CYP2C8 rs11572080 and CYP3A4 rs2740574 risk genotypes in paclitaxel-treated premenopausal breast cancer patients.

Breast cancer (BC) is the most prevalent malignancy in women globally. At time of diagnosis, premenopausal BC is considered more aggressive and harder to treat than postmenopausal cases. Cytochrome P450 (CYP) enzymes are responsible for phase I of estrogen metabolism and thus, they are prominently involved in the pathogenesis of BC. Moreover, CYP subfamily 2C and 3A play a pivotal role in the metabolism of taxane anticancer agents. To understand genetic risk factors that may have a role in pre-menopausal BC we studied the genotypic variants of CYP2C8, rs11572080 and CYP3A4, rs2740574 in female BC patients on taxane-based therapy and their association with menopausal status. Our study comprised 105 female patients with histologically proven BC on paclitaxel-therapy. They were stratified into pre-menopausal (n = 52, 49.5%) and post-menopausal (n = 53, 50.5%) groups. Genotyping was done using TaqMan assays and employed on Quantstudio 12 K flex real-time platform. Significant increased frequencies of rs11572080 heterozygous CT genotype and variant T allele were established in pre-menopausal group compared to post-menopausal group (p = 0.023, 0.01, respectively). Moreover, logistic regression analysis revealed a significant association between rs11572080 CT genotype and premenopausal BC. However, regarding rs2740574, no significant differences in genotypes and allele frequencies between both groups were detected. We reported a significant association between CYP2C8 genotypic variants and premenopausal BC risk in Egyptian females. Further studies on larger sample sizes are still needed to evaluate its importance in early prediction of BC in young women and its effect on treatment outcome.

Rates of paclitaxel hypersensitivity reactions using a modified Markman's infusion protocol as primary prophylaxis.

PURPOSE: Markman's desensitisation protocol allows successful retreatment of patients who have had significant paclitaxel hypersensitivity reactions. We aimed to reduce the risk and severity of paclitaxel hypersensitivity reactions by introducing this protocol as primary prophylaxis. METHODS: We evaluated all patients with a gynaecological malignancy receiving paclitaxel before (December 2018 to September 2019) and after (October 2019 to July 2020) the implementation of a modified Markman's desensitisation protocol. The pre-implementation group received paclitaxel over a gradually up-titrated rate from 60 to 180 ml/h. The post-implementation group received paclitaxel via 3 fixed-dose infusion bags in the first 2 cycles. Rates and severity of paclitaxel hypersensitivity reactions were compared. RESULTS: A total of 426 paclitaxel infusions were administered to 78 patients. The median age was 64 years (range 34-81), and the most common diagnosis was ovarian, fallopian tube and primary peritoneal cancer (67%, n = 52/78). Paclitaxel hypersensitivity reaction rates were similar in the pre-implementation (8%, n = 16/195) and post-implementation groups (9%, n = 20/231; p = 0.87). Most paclitaxel hypersensitivity reactions occurred within 30 min (pre- vs. post-implementation, 88% [n = 14/16] vs. 75% [n = 15/20]; p = 0.45) and were grade 2 in severity (pre- vs. post-implementation, 81% [n = 13/16] vs. 75% [n = 15/20]; p = 0.37). There was one grade 3 paclitaxel hypersensitivity reaction in the pre-implementation group. All patients were successfully rechallenged in the post-implementation group compared to 81% (n = 13/16) in the pre-implementation group (p = 0.43). CONCLUSION: The modified Markman's desensitisation protocol as primary prophylaxis did not reduce the rate or severity of paclitaxel hypersensitivity reactions, although all patients could be successfully rechallenged.

ONYCHOLYSIS AS A COMPLICATION OF TAXANE-BASED CHEMOTHERAPY WITH CONCOMITANT CRYOTHERAPY IN BREAST CANCER PATIENTS: TWO CASE REPORTS.

Nail changes are a common side effect of taxane chemotherapy, although onycholysis is quite a rare complication the correct management of which is poorly standardized. These case reports provide a description and analysis of onycholysis, a rare but noteworthy complication observed during taxane-based chemotherapy with concomitant cryotherapy in two patients with breast cancer. Despite prophylactic measures, both cases experienced nail complications during Paclitaxel treatment, underlining the complex nature of onycholysis during taxane therapy and highlighting the critical role of nail assessment and infection screening.

The Serotonin-Mediated Anti-Allodynic Effect of Yokukansan on Paclitaxel-Induced Neuropathic Pain.

Refractory peripheral neuropathy can occur as a side effect in 60-70% of patients receiving Paclitaxel (PTX). Yokukansan (YKS) is a Japanese herbal medicine reported to have analgesic properties for entrapment nerve injuries. Therefore, we investigated the anti-allodynic effect of Yokukansan on Paclitaxel-induced neuropathic pain. All experiments used 6-week-old male Sprague Dawley rats. Mechanical allodynia was evaluated using a dynamic plantar aesthesiometer. A mobile touch-stimulator unit applied progressively increasing force to the mid-plantar region of the hind paw in a vertical direction until the animal withdrew its paw. This was carried out before the Paclitaxel administration and during the first, second, third, and fourth weeks. Using a rat model of PTX-induced neuropathic pain (PTX rat), we injected PTX (intraperitoneally, 2 mg/kg) five times every 2 days. Using the dynamic plantar test, we evaluated the anti-allodynic effect of YKS (orally administered, 1 g/kg). YKS administration on a daily basis significantly enhanced the withdrawal threshold in PTX rats and reduced the expression level of activated microglia immunostaining with Iba1, a specific marker for microglia. The intrathecal administration of WAY-100635 (5-hydroxytryptamine [5-HT]1A receptor antagonist) and Ketanserin (5-HT2A/2C receptor antagonist) inhibited the protective effects of YKS. YKS exhibited an anti-allodynic effect in a rodent model of PTX-induced neuropathic pain by reducing the sensitivity to pain stimuli. These results suggest that Yokukansan may activate 5-HT receptors in the spinal cord, mediating Paclitaxel-induced neuropathic pain.

A three-arm randomised phase II study of the MEK inhibitor selumetinib alone or in combination with paclitaxel in metastatic uveal melanoma.

AIMS: The MAPK pathway is constitutively activated in uveal melanoma (UM). Selumetinib (AZD6244, ARRY-142886), a MEK inhibitor, has shown limited activity as monotherapy in metastatic UM. Pre-clinical studies support synergistic cytotoxic activity for MEK inhibitors combined with taxanes, and here we sought to assess the clinical efficacy of combining selumetinib and paclitaxel. PATIENTS AND METHODS: Seventy-seven patients with metastatic UM who had not received prior chemotherapy were randomised to selumetinib alone, or combined with paclitaxel with or without interruption in selumetinib two days before paclitaxel. The primary endpoint was progression free survival (PFS). After amendment, the combination arms were combined for analysis and the sample size adjusted to detect a hazard ratio (HR): 0.55, 80% power at 1-sided 5% significance level. RESULTS: The median PFS in the combination arms was 4.8 months (95% CI: 3.8 - 5.6) compared with 3.4 months (2.0 - 3.9) in the selumetinib arm (HR 0.62 [90% CI 0.41 - 0.92], 1-sided p-value = 0.022). ORR was 14% and 4% in the combination and monotherapy arms respectively. Median OS was 9 months for the combination and was not significantly different from selumetinib alone (10 months) with HR of 0.98 [90% CI 0.58 - 1.66], 1-sided p-value = 0.469. Toxicity was in keeping with the known profiles of the agents involved. CONCLUSIONS: SelPac met its primary endpoint, demonstrating an improvement in PFS for combination selumetinib and paclitaxel. No improvement in OS was observed, and the modest improvement in PFS is not practice changing.

A prospective comparison study utilizing patient-reported outcomes of taxane-related peripheral neuropathy between nab-paclitaxel and standard paclitaxel in patients with breast cancer.

BACKGROUND: Characteristics of taxane-induced peripheral neuropathy (PN) could be different between paclitaxel and nab-paclitaxel. The purpose of this prospective observational multicenter cohort study was to compare tri-weekly nab-paclitaxel to weekly standard paclitaxel regarding the severity, onset and recovery of sensory and motor PN in patients with breast cancer. METHODS: Patients with histologically confirmed breast cancer who were scheduled to receive standard weekly paclitaxel (80 mg/m2) or tri-weekly nab-paclitaxel (260 mg/m2) at institutions in our multicenter group were eligible for this study. Sensory and motor PN were evaluated every 3 weeks until PN improved for up to one year using patient-reported outcome. RESULTS: Between February 2011 and April 2013, 115 patients were enrolled, including 57 and 58 in the paclitaxel and nab-paclitaxel groups, respectively. The incidence of moderate or severe sensory PN was not significantly different between the two groups (p = 0.40). The incidence of moderate or higher motor PN was more frequent in the nab-paclitaxel group than in the paclitaxel group (p = 0.048). The median period for demonstrating PN were shorter in the nab-paclitaxel group than in the paclitaxel group (sensory, p = 0.003; motor, p = 0.001). The recovery of motor PN was slower in the nab-paclitaxel group than in the paclitaxel group (p = 0.035), while the recovery period of sensory PN was not statistically different. CONCLUSION: Nab-paclitaxel induced sensory PN sooner than paclitaxel, and no difference was observed in the severity and recovery duration between the two agents. Motor PN was more severe, started sooner, and improved over a longer period in the nab-paclitaxel-treated patients than in the paclitaxel-treated patients.

Paclitaxel-induced acute myocardial infarction: a case report and literature review.

BACKGROUND: Paclitaxel is a chemotherapeutic agent commonly used for ovarian, lung, breast carcinoma, and Kaposi's sarcoma. Its common side effects include hypersensitivity reaction, bone marrow suppression, and peripheral neuropathy. However, a rare and life-threatening side effect is paclitaxel-induced myocardial infarction. CASE PRESENTATION: A 71-year-old man with type 2 diabetes mellitus, hypertension, heavy smoking history, previous coronary artery disease with percutaneous coronary intervention (PCI) in left anterior descending artery (LAD), and non-small lung cancer presented with non-ST elevation myocardial infarction during infusion of paclitaxel infusion. Coronary angiogram showed de novo three vessel disease with 70% stenosis in ostial to distal left main artery (LM) and 80% in-stent re-stenosis in proximal to mid left anterior descending artery. CONCLUSIONS: Physicians should be keeping this in mind when dealing with patients on paclitaxel, especially if they have previous risk factors for coronary artery disease.

Genetic determinants of taxane-induced peripheral neuropathy.

The efficacy of taxane­containing regimens has been demonstrated for various cancers, particularly ovarian, endometrial, breast, lung, and prostate cancers. However, extensive taxane-induced toxicities limit their use. Prediction and management of many toxic complications in cancer patients have evolved significantly over the last decade. Peripheral neuropathy is the most typical non-hematological taxane-related complication, and it has a multifactorial pathogenesis. It is often dose-dependent and progressive during therapy and sometimes even after treatment. Unfortunately, the prediction of these common adverse events remains unclear. In the past few years, several polymorphisms of candidate genes with a possible role in the development of this consequence were studied. This minireview aims to highlight the critical yet underappreciated roles of genetic predictors that may increase susceptibility to taxane-induced peripheral neuropathy in cancer patients (Ref. 40). Keywords: taxanes, paclitaxel, docetaxel, peripheral neuropathy, risk factors, genetic polymorphisms.

Blocking Pannexin 1 Channels Alleviates Peripheral Inflammatory Pain but not Paclitaxel-Induced Neuropathy.

BACKGROUND: Pannexin1 (Panx1) is a membrane channel expressed in different cells of the nervous system and is involved in several pathological conditions, including pain and inflammation. At the central nervous system, the role of Panx1 is already well-established. However, in the periphery, there is a lack of information regarding the participation of Panx1 in neuronal sensitization. The dorsal root ganglion (DRG) is a critical structure for pain processing and modulation. For this reason, understanding the molecular mechanism in the DRG associated with neuronal hypersensitivity has become highly relevant to discovering new possibilities for pain treatment. Here, we aimed to investigate the role of Panx1 in acute nociception and peripheral inflammatory and neuropathic pain by using two different approaches. METHODS: Rats were treated with a selective Panx1 blocker peptide (10Panx) into L5-DRG, followed by ipsilateral intraplantar injection of carrageenan, formalin, or capsaicin. DRG neuronal cells were pre-treated with 10Panx and stimulated by capsaicin to evaluate calcium influx. Panx1 knockout mice (Panx1-KO) received carrageenan or capsaicin into the paw and paclitaxel intraperitoneally. The von Frey test was performed to measure the mechanical threshold of rats' and mice's paws before and after each treatment. RESULTS: Pharmacological blockade of Panx1 in the DRG of rats resulted in a dose-dependent decrease of mechanical allodynia triggered by carrageenan, and nociception decreased in the second phase of formalin. Nociceptive behavior response induced by capsaicin was significantly lower in rats treated with Panx1 blockade into DRG. Neuronal cells with Panx1 blockage showed lower intracellular calcium response than untreated cells after capsaicin administration. Accordingly, Panx1-KO mice showed a robust reduction in mechanical allodynia after carrageenan and a lower nociceptive response to capsaicin. A single dose of paclitaxel promoted acute mechanical pain in wildtype (WT) but not in Panx1-KO mice. Four doses of chemotherapy promoted chronic mechanical allodynia in both genotypes, although Panx1-KO mice had significant ablation in the first eight days. CONCLUSION: Our findings suggest that Panx1 is critical for developing peripheral inflammatory pain and acute nociception involving transient receptor potential vanilloid subtype 1 (TRPV1) but is not essential for neuropathic pain chronicity.

Spinal microglial M1 polarization contributes paclitaxel-induced neuropathic pain by triggering cells necroptosis.

Paclitaxel (PTX) is a chemotherapeutic agent that is widely used for the treatment of several types of tumors. However, PTX-induced peripheral neuropathy (PIPN) is an adverse effect generally induced by long-term PTX use that significantly impairs the quality of life. Necroptosis has been implicated in various neurodegenerative disorders. Necroptosis of dorsal root ganglion neurons triggers the pathogenesis of PIPN. Therefore, the present study aims to investigate the role of spinal neuronal necroptosis in PIPN. It also explores the potential role of microglial polarization in necroptosis. We established rat models of PIPN via quartic PTX administration on alternate days (accumulated dose: 8 mg/kg). PTX induced obvious neuronal necroptosis and upregulated the expression of receptor-interacting protein kinase (RIP3) and mixed lineage kinase domain-like protein (MLKL) in the spinal dorsal horn. These effects were inhibited with a necroptosis pathway inhibitor, necrostatin-1 (Nec-1). The effect of microglial polarization on the regulation of spinal necroptosis was elucidated by administering minocycline to inhibit PTX-induced M1 polarization of spinal microglia caused by PTX. We observed a significant inhibitory effect of minocycline on PTX-induced necroptosis in spinal cord cells, based on the downregulation of RIP3 and MLKL expression, and suppression of tumor necrosis factor-α and IL-ß synthesis. Additionally, minocycline improved hyperalgesia symptoms in PIPN rats. Overall, this study suggests that PTX-induced polarization of spinal microglia leads to RIP3/MLKL-regulated necroptosis, resulting in PIPN. These findings suggest a potential target for the prevention and treatment of neuropathic pain.

Five-Year Safety and Effectiveness of Paclitaxel Drug-Coated Balloons Alone or With Provisional Bare Metal Stenting for Real-World Femoropopliteal Lesions: IN.PACT Global Study Subgroup Analysis.

BACKGROUND: The treatment of complex infra-inguinal disease with drug-coated balloons (DCBs) is associated with a significant number of patients undergoing provisional stenting to treat a suboptimal result. To determine the potential long-term impact of DCB treatment with provisional bare metal stenting in complex lesions in real-world patients, a post hoc analysis was performed on data from the IN.PACT Global Study (The IN.PACT Global Clinical Study for the Treatment of Comprehensive Superficial Femoral and/or Popliteal Artery Lesions Using the IN.PACT Admiral Drug-Eluting Balloon). Five-year outcomes were compared between participants who were stented after DCB treatment versus those treated with DCB alone. METHODS: The IN.PACT Global Study enrolled 1535 participants with intermittent claudication and/or ischemic rest pain caused by femoropopliteal lesions; 1397 patients were included in this subgroup analysis (353 stented and 1044 nonstented). Effectiveness was assessed as freedom from clinically driven target lesion revascularization through 60 months. The primary safety composite end point was defined as freedom from device- and procedure-related death through 30 days, and freedom from major target limb amputation and clinically driven target vessel revascularization through 60 months. RESULTS: Lesions in the stented group were longer (15.37 versus 10.98 cm; P<0.001) and had more total occlusions (54.7% versus 28.6%; P<0.001) compared with the nonstented group. The 5-year Kaplan-Meier estimated freedom from clinically driven target lesion revascularization was similar between groups (66.8% stented versus 70.0% nonstented group, log-rank P=0.22). The safety composite end point was achieved in 64.5% stented versus 68.2% nonstented participants (log-rank P=0.19) as estimated by the Kaplan-Meier method. No significant difference was observed in the cumulative incidence of major adverse events (49.1% stented versus 45.0% nonstented; log-rank P=0.17), including all-cause death (19.6% stented versus 19.3% nonstented, log-rank P=0.99). CONCLUSIONS: In this real-world study, revascularization of complex femoropopliteal artery lesions with DCB angioplasty alone or DCB followed by provisional bare metal stenting in certain lesions achieved comparable long-term safety and clinical effectiveness. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01609296.

Drug-coated balloon therapy for in-stent restenosis in patients with iliofemoral deep vein thrombosis: A single-arm observational study.

BACKGROUND: Iliofemoral deep vein thrombosis (IFDVT) causes severe symptoms and affect the quality of life to a great extent. Endovascular thrombectomy and stent implantation have been a feasible strategie to alleviate the signs and symptoms of IFDVT. However, venous in-stent restenosis (ISR) has become an emerging non-negligible problem. METHODS: To evaluate the histological characteristics of venous ISR, neointima of arterial and venous ISR patients were collected and examed. To explore the effect of drug-coated balloon (DCB) on venous ISR lesions, we conducted a single-center retrospective case series study involving IFDVT patients with ISR after venous stenting who were treated with paclitaxel-coated balloon dilatation. RESULTS: We found a collagen-rich matrix but not elastin, as well as fewer cells and less neovascularization in venous intimal hyperplasia compared with neointima in arteries. Thirteen IFDVT patients were involved in the study, with average preoperative stenosis degree of 87.69% ± 13.48%. After intervention, the stenosis degree was significantly reduced to 14.6% ± 14.36% immediately (p < 0.0001) and to 16.54% ± 15.73% during follow-up (p < 0.0001). During follow-up, the VEINES-QOL scores (p < 0.0001), VEINES-Sym scores (p < 0.0001), and Villalta scores (p = 0.04) of patients was improved significantly compared with those before intervention. No major adverse events were observed. CONCLUSIONS: The use of DCB may have a positive effect in the treatment of venous ISR by targeting intimal hyperplasia. Moreover, the application of DCB dilatation in IFDVT stenting patients with ISR is deemed safe and effective.

PD-1 inhibitor combined with albumin paclitaxel and apatinib as second-line treatment for patients with metastatic gastric cancer: a single-center, single-arm, phase II study.

BACKGROUND: Immune checkpoint inhibitors have been approved for first- and third-line treatment of advanced gastric cancer. However, pembrolizumab alone in the second line did not improve overall survival compared to chemotherapy in the KEYNOTE-061 study. In this study, we aimed to explore the efficacy and safety of a three-drug regimen of PD-1 inhibitor combined with albumin paclitaxel and apatinib (a VEGFR inhibitor) for the second-line treatment of patients with metastatic gastric cancer (mGC). METHODS: This was a single-center, single-arm, phase II clinical study. Patients with mGC with stable microsatellite and negative HER-2 expression who failed first-line chemotherapy were enrolled. The enrolled patients were treated with PD-1 inhibitor (selected according to patients' requirements) in combination with albumin paclitaxel (125 mg/m2, intravenously, days 1 and 8, or 250 mg/m2, intravenously, day 1) and apatinib (250 or 500 mg, orally, days 1-21) every 3 weeks. The primary endpoint was progression-free survival (PFS), and the secondary endpoints were overall survival (OS), objective response rate (ORR), disease control rate (DCR), duration of response, and adverse events (AEs). RESULTS: From July 11, 2019, to October 13, 2022, a total of 43 patients were enrolled, of whom 10 were PD-L1 negative, 11 were PD-L1 positive, and 22 had unknown PD-L1 expression. As of the data cutoff on April 1st, 2023, nine patients had partial response, 29 had stable disease, and five experienced progressive disease, with the ORR of 20.9% and DCR of 88.3%. The median PFS was 6.2 months (95% CI, 3.9-9.3), and the median OS was 10.1 months (95% CI, 7.5-14.1). All patients suffered from alopecia and neurotoxicity. The other main AEs of grade 1 or 2 were bone marrow suppression (N = 21, 48.8%), hand-foot reaction (N = 19, 44.2%), hypertension (N = 18, 41.9%), hypothyroidism (N = 11, 25.6%), gastrointestinal bleeding (N = 3, 7.0%), and liver function damage (N = 5, 11.6%). Two patients reported grade 3-4 immune-related liver damage. CONCLUSION: Second-line PD-1 inhibitor combined with albumin paclitaxel and apatinib showed certain efficacy and safety in patients with mGC. TRIAL REGISTRATION: Clinical trials, NCT04182724. Registered 27 November 2019; retrospectively registered, https://clinicaltrials.gov/study/NCT04182724.

Analysis of the contributing role of drug transport across biological barriers in the development and treatment of chemotherapy-induced peripheral neuropathy.

BACKGROUND: Chemotherapy-induced peripheral neuropathy (CIPN) represents a major unmet medical need that currently has no preventive and/or curative treatment. This is, among others, driven by a poor understanding of the contributive role of drug transport across biological barriers to target-site exposure. METHODS: Here, we systematically investigated the transport of 11 small-molecule drugs, both, associated and not with CIPN development, at conventional (dorsal root ganglia, sciatic nerve) and non-conventional (brain, spinal cord, skeletal muscle) CIPN sites. We developed a Combinatory Mapping Approach for CIPN, CMA-CIPN, combining in vivo and in vitro elements. RESULTS: Using CMA-CIPN, we determined the unbound tissue-to-plasma concentration ratio (Kp,uu) and the unbound intracellular-to-extracellular concentration ratio (Kp,uu,cell), to quantitatively assess the extent of unbound drug transport across endothelial interfaces and parenchymal cellular barriers of investigated CIPN-sites, respectively, in a rat model. The analysis revealed that unique pharmacokinetic characteristics underly time-dependent accumulation of the CIPN-positive drugs paclitaxel and vincristine at conventional (dorsal root ganglia and sciatic nerve) and non-conventional (skeletal muscle) CIPN sites. Investigated CIPN-positive drugs displayed intracellular accumulation contrary to CIPN-negative drugs nilotinib and methotrexate, which lacked this feature in all investigated tissues. CONCLUSIONS: Hence, high unbound drug intracellular and extracellular exposure at target sites, driven by an interplay of drug transport across the endothelial and parenchymal cellular barriers, is a predisposing factor to CIPN development for CIPN-positive drugs. Critical drug-specific features of unbound drug disposition at various CIPN- sites provide invaluable insights into understanding the pharmacological/toxicological effects at the target-sites which will inform new strategies for monitoring and treatment of CIPN.

Low-dose Paclitaxel with Pembrolizumab Enhances Clinical and Immunologic Responses in Platinum-refractory Urothelial Carcinoma.

PURPOSE: Single-agent checkpoint inhibition is effective in a minority of patients with platinum-refractory urothelial carcinoma; therefore, the efficacy of combining low-dose paclitaxel with pembrolizumab was tested. MATERIALS AND METHODS: This was a prospective, single-arm phase II trial with key inclusion criteria of imaging progression within 12 months of platinum therapy and Eastern Cooperative Oncology Group ≤1. Treatment was pembrolizumab 200 mg day 1 and paclitaxel 80 mg/m2 days 1 and 8 of a 21-day cycle for up to eight cycles unless progression or unacceptable adverse events (AE). The primary endpoint was overall response rate (ORR) with overall survival (OS), 6-month progression-free survival (PFS), and safety as key secondary endpoints. Change in circulating immune cell populations, plasma, and urinary miRs were evaluated. RESULTS: Twenty-seven patients were treated between April 2016 and June 2020, with median follow-up of 12.4 months. Baseline median age was 68 years, with 81% men and 78% non-Hispanic White. ORR was 33% by intention to treat and 36% in imaging-evaluable patients with three complete responses. Six-month PFS rate was 48.1% [95% confidence interval (CI): 28.7-65.2] and median OS 12.4 months (95% CI: 8.7 months to not reached). Common ≥ grade 2 possibly-related AEs were anemia, lymphopenia, hyperglycemia, and fatigue; grade 3/4 AEs occurred in 56%, including two immune-mediated AEs (pneumonitis and nephritis). Responding patients had a higher percentage of circulating CD4+IFNγ+ T cells. Levels of some miRs, including plasma miR 181 and miR 223, varied in responders compared with nonresponders. CONCLUSIONS: The addition of low-dose paclitaxel to pembrolizumab is active and safe in platinum-refractory urothelial carcinoma. SIGNIFICANCE: We found that combining pembrolizumab with low-dose paclitaxel may be effective in patients with urothelial carcinoma progressing on platinum chemotherapy, with favorable safety profiles.