug Administration (FDA)". However, no study has described constructing high-throughput analytical methodology for LOR quantitation in dosage form. For the first time, this work details the construction of a high-throughput, innovative microwell spectrophotometric assay (MW-SPA) for single-step assessment of LOR in its tablet form, for use in pharmaceutical quality control. Materials and Methods: Assay depended on charge transfer complex (CTC) formation between LOR, as electron donor, with 2,3-dichloro-3,5-dicyano-1,4-benzoquinone (DDQ), as π-electron acceptor. Reaction conditions were adjusted, the CTC was characterized by ultraviolet (UV)-visible spectrophotometry and computational molecular modeling, and its electronic constants were determined. Site of interaction on LOR molecule was allocated and reaction mechanism was suggested. Under refined optimum reaction conditions, the procedures of MW-SPA were performed in 96-well assay plates, and the responses were recorded by an absorbance plate reader. Validation of the current methodology was performed in accordance with guidelines of "the International Council on Harmonization (ICH)", and all validation parameters were acceptable. Results: Limits of detection and quantitation of MW-SPA were 1.8 and 5.5 µg/well, respectively. The assay was applied with great success for determining LOR in its tablets. Conclusions: This The assay is straightforward, economic and has high-throughput characteristics. Consequently, the assay is recommended as a valuable analytical approach in quality control laboratories for LOR's tablets' analysis.

Lorlatinib for ALK-fused, infant-type hemispheric glioma with lung metastasis: a case report.

Infant-type hemispheric glioma, a new subtype of pediatric high-grade glioma, arises in the cerebral hemispheres. Despite better survival outcomes, the treatment of infant-type hemispheric glioma is still facing challenges. Here, we reported a case of QKI-ALK fusion, infant-type hemispheric glioma with lung metastasis who achieved a complete clinical response after lorlatinib treatment. This typical case demonstrated the importance of appropriate molecularly targeted treatments in ALK-fused tumors, and lorlatinib may serve as an effective complement to conventional chemotherapy and radiotherapy in primary glioma harboring ALK fusions and its metastasis.

Real-world therapeutic effectiveness of lorlatinib after alectinib in Japanese patients with ALK-positive non-small-cell lung cancer.

Alectinib, an anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitor (TKI), is the recommended first-line treatment for ALK-positive non-small-cell lung cancer (NSCLC) in Japan. Lorlatinib was approved as a subsequent therapeutic option after progression while receiving ALK TKI treatment. However, data on the use of lorlatinib in the second- or third-line setting after alectinib failure are limited in Japanese patients. This retrospective real-world observational study investigated the clinical effectiveness of lorlatinib in second- or later-line settings after alectinib failure in Japanese patients. Clinical and demographic data collected in the Japan Medical Data Vision (MDV) database between December 2015 and March 2021 were used. Patients diagnosed with lung cancer who received lorlatinib following alectinib failure after the November 2018 marketing approval of lorlatinib in Japan were included. Of 1954 patients treated with alectinib, 221 were identified from the MDV database as receiving lorlatinib after November 2018. The median age of these patients was 62 years. Second-line lorlatinib treatment was reported for 154 patients (70%); third- or later-line lorlatinib treatment was reported for 67 patients (30%). The median duration of treatment (DOT) for all lorlatinib-treated patients was 161 days (95% confidence interval [CI], 126-248), and 83 patients (37.6%) continued treatment after data cut-off (March 31, 2021). Median DOTs of 147 days (95% CI, 113-242) and 244 days (95% CI, 109 to not reached) were reported with second-line and third- or later-line treatment, respectively. Consistent with clinical trial data, this real-world observational study supports data suggesting the effectiveness of lorlatinib after alectinib failure in Japanese patients.