Exploring the Role of Target Expression in Treatment Efficacy of Antibody-Drug Conjugates (ADCs) in Solid Cancers: A Comprehensive Review.

PURPOSE OF REVIEW: Antibody-drug conjugates (ADCs) offer a promising path for cancer therapy, leveraging the specificity of monoclonal antibodies and the cytotoxicity of linked drugs. The success of ADCs hinges on precise targeting of cancer cells based on protein expression levels. This review explores the relationship between target protein expression and ADC efficacy in solid tumours, focusing on results of clinical trials conducted between January 2019 and May 2023. RECENT FINDINGS: We hereby highlight approved ADCs, revealing their effectiveness even in low-expressing target populations. Assessing target expression poses challenges, owing to variations in scoring systems and biopsy types. Emerging methods, like digital image analysis, aim to standardize assessment. The complexity of ADC pharmacokinetics, tumour dynamics, and off-target effects emphasises the need for a balanced approach. This review underscores the importance of understanding target protein dynamics and promoting standardized evaluation methods in shaping the future of ADC-based cancer therapies.

Sequence analyses of relapsed or refractory diffuse large B-cell lymphomas unravel three genetic subgroups of patients and the GNA13 mutant as poor prognostic biomarker, results of LNH-EP1 study.

Advances in molecular profiling of newly diagnosed diffuse large B-cell lymphoma (DLBCL) have recently refine genetic subgroups. Genetic subgroups remain undetermined at the time of relapse or refractory (RR) disease. This study aims to decipher genetic subgroups and search for prognostic molecular biomarkers in patients with RR-DLBCL. From 2015 to 2021, targeted next-generation sequencing analyses of germline-matched tumor samples and fresh tissue from RR-DLBCL patients were performed. Unsupervised clustering of somatic mutations was performed and correlations with patient outcome were sought. A number of 120 patients with RR-DLBCL were included in LNH-EP1 study and a molecular tumor landscape was successfully analyzed in 87% of patients (104/120 tumor samples). The median age was 67.5 years (range 27.4-87.4), median number of previous treatments was 2 (range 1-9). The most frequently mutated genes were TP53 (n = 53 mutations; 42% of samples), CREBBP (n = 39; 32%), BCL2 (n = 86; 31%), KMT2D (n = 39; 28%) and PIM1 (n = 54; 22%). Unsupervised clustering separated three genetic subgroups entitled BST (enriched in BCL2, SOCS1, and TNFRSF14 mutations); TKS (enriched in TP53, KMT2D, and STAT6 mutations); and PCM (enriched in PIM1, CD79B, and MYD88 mutations). Median overall survival (OS) was 11.0 (95% confidence interval [CI]: 8.1-12.6) months. OS was not significantly different between the three genetic subgroups. GNA13 mutant was significantly associated with an increased risk of death (hazard ratio: 6.6 [95% CI: 2.1-20.6]; p = .0011) and shorter OS (p = .0340). At the time of relapse or refractory disease, three genetic subgroups of DLBCL patients were delineated, which could help advance precision molecular medicine programs.

Phase I open-label study of afatinib plus vinorelbine in patients with solid tumours overexpressing EGFR and/or HER2.

BACKGROUND: This phase Ib study evaluated afatinib plus vinorelbine in patients with advanced solid tumours overexpressing epidermal growth factor receptor (EGFR) and/or human EGFR 2 (HER2). METHODS: Maximum tolerated doses (MTDs) were determined for afatinib (20, 40 or 50 mg, once daily) combined with standard intravenous vinorelbine (part A; 25 mg m-2 per week) or oral vinorelbine (part B; 60 mg m-2 per week, increased to 80 mg m-2 per week at week 3). Secondary end points for expanded MTD cohorts included assessments of safety, pharmacokinetics, tumour response and progression-free survival (PFS). RESULTS: The afatinib MTD was 40 mg with intravenous (MTDA) and oral (MTDB) vinorelbine. The most frequent cycle 1 dose-limiting toxicities were febrile neutropenia and diarrhoea, consistent with individual safety profiles of vinorelbine and afatinib. Common treatment-related adverse events included: diarrhoea (92.7%), asthenia (76.4%), nausea (63.6%), neutropenia (56.4%) and vomiting (54.5%). No notable pharmacokinetic interactions were observed. Best overall tumour response was stable disease in part A (16 out of 28 patients), and partial response in part B (3 out of 27 patients). Median PFS was 14.6 and 15.9 weeks for patients treated at the MTDA and MTDB, including dose-escalation and expansion cohorts. CONCLUSIONS: Afatinib in combination with intravenous or oral vinorelbine demonstrated a manageable safety profile and antitumour activity at the MTD of 40 mg per day.

Phase I trial of bortezomib daily dose: safety, pharmacokinetic profile, biological effects and early clinical evaluation in patients with advanced solid tumors.

Purpose This phase I study investigated bortezomib in solid tumors used as a daily subcutaneous regimen. Previous regimens showed only modest activity in solid tumors which was potentially related to sub-optimal tumor penetration. We aimed at exploring if daily low dose administration of bortezomib may allow a greater and tolerable pharmacokinetic exposure which might be required for antitumor activity in solid tumors. Patients and methods This 3 + 3 design, dose escalation, monocentric study aimed at defining the maximum tolerated dose of daily low dose schedule of bortezomib. Tolerability, pharmacokinetics, pharmacodynamics, antitumor activity, biomarkers for proteasome inhibition, pre- and post-treatment tumor biopsies were also evaluated. Results A total of eighteen patients were dosed in 3 bortezomib cohorts (0.5, 0.6 and 0.7 mg/m2), with 3, 11 and 4 patients respectively. Three patients experienced dose-limiting toxicities: Grade (G) 3 Sweet's syndrome (at 0.6 mg/m2), G3 asthenia and anorexia or ataxia (2 patients at 0.7 mg/m2). The most common study drug-related adverse events (all grades) were thrombocytopenia (72%), fatigue (56%), neuropathy (50%), anorexia (44%) and rash (39%). Dose 0.6 mg/m2 of bortezomib was considered as the recommended phase II dose. A significant tumor shrinkage (-36% according to WHO criteria) was observed in one patient with heavily pre-treated GIST, and 2 minor responses (-20%) were recorded in two patients with melanoma and mesothelioma. Conclusion This daily subcutaneous regimen of bortezomib showed a dose dependent plasma exposure, evidence of target inhibition and preliminary signs of clinical activity. However, cumulative neurological toxicity of this dose-dense daily regimen might preclude its further clinical development.

Phase I dose-escalation studies of roniciclib, a pan-cyclin-dependent kinase inhibitor, in advanced malignancies.

BACKGROUND: To evaluate safety, pharmacokinetics, and maximum tolerated dose of roniciclib in patients with advanced malignancies, with dose expansion to evaluate clinical benefit at the recommended phase II dose (RP2D). METHODS: Two phase I dose-escalation studies evaluated two roniciclib dosing schedules: 3 days on/4 days off or 4 weeks on/2 weeks off. The expansion phase included patients with small-cell lung cancer (SCLC), ovarian cancer, or tumour mutations involving the CDK signalling pathway. RESULTS: Ten patients were evaluable in the 4 weeks on/2 weeks off schedule (terminated following limited tolerability) and 47 in the 3 days on/4 days off schedule dose-escalation cohorts. On the 3 days on/4 days off schedule, RP2D was 5 mg twice daily in solid tumours (n=40); undetermined in lymphoid malignancies (n=7). Common roniciclib-related adverse events included nausea (76.6%), fatigue (65.8%), diarrhoea (63.1%), and vomiting (57.7%). Roniciclib demonstrated rapid absorption and dose-proportional increase in exposure. One partial response (1.0%) was observed. In RP2D expansion cohorts, the disease control rate (DCR) was 40.9% for patients with ovarian cancer (n=25), 17.4% for patients with SCLC (n=33), and 33.3% for patients with CDK-related tumour mutations (n=6). CONCLUSIONS: Roniciclib demonstrated an acceptable safety profile and moderate DCR in 3 days on/4 days off schedule.

Predictive factors of renal toxicities related to anti-VEGFR multikinase inhibitors in phase 1 trials.

Purpose Renal toxicities are common with angiogenesis multikinase inhibitors (AMKI), and can be limiting in phase I trials. Factors associated with such toxicities are poorly known. The aims of this exploratory study were to describe renovascular toxicities associated with AMKI, impact on drug development and to identify baseline parameters associated with the occurrence of renal toxicities in phase I trials. Methods Consecutive patients treated with AMKI in Gustave Roussy phase I unit between October 2005 and August 2013 were included. We retrospectively collected baseline characteristics and renovascular side effects. Associations were assessed in univariate and multivariate analyses. Results Overall, 168 patients were included: male 53.0 %, mean age 55.5 years old, history of hypertension 26.8 %, diabetes 6.0 %, atherosclerosis 13.6 %, stage 3 Chronic Kidney Disease (CKD, NKF-KDOQI) 17.2 %. Incidences of reno-vascular side effects were: hypertension 47.6 %, proteinuria 19.0 %, renal failure 11.9 % and thrombotic microangiopathy 10.1 %. Eighty percent of dose limiting toxicities (DLTs) were related to a renal toxicity. Multivariate analysis showed that onset of renal failure was associated with history of hypertension (p = 0.0003) and stage 3 CKD (p = 0.032). Conclusions A majority of the DLTs associated with AMKI in phase 1 trials are renal toxicities. Baseline hypertension and stage 3 CKD (NKF-KDOQI) might help to better identify patients at risk of AMKI-related renal toxicities.

Phase I dose-escalation study of pazopanib combined with bevacizumab in patients with metastatic renal cell carcinoma or other advanced tumors.

BACKGROUND: Vascular endothelial growth factor (VEGF) directed therapies are being used in a large number of advanced tumors. Metastatic renal cell carcinoma (mRCC) is highly dependent on the VEGF pathway; VEGF receptor (VEGFR) tyrosine kinase inhibitors (TKI) and humanized VEGF monoclonal antibody have been registered for clinical use in advanced renal cell carcinoma. The VEGFR TKI, pazopanib, with a rather manageable toxicity profile, was preferred to sunitinib by mRCC patients. We investigate the combination of pazopanib and bevacizumab to determine the maximum tolerated dose (MTD) in mRCC and other advanced solid tumors. METHODS: In this bicentric phase I trial with a 3 + 3 + 3 dose-escalation design, patients received oral pazopanib once daily plus intravenous infusion of bevacizumab every 2 weeks from D15, at one of the four dose levels (DL) planned according to the occurrence of dose limiting toxicities (DLT). 400 and 600 mg pazopanib were respectively combined with 7.5 mg/kg bevacizumab in DL1 and DL2, and 600 and 800 mg pazopanib with 10 mg/kg bevacizumab in DL3 and DL4. Tumor response was evaluated every 8 weeks. Blood samples were assayed to investigate pazopanib pharmacokinetics. RESULTS: Twenty five patients including seven mRCC were enrolled. Nine patients received the DL1, ten received the DL2. No DLT were observed at DL1, five DLT at DL2, and 3 DLT in the six additional patients who received the DL1. A grade 3 microangiopathic hemolytic anemia syndrome was observed in four (16%) patients. Five (22%) patients achieved a partial response. The mean (range) plasmatic concentrations of 400 and 600 pazopanib were respectively 283 (139-427) and 494 (227-761) µg.h/mL at Day 1, and 738 (487-989) and 1071 (678-1464) µg.h/mL at Day 15 i.e. higher than those previously reported with pazopanib, and were not directly influenced by bevacizumab infusion. CONCLUSIONS: The combination of pazopanib and bevacizumab induces angiogenic toxicity in patients without any pre-existing renal or vascular damage. Even if a marginal efficacy was reported with five (22%) patients in partial response in different tumor types, the toxicity profile compromises the development of this combination. TRIAL REGISTRATION: The study was retrospectively registered on ClinicalTrials.gov (number NCT01202032 ) on 2010, Sept 14th.

Phase I Dose-Escalation and Pharmacokinetic Study of Intravenous Aflibercept in Combination with Docetaxel, Cisplatin, and 5-Fluorouracil in Patients with Advanced Solid Malignancies.

PURPOSE: This phase I study (EudraCT No. 2006-001177-25) investigated aflibercept, a vascular endothelial growth factor decoy receptor protein (VEGF Trap), in combination with docetaxel, cisplatin, and 5-fluorouracil in patients with advanced solid tumors. PATIENTS AND METHODS: Patients received 2, 4, or 6 mg/kg of intravenous aflibercept with docetaxel 75 mg/m2, cisplatin 75 mg/m2, and 5-fluorouracil 750 mg/m2 in 3-week cycles until disease progression or unacceptable toxicity. Primary objectives were to evaluate dose-limiting toxicities (DLTs) during cycle 1 and to determine the recommended phase II dose. Pharmacokinetics, tolerability, and antitumor activity were also investigated. RESULTS: Forty-four patients were enrolled and treated (29 patients in a dose-escalation phase and 15 patients in an expansion cohort). Following three cases of febrile neutropenia in patients receiving aflibercept at 4 mg/kg, the protocol was amended to allow earlier granulocyte colony-stimulating factor support (from day 6) and prophylactic use of ciprofloxacin. Subsequently, there were two DLTs: febrile neutropenia (2 mg/kg) and grade 4 pulmonary embolism (6 mg/kg). An excess of free over VEGF-bound aflibercept was observed at 6 mg/kg. The most frequent grade 3/4 adverse events (AEs) were neutropenia (54.5%), lymphopenia (47.7%), and stomatitis (38.6%). AEs associated with VEGF blockade (any grade) included epistaxis (61.4%), dysphonia (40.9%), hypertension (38.6%), and proteinuria (11.4%). There were 15 partial responses, including 9 in patients with gastroesophageal cancers. Thirteen patients had stable disease. CONCLUSION: Aflibercept 6 mg/kg administered every 3 weeks in combination with docetaxel, cisplatin, and 5- fluorouracil is the recommended dose for further clinical development based on tolerability, pharmacokinetics, and antitumor activity.

Phase I study of afatinib combined with nintedanib in patients with advanced solid tumours.

BACKGROUND: This Phase I study evaluated continuous- and intermittent-dosing (every other week) of afatinib plus nintedanib in patients with advanced solid tumours. METHODS: In the dose-escalation phase (n=45), maximum tolerated doses (MTDs) were determined for continuous/intermittent afatinib 10, 20, 30 or 40 mg once daily plus continuous nintedanib 150 or 200 mg twice daily. Secondary objectives included safety and efficacy. Clinical activity of continuous afatinib plus nintedanib at the MTD was further evaluated in an expansion phase (n=25). RESULTS: The most frequent dose-limiting toxicities were diarrhoea (11%) and transaminase elevations (7%). Maximum tolerated doses were afatinib 30 mg continuously plus nintedanib 150 mg, and afatinib 40 mg intermittently plus nintedanib 150 mg. Treatment-related adverse events (mostly Grade⩽3) included diarrhoea (98%), asthenia (64%), nausea (62%) and vomiting (60%). In the dose-escalation phase, two patients had partial responses (PRs) and 27 (60%) had stable disease (SD). In the expansion phase, one complete response and three PRs were observed (all non-small cell lung cancer), with SD in 13 (52%) patients. No pharmacokinetic interactions were observed. CONCLUSIONS: MTDs of continuous or intermittent afatinib plus nintedanib demonstrated a manageable safety profile with proactive management of diarrhoea. Antitumour activity was observed in patients with solid tumours.

Phase I clinical and pharmacokinetic study of ombrabulin (AVE8062) combined with cisplatin/docetaxel or carboplatin/paclitaxel in patients with advanced solid tumors.

PURPOSE: Preclinical evidence supports synergy between the vascular disrupting agent ombrabulin and various chemotherapy agents. Ombrabulin was combined with two standard taxane/platinum doublets in a phase I study to determine the recommended combination doses. METHODS: Ombrabulin (30-min infusion, day 1 every 3 weeks) was escalated from 15.5 to 35 mg/m(2) with two chemotherapy doublets; OCD, 75 mg/m(2) cisplatin (C), day 1 (cohort 1) or day 2 (cohort 2) with 60/75 mg/m(2) docetaxel (D), day 2; and OCP, AUC5/6 carboplatin (C) and paclitaxel (P) 175 mg/m(2) (cohort 3) or 200 mg/m(2) (cohort 4), day 2. Safety, pharmacokinetics, and tumor response were evaluated. RESULTS: Sixty-nine patients were treated (32 OCD, 37 OCP). Four had DLTs in cycle 1, two in cohort 1 (grade 4 febrile neutropenia, grade 4 pulmonary embolism) and one each in cohorts 2 (grade 3 ALT elevation) and 4 (grade 3 peripheral ischemia). Ombrabulin escalation in cohorts 2, 3 and 4 was halted at the highest planned dose (35 mg/m(2)). Asthenia, nausea, paresthesia, alopecia, vomiting, and stomatitis were common, as was grade 3-4 neutropenia. Ombrabulin clearance was high with a short terminal half-life and a medium volume of distribution. Pharmacokinetic analysis showed no clinically relevant drug interactions between the taxane-platinum doublet and ombrabulin or its active metabolite RPR258063, however docetaxel and carboplatin pharmacokinetics were slightly altered. One complete and 15 partial responses (10 OCD, 5 OCP; median duration 5.5 and 4.4 months, respectively) were reported. CONCLUSIONS: The addition of ombrabulin to standard doses of cisplatin/docetaxel or carboplatin/paclitaxel proved feasible with manageable overlapping toxicities but appears to have limited impact on the efficacy of these doublets. Recommended combination doses are 35 mg/m(2) ombrabulin with 75 mg/m(2) cisplatin/75 mg/m(2) docetaxel or 200 mg/m(2) paclitaxel/AUC6 carboplatin, every 3 weeks.

Is Local Ablative Stereotactic Radiation Therapy a Valuable Rescue Strategy for Time on Drug in Patients Enrolled in Phase I Trials?

PURPOSE: Patients with advanced tumors enrolled in phase I trials display strong treatment expectations and few therapeutic alternatives. When oligoacquired resistance (OAR; ≤3 lesions of disease progression) occurs, local ablative stereotactic radiation therapy (SRT) could allow disease control and continuing the experimental systemic treatment. METHODS AND MATERIALS: Data from patients enrolled in phase I trials evaluating systemic treatments, who experienced OAR while on the phase I systemic therapy and subsequently received SRT between January 2014 and April 2023, were retrospectively analyzed. Progression-free survival (PFS)1 (trial entry to OAR), PFS2 (SRT to first subsequent relapse), time to next systemic treatment (TTNT), and overall survival (OS) were assessed. First subsequent patterns of relapse after SRT were distinguished as OAR2, which could be locally rechallenged, or systemic acquired resistance (SAR; >3 lesions of disease progression). When available, correlations between molecular profile and pathway enrichments of OAR and SAR were explored. RESULTS: Forty-two patients with 52 oligoprogressive lesions were analyzed. The median follow-up was 24 months. SRT allowed a median PFS2 of 7.1 months and a median TTNT of 12.8 months. PFS2 included 49% OAR2 and 51% SAR. Median time to first subsequent relapse (9.6 vs 3.5 months; P = .014) and TTNT (22.4 vs 7.6 months; P < .001) were longer for OAR2 compared with that for SAR. No severe toxicities were reported. A PFS1 of <6 months and de novo oligoprogressive lesions were associated with the presence of SAR. More diverse enriched gene pathways were observed for SAR compared with that for OAR2. CONCLUSIONS: In patients enrolled in phase I trials, OAR managed with SRT may increase time on investigational systemic treatments. Predictive factors reflecting tumor aggressiveness and clonal heterogeneity could help deciphering OAR2 from SAR and maximize SRT output in the oligoprogressive setting.

Understanding and Overcoming Resistance to Selective FGFR inhibitors Across FGFR2-Driven Malignancies.

PURPOSE: Understanding resistance to selective FGFR inhibitors is crucial to improve the clinical outcomes of patients with FGFR2-driven malignancies. EXPERIMENTAL DESIGN: We analyzed sequential ctDNA, +/- WES or targeted NGS on tissue biopsies from patients with tumors harboring activating FGFR2 alterations progressing on pan-FGFR-selective inhibitors, collected in the prospective UNLOCK program. FGFR2::BICC1 Ba/F3 and patient-derived xenografts (PDX) models were used for functional studies. RESULTS: Thirty-six patients were included. In cholangiocarcinoma, at resistance to both reversible inhibitors (e.g. pemigatinib, erdafitinib) and the irreversible inhibitor futibatinib, polyclonal FGFR2 kinase domain mutations were frequent (14/27 patients). Tumors other than cholangiocarcinoma shared the same mutated FGFR2 residues, but polyclonality was rare (1/9 patients). At resistance to reversible inhibitors, 14 residues in the FGFR2 kinase domain were mutated; after futibatinib, only the molecular brake N550 and the gatekeeper V565. Off-target alterations in PI3K/mTOR and MAPK pathways were found in 11 patients, often together with on-target mutations. At progression to a first FGFR inhibitor, 12 patients received futibatinib or lirafugratinib (irreversible inhibitors), with variable clinical outcomes depending on previous resistance mechanisms. Two patients with TSC1 or PIK3CA mutations benefitted from everolimus. In cell viability assays on Ba/F3 and in pharmacologic studies on PDX, irreversible inhibitors retained better activity against FGFR2 kinase domain mutations, with lirafugratinib active against the recalcitrant V565L/F/Y. CONCLUSIONS: At progression to FGFR inhibitors, FGFR2-driven malignancies are characterized by high intra- and inter-patient molecular heterogeneity, particularly in cholangiocarcinoma. Resistance to FGFR inhibitors can be overcome by sequential, molecularly-oriented treatment strategies across FGFR2-driven tumors.

Reactions and adverse events induced by T-cell engagers as anti-cancer immunotherapies, a comprehensive review.

T-cell engagers (TCE) are cancer immunotherapies that have recently demonstrated meaningful benefit for patients with hematological malignancies and solid tumors. The anticipated widespread use of T cell engagers poses implementation challenges and highlights the need for guidance to anticipate, mitigate, and manage adverse events. By mobilizing T-cells directly at the contact of tumor cells, TCE mount an obligatory and immediate anti-tumor immune response that could result in diverse reactions and adverse events. Cytokine release syndrome (CRS) is the most common reaction and is largely confined to the first drug administrations during step-up dosage. Cytokine release syndrome should be distinguished from infusion related reaction by clinical symptoms, timing to occurrence, pathophysiological aspects, and clinical management. Other common reactions and adverse events with TCE are immune effector Cell-Associated Neurotoxicity Syndrome (ICANS), infections, tumor flare reaction and cytopenias. The toxicity profiles of TCE and CAR-T cells have commonalities and distinctions that we sum-up in this review. As compared with CAR-T cells, TCE are responsible for less frequently severe CRS or ICANS. This review recapitulates terminology, pathophysiology, severity grading system and management of reactions and adverse events related to TCE.

Single-cell multiomics profiling reveals heterogeneous transcriptional programs and microenvironment in DSRCTs.

Desmoplastic small round cell tumor (DSRCT) is a rare, aggressive sarcoma driven by the EWSR1::WT1 chimeric transcription factor. Despite this unique oncogenic driver, DSRCT displays a polyphenotypic differentiation of unknown causality. Using single-cell multi-omics on 12 samples from five patients, we find that DSRCT tumor cells cluster into consistent subpopulations with partially overlapping lineage- and metabolism-related transcriptional programs. In vitro modeling shows that high EWSR1::WT1 DNA-binding activity associates with most lineage-related states, in contrast to glycolytic and profibrotic states. Single-cell chromatin accessibility analysis suggests that EWSR1::WT1 binding site variability may drive distinct lineage-related transcriptional programs, supporting some level of cell-intrinsic plasticity. Spatial transcriptomics reveals that glycolytic and profibrotic states specifically localize within hypoxic niches at the periphery of tumor cell islets, suggesting an additional role of tumor cell-extrinsic microenvironmental cues. We finally identify a single-cell transcriptomics-derived epithelial signature associated with improved patient survival, highlighting the clinical relevance of our findings.

Evaluating Debio 1347 in Patients with FGFR Fusion-Positive Advanced Solid Tumors from the FUZE Multicenter, Open-Label, Phase II Basket Trial.

PURPOSE: This multicenter phase II basket trial investigated the efficacy, safety and pharmacokinetics of Debio 1347, an investigational, oral, highly selective, ATP-competitive, small molecule inhibitor of FGFR1-3, in patients with solid tumors harboring a functional FGFR1-3 fusion. PATIENTS AND METHODS: Eligible adults had a previously treated locally advanced (unresectable) or metastatic biliary tract (cohort 1), urothelial (cohort 2) or other histologic cancer type (cohort 3). Debio 1347 was administered at 80 mg once daily, continuously, in 28-day cycles. The primary endpoint was the objective response rate (ORR). Secondary endpoints included duration of response, progression-free survival, overall survival, pharmacokinetics, and incidence of adverse events. RESULTS: Between March 22, 2019 and January 8, 2020, 63 patients were enrolled and treated, 30 in cohort 1, four in cohort 2, and 29 in cohort 3. An unplanned preliminary statistical review showed that the efficacy of Debio 1347 was lower than predicted and the trial was terminated. Three of 58 evaluable patients had partial responses, representing an ORR of 5%, with a further 26 (45%) having stable disease (≥6 weeks duration). Grade ≥3 treatment-related adverse events occurred in 22 (35%) of 63 patients, with the most common being hyperphosphatemia (13%) and stomatitis (5%). Two patients (3%) discontinued treatment due to adverse events. CONCLUSIONS: Debio 1347 had manageable toxicity; however, the efficacy in patients with tumors harboring FGFR fusions did not support further clinical evaluation in this setting. Our transcriptomic-based analysis characterized in detail the incidence and nature of FGFR fusions across solid tumors.

Results of an Open-label, Phase Ia/b Study of Pembrolizumab plus Olaratumab in Patients with Unresectable, Locally Advanced, or Metastatic Soft-Tissue Sarcoma.

PURPOSE: The study evaluated safety and efficacy of olaratumab + pembrolizumab in patients with unresectable locally advanced/metastatic soft-tissue sarcoma (STS) with disease progression on standard treatment. PATIENTS AND METHODS: This was open-label, multicenter, nonrandomized, phase Ia/Ib dose-escalation study followed by cohort expansion (olaratumab + pembrolizumab intravenous infusion). Primary objectives were safety and tolerability. RESULTS: The majority of patients enrolled (n = 41) were female [phase Ia: 9 of 13, phase Ib/dose-expansion cohort (DEC), 17 of 28], aged < 65 years. In phases Ia and Ib, 13 and 26 patients received prior systemic therapy, respectively. Patients received olaratumab 15 mg/kg (phase Ia; cohort 1) or 20 mg/kg (phase Ia; cohort 2 and phase Ib) and pembrolizumab 200 mg (phase Ia/Ib). The median (Q1-Q3) duration of therapy (olaratumab) was 6.0 (3.0-11.9; cohort 1), 14.4 (12.4-20.9; cohort 2), and 14.0 (6.0-21.8) weeks (DEC). No dose-limiting toxicities and few grade ≥ 3 treatment-emergent adverse events [TEAE; 15 mg/kg: 2 (increased lipase); 20 mg/kg: 1 (increased lipase), 1 (colitis), 2 (diarrhea), 3 (anemia)] were reported. Two TEAEs (increased lipase) were related to study discontinuations. Twenty-one patients reported mild (grade ≤ 2) TEAEs [phase Ia, disease control rate (DCR):14.3% (1/7, cohort 1); 66.7% (4/6, cohort 2); no responses were reported; phase Ib, DCR: 53.6% (15/28); objective response rate: 21.4% (6/28; RECIST and irRECIST criteria)]. No response was observed in patients with programmed death ligand-1-positive tumors. CONCLUSIONS: Antitumor activity was observed in some patients in DEC, and combination was well tolerated with manageable safety profile. Further studies are warranted to evaluate the efficacy and mechanistic impact of platelet-derived growth factor receptor inhibitors with immune checkpoint modulator coadministration.

Single-agent gemcitabine in patients with advanced, pre-treated angiosarcoma: A multicenter, retrospective study.

Gemcitabine has shown clinical activity against angiosarcoma in small series, alone, or combined with taxanes. We aimed to evaluate its activity as a single-agent in a larger series of patients with advanced angiosarcoma. We retrospectively reviewed the electronic medical records of consecutive adult patients with advanced angiosarcoma treated with single-agent gemcitabine at our institutions from January 2010 to January 2021. Response was evaluated according to RECIST 1.1, and toxicity was graded according to NCI-CTC v5.0. 42 patients were identified. 38 patients (90%) had received prior anthracyclines and weekly paclitaxel, and 9 (21%) had received pazopanib. The best tumor response was partial response (PR) in 16 patients (38%), or stable disease (10 patients, 24%). All 8 patients with cardiac angiosarcoma experienced a PR. Median PFS was 5.4 months (95%CI: 3.1-6.5), and median OS was 9.9 months (95%CI: 6.6-13.4). Single-agent gemcitabine has clinically meaningful activity in advanced, heavily pre-treated angiosarcoma.

Resistance to Selective FGFR Inhibitors in FGFR-Driven Urothelial Cancer.

Several fibroblast growth factor receptor (FGFR) inhibitors are approved or in clinical development for the treatment of FGFR-driven urothelial cancer, and molecular mechanisms of resistance leading to patient relapses have not been fully explored. We identified 21 patients with FGFR-driven urothelial cancer treated with selective FGFR inhibitors and analyzed postprogression tissue and/or circulating tumor DNA (ctDNA). We detected single mutations in the FGFR tyrosine kinase domain in seven (33%) patients (FGFR3 N540K, V553L/M, V555L/M, E587Q; FGFR2 L551F) and multiple mutations in one (5%) case (FGFR3 N540K, V555L, and L608V). Using Ba/F3 cells, we defined their spectrum of resistance/sensitivity to multiple selective FGFR inhibitors. Eleven (52%) patients harbored alterations in the PI3K-mTOR pathway (n = 4 TSC1/2, n = 4 PIK3CA, n = 1 TSC1 and PIK3CA, n = 1 NF2, n = 1 PTEN). In patient-derived models, erdafitinib was synergistic with pictilisib in the presence of PIK3CA E545K, whereas erdafitinib-gefitinib combination was able to overcome bypass resistance mediated by EGFR activation. SIGNIFICANCE: In the largest study on the topic thus far, we detected a high frequency of FGFR kinase domain mutations responsible for resistance to FGFR inhibitors in urothelial cancer. Off-target resistance mechanisms involved primarily the PI3K-mTOR pathway. Our findings provide preclinical evidence sustaining combinatorial treatment strategies to overcome bypass resistance. See related commentary by Tripathi et al., p. 1964. This article is featured in Selected Articles from This Issue, p. 1949.