P16.01.A Factors predicting cognitive impairment after intrathecal methotrexate treatment in patients with non-small cell lung cancer and leptomeningeal disease

Background

Leptomeningeal disease (LD) is a devastating cancer-related neurological complication. LD accounts for 4-15% of patients with non-small cell lung cancer (NSCLC). In this population, the median overall survival (OS) with intrathecal (IT) methotrexate (MTX) plus systemic therapy (ST) is 4-6 months (m). Until now, disease and treatment-related cognitive impairment (CI) has been poorly studied in this group.

Material and Methods

Patients with NSCLC and LD treated with IT MTX in our institution between 2010 and 2021 were retrospectively studied. LD was diagnosed based on positive cerebrospinal fluid cytology or radiological findings in the brain/spinal MRI plus suitable clinical signs/symptoms. IT MTX (12mg twice weekly for 4 weeks, then 12mg weekly for 4 weeks) was given in combination with ST. Patients’ clinical characteristics and patient-reported CI were assessed at baseline and at 3-months post IT MTX. A Kaplan-Meier survival analysis was performed. Primary endpoint: predictive factors of CI at 3m post IT MTX. Secondary endpoint: prognostic factors.

Results

Out of 55 patients included, 51% were male and median age at LD diagnosis was 59 years old (range 38-78). Most patients had an ECOG PS≤1 (76.4%) and adenocarcinoma histology (83.6%). 47% of patients harbored EGFR mutation. In 23.6% of patients LD was diagnosed synchronously with lung tumor and for patients without LD at tumor diagnosis, the median time to LD development was 8m (range 0-73). Clinical features at LD diagnosis were 43.7% infratentorial symptoms, 29% CI, 20% multiple symptoms and 7% asymptomatic. At LD diagnosis, 53% of patients had synchronous brain metastases (BM) and in 38% the systemic disease was not controlled. 85.5% of patients received ST concurrently with IT MTX (N=22 chemotherapy, N=22 TKIs and N=3 immunotherapy). 14.5% of patients did not receive ST.

Median OS from IT was 5m (95% CI 1.3-8.6). ECOG PS and ST administered concurrently with IT MTX was associated with longer OS (p<0.05). 23.6% of patients developed CI at 3m post IT therapy. Median OS for patients without and with CI post IT therapy was 6m (95% CI 0.7-11.3) vs 4m (95% CI 0.5-75) respectively (p=0.15). Patients with leukoencephalopathy at baseline (score≥2in the periventricular Fazekas’ score) (p=0.033), women (p<0.01) and those ≥60 years (p=0.04) were more likely to present CI 3m post IT MTX. The presence of cardiovascular risk factors, previous brain radiotherapy and concurrent BM was not statistically associated with CI.

Conclusion

In this cohort, 24% of patients with NSCLC and LD treated with IT MTX will develop CI 3m post treatment. Baseline leukoencephalopathy, female gender, elder than 60 years old were more likely to exhibit CI after IT MTX. A better characterization of these patients is warranted to develop new treatment strategies to prevent/reduce CI.

P14.58 Efficacy and safety of lomustine versus fotemustine as first and second line treament in relapsed glioblastoma patients

BACKGROUND

Glioblastoma (GB) is the most aggressive primary brain tumour. Despite the survival benefit associated with adjuvant therapy, most of patients (pts) relapse after initial therapy. Nitrosoureas (NU) are the standard treatment at relapse in Europe. Both fotemustine (FM) (Addeo schema) and lomustine (LM) (administered orally every 6 weeks) are used in this context.

MATERIAL AND METHODS

This retrospective cohort study included pts diagnosed with GB treated with NU at relapse in four Catalonia hospitals from 2010 to 2020. Clinical and pathological data were collected from medical records. We analysed 6months-progression-free survival (6m-PFS), progression-free survival (PFS) and overall survival (OS) from the start of NU to progression or death respectively. Differences in toxicity grade using CTCAE v5.0 were analysed globally as ‘non-toxicity’, ‘mild toxicity (grade 1 or 2)’ and ‘high toxicity (grade 3 or 4)’.

RESULTS

We identified 236 GB pts with a median age of 58 years old. 29% of the pts presented MGMT promotor methylation and only 3%(n=7) had IDH mutation. After a median follow-up of 20 months, 94% of the pts were dead at the time of the analyses. At first line, 83 pts were treated with FM and 18 with LM. Pts treated with FM had better performance status (PS) than those treated with LM (p=.010). Median PFS was 2 months and 6m-PFS was 12% vs 6% in FM and LM group respectively (p=.87). Median OS was 3 months with LM vs 6 months with FM, with no statistically significant differences even adjusted for prognostic factors (p=.79 HR:0.9 CI 95% 0.41–1.96).At second line, 78 were treated with FM and 24 with LM, no differences between groups. Median PFS was 2 months in both groups and median OS was 3 vs 5 months for pts treated with LM vs FM respectively, with no significant differences. 6m-PFS was 13% for LM vs 0% for the FM group (p=.39).Pts received a mean of 1.7 cycles (every 6 weeks) and 4.1 cycles (every 2 weeks) in LM and FM group, respectively. Thrombocytopenia was the most common serious side-effect, with a higher proportion of grade 1–2 toxicity in the FM group (p=.03) that also required more treatment delays (p=.01).

CONCLUSION

Despite being retrospective study and a few pts were treated with LM, there were no differences neither in PFS nor in OS in pts treated with LM vs FM at first or second line. Higher G1-2 thrombocytopenia was shown in the FM group probably due to a higher number of hematology samples collected.

Immunotherapy in NSCLC patients with brain metastases. Understanding brain tumor microenvironment and dissecting outcomes from immune checkpoint blockade in the clinic

BACKGROUND

Brain metastases are frequent complications in patients with non-small-cell lung cancer (NSCLC) associated with significant morbidity and poor prognosis. Our goal is to give a global overlook on clinical efficacy from immune checkpoint inhibitors in this setting and to review the role of biomarkers and molecular interactions in brain metastases from patients with NSCLC.

METHODS

We reviewed clinical trials reporting clinical outcomes of patients with NSCLC with brain metastases as well as publications assessing the tumor microenvironment and the complex molecular interactions of tumor cells with immune and resident cells in brain metastases from NSCLC biopsies or preclinical models.

RESULTS

Although limited data are available on immunotherapy in patients with brain metastases, immune checkpoint inhibitors alone or in combination with chemotherapy have shown promising intracranial efficacy and safety results. The underlying mechanism of action of immune checkpoint inhibitors in the brain niche and their influence on tumor microenvironment are still not known. Lower PD-L1 expression and less T CD8⁺ infiltration were found in brain metastases compared with matched NSCLC primary tumors, suggesting an immunosuppressive microenvironment in the brain. Reactive astrocytes and tumor associated macrophages are paramount in NSCLC brain metastases and play a role in promoting tumor progression and immune evasion.

CONCLUSIONS

Discordances in the immune profile between primary tumours and brain metastases underscore differences in the tumour microenvironment and immune system interactions within the lung and brain niche. The characterization of immune phenotype of brain metastases and dissecting the interplay among immune cells and resident stromal cells along with cancer cells is crucial to unravel effective immunotherapeutic approaches in patients with NSCLC and brain metastases.

Immune checkpoint inhibitors in non-small cell lung cancer (NSCLC): Approaches on special subgroups and unresolved burning questions

Immune checkpoint inhibitors (ICIs) have been incorporated in the treatment strategy of advanced non-small cell lung cancer (NSCLC). Beyond the already approved indications in first- and second-line setting of advanced NSCLC, new data has recently emerged demonstrating its efficacy in locally advanced disease as maintenance after chemo-radiotherapy and currently several trials are also exploring its efficacy in earlier stages of the disease to evaluate whether these results could be extrapolated to the adjuvant setting. With the advent of all these new therapies, their potential in other thoracic malignancies such as mesothelioma and small-cell lung cancer are also being evaluated with encouraging preliminary data that endorses their short-term incorporation as new therapeutic options in these thoracic malignancies. However, despite all these new evidence, there are still several open questions that remain to be solved like the use of immune agents in special subpopulations such as elderly or fragile patients or the case of patients with brain metastases or autoimmune disorders. In addition some other open questions remain with regards ICIs activity in patients receiving corticosteroid or antibiotics, the potential use in oncogenic addicted tumours, as well as the safety of retreatment after the onset of immune-related adverse events (ir-AE) or the optimal dose schedule or time on treatment for ICIs administration. Herein, we propose to address all these questions, reviewing most recent evidence available in order to give readers some practical advises and guidance on how to deal with these challenges when treating NSCLC patients with immunotherapy.

A form of apolipoprotein a-I is found specifically in relapses of focal segmental glomerulosclerosis following transplantation

Recurrence of idiopathic focal segmental glomerulosclerosis (FSGS) following kidney transplantation occurs in a large percentage of patients. Accurate prediction of recurrence and elucidation of its pathogenesis are major therapeutic goals. To detect differential proteins related to FSGS recurrence, proteomic analysis was performed on plasma and urine samples from 35 transplanted idiopathic FSGS patients, divided into relapsing and nonrelapsing. Several proteins were detected increased in urine of relapsing FSGS patients, including a high molecular weight form of apolipoprotein A-I, named ApoA-Ib, found exclusively in relapsing patients. This finding was verified by Western blot individually in the 35 patients and validated in an independent group of 40 patients with relapsing or nonrelapsing FSGS, plus two additional groups: FSGS-unrelated patients showing different proteinuria levels (n = 30), and familial FSGS transplanted patients (n = 14). In the total of 119 patients studied, the ApoA-Ib form was detected in 13 of the 14 relapsing FSGS patients, and in one of the 61 nonrelapsing patients. Only one of the 30 patients with FSGS-unrelated proteinuria tested positive for ApoA-Ib, and was not detected in familial patients. Urinary ApoA-Ib is associated with relapses in idiopathic FSGS and warrants additional investigation to determine its usefulness as biomarker of relapse following transplantation.

Okadaic acid, a protein phosphatase inhibitor, stimulates the activity of Na+/H+ and Na+-independent Cl-/HCO3- exchangers in human lymphocytes

The cytosolic pH (pHi) regulatory mechanisms of peripheral blood human lymphocytes and the effect of okadaic acid on the activity of these mechanisms were studied by means of fluorescence imaging microscopy of 2',7'-bis-(carboxyethyl)-5(6')-carboxyfluorescein (BCECF)-loaded individual cells. Lymphocytes recover from a CO(2)-induced acid load in an extracellular Na+-dependent, intracellular Cl- -independent fashion. This pHi recovery is highly sensitive to the anion exchange inhibitor 4,4'-diisothiocyanato-stilbene-2,2'-disulfonic acid (DIDS) and minimally sensitive to the Na+/H+ exchange inhibitor amiloride, suggesting that it is mostly due to the action of a Na+-dependent HCO3- transporter. Extracellular Cl- and Na+ removal experiments point to the existence of a DIDS-sensitive Na+-independent Cl-/HCO3- exchanger. Preincubation with okadaic acid stimulates the pHi recovery rate from a CO2-induced acid load in the presence of DIDS (0.002 pHu/min vs. 0.065 pHu/min), but not in the presence of amiloride. Okadaic acid also accelerates the pHi elevation induced by Cl- removal (0.039 pHu/min vs. 0.067 pHu/min). In summary, these results indicate that okadaic acid stimulates the activity of Na+/H+ and Na+-independent Cl-/HCO3- exchangers, but has no effect on the activity of the Na+-dependent HCO3- transporter of human lymphocytes.

Maitotoxin-induced calcium entry in human lymphocytes: modulation by yessotoxin, Ca(2+) channel blockers and kinases

We have studied the effect of the ciguatera-related toxin maitotoxin (MTX) on the cytosolic free calcium concentration ([Ca(2+)]i) of human peripheral blood lymphocytes loaded with the fluorescent probe Fura2 and the regulation of MTX action by different drugs known to interfere in cellular Ca(2+) signalling mechanisms and by the marine phycotoxin yessotoxin (YTX). MTX produced a concentration-dependent elevation of [Ca(2+)]i in a Ca(2+)-containing medium. This effect was stimulated by pretreatment with YTX 1 microM and NiCl(2) 15 microM. The voltage-independent Ca(2+) channel antagonist 1-[beta-[3-(4-methoxyphenyl)propoxyl]-4-methoxyphenyl]-1H-imidazole hydrochloride (SKF96365) blocked the MTX-induced [Ca(2+)]i elevation, while the L-type channel blocker nifedipine had no effect. Pretreatment with NiCl(2) or nifedipine did not modify YTX-induced potentiation of MTX effect, and SKF96365-induced inhibition was reduced in the presence of YTX, which suggest different pathways to act on [Ca(2+)]i. Preincubation with N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide.2HCl (H-89) or genistein (10 microM) also had no effect on the MTX-induced [Ca(2+)]i increment. In contrast, the PKC inhibitor bisindolilmaleimide I (GF109203X 1 microM) potentiated the MTX effect, whereas phosphatidylinositol (PI) 3-kinase inhibition with wortmannin (10 nM) reduced the MTX-elicited Ca(2+) entry. In summary, MTX produced Ca(2+) influx into human lymphocytes through a SKF96365-sensitive, nifedipine-insensitive pathway. The MTX-induced [Ca(2+)]i elevation was stimulated by the marine toxin YTX through a mechanism insensitive to SKF96365, nifedipine or NiCl(2). It was also stimulated by the divalent cation Ni(2+) and PKC inhibition and was partially inhibited by PI 3-kinase inhibition.

Modulation of thapsigargin-induced calcium mobilisation by cyclic AMP-elevating agents in human lymphocytes is insensitive to the action of the protein kinase A inhibitor H-89

Ca2+ mobilisation from internal stores and from the extracellular medium is one of the primary events involved in lymphocyte activation and proliferation. Regulation of these processes by adenosine 3',5'-cyclic monophosphate (cAMP) and cAMP-dependent protein kinase (PKA) was studied in Fura2-loaded human peripheral blood lymphocytes. Cytosolic Ca2+ concentration ([Ca2+]i) was measured in single cells by the use of a ratio imaging fluorescence microscope and Ca2+ mobilisation was achieved by the use of the endoplasmic reticulum (ER) Ca2+ ATPase inhibitor, thapsigargin (Thg). Our results show that both activation and inhibition of PKA, with forskolin (FSK) and N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide.2HCl (H-89), respectively, inhibited the Thg-induced Ca2+ entry. Furthermore, FSK also reduced the ability of Thg to release Ca2+ from internal stores. This reduction was inhibited by the adenylyl cyclase (AC) inhibitor 9-(tetrahydro-2-furanyl)-9-H-purin-6-amine (SQ22,536), but not by the PKA inhibitor H89, indicating that cAMP but not PKA is responsible for this effect. FSK effect was mimicked by dibutyryl cAMP (dbcAMP) and by inhibition of phosphodiesterases (PDEs) with rolipram (ROL) and milrinone (MIL). We also showed that a very high concentration of H-89 (100 microM) releases Ca2+ from an intracellular pool, although this action is probably independent of PKA inhibition. Neither 10 microM H-89 nor other cAMP/PKA-modulating drugs had any effect on the basal [Ca2+]i of human lymphocytes. We conclude that PKA may act as a fine modulator of capacitative Ca2+ entry, while cAMP has a PKA-independent interaction with the Ca2+ stores of human lymphocytes.

Modulation of cytosolic calcium levels of human lymphocytes by yessotoxin, a novel marine phycotoxin

Yessotoxin (YTX) is a polyether toxin of marine origin that has been classified among the diarrheic shellfish poisoning (DSP) toxins group due to its lipophilic nature. However, unlike other DSP toxins, YTX does not produce diarrhea and its mechanisms of action are unknown. We studied the effect of YTX on the cytosolic calcium levels of freshly isolated human lymphocytes by means of fluorescence imaging microscopy. We showed that YTX produced a calcium influx through nifedipine and SKF 96365 (1-[beta-[3-(4-methoxyphenyl)propoxyl]-4-methoxyphenyl]-1H-imidazole hydrochloride)-sensitive channels. This Ca2+ entry was not affected by the DSP toxin okadaic acid, which inhibits protein phosphatases. In addition, YTX also produced an inhibition of capacitative calcium entry activated by thapsigargin or by preincubation in a Ca2+-free medium. This capacitative calcium entry was not sensitive to nifedipine. Furthermore, the inhibitory effect of YTX was dependent on the time of addition of the toxin. We suggest that YTX may interact with calcium channels in a way similar to that described for other polyether marine compounds such as brevetoxins and maitotoxin, although an involvement of other second messengers is also likely.

HCO(3)(-) ions modify the role of PKC isoforms in the modulation of rat mast cell functions

PKC and the intracellular calcium signal are two well-known intracellular signaling pathways implicated in the induction of mast cell exocytosis. Both signals are modified by the presence or absence of HCO(3)(-) ions in the external medium. In this work, we studied the regulation of the exocytotic process by PKC isozymes and its relationship with HCO(3)(-) ions and PKC modulation of the calcium entry. The calcium entry, induced by thapsigargin and further addition of calcium, was inhibited by PMA, a PKC activator, and enhanced by 500 nM GF109203X, which inhibits Ca(2+)-independent PKC isoforms. PMA inhibition of the Ca(2+) entry was reverted by 500 and 50 nM GF109203X, which inhibit Ca(2+)-independent and Ca(2+)-dependent isoforms, respectively, and Gö6976, a specific inhibitor of Ca(2+)-dependent PKCs. Thus, activation of Ca(2+)-dependent and Ca(2+)-independent PKC isoforms inhibit Ca(2+) entry in rat mast cells, either in a HCO(3)(-)-buffered or a HCO(3)(-)-free medium. PMA, GF109203X, Gö6976 and rottlerin, a specific inhibitor of PKC delta, were also used to study the role of PKC isoforms in the regulation of exocytosis induced by thapsigargin, ionophore A23187 and PMA. The results demonstrate that Ca(2+)-dependent PKC isoforms inhibit exocytosis in a HCO(3)(-)-dependent way. Moreover, Ca(2+)-independent PKC delta was the main isoform implicated in promotion of Ca(2+)-dependent mast cell exocytosis in the presence or absence of HCO(3)(-). The role of PKC isoforms in the regulation of mast cell exocytosis depends on the stimulus and on the presence or absence of HCO(3)(-) ions in the medium, but it is independent of PKC modulation of the Ca(2+) entry.

HCO3(-) ions increase mast cell sensitivity to thapsigargin-induced Ca(2+) entry

In rat mast cells Ca(2+) entry is modified by the presence or absence of other ions in the external medium. HCO3(-) ions, which modify mast cell degranulation, seemed to modulate the Ca(2+) entry elicited by the intracellular Ca(2+)-ATPase inhibitor thapsigargin. In this work we studied the regulation of the Ca(2+) entry by HCO3(-) and its relationship with exocytosis. The Ca(2+) entry was activated by thapsigargin and Ca(2+) in mast cells bathed by a HCO3(-)-buffered medium or a HCO3(-)-free medium. Both Ca(2+) entry and exocytosis were enhanced by the presence of HCO3(-) ions. Nondegranulated mast cells showed a low Ca(2+) entry either in the presence or absence of HCO3(-). Thus, mast cells with a high [Ca(2+)](i) increase in a HCO3(-)-buffered medium undergo degranulation. In the same cells a second Ca(2+) entry was significantly higher than the first Ca(2+) entry in a HCO3(-)-free medium, while in a HCO3(-)-buffered medium the first and second Ca(2+) entries reached similar [Ca(2+)](i) levels. Although the second Ca(2+) entry is high in a HCO3(-)-free medium, degranulation is still low. Our results demonstrate that HCO3(-) ions increase the capacitative Ca(2+) entry and the sensitivity of mast cells to intracellular Ca(2+) in order to induce degranulation.

Modulatory effect of HCO3- on rat mast cell exocytosis: cross-talks between bicarbonate and calcium

HCO-3 modulation of histamine release and its relationship with the Ca2+ signal were studied in serosal rat mast cells. Histamine release was induced by Ca2+ mobilizing stimuli, namely compound 48/80, thapsigargin, Ca2+ chelators, ionophore A23187, and PMA and ionophore A23187 in a HCO-3-buffered medium or a HCO-3-free medium. The presence of HCO-3 reduced histamine release by 48/80, Ca2+ chelators, A23187, and PMA/A23187, but increased histamine release induced by thapsigargin. Histamine release by PMA was significantly higher in a HCO-3-free medium than in a HCO-3-free medium, as it was the PMA potentiation of histamine release by A23187. [Ca2+]i changes induced by these drugs were measured in fura-2-loaded mast cells. In thapsigargin and EGTA or BAPTA preincubated mast cells [Ca2+]i increase was higher in a HCO-3-buffered medium than in a HCO-3-free medium in the presence of Ca2+. On the contrary, in compound 48/80 and PMA/A23187 activated mast cells the [Ca2+]i increase is the same both in the presence and in the absence of HCO-3. The effect of HCO-3 on histamine release in serosal rat mast cells depends on the stimulus, but it is not related to the presence of Cl-. In thapsigargin-stimulated mast cells the effect of HCO-3 on histamine release may be related to the Ca2+ signal, but in compound 48/80, EGTA, and PMA/A23187-activated mast cells there is no relationship between intracellular Ca2+ and the inhibitory effect of HCO-3 on histamine release. Additionally, the PKC pathway is implicated in the inhibitory effect of HCO-3 on histamine release, the higher the chelation of calcium rendering the higher the enhancement of the response after adding calcium in the absence of HCO-3.

Role of HCO3- ions in cytosolic pH regulation in rat mast cells: evidence for a new Na+-independent, HCO3--dependent alkalinizing mechanism

The role of external HCO3- in pHi regulation in rat mast cells was studied with BCECF. In a HCO3--free medium cells undergo an alkalinization after the addition of 40 mM HCO3Na. This alkalinization is unaffected by pH. In a Na+-free medium, the addition of 20 mM HCO3Na induced a higher alkalinization than 20 mM HCO3K. Amiloride (1 mM), a Na+/H+ exchanger inhibitor, inhibited by 45% the alkalinization induced by HCO3Na, but it did not change that induced by HCO3K. The anion exchanger inhibitor DIDS reduced 20% the alkalinization induced by both salts. An alkalinization of 0.085 units is observed after the addition of 20 mM HCO3K, even when these exchangers are inhibited (in the absence of Na+ and presence of DIDS). We conclude that the Na+/H+ exchanger and the Cl-/HCO3- exchangers are alkalinizing mechanisms that regulate pHi in these cells. Also, there is some HCO3--dependent, Na+-independent mechanism responsible for the intracellular alkalinization.

The antineoplastic drug vinorelbine activates non-immunological histamine release from rat mast cells

OBJECTIVE AND DESIGN

We explore the mechanism of the antineoplastic drug vinorelbine activation in its rat mast cell exocytosis.

MATERIALS

The study was carried out on mast cells obtained from Sprague-Dawley rats.

TREATMENT

Vinorelbine (5-100 micrograms/mL), cholera toxin (200 ng/mL), pertussis toxin (100 ng/mL), benzalkonium chloride (10 micrograms/mL), compound 48/80 (1 microgram/mL), okadaic acid (1 microM), 12-tetradecanoate-acetate (50 ng/ml), perphenazine (1 microgram/ml), theophylline (10 mM), IBMX (1 mM), rolipram (15 microM).

METHODS

Histamine release was measured fluorimetrically.

RESULTS

The drugs that modify G-protein activity, cholera toxin, pertussis toxin or benzalkonium chloride, do not modify the response profile. The exocytosis elicited by compound 48/80 is decreased by Gs or Gi modulation, which suggests that G proteins are not involved in vinorelbine stimulated secretion. The phosphatase inhibitor okadaic acid shows no effect on vinorelbine-stimulated release, nor on the activation or inhibition of protein kinase C with phorbol 12-tetradecanoate-acetate or perphenazine. The unspecific phosphodiesterase inhibitors theophylline and IBMX inhibited histamine release, but not the phosphodiesterase IV inhibitor rolipram.

CONCLUSIONS

The overall results show that vinorelbine activates histamine release through a rather selective mechanism that may be mediated by certain phosphodiesterase-dependent transduction pathways.