A phase 1a dose-escalation study of PY314, a TREM2 (Triggering Receptor Expressed on Macrophages 2) targeting monoclonal antibody

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Background: To characterize the safety and tolerability of PY314, an immunosuppressive macrophage depleting antibody, as a single agent and in combination with pembrolizumab in subjects with advanced refractory solid tumors including subject’s refractory to checkpoint inhibitors if approved for that indication. Methods: Two were evaluated in subjects with advanced solid tumors, single agent PY314 and PY314 in combination with 200 mg of pembrolizumab using a 3+3 dose escalation study design. Dosing was intravenous and administered once every 3-weeks, a defined cycle. Disease assessment by RECIST 1.1 was performed every 6 weeks. Each stratum included 4 dose levels of PY314 (1, 3, 10, and 20 mg/kg). Pharmacokinetics were evaluated at specified time points. Archival tumor tissue was analyzed for TREM2 expression by immunohistochemistry. Based on preclinical evaluation of TREM2 expression, HR+ HER2- and triple negative breast cancer, colorectal cancer, renal cell cancer, non-small cell lung cancer and gynecologic cancers were studied. Results: 28 subjects (median age 60 years [range 26-76], 22 females and 6 ) with an ECOG PS <2 were enrolled and all, but one was (1 subject withdrew consent after dosing). 15 subjects were treated with single agent PY314 and 13 were treated with the combination. No infusion-related reactions, dose limiting toxicities, suspected unexpected serious adverse reactions or high-grade treatment related adverse events (TRAEs) that resulted in treatment discontinuance was seen. 12 subjects experienced at least one TRAE, and in all but one subject, these were low grade. One subject experienced a treatment-related immune system disorder. serious adverse events, all unrelated to treatment. TREM2 expression in archival tumor ranged from 0.0-20%. PY314 pharmacokinetics were linear, dose proportional, unaffected by concomitant pembrolizumab and with a half-life of 8-9 days. Best radiographic response was stable disease seen in 11 subjects (39.3%) ranging in duration from 9-42 weeks. 6 subjects with stable disease have progressed and 5 remain on treatment. Conclusions: PY314 was well tolerated and has an excellent safety profile both as a single agent and in combination with pembrolizumab. A recommended dose for expansion was derived and enrollment in five prespecified cancers is ongoing. Clinical trial information: 04691375.

Effect of continuing osimertinib with chemotherapy in the post-progression setting on progression-free survival among patients with metastatic epidermal growth factor receptor (EGFR) positive non-small cell lung cancer

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Background: Continuing a 1st generation EGFR TKI with chemotherapy upon TKI progression was not shown to be beneficial in the IMPRESS trial. However, the validity of this approach with osimertinib remains under explored. We attempted to characterize the efficacy of continuing osimertinib with chemotherapy in the post-progression setting. Methods: A single-center retrospective review of patients with metastatic EGFR mutant NSCLC who had progressed on osimertinib was performed. Clinical characteristics and treatment outcomes were noted. Progression free survival (PFS), duration of treatment (DOT), overall survival (OS) and rates of intracranial progression were captured. ANOVA or a Fisher exact test were used to identify associations between cohort characteristics and treatment outcomes. Differences in PFS, DOT and OS were assessed using a log-rank test. A Cox proportional hazard model was used to adjust for potential confounders. Results: 73 patients with EGFR mutant NSCLC with post-osimertinib treatment outcomes were identified. Cohort characteristics are summarized in Table. Median duration of follow up was 41 months. Upon progression, osimertinib was discontinued in 34 patients (Cohort A) and continued with next line of therapy in 39 patients (Cohort B). Survival analyses were adjusted for prior lines of therapy, use of platinum doublet chemotherapy, and use of immune checkpoint inhibitors in the post-progression setting. After adjusting for covariates, continuing osimertinib post-progression was associated with an improved PFS (7 vs 4 months; HR 0.58; 95% CI 0.34 – 1.00; p = 0.003) and DOT (7 vs 4 months; HR 0.52; 95% CI 0.31 – 0.87; p = 0.006). There was no difference in OS between Group A and B (52 vs 41 months; HR 0.73; 95% CI 0.43 – 1.24; p = 0.234). Rates of intracranial progression were similar between Group A and B (28% vs 23%; p = 0.649). Conclusions: After adjusting for covariates, continuing osimertinib with chemotherapy in the post-progression setting was associated with a significant difference in PFS and DOT, but with no differences in OS. Continuing osimertinib does not appear to influence the rate of subsequent intracranial progression. Prospective studies are needed to identify the optimal practice pattern.[Table: see text]

Duration of pemetrexed maintenance therapy with or without pembrolizumab is associated with risk of renal toxicity in patients with metastatic nonsquamous NSCLC

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Background: Use of maintenance pemetrexed with pembrolizumab is the standard of care among patients with metastatic nonsquamous NSCLC without EGFR or ALK alterations treated with the KEYNOTE-189 regimen. Whether the addition of pembrolizumab to pemetrexed maintenance alters the risk of renal toxicity is not well characterized. Methods: A single center retrospective study was performed. The frequency of acute kidney injury as well as the rates of discontinuation due to renal injury was assessed. Acute renal injury was defined as ≥ 0.3 increase in serum creatinine (sCr) above the upper limit of normal or a rise in sCr ≥ 1.5 times baseline per KDIGO criteria. A Fisher exact test was conducted to compare the rate of renal injury between the two groups. Logistic regression adjusting for performance status, prior lines of treatment, and number of maintenance cycles was performed. Results: We identified 114 patients who received either maintenance pemetrexed or pemetrexed + pembrolizumab. The median number of cycles for the maintenance pemetrexed and pemetrexed + pembrolizumab groups was 5 and 7 cycles respectively. Of these, 41% (47/114) patients developed acute renal injury during their treatment course. Renal injury was seen in 14.3% (5/35) patients who received single agent pemetrexed maintenance and 25% (3/12) who received maintenance pemetrexed + pembrolizumab with no significant difference in the rates of renal injury between both arms (p = 0.403). Among patients who developed acute renal injury, 9% (4/47) permanently discontinued maintenance due to nephrotoxicity. All patients who permanently discontinued therapy received maintenance pemetrexed alone. When adjusting for covariates, ECOG performance status and number of prior lines of therapy did not increase the risk of renal toxicity. Logistic regression analysis identified that the rate of renal injury was significantly associated with the number of maintenance cycles received (p-value = 0.017, OR = 1.14, 95% CI 1.03 - 1.29). The odds of developing renal injury were 1.14 times higher with each additional cycle of maintenance therapy received. Conclusions: Renal injury is common among patients treated with patients receiving maintenance therapy. The addition of pembrolizumab to maintenance pemetrexed did not significantly increase the rate of renal injury. The risk of renal injury appears to correlate with the total number of maintenance cycles received suggesting a cumulative risk of nephrotoxicity over time.

Early pulmonary function changes associated with brigatinib initiation

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Background: Phase I-III studies reported symptomatic pulmonary toxicity within the first week of initiating brigatinib in 6% patients post-crizotinib and 3% in TKI naive patients with standard dosing (90mg QD for 7 days then 180mg QD as tolerated). A prospective observational study of pulmonary function testing (PFT) on initiating brigatinib was conducted. Methods: Patients PS≤2, with resting O2 sats on RA ≥90% and Hg ≥10 g/dL, without significant heart/lung disease or steroid use initiating brigatinib 90 mg QD were eligible. PFT with DLCO, Borg dyspnea and 6-minute walk tests were performed at baseline (prior to brigatinib), and on day 2 (D2), 8 (D8), and 15 (D15) of brigatinib. D15 analyses were initially as clinically indicated but became mandatory if DLCO had not returned to baseline by D8. Peripheral blood was collected at baseline, D2 and D8 for CyTOF analysis. The primary endpoint was the incidence of Early Onset Pulmonary Events (EOPEs), defined as a DLCO reduction of ≥ 20% from baseline. An interim analysis was performed on the first 10 patients due to a higher than expected incidence of DLCO reduction. Results: D2 and D8 measurements were captured in all 10 patients, D15 in 7 patients. Ninety percent (9/10) of patients experienced DLCO reduction with nadir occurring on D2 in 4/9 and on D8 in 5/9 patients. Median DLCO nadir was −13.33% from baseline (range: −34.44 to −5.00). Three patients (30%) met EOPE criteria, all on D8, all without symptoms. Brigatinib was not held and all 10 patients escalated to 180mg on D8. Despite continued dosing, 4/9 patients recovered DLCO to baseline or above by D15 (2/3 EOPEs cases), 2/9 recovered above nadir but below baseline by D15 (1/3 EOPE case), and 3/9 did not have improvement from nadir values but no D15 assessment was performed. Dyspnea and 6-minute walk test did not correlate with DLCO changes. Patients who experienced an EOPE had significantly higher levels of activated neutrophils (pERKhi) at baseline. On the day of the EOPE event, patients who met EOPE criteria had significantly higher levels of activated neutrophils and fewer activated CD4+ effector memory T cells. Conclusions: Modest DLCO reduction occurred in 90% (9/10) patients during the first 8 days of brigatinib-dosing without associated symptoms. When rechecked on D15, DLCO improved in 100% patients (6/6) despite continued dosing and standard dose escalation at D8. Patients unlikely to tolerate even this modest, short-lived change should consider shallower step-up dosing or alternative drugs. CyTOF analysis suggests levels of pretreatment neutrophils may be a biomarker for developing EOPEs. Clinical trial information: NCT03389399 .

Clinicopathologic profile and treatment outcomes of non-sensitizing EGFR and HER2 (ERBB2) activating mutations in NSCLC: Results from a single-center retrospective study

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Background: The clinicopathologic characteristics and optimal treatment strategies for non-sensitizing EGFR ( ns- EGFR) and HER2 activating mutations in NSCLC remain unclear. Methods: Single-center retrospective study of patients seen at University of Colorado from 2008 – 2018 with stage IV NSCLC was performed. Clinicopathologic features and treatment outcomes of patients with ns-EGFR (Exon 18, Exon 20, L861Q) and HER2 mutations were collected. Best response to TKI was determined (RECIST v1.1). PFS was calculated using Kaplan-Meier method. Results: Among 359 patients, we identified 49 ns-EGFR (36 Exon 20, 10 Exon 18, 3 L861Q) and 28 HER2 mutations (27 Exon 20, 1 gene amplification) detected via NGS (65/77), real-time PCR (9/77), FISH (1/77) and undocumented (2/77). PDL1 > 50% was seen in 44% ns- EGFR and 57% HER2. Adenocarcinoma was the most common histology (97%). Most patients were female (62%), never smokers (63%), and presented with metastatic disease (stage: I 5%, II 4%, III 6%, IV 85%). HER2+ NSCLC demonstrated a tropism for lung metastases (64%) that was significant when compared to EGFR Exon 19, EGFR L858R, ALK, ROS1, and KRAS cohorts (p < 0.001). No differences were found when other metastatic sites were compared. Among evaluable patients, response rates to TKI therapy is shown. Aggregate median PFS on TKI for ns-EGFR and HER2+ NSCLC was 6 months compared to EGFR Exon 19 (15 months; p < 0.01; HR 0.4; CI 0.24 – 0.67) and EGFR L858R (22 months; p < 0.01; HR 0.27 and 0.8; CI 0.14 – 0.54). Aggregate median OS for ns-EGFR and HER2+ NSCLC was 28 months with no differences when compared to EGFR Exon 19 and L858R subgroups. Conclusions: HER2+ NSCLC appears to have a predisposition for lung metastases. Higher DCR was observed with newer generation TKIs, but novel targeted therapeutic approaches are needed as overall outcomes remain poor. [Table: see text]

Clinical outcomes of patients on check point inhibitor therapy who receive routine vaccinations

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Background: Routine vaccination reduces preventable illness and infection in cancer patients even while undergoing therapy. Increasingly, patients with advanced malignancies receive check point inhibitors (CPI) and, with tumor response, can remain on therapy for extended periods of time. These agents promote tumor clearance by impeding a normal route of immune regulation which can result in autoimmunity. To the best of our knowledge, clinical outcomes for patients on CPI therapy who receive routine vaccinations have not been studied. Methods: The medical records of patients who received CPI therapy at Mayo Clinic in Rochester, Minnesota from March 25, 2011 to August 25, 2015 were reviewed for type and date of immunizations, CPI duration, adverse events (AE) at least possibly related to therapy, and survival from start of CPI. Patients who received > 1 dose of pembrolizumab or nivolumab were included in analysis. Patients were excluded if no follow up was done at our institution. Results: One hundred and eight patients were included in the analysis. Most patients received CPI therapy for metastatic melanoma (n = 71) or non-small cell lung cancer (n = 23). A total of 53 routine vaccinations were administered to 30 patients while on CPI therapy. Eighteen patients received a single vaccination. Annual influenza vaccination was most frequently administered (n = 38) followed by pneumococcal vaccines (n = 9). AEs were reported in 17/30 vaccinated patients and in 22/78 non-vaccinated patients (p = 0.004). In the vaccinated cohort, 11 patients experienced AEs after immunization and was not significantly different from the non-vaccinated patients (p = 0.265). For both cohorts, thyroid, rash, and pneumonitis were the most common AEs. Grade 3 AEs occurred with similar frequency between the 2 groups. Patients in the vaccinated cohort received more cycles of therapy (median 20.5 vs 6 cycles, p < 0.001). Median survival of patients who were not vaccinated was 503 days and median survival was not reached in the vaccinated group (p = 0.005). Conclusions: Routine vaccination of patients receiving CPI therapy did not significantly increase number or severity of adverse events. Routine vaccination did not reduce patient benefit from CPIs.