ABSTRACT
BACKGROUND: The high mobilization failure rate with the mobilization strategy of combining chemotherapy and filgrastim (rhG-CSF) in autologous hematopoietic stem cell transplantation (auto-HSCT) in lymphomas is one of the unresolved issues. Whether the combination of polyethylene glycol filgrastim [pegfilgrastim (PEG-FIL), PEG-rhG-CSF] and filgrastim (FIL) improves the mobilization success rate and the timing of combination therapy has not been studied. METHODS: 107 lymphoma patients who received auto-HSCT were retrospectively enrolled and divided into groups of PEG+FIL and FIL. The group of PEG+FIL received pegfilgrastim (9 mg) on the third day of the chemotherapy, followed by filgrastim (10 µg/kg/day) based on the counts of peripheral blood stem cells (PBSC). The group of FIL received filgrastim 10 µg /kg/day depending on the number of PBSCs. RESULTS: The incidence of neutropenic fever in the group of PEG+FIL was significantly lower than in the group of FIL. The mean recovery time of leukocytes at autologous stem cell transplantation was significantly shorter in the group of PEG+FIL than in the group of FIL. Compared to the groups of FIL, the group of PEG+FIL had lower hospitalization costs. We found that the combination therapy is more recommended for patients with a bone marrow hematopoietic area of less than 30%. Filgrastim is best administered 5-6 days after pegfilgrastim administration. CONCLUSIONS: Compared to conventional filgrastim mobilization, the combination of pegfilgrastim and filgrastim schedule has high efficacy, non-inferior safety, and superior health economic benefits during auto-HSCT.
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Background: MIL62, a novel glycoengineered type â ¡ anti-CD20 monoclonal antibody, with a nearly completely afucosylated N-glycans in Fc region, has demonstrated superior activity compared with rituximab and obinutuzumab in vitro and in vivo, respectively. Methods: This multicentre, single-arm, phase 1b/2 trial aimed to explore the efficacy, pharmacokinetics, and safety of MIL62 combined with lenalidomide in patients with relapsed/refractory (R/R) follicular lymphoma (FL) or marginal zone lymphoma (MZL). Eligible patients included those who had histopathologically confirmed CD20 positive FL (grade 1-3a) or MZL and failed to be treated with rituximab. Patients received intravenously infused MIL62 1000 mg (cycle 1: day 1, 15; cycles 2-8: day 1, cycles 10 and 12: day 1) combined with oral lenalidomide (once a day, days 2-22, the initial dose was 10 mg, and the maximum dose was 20 mg) for 12 cycles, 28 days as a cycle. The primary endpoint was objective response rate (ORR) assessed by investigator per Lugano 2014 criteria every 3 cycles. This study was registered in ClinicalTrials.gov (NCT04110301). Findings: Between November 22, 2019 and December 22, 2020, 54 patients were enrolled from 11 hospitals in China and received study treatment. Fifty patients were included in the efficacy analysis set, and 43 patients (86%, 95% CI: 73, 94) achieved objective response, meeting the pre-specified primary endpoint. Disease control rate was 96% (48/50, 95% CI: 86, 100), proportion of patients with duration of response (DoR) > 6 months was 77% (33/43). The median follow-up for survival was 12.3 months (IQR 12.0-12.6). The 1-year progression-free survival rate was 72% (95% CI: 57, 83), 9-month DoR rate was 74% (95% CI: 58, 85), and 1-year overall survival rate was 98% (95% CI: 85, 100). Most common TRAEs were neutropenia (93%, 50/54), leukopenia (85% 46/54), thrombocytopenia (61% 33/54), lymphopenia (32% 17/54), and alanine aminotransferase increased (20% 11/54). Interpretation: MIL62 combined with lenalidomide showed promising efficacy in patients with R/R FL and MZL. A multicentre, randomized, open-label, phase â ¢ trial of MIL62 combined with lenalidomide versus lenalidomide in anti-CD20 monoclonal antibody refractory FL patients is ongoing (NCT04834024). Funding: Beijing Mabworks Biotech Co. Ltd, Beijing China and the National Science and Technology Major Project for Key New Drug Development (2017ZX09304015).
ABSTRACT
In this paper, cascaded modal interferometers constructed by strongly-coupled seven-core fiber (SC-SCF) with different lengths are demonstrated for enhanced bending sensing based on Vernier effect. The free spectral range (FSR) of a single SC-SCF interferometer is determined by the length of SC-SCF. Two SC-SCF interferometers with different FSRs are cascaded, in which, one functions as the sensor while the other functions as the reference. The wavelength shift of the envelope of the output spectrum is much larger than that of a single SC-SCF interferometer due to the Vernier effect. Therefore, enhanced sensing can be achieved. Experimental results show that the bending sensitivity of the proposed sensor is improved from -2.20â nm/m-1 (single SC-SCF interferometer) to 42.32â nm/m-1 (cascaded SC-SCF interferometers). The temperature response of the sensor is also investigated. Our proposed cascaded SC-SCF sensor has advantages of high sensitivity, ease of fabrication, and low cost. It is attractive for high precision bending sensing applications.
ABSTRACT
Operando decoding of the key parameters of photo-electric catalysis provides reliable information for catalytic effect evaluation and catalytic mechanism exploration. However, to capture the details of surface-localized and rapid chemical and thermal events at the nanoscale in real-time is highly challenging. A promising approach based on a lab-around-microfiber sensor capable of simulating photo-electric catalytic reactions on the surface of optical fibers as well as monitoring reactant concentration changes and catalytic heat generation processes is demonstrated. Due to the penetration depth of submicron size and the fast response ability of the evanescent field, the lab-around-microfiber sensor overcame the difficulty of reading instantaneous surface parameters in the submicron range. This sensor operando dismantled the changes in reactant concentration and temperature on the catalyst surface induced by light and voltage, respectively. It also decoded the impact of catalyst composition on the adsorption efficiency and catalytic efficiency across various wavelengths and determined the synchronized occurrence of pollutant degradation and catalytic thermal effects. Stable correlations between the real-time parameters and catalytic activities are obtained, helping to provide a basic understanding of the catalytic process and mechanism. This approach fills an important gap in the current monitoring methods of catalytic processes and heat production.
ABSTRACT
Glass ceramics (GCs) containing PbS quantum dots (QDs) are prepared for temperature sensing. Broadband emissions are detected in the GCs when PbS QDs are precipitated from the glasses, and emissions centers are modulated from 1250 nm to 1960 nm via heat treatments. The emission centers of GCs exhibit blue-shifts when environment temperatures increase from room temperature to 210 °C. Importantly, the shift values of emission centers increase linearly with the test temperature, which is beneficial for applications in temperature sensing. A temperature sensor based on PbS QDs GC is heat-treated at 500 °C for 10 h, possesses the highest sensitivity of 0.378 nm/°C, and exhibits excellent stability and repeatability at high temperatures (up to 210 °C). Moreover, GC fibers are fabricated by using the GCs as the fiber core. The sensitivity of the temperature-sensing sensor of the GC fibers is also demonstrated and the sensitivity is as high as 0.558 nm/°C. The designed PbS QDs GCs provide a significant materials base for the manufacturing of fluorescent temperature sensors and the GC fibers offer significant opportunities for temperature detection in complex, integrated and compact devices.
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OBJECTIVE: Recent studies have found a high prevalence of hepatitis B virus (HBV) infection in patients with non-Hodgkin's lymphoma (NHL), especially B-cell non-Hodgkin's lymphoma (B-NHL). However, most studies did not classify it and analyze the correlation between HBV and its various subtypes. METHODS: The authors retrospectively analyzed 1424 patients with lymphoma. Differences in the prevalence of HBV infection in patients with different pathological types of lymphoma were analyzed. The clinical characteristics, progression-free survival (PFS), and overall survival (OS) of HBV-positive and negative B-NHL subtypes were compared according to HBV infection. RESULTS: The HBV infection rate in NHL patients was 7.65%, which was higher than that in HL patients (2.59%, p < 0.05). The HBV infection rate in the B-NHL was higher than that in the T-cell non-Hodgkin's lymphoma (T-NHL) (8.14% vs. 4.95%). The HBV infection rate in the aggressive B-NHL was similar to that of the indolent B-NHL (8.30% vs. 7.88%), and the highest HBV infection rates were found in diffuse large B-cell lymphoma and chronic lymphocytic leukemia/small lymphocytic lymphoma, but no significant differences in clinical characteristics, PFS, and OS were seen between HBV-positive and negative patients in the two subtypes. CONCLUSIONS: There was an association between HBV infection and the development of NHL and HBV infection may play a role in the pathogenesis of B-NHL, but not T-NHL.
Subject(s)
Hepatitis B virus , Hepatitis B , Humans , Retrospective Studies , Male , Female , Middle Aged , Hepatitis B/complications , Hepatitis B/virology , Hepatitis B/epidemiology , Adult , Aged , Hepatitis B virus/isolation & purification , Young Adult , Prevalence , Lymphoma, Non-Hodgkin/virology , Lymphoma, Non-Hodgkin/epidemiology , Adolescent , Aged, 80 and over , Lymphoma, B-Cell/virology , Lymphoma, B-Cell/epidemiology , Lymphoma, B-Cell/pathology , Lymphoma, B-Cell/mortality , Progression-Free SurvivalABSTRACT
Hydrovoltaic is an emerging technology that aims to harvest energy from water flow and evaporation, in which the plasmonic hydrogen ions are generated by the interaction between water and hydrovoltaic device. However, the volume of the water sample for the interaction is usually ultra-small due to the compact size of hydrovoltaic device, making the quantification and characterization of the hydrogen ions in such water sample an elusive goal. To address this issue, a miniature fiber-optic pH probe is proposed using a unilaterally tapered-microfiber Bragg grating. The microfiber Bragg grating has an intrinsic Bragg reflection signal with a narrow linewidth. The fiber probe is functionalized by coating the sodium alginate, which can respond to the variation of pH mediated by the alteration of the hydrophilicity. The rigidity and robustness of microfiber Bragg grating facilitates the encapsulation of the sensor into a sampling capillary, allowing for the detection of trace aqueous sample less than 2 µL. The pH sensitivity of the tapered-µFBG-based sensor is 62.8 p.m./pH (R2 = 0.995) with a limit resolution of 0.096 pH. The sensor performed a practical application in the monitoring and characterization of the hydrovoltaic microdevice, which can generate microcurrent as soaked in the water. This work demonstrates a promising technology in the fields of materials, energy, biology and medicine, in which the detection of the microsamples is inevitable.
ABSTRACT
The development of lymphoma is a complex multistep process that integrates numerous experimental findings and clinical data that have not yet yielded a definitive explanation. Studies of oncogenic viruses can help to deepen insight into the pathogenesis of lymphoma, and identifying associations between lymphoma and viruses that are established and unidentified should lead to cellular and pharmacologically targeted antiviral strategies for treating malignant lymphoma. This review focuses on the pathogenesis of lymphomas associated with hepatitis B and C, Epstein-Barr, and human immunodeficiency viruses as well as Kaposi sarcoma-associated herpesvirus to clarify the current status of basic information and recent advances in the development of virus-associated lymphomas.
Subject(s)
Herpesvirus 8, Human , Lymphoma , Humans , Lymphoma/etiology , Oncogenic VirusesABSTRACT
Invasive fungal infections pose a significant public health threat. The lack of precise and timely diagnosis is a primary factor contributing to the significant increase in patient mortality rates. Here, an interface-modulated biosensor utilizing an optical fiber for quantitative analysis of fungal biomarkers at the early stage of point-of-care testing (POCT), is reported. By integrating surface refractive index (RI) modulation and plasmon enhancement, the sensor to achieve high sensitivity in a directional response to the target analytes, is successfully optimized. As a result, a compact fiber-optic sensor with rapid response time, cost-effectiveness, exceptional sensitivity, stability, and specificity, is developed. This sensor can successfully identify the biomarkers of specific pathogens from blood or other tissue specimens in animal models. It quantifies clinical blood samples with precision and effectively discriminates between negative and positive cases, thereby providing timely alerts to potential patients. It significantly reduces the detection time of fungal infection to only 30 min. Additionally, this approach exhibits remarkable stability and achieves a limit of detection (LOD) three orders of magnitude lower than existing methods. It overcomes the limitations of existing detection methods, including a high rate of misdiagnosis, prolonged detection time, elevated costs, and the requirement for stringent laboratory conditions.
Subject(s)
Biomarkers , Biosensing Techniques , Optical Fibers , Biosensing Techniques/methods , Biosensing Techniques/instrumentation , Biomarkers/analysis , Biomarkers/blood , Humans , Animals , Fungi , Limit of Detection , Fiber Optic Technology , Mycoses/diagnosis , Point-of-Care Testing , MiceABSTRACT
Marginal zone lymphoma (MZL) is the second most common subtype of inert B-cell non-Hodgkin's lymphoma, accounting for 5-15% of non-Hodgkin's lymphoma cases. Patients with MZL have a long survival period, with a median survival of >10 years, and patients treated with a combination of anti-CD20 monoclonal antibody can achieve an overall effective rate of 81%. However, 20% of patients with MZL show relapse or experience disease progression within 2 years, with a median survival of only 3-5 years. Currently, the treatment options for patients with relapsed/refractory (R/R) MZL are limited, underscoring the pressing need for novel therapeutic drugs. The advent of novel anti-CD20 monoclonal antibodies, small molecule kinase inhibitors, immunomodulators, and other therapeutic strategies has ushered in a new era in the treatment of R/R MZL. Our objective is to summarize the existing treatment strategies, including immunotherapy and the emergent targeted therapies, and to evaluate their effectiveness and safety in the management of R/R MZL. By doing so, we aim to provide a clear understanding of the therapeutic landscape for R/R MZL, and to guide future research directions toward improving the prognosis and quality of life for patients afflicted with this challenging disease.
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Objective: The development of diffuse large B-cell lymphoma (DLBCL) is closely related to the host infection status. China is a highly endemic area for hepatitis B virus (HBV) infection. It is not clear whether HBV infection has a consistent effect on the prognostic implications of patients with DLBCL in different treatment settings. Materials and methods: We conducted a cohort study of 692 patients with DLBCL receiving three or more cycles of treatment with a CHOP or R-CHOP regimen from the First Hospital of Jilin University between July 2011 and July 2022. The patients were divided into two groups based on their hepatitis B surface antigen (HBsAg) status: HBsAg-positive (n = 84, 12.1%) and HBsAg-negative (n = 608, 87.9%) groups. Tumor specimens from 180 patients with primary DLBCL were collected for next-generation sequencing (NGS). Results: The HBsAg-positive group had more frequent abnormal liver function (P = 0.003), hypoalbuminemia (P < 0.001), incidence of > 2 extranodal organs (P = 0.011), and spleen involvement (P < 0.001) than the HBsAg-negative group. HBsAg-positive patients had lower complete response (CR) and overall response rates (ORR) rates (all the p values < 0.05), in either the CHOP group or R-CHOP group. Among patients receiving R-CHOP, the rates of disease progression within 12 and 24 months were higher in the HBsAg-positive group than in the HBsAg-negative group (P=0.018, P=0.029). However, no significant difference in disease progression was observed between HBsAg-positive and HBsAg-negative patients in the CHOP group(P > 0.05). HBsAg positivity (OS: HR [95% CI] = 2.511 [1.214-5.192], P = 0.013) was only associated with poorer OS in the CHOP group. Whereas in the R-CHOP group, HBsAg positivity was associated with both poorer OS and PFS (OS: HR [95% CI] = 1.672 [1.050-2.665], P = 0.030; PFS: HR [95% CI] = 1.536 [1.013-2.331], P = 0.043). Additionally, HBsAg-positive patients with DLBCL also had a higher prevalence of mutations in MYC, ATM, PTPN6, and epigenetically regulated genes. Conclusion: These findings suggest that HBsAg-positive DLBCL patients may represent a distinct subgroup with a poorer prognosis. The standard therapies may be insufficient and new therapeutic strategies should be developed based on a better understanding of the underlying mechanisms of chemoresistance.
Subject(s)
Hepatitis B Surface Antigens , Lymphoma, Large B-Cell, Diffuse , Humans , Cohort Studies , Cyclophosphamide/therapeutic use , Disease Progression , Doxorubicin/therapeutic use , Lymphoma, Large B-Cell, Diffuse/drug therapy , Prednisone/therapeutic use , Rituximab/therapeutic use , Vincristine/therapeutic useABSTRACT
Oxyfluoride transparent glass-ceramics (GC) are widely used as the matrix for rare-earth (RE) ions due to their unique properties such as low phonon energy, high transmittance, and high solubility for RE ions. Tb3+ doped oxyfluoride glasses exhibit a large absorption cross section for ultraviolet (UV) excitation, high stability, high photoluminescence quantum efficiency, and sensitive spectral conversion characteristics, making them promising candidate materials for use as the spectral converter in UV photodetectors. Herein, a Tb3+ doped oxyfluoride GC is developed by using the melt-quenching method, and the microstructure and optical properties of the GC sample are carefully investigated. By combining with a Si-based photo-resistor,a solar-blind UV detector is fabricated, which exhibits a significant photoelectric response with a broad detection range from 188 to 400 nm. The results indicate that the designed UV photodetector is of great significance for the development of solar-blind UV detectors.
ABSTRACT
HLX01 (HanliKang®) is a rituximab biosimilar that showed bioequivalence to reference rituximab in untreated CD20-positive diffuse large B-cell lymphoma (DLBCL) in the phase 3 HLX01-NHL03 study. Here, we report the 5-year follow-up results from the open-label extension part. Patients were randomised to either rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) or HLX01 plus CHOP (H-CHOP) every 21 days for up to six cycles. The primary efficacy endpoint was overall survival (OS), and secondary efficacy endpoint was progression-free survival (PFS). Of the 407 patients enrolled in HLX01-NHL03, 316 patients (H-CHOP = 157; R-CHOP = 159) were included in the 5-year follow-up for a median duration of 65.1 (range, 2.2-76.5) months. 96.5% of the patients had an International Prognostic Index (IPI) of 1 or 2, and 17.7% had bone marrow involvement. The 5-year OS rates were 81.0% (95% CI: 74.9-87.5%) and 75.4% (95% CI: 68.9-82.6%)( HR: 0.75, 95% CI 0.47-1.20; p = 0.23) while 5-year PFS rates were 77.7% (95% CI: 71.4-84.6%) and 73.0% (95% CI: 66.3-80.3%) (HR: 0.84, 95% CI 0.54-1.30; p = 0.43) in the H-CHOP and R-CHOP groups, respectively. Treatment outcomes did not differ between groups regardless of IPI score and were consistent with the primary analysis. H-CHOP and R-CHOP provided no significant difference in 5-year OS or PFS in previously untreated patients with low or low-intermediate risk DLBCL.
Subject(s)
Biosimilar Pharmaceuticals , Lymphoma, Large B-Cell, Diffuse , Humans , Biosimilar Pharmaceuticals/adverse effects , Rituximab/adverse effects , Follow-Up Studies , Lymphoma, Large B-Cell, Diffuse/drug therapy , Cyclophosphamide/adverse effects , Doxorubicin , Prednisone/adverse effectsABSTRACT
We report the development of a head-mounted photoacoustic fiberscope for cerebral imaging in a freely behaving mouse. The 4.5-gram imaging probe has a 9-µm lateral resolution and 0.2-Hz frame rate over a 1.2-mm wide area. The probe can continuously monitor cerebral oxygenation and hemodynamic responses at single-vessel resolution, showing significantly different cerebrovascular responses to external stimuli under anesthesia and in the freely moving state. For example, when subjected to high-concentration CO2 respiration, enhanced oxygenation to compensate for hypercapnia can be visualized due to cerebral regulation in the freely moving state. Comparative studies exhibit significantly weakened compensation capabilities in obese rodents. This new imaging modality can be used for investigating both normal and pathological cerebrovascular functions and shows great promise for studying cerebral activity, disorders and their treatments.
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Pre-eclampsia is a serious multi-organ complication that severely threatens the safety of pregnant women and infants. To accurate and timely diagnose pre-eclampsia, point-of-care (POC) biosensing of the specific biomarkers is urgently required. However, one of the key biomarkers of pre-eclampsia, placental growth factor (PlGF), has a reduced level of expression in patients, which challenges the quantification capability and Limit-of-detection (LOD) of biosensors. Herein, we reported a microfiber Bragg grating biosensor for the quantification of PlGF in clinical serum samples. The Bragg grating was inscribed in a unilateral tapered fiber to generate the segmented Fabry-Perot spectrum for improving the capability of detection. Furthermore, a temperature-calibrated Bragg grating was added to enable dual parametric detection of PlGF and temperature simultaneously for removing the crosstalk. Finally, the biosensor was envisaged to be perfectly compatible with microfluidic chips, and thus dramatically reducing the sample consumption to as small as 10 µL. The proposed biosensor can respond to PlGF with concentrations ranging from 5 to 120 pg mL-1, attaining a LOD of 5 pg mL-1 of clinical relevance. More importantly, the biosensor achieved micro volume detection of clinical serum samples from patients, and the ROC curve with an AUC of 0.977 confirmed the viability of the device. Our study paves the way to a new idea for cost-effective and high-precision screening of patients with pre-eclampsia, and hence envisages a promising prospect for point-of-care (POC) diagnosis of patients with pre-eclampsia.
Subject(s)
Biosensing Techniques , Pre-Eclampsia , Pregnancy , Female , Humans , Pre-Eclampsia/diagnosis , Placenta Growth Factor , Point-of-Care Systems , BiomarkersABSTRACT
Dynamic access to quasi-bound states in the continuum (q-BICs) offers a highly desired platform for silicon-based active nanophotonic applications, while the prevailing tuning approaches by free carrier injections via an all-optical stimulus are yet limited to THz and infrared ranges and are less effective in visible bands. In this work, we present the realization of active manipulations on q-BICs for nanoscale optical switching in the visible by introducing a local index perturbation through a photothermal mechanism. The sharp q-BIC resonance exhibits an ultrasensitive susceptibility to the complex index perturbation, which can be flexibly fulfilled by optical heating of silicon. Consequently, a mild pump intensity of 1 MW/cm2 can yield a modification of the imaginary part of the refractive index of less than 0.05, which effectively suppresses the sharp q-BIC resonances and renders an active modulation depth of reflectance exceeding 80%. Our research might open up an enabling platform for ultrasensitive dynamic nanophotonic devices.
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The use of light as a powerful tool for disease treatment has introduced a new era in tumor treatment and provided abundant opportunities for light-based tumor theranostics. This work reports a photothermal theranostic fiber integrating cancer detection and therapeutic functions. Its self-heating effect can be tuned at ultralow powers and used for self-heating detection and tumor ablation. The fiber, consisting of a dual-plasmonic nanointerface and an optical microfiber, can be used to distinguish cancer cells from normal cells, quantify cancer cells, perform hyperthermal ablation of cancer cells, and evaluate the ablation efficacy. Its cancer cell ablation rate reaches 89% in a single treatment. In vitro and in vivo studies reveal quick, deep-tissue photonic hyperthermia in the NIR-II window, which can markedly ablate tumors. The marriage of a dual-plasmonic nanointerface and an optical microfiber presents a novel paradigm in photothermal therapy, offering the potential to surmount the challenges posed by limited light penetration depth, nonspecific accumulation in normal tissues, and inadvertent damage in current methods. This work thus provides insight for the exploration of an integrated theranostic platform with simultaneous functions in cancer diagnostics, therapeutics, and postoperative monitoring for future practical applications.
Subject(s)
Hyperthermia, Induced , Nanoparticles , Neoplasms , Humans , Precision Medicine , Neoplasms/therapy , Neoplasms/drug therapy , Phototherapy/methods , Theranostic Nanomedicine/methods , Hyperthermia, Induced/methods , Cell Line, Tumor , Nanoparticles/therapeutic useABSTRACT
We present a detailed investigation into the sensing characteristics of a structural microfiber long-period grating (mLPG) sensor. By spirally winding a thinner microfiber to another thicker microfiber, periodic refractive index modulation is formed while the optical signal transmitted in the thicker microfiber is resonantly coupled out to the thinner microfiber, and then a 5-period four-port mLPG can be obtained with a device length of only â¼570â µm demonstrated a strong resonant dip of 25â dB. We studied the sensitivity characteristics of the four-port mLPG with surrounding strain, force, temperature and refractive index, and the obtained sensitivities were -6.4 pm/µÉ, -8418.6â nm/N, 7.62 pm/°C and 2122â nm/RIU, respectively. With the advantages of high refractive index sensitivity and wide wavelength tunable range, the four-port mLPG has great potential in applications such as tunable filters and biochemical sensor.
ABSTRACT
Hydrogen (H2) sensors are critical to various applications such as the situation where H2 is used as the clean energy for industry or the indicator for human disease diagnosis. Palladium (Pd) is widely used as the hydrogen sensing material in different types of sensors. Optical fiber H2 sensors are particularly promising due to their compactness and spark-free operation. Here, we report a Fabry-Pérot (FP)-cavity-based H2 sensor that is formed with a freestanding Pd membrane and integrated on a conventional single-mode optical fiber end. The freestanding Pd membrane acts both as the active hydrogen sensing material and as one of the reflective mirrors of the cavity. When the Pd film absorbs H2 to form PdHx, it will be stretched, resulting in a change of the cavity length and thus a shift of the interference spectrum. The H2 concentration can be derived from the amplitude of the wavelength shift. Experimental results showed that H2 sensors based on suspended Pd membranes can achieve a detection sensitivity of about 3.6 pm/ppm and a detection limit of about 3.3 ppm. This highly sensitive detection scheme is expected to find applications for sensing low-concentration H2.