Dose Of Pembrolizumab Research Articles

Krascendo-170 Lung: A phase Ib/II study of divarasib + pembrolizumab ± platinum-based chemotherapy and pemetrexed in untreated KRAS G12C+advanced non-small cell lung cancer (NSCLC).

TPS8651 Background: The KRAS G12C mutation, present in ~12% of NSCLC patients, drives oncogenic signaling and cancer formation and is associated with poor prognosis. The current first-line treatment for advanced KRAS G12C+ NSCLC is checkpoint inhibitor (CPI) ± chemotherapy (CT). Novel combinations using a more targeted, biomarker-directed approach are supported by pre-clinical evidence and may further improve outcomes. Divarasib is an oral KRAS G12C inhibitor with potent pre-clinical and clinical anti-tumor activity. We hypothesize that divarasib + CPI ± CT may improve outcomes for patients with KRAS G12C+ NSCLC. Methods: Krascendo-170 Lung (NCT05789082) is a phase Ib/II, open-label study evaluating the safety and activity of divarasib + pembrolizumab in patients with PD-L1 tumor cell expression ≥1% (Cohort A) and of divarasib + pembrolizumab with platinum-based CT and pemetrexed in patients with any PD-L1 tumor cell expression level (Cohort B). Patients must be ≥18 years old with untreated unresectable/metastatic non-squamous NSCLC (measurable per RECIST v1.1), a confirmed KRASG12C mutation, and an Eastern Cooperative Oncology Group performance status 0/1. Each cohort will have two stages: divarasib combination dose finding and dose expansion, with two planned dose levels of divarasib (Table). Tumor assessments will be performed at baseline and every 6 weeks for 48 weeks, then every 9 weeks thereafter. Plasma samples will be taken at various timepoints before and after divarasib and pembrolizumab dosing to characterize pharmacokinetics. Patients will be treated until disease progression per RECIST v1.1 or unacceptable toxicity. The co-primary endpoints are adverse events and change from baseline in targeted safety parameters. Key secondary endpoints include objective response rate, progression-free survival and duration of response (all investigator assessed per RECIST v1.1). Enrollment into the combination dose finding stage of Cohort A has been completed without dose-limiting toxicities and enrollment into the dose expansion stage is continuing. Clinical trial information: NCT05789082 . [Table: see text]

Projected environmental and public health benefits of extended-interval dosing: an analysis of pembrolizumab use in a US national health system

Health care is a major source of greenhouse gas emissions, leading to climate change and public health harms. Changes are needed to improve the environmental sustainability of health-care practices, but such changes should not sacrifice patient outcomes or financial sustainability. Alternative dosing strategies that reduce the frequency with which specialty drugs are administered, without sacrificing patient outcomes, are an attractive possibility for improving environmental sustainability. We sought to inform environmentally sustainable cancer care by estimating and comparing the environmental and financial effects of alternative, clinically equivalent strategies for pembrolizumab administration. We conducted a retrospective analysis using a cohort of patients from the Veterans Health Administration (VHA) in the USA who received one or more pembrolizumab doses between May 1, 2020, and Sept 30, 2022. Using baseline, real-world administration of pembrolizumab, we generated simulated pembrolizumab use data under three near-equivalent counterfactual pembrolizumab administration strategies defined by combinations of weight-based dosing, pharmacy-level vial sharing and dose rounding, and extended-interval dosing (ie, every 6 weeks). For each counterfactual dosing strategy, we estimated greenhouse gas emissions related to pembrolizumab use across the VHA cohort using a deterministic environmental impact model that estimated greenhouse gas emissions due to patient travel, drug manufacture, and medical waste as the primary outcome measure. We identified 7813 veterans who received at least one dose of pembrolizumab-containing therapy in the VHA during the study period. 59 140 pembrolizumab administrations occurred in the study period, of which 46 255 (78·2%) were dosed at 200 mg every 3 weeks, 12 885 (21·8%) at 400 mg every 6 weeks, and 14 955 (25·3%) were coadministered with infusional chemotherapies. Adoption of weight-based, extended-interval pembrolizumab dosing (4 mg/kg every 6 weeks) and pharmacy-level stewardship strategies (ie, dose rounding and vial sharing) for all pembrolizumab infusions would have resulted in 24·7% fewer administration events than baseline dosing (44 533 events vs 59 140 events) and an estimated 200 metric tons less CO2 emitted per year as a result of pembrolizumab use within the VHA (650 tons vs 850 tons of CO2, a relative reduction of 24%), largely due to reductions in distance travelled by patients to receive treatment. Similar results were observed when weight-based and extended-interval dosing were applied only to pembrolizumab monotherapy and pembrolizumab in combination with oral therapies. Alternative pembrolizumab administration strategies might have environmental advantages over the current dosing and compounding paradigms. Specialty medication dosing can be optimised for health-care spending and environmental sustainability without sacrificing clinical outcomes. None.

A cost comparison of pembrolizumab: Fixed and weight-based dosing.

Pembrolizumab, an immune checkpoint inhibitor, indicated to treat multiple cancers, was initially approved in Australia as weight-based dosing at 2 mg/kg every 3 weeks (Q3W). Subsequent approvals used 'fixed' dosages of 200 mg Q3W or 400 mg every 6 weeks (Q6W). Pharmacokinetic equivalence was demonstrated between dosing strategies, with no significant differences in efficacy or toxicity. Fixed dosing regimens are routinely used in Australia. To model and compare the cost of weight-based dosing of pembrolizumab to standard fixed dosing regimens. A single centre, retrospective review was conducted. Patients, identified from dispensing software, who commenced on pembrolizumab between January and December 2022 were included. Patient demographic and treatment data was extracted from electronic medical records. Costs of weight-based doses were calculated and compared to the cost of fixed dosing. Variables such as acquisition cost, funding mechanisms and 'vial sharing' were considered. Fifty-two patients were included (63% male, median age 68 years). Of the 211 doses of pembrolizumab administered (average 4.1 doses/patient), 161 were Q3W doses, and 50 were Q6W doses. The acquisition cost for a fixed 200 mg and 400 mg dose was $7646, and $15,292, respectively. The average patient weight was 77.6 kg (SD 19 kg), which equated to $5933 for a weight-based Q3W dose, and $11,867 for the Q6W dose; a potential cost avoidance of $1965 and $3930 per dose, respectively. This represented a possible 23.5% avoidance in medication acquisition cost. Over the study period of 1 year, using weight-based dosing for pembrolizumab had the potential to reduce medication expenditure by $467,996. Significant cost avoidance could be achieved via weight-based pembrolizumab dosing. Given the substantial total cost of pembrolizumab, the growing number of indications and the expected equivalent treatment outcomes with weight-based pembrolizumab, the potential cost reductions of weight-based pembrolizumab at both institution and government level should be further explored.

Pembrolizumab monotherapy for high-risk non-muscle-invasive bladder cancer without carcinoma in situ and unresponsive to BCG (KEYNOTE-057): a single-arm, multicentre, phase 2 trial

The KEYNOTE-057 trial evaluated activity and safety of pembrolizumab in patients with BCG-unresponsive high-risk non-muscle-invasive bladder cancer who were ineligible for or declined radical cystectomy. In cohort A (patients with carcinoma in situ, with or without papillary tumours) of the KEYNOTE-057 study, pembrolizumab monotherapy led to a complete response rate of 41% at 3 months, and 46% of responders maintained a response lasting at least 12 months. Here, we evaluate pembrolizumab monotherapy in cohort B of patients with papillary tumours without carcinoma in situ. KEYNOTE-057 is a single-arm, phase 2 study in 54 sites (hospitals and cancer centres) in 14 countries. Cohort B eligible patients were aged 18 years and older, had an Eastern Cooperative Oncology Group performance status of 0-2, and had BCG-unresponsive high-risk non-muscle-invasive bladder cancer with papillary tumours (high-grade Ta or any-grade T1) without carcinoma in situ. Transurethral resection of bladder tumour within 12 weeks of first pembrolizumab dose was required. Patients received pembrolizumab 200 mg intravenously every 3 weeks for a maximum of 35 cycles. Primary endpoint was 12-month disease-free survival of high-risk non-muscle-invasive bladder cancer or progressive disease as assessed by cystoscopy, cytology, and central pathology and radiology review. Activity was assessed in all patients who received at least one dose of the study drug and had a baseline evaluation. Safety was assessed in all patients who received at least one dose of the study drug. This trial is registered with ClinicalTrials.gov number, NCT02625961, and is ongoing. Between April 12, 2016, and June 17, 2021, 132 patients (104 [79%] men and 28 [21%] women) who had received a median of ten (IQR 9-15) previous BCG instillations were enrolled into cohort B of the study. Patients received a median of 10 cycles (IQR 6-27) of pembrolizumab. At data cutoff date, Oct 20, 2022, median follow-up was 45·4 months (IQR 36·4-59·3) and five (4%) of 132 patients remained on treatment. The 12-month disease-free survival was 43·5% (95% CI 34·9-51·9). Treatment-related adverse events occurred in 97 (73%) of 132 patients; 19 (14%) had a grade 3 or 4 treatment-related adverse event; the most common grade 3 or 4 treatment-related adverse events were colitis (in three [2%] patients) and diarrhoea (in two [2%]). 17 (13%) of 132 patients experienced serious treatment-related adverse events, of which colitis (three patients [2%]) was most common. No treatment-related deaths occurred. Pembrolizumab monotherapy showed antitumour activity and manageable toxicity in patients with BCG-unresponsive high-risk Ta or T1 bladder cancer without carcinoma in situ and could potentially be a suitable treatment option for patients who decline or are ineligible for radical cystectomy. Findings will need to be confirmed in a randomised controlled trial. Merck Sharp & Dohme.

Abstract PO1-18-04: Neoadjuvant pembrolizumab + decitabine followed by standard neoadjuvant chemotherapy for locally advanced HER2- breast cancer (NCT02957968)

Abstract Background: Higher levels of stromal tumor-infiltrating lymphocytes (sTILs) in breast cancers are associated with increased likelihood of pathologic complete response (pCR) to chemotherapy and improved outcomes. DNA methyltransferase inhibitors (DNMTi) can augment immune responses to cancers by upregulating tumor antigen and MHC expression, decreasing numbers and activity of myeloid derived suppressor cells (MDSC), and increasing responsiveness of T lymphocytes. We have shown that the DNMTi decitabine augments the effectiveness of immunotherapy against murine triple negative breast cancer (TNBC) using murine 4T1 and E0771 mammary carcinoma models. Methods: In a single-arm phase 2 study, patients with HER2-negative breast cancer who were candidates for neoadjuvant chemotherapy (NCT) received decitabine (15 mg/m2 × 4 doses over 5 days) followed by 2 doses of pembrolizumab (pembro) (200 mg, 2 weeks apart) – collectively, window immunotherapy – prior to starting NCT. Two research biopsies were obtained: 1 prior to the window immunotherapy and 1 afterwards, prior to starting NCT. Biopsies were analyzed using established procedures to quantify sTILs and PD-L1 expression. Patients proceeded to NCT and tumor resection per standard of care and were followed up for immune-related adverse events (irAEs) and response. The primary endpoint was change in sTILs. Key secondary endpoints were occurrence of irAEs and pCR following neoadjuvant treatment. After the study was opened, reported results of a phase 3 trial (KEYNOTE 522) led to allowing patients with TNBC to receive additional pembro (200 mg q3w) concurrently with standard NCT and adjuvantly following resection (Cohort A2). Results: 46 patients (median age 54.5 yrs, range 28-72; 71.7% White, 28.3% Black; 100% female) were enrolled and treated on study. 21 patients had TNBC and did not receive neoadjuvant pembro concurrently with NCT nor adjuvant pembro (Cohort A), 7 patients had TNBC and did receive neoadjuvant and/or adjuvant pembro (Cohort A2), and 18 patients were ER+ or PR+ and received neither concurrent nor adjuvant pembro (Cohort B). Blood samples collected after decitabine administration before the first pembro dose showed a 59% decrease (P< 0.01) in monocytic MDSCs compared to baseline; decrease in granulocytic MDSCs was not statistically significant. 37 patients had paired biopsies adequate for sTIL evaluation with a mean change from 23.4% to 30.3% (absolute change 6.9%, P< 0.001). Cohorts A/A2 experienced an absolute sTIL increase of 7.4% (P< 0.01); Cohort B experienced absolute sTIL increase of 6.1% (P=0.01). PD-L1 expression in tumors (H-score using MoAb 22C3 clone) increased by 43% (P< 0.01) across all cohorts. 16 of the 39 patients (41.0%) who proceeded to resection achieved pCR (n=12 of 27 [44.4%] in Cohorts A/A2 and n=4 of 13 [30.8%] in Cohort B). The most frequently reported irAEs were adrenal insufficiency (n=5, 10.9%), maculopapular rash (n=3, 6.5%), and hypothyroidism (n=3, 6.5%). Conclusions: Treatment in the pre-neoadjuvant window with decitabine and pembro could potentially sensitize breast cancers to standard NCT by recruitment of TILs to the tumor tissue. The treatment was well -tolerated at the tested doses. Funding: financial support and drug (pembrolizumab) were provided by Merck Citation Format: Harry Bear, Xiaoyan Deng, Dipankar Bandyopadhyay, Michael Idowu, Maciej Kmieciak, Monique Williams, Giovanni Archer, Lindsey Gwaltney, Patrick Dillon, Daniel Flora, Daniel Stover, Andrew Poklepovic, Mary Hackney, Masey Ross, Hetal Vachhani, Raphael Louie, Kandace McGuire, Amelia Grover, Tasnim Rahman, Amber Hendrix. Neoadjuvant pembrolizumab + decitabine followed by standard neoadjuvant chemotherapy for locally advanced HER2- breast cancer (NCT02957968) [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-18-04.

Abstract PO5-03-11: Ultra-low dose nivolumab added to dose-dense, cisplatin-based neoadjuvant chemotherapy in locally advanced, borderline operable triple negative breast cancer: A matched case-control study

Abstract Background In India, the majority of patients with triple negative breast cancer(TNBC) present with locally advanced and often inoperable disease due to lack of screening, awareness, and social stigma. This makes pathological complete response(pCR) after neoadjuvant chemotherapy(NAC) less likely, leading to early recurrence and poor survival outcomes. Immune checkpoint inhibitors(ICI) in addition to platinum agents have improved both pCR and disease-free survival(DFS). However, these are accessible only to a very small proportion(< 3%) of patients in LMICs due to exorbitant costs. The activity and cost-effectiveness of low dose ICI has been demonstrated in head and neck. The efficacy of low dose ICI in the neoadjuvant setting for TNBC has not been studied. We examined our outcomes with ultra-low dose nivolumab(< 0.6 mg/kg every 2 weeks) added to NAC for locally advanced and borderline operable TNBC. Methods A retrospective analysis of 132 patients with TNBC who received NAC with the ddDCEP regimen(Docetaxel 75mg/m2 and Cyclophosphamide 600 mg/m2 alternating with Epirubicin 90mg/m2 and Cisplatin 60mg/m2 every 2 weeks for 8 cycles) or ddDCEP plus low dose nivolumab(< 0.6mg/kg/2 weeks) and underwent mastectomy at our centre between 2018-2023 was carried out. 105 and 27 patients received ddDCEP alone and ddDCEP + low dose nivolumab respectively. Using rigorous exact matching, 26 matched pairs(52 patients) were obtained based on tumour grade and AJCC TNM stage. pCR in the surgical specimen was the principal outcome assessed. Survival data, adverse events and cost were also analysed. Results The median age of cases and controls was 42 and 40 years respectively. Tumour histology was ductal carcinoma most patients. Across both groups the stage distribution was the same with nearly 85% stage III(IA 3.8%;IIB 7.7%; IIIA 23.1%;IIIB 43.2%;IIIC 19.2%). 92% of cases and 85% of controls had node positive disease. 62% of cases and 46% of controls had T4 disease. At a median follow up of 9 months, there were no recurrences or deaths among the cases. The most common immune mediated adverse event was hypothyroidism seen in 11.5% of cases. The rates of grade 3/4 anaemia, thrombocytopenia and febrile neutropenia were approximately 38%, 10% and 3.8% across cases and controls respectively. The median dose of nivolumab was 0.27mg/kg/2weeks as opposed to the approved dose of 3mg/kg/2weeks for most indications. The range of doses varied from 0.07 to 0.58mg/kg/2weeks. In the overall cohort, the addition of nivolumab did not have any apparent effect on the pCR rates which were identical at 42.3% in both cases and controls. However, there was a positive correlation between the total dose of nivolumab/kg(body weight) and the likelihood of pCR(coefficient 0.34; p-value 0.046). Patients who received higher than the median dose of nivolumab had a significantly higher likelihood of attaining pCR than those who received lower doses (69.2% pCR vs.15.4%;p-value 0.015). The cost of nivolumab at 0.6 mg/kg for 4 doses is approximately USD2000 compared to USD34400 for 8 doses of pembrolizumab in the neoadjuvant component of the KEYNOTE-522 regimen. Conclusion In this cohort with locally advanced/inoperable TNBC, the addition of ultra-low dose nivolumab did not improve pCR overall compared to a matched control set who did not receive ICI. However, in the subset of patients who received between 0.27-0.58 mg/kg/2weeks, the pCR rates were significantly higher at 69%. This presents a promising and cost-effective approach for TNBC management in LMICs. This effect needs verification in larger phase II/III trials. Table. Citation Format: Zachariah Thomas, Josh Georgy, Ashish Singh, Anjana Joel, Divya Thumaty, Ajoy John, Jerryes Wisely, Grace Rebekah, Elanthenral Sigamani, Anish Cherian, Deepak Abraham, Paul Jacob, Rajesh Balakrishnan, Patricia Solomon, Selvamani Backianathan, Raju Chacko. Ultra-low dose nivolumab added to dose-dense, cisplatin-based neoadjuvant chemotherapy in locally advanced, borderline operable triple negative breast cancer: A matched case-control study [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-03-11.

Abstract PO2-20-07: A case report of a severe cutaneous adverse event in triple negative breast cancer treated with chemoimmunotherapy

Abstract Introduction Cutaneous adverse events related to immune checkpoint inhibitors (ICI) are common and most are mild. However, numerous case reports have documented severe ICI-related skin-toxicities such as Stevens-Johnsons Syndrome (SJS) most commonly among patients with melanoma and lung cancer as immunotherapy has now become a mainstay of treatment in these tumors. The use of ICIs in breast cancer treatment has only recently become standard of care for treatment of metastatic and high risk early-stage triple negative breast cancer with the publication of two landmark clinical trials, KEYNOTE-355 and KEYNOTE-522, respectively. While these trials report low rates of severe skin reactions, little is known about ICI-related severe skin toxicities in patients with breast cancer. Case description A 58-year-old female with clinical stage IIB (cT2N0M0) triple negative breast cancer was undergoing neoadjuvant treatment with pembrolizumab, an anti-programmed death (PD-1) monoclonal antibody, coupled with a chemotherapy back-bone of 12 weekly treatments of carboplatin and paclitaxel followed by 4 cycles of doxorubicin and cyclophosphamide. She developed an erythematous and itchy rash on the right breast and axilla approximately 61 days into her treatment course after having received her fourth dose of pembrolizumab. Over the next 10 days, she developed progression of the rash with painful red papules coalescing into reticulated plaques and dusky blistering of the skin involving the right arm, axilla, abdomen, inguinal folds, thigh, and back, totaling < 10% total body surface area. Notably, the rash did not have mucosal involvement. She was hospitalized for close monitoring and treatment. A punch biopsy of the rash revealed interface dermatitis with areas of full thickness skin necrosis consistent with erythema multiforme, SJS, toxic epidermal necrolysis (TEN), or a fixed drug eruption. Her skin continued to slough in the distribution of rash and a diagnosis of SJS was made. The patient had no response to initial treatment with high dose steroids. Cyclosporine was added, resulting in rapid improvement of her rash. The patient’s neoadjuvant treatment was stopped given the grade 3 SJS she experienced. Despite this truncated neoadjuvant treatment, she had excellent clinical response as her tumor was no longer palpable. She proceeded with a partial mastectomy and sentinel lymph node biopsy. Pathology revealed a pathological complete response. She did not receive any further systemic therapy in the adjuvant setting. Three months later, she was evaluated in clinic without evidence of SJS on physical exam. She was rapidly tapered off cyclosporine over one week without recurrence of her rash. Discussion Severe cutaneous adverse events related to ICIs remains an emerging area of study. In SJS, drug-specific CD8+ T lymphocytes utilize granulysin to mediate keratinocyte apoptosis. It is hypothesized that the blocking of the PD-1/PD-L1 interaction by ICIs results in the disruption of T-cell homeostasis leading to self-directed cytotoxic and inflammatory reactions and ultimately epidermal detachment. In contrast, Molina et al 2020 postulate that such ICI-related skin reactions may represent a separate clinical entity from SJS. In their case report of seven patients, they propose the term “progressive immunotherapy-related mucocutaneous eruption” (PIRME), which the authors suggest is characterized by delayed symptom onset, mild initial presentation, rare ocular involvement, benign clinical course, and favorable treatment response. Further characterization of ICI-related cutaneous adverse events is needed to understand the disease course, optimal treatment, and importantly, implications for re-challenging patients with immunotherapy. Clinicians taking care of breast cancer patients treated with ICIs need to be educated to recognize the associated skin toxicities as patients can rapidly worsen without appropriate treatment. Citation Format: Annie Zhang, Mara Beveridge, Bahar Moftakhar. A case report of a severe cutaneous adverse event in triple negative breast cancer treated with chemoimmunotherapy [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-20-07.

Renal pelvic plasmacytoid subtype urothelial carcinoma accompanied with solitary mammary metastasis.

A 72-year-old female was referred to our institution for further evaluation of right renal tumor detected during work-up for macroscopic hematuria in other hospital. CT urography performed at our institution suggested renal pelvic tumor. Voiding cytology was atypical. CT also revealed a small mass in the right mammary gland. Percutaneous needle biopsies were performed on the right mammary gland and renal mass, leading to a pathological diagnosis of UC with plasmacytoid subtype, suggesting metastasis from the renal pelvic UC to the mammary gland. She had a favorable response to four cycles of dose-dense MVAC therapy; therefore, we performed nephroureterectomy. One month after nephroureterectomy, new intraperitoneal metastatic lesions were observed and pembrolizumab therapy was started. After seven doses of pembrolizumab, CT revealed a marked size reduction of intraperitoneal metastases and the mammary metastasis remained small.

Abstract CT286: TILVANCE-301, a phase 3 study of lifileucel tumor-infiltrating lymphocyte (TIL) cell therapy in combination with pembrolizumab vs pembrolizumab alone in treatment-naive unresectable or metastatic melanoma

Abstract Introduction: Novel early-line therapies for advanced (unresectable or metastatic) melanoma are needed to improve the rate of deep and durable responses and increase the proportion of patients with long-term benefit. TILVANCE-301 will evaluate the efficacy and safety of lifileucel autologous TIL cell therapy plus pembrolizumab in patients with untreated advanced melanoma. Methods: TILVANCE-301 (NCT05727904) is a phase 3, multicenter, randomized, open-label, parallel group study that will randomize ~670 patients (1:1; Day 0) to Arm A: lifileucel plus pembrolizumab (Day 3: tumor tissue resection for TIL manufacturing; Day 5: pembrolizumab 200 mg; Day 26: pembrolizumab 400 mg; Day 28-29: cyclophosphamide 60 mg/kg; Day 28-32: fludarabine 25 mg/m2; Day 33: lifileucel; Day 34-37: ≤6 doses of high-dose IL-2; Week 10: pembrolizumab 400 mg Q6W) or Arm B: pembrolizumab alone (same pembrolizumab dosing as Arm A). Patients in Arm B with confirmed progressive disease verified by blinded independent review committee (BIRC) have the option to receive lifileucel monotherapy as immediate next treatment and may continue pembrolizumab until start of nonmyeloablative lymphodepletion. Eligible adults have histologically confirmed advanced melanoma, Eastern Cooperative Oncology Group performance status of 0-1, estimated life expectancy >6 months, ≥1 resectable lesion to generate lifileucel, and ≥1 remaining measurable lesion. Prior neoadjuvant or adjuvant treatment including immune checkpoint inhibitors may be allowed. Prior therapy for metastatic disease, symptomatic untreated brain metastases, organ allograft or prior cell therapy, uveal/ocular melanoma, and chronic systemic steroid therapy are not permitted. The dual primary efficacy endpoints are BIRC-assessed (RECIST v1.1) objective response rate (ORR) and progression-free survival (PFS). Key secondary efficacy endpoint is overall survival. Additional secondary efficacy endpoints include BIRC-assessed complete response (CR) rate, duration of response (DOR), and event-free survival (EFS); investigator-assessed ORR, PFS, CR rate, DOR, EFS, and PFS2; and safety as characterized by severity and seriousness of treatment-emergent adverse events and relationship to study drug. Exploratory endpoints include in vivo T-cell persistence (unique CDR3 sequences in peripheral blood mononuclear cell [PBMC] over time) and correlative biomarkers (eg, lifileucel phenotypic and functional characteristics; lifileucel, tumor, and PBMC gene expression profiles; tumor mutational landscape). The study will enroll globally, with initial sites in Europe, North America, and Australia. Trial registration: NCT05727904 Citation Format: Sajeve Thomas, Young Ki Hong, Yazan Samhouri, James Larkin, David J. Olson, Gino K. In, Victoria Atkinson, Philip Lammers, Andrew J. Furness, Juan Martin-Liberal, Patrick Terheyden, Andrew S. Poklepovic, Ryan H. Nguyen, Idit Peretz, Marcus Butler, Adnan Khattak, Lavinia Spain, E.M. Gaughan, Melissa Wilson, John W. Dubay, Anja Williams, Stephanie Goff, Gary C. Doolittle, Jason Chesney, Friedrich Graf Finckenstein, Jeffrey Chou, Xiao Wu, Giri Sulur, Wen Shi, John Haanen. TILVANCE-301, a phase 3 study of lifileucel tumor-infiltrating lymphocyte (TIL) cell therapy in combination with pembrolizumab vs pembrolizumab alone in treatment-naive unresectable or metastatic melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT286.

Abstract CT259: Results from monotherapy dose escalation of MDNA11, a long-acting IL-2 superkine, in a phase 1/2 trial show evidence of single-agent activity in advanced solid tumors

Abstract Background: MDNA11 is an albumin-fused ‘beta-enhanced not-alpha’ IL-2 agonist engineered to preferentially expand and activate CD8+ T and NK cells with minimal impact on Tregs. The ABILITY-1 (A Beta-only IL-2 ImmunoTherapY) is a global Phase 1/2 study evaluating the safety, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary clinical activity of MDNA11, both as single agent and in combination with a PD-1 inhibitor, in pre-treated patients with advanced solid tumors. Method: The ABILITY-1 study (NCT05086692) comprises monotherapy dose escalation/evaluation with a modified 3+3 design (enrollment complete); monotherapy dose expansion (enrolling); combination with pembrolizumab dose escalation (enrolling) followed by combination expansion. Thirty participants were enrolled in the monotherapy cohorts (3, 10, 30, 60, 90, and 120 μg/kg, IV, Q2W): 23 in dose escalation and 7 in dose evaluation. To enhance tolerability, step-up dosing with 2 or 3 priming doses was implemented starting at 60 μg/kg. Primary endpoints were incidence and severity of adverse events (AEs) and secondary endpoints included PK, PD, and tumor response (RECIST 1.1 and iRECIST). Results: As of December 22, 2023, 30 patients were enrolled in dose-escalation/evaluation, comprising 16 melanoma, 3 NSCLC, 3 PDAC, 2 RCC, 2 sarcoma, 2 ovarian cancer, 1 tonsillar squamous cell carcinoma and 1 gastro-esophageal adenocarcinoma. No dose-limiting toxicities (DLTs) were observed. Most common treatment related AEs were infusion-related reactions (53.3%), primarily grade 1-2, encompassing pyrexia (43.3%), nausea (33.3%), chills (33.3%), hypotension (30%), and fatigue (26.6%) that resolved within 48-72 hours. PK analysis showed sustained dose-dependent increase in serum concentration of MDNA11 with repeat doses. PD evaluation showed robust and durable dose-dependent increase in lymphocyte counts without eosinophilia. Immune effector cells, particularly CD8+ T cells, showed durable expansion with evidence of activation markers (CD25, ICOS and OX40) peaking at the 90 μg/kg dose. Single-agent anti-tumor activity was evident among 26 evaluable patients with confirmed partial responses (PRs) in a PDAC (MSI-H) patient (60 μg/kg cohort) and a melanoma patient (90 μg/kg cohort) as well as 8 (30.7%) stable disease (SD) including 3 melanoma patients with durable SD (>6 months, >8 months, >1.5 years). Based on the combined safety, PK, PD and preliminary anti-tumor activity, a recommended dose for expansion (RDE) of 90 μg/kg (preceded by priming doses of 30 and 60 μg/kg; Q2W) was selected for the ongoing monotherapy dose expansion of the ABILITY-1 study. Conclusions: MDNA11 was well-tolerated with no DLTs observed at all dose levels up to 120 μg/kg. With study currently ongoing, single agent clinical activity was evident with an ORR of 7.7% and Clinical Benefit Rate (CBR) of 19.2% (2 PRs + 3 SDs > 6 months) in dose escalation to date. Monotherapy dose expansion at 90 μg/kg and combination dose escalation with pembrolizumab are enrolling. Citation Format: Victoria G. Atkinson, Jesus F. Antras, Philippe Bedard, Warren Brenner, Jacqueline Brown, Charlotte R. Lemech, Peter Lloyd, Kim Margolin, Matthen Mathew, John J. Park, Sajeve Thomas, Przemyslaw Twardowski, Humphrey Gardner, Amy Prawira, Melissa Coello, Walead Ebrahimimizadeh, Minh D. To, Rosemina Merchant, Sudhir Madduri Karanam, Arash Yavari, Lillian L. Siu, Hussein A. Tawbi, Paolo A. Ascierto. Results from monotherapy dose escalation of MDNA11, a long-acting IL-2 superkine, in a phase 1/2 trial show evidence of single-agent activity in advanced solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT259.

An autopsy case of lung adenocarcinoma with immune checkpoint inhibitor-induced pneumonia and fulminant myocarditis following pembrolizumab administration: a case report.

Immune checkpoint inhibitors (ICIs) are the current standard of care for non-small-cell lung cancer (NSCLC). Myocarditis is a rare but serious immune-related adverse event (irAE) associated with ICI therapy. We present a patient who received a single dose of pembrolizumab for NSCLC and developed ICI-associated pneumonia. Although pneumonia improved with corticosteroid therapy, the patient subsequently developed ICI-associated fulminant myocarditis. Despite high-dose corticosteroid therapy, the patient died on day 30 after pembrolizumab initiation. Even if an observed irAE was effectively treated, clinicians should remain vigilant for other irAEs, especially those that are difficult to control with low-dose corticosteroids.

Abstract 7518: Neoadjuvant-adjuvant pembrolizumab in resectable advanced basal cell carcinoma of the head and neck: An open-label, single-arm, phase 1b trial

Abstract Introduction: BCC is a common form of skin cancer that shares treatment-related aspects with the more well-studied skin malignancy, melanoma, including sensitivity to anti-PD-1/PD-L1 immunotherapy. However, despite major advances in peri-operative immunotherapy for melanoma, little is known regarding these strategies in BCC. This phase 1B, single-arm study evaluated neoadjuvant-adjuvant treatment with pembrolizumab (PEMBRO) together with standard of care (SOC) resection in advanced BCC of the head and neck. Methods: Eligible patients had resectable, locally advanced BCC of the head and neck, defined by at least one of the following high-risk characteristics: a measurement of ≥ 20 mm, indication for post-operative radiation, or perineural invasion (PNI) in multiple nerves. Patients were naive to hedgehog inhibitors (HHI) and had an ECOG of 0 or 1. All patients received IV PEMBRO at a dose of 200 mg every 3 weeks for a total of 4 cycles, then within 4 weeks underwent a SOC resection followed by adjuvant PEMBRO until a total of 17 cycles was completed. After the 30-day post treatment safety follow-up visit, patients were followed for up to 5 years post-operatively. The primary endpoint was pathological response rate. Secondary endpoints included RECIST response by radiographic or physical exam, adverse events (AE), and recurrence-free survival (RFS). Results: 13 patients were enrolled in the trial from July 2020 to May 2023, and received at least one dose of PEMBRO. Two patients withdrew from the trial after one dose of PEMBRO, one following treatment-related G3 hepatitis and a second due to an unrelated medical complication (cholecystitis). Out of 11 patients undergoing surgical resection, 10 patients received 4 out of 4 and 1 patient received 3 out of 4 planned cycles of neoadjuvant PEMBRO (investigator preference without new related AE). Pathological complete response (pCR) was observed in 3 patients (23%). For those with RECIST measurable disease, 2 patients demonstrated a complete response (CR), 1 patient a partial response (PR), and 5 patients showed stable disease (SD). Two patients had progressive disease (PD). One patient with a complete pathologic response had a discordant RECIST response with PD noted radiographically. All 13 patients experienced at least one AE of G1 or 2. The highest grade of related AEs were noted in 2 patients with grade 3 hepatitis and pruritus respectively that resolved with supportive therapy. As of November 2023, the median follow-up time is 17.6 months with no recurrences noted. Conclusions: Neoadjuvant-adjuvant PEMBRO shows promising efficacy and an acceptable safety profile in resectable advanced BCC of the head and neck. Given these positive results and the healthcare burden BCC accounts for, these findings warrant further study. Citation Format: Grace M. Jones, James Isaacs, Lucy Boyce Kennedy, Jennifer Ko, Allison Vidimos, Alok Vij, Christine Poblete-Lopez, Jennifer Lucas, Yee Peng Phoon, Melissa McEnery-Stonelake, Jon Meine, Thach-Giao Truong, Pauline Funchain, Brian Gastman. Neoadjuvant-adjuvant pembrolizumab in resectable advanced basal cell carcinoma of the head and neck: An open-label, single-arm, phase 1b trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7518.

Abstract 4114: AST-201 (pUMVC3-hIGFBP2 N-terminus) demonstrates anti-tumor effect in an ovarian cancer mouse model

Abstract Background: IGFBP2, known to enhance the invasion capacity of ovarian cancer cells, has been suggested that its inhibition could be potentially a treatment strategy of ovarian cancer. AST-201 (pUMVC3-hIGFBP2) is a therapeutic cancer vaccine using a plasmid DNA encoding IGFBP2 N-terminus. In a phase 1 study (NCT01322802) completed, 100 μg AST-201 (intradermal immunization, id) showed not only a significant efficacy by inducing the Th1-cell immunity against IGFBP2 but also safety and tolerability profiles in ovarian cancer patients. The primary objective of this study is to evaluate whether the administration of AST-201 alone and the combination with pembrolizumab could show anti-tumor efficacy and/or synergic effect in the ID8-Luc2 ovarian cancer mouse model. Also, immunological responses were observed as explorative endpoint. Methods: AST-201 (100 μg/animal, id, mixed with mGM-CSF as an immune adjuvant) was immunized to mice (C57BL/6) once a week for a total of 4 times on different days, either alongside pembrolizumab (10 mg/kg, intraperitoneal injection) twice a week for a total of 3 times on different days. Also, AST-201 was immunized was a mono treatment. The efficacy was evaluated by a tumor growth inhibition (TGI) rate at the last day, and immune cell profiling via FACS analysis was conducted with splenocytes and tumor tissues collected at 8 weeks after the first injection. Results: As a primary endpoint, a TGI rate at Day 55 of AST-201 mono treatment was 67%, comparing to a control group (p<0.05). The anti-tumor effect of AST-201 combining with pembrolizumab was better than standard dose pembrolizumab, based on a TGI rate at Day 55 (78% vs 66%, not significant). Immune profiling showed that AST-201 and pembrolizumab combination regimen could inhibit a tumor growth by transforming TME into inflamed-type (‘hot’) form the low immunoreactivity, which was supported by increased CD4+TEM, and CD8+TEM and T helper cells in splenocyte and TIL analysis. Conclusion: A study demonstrated that AST-201 (IGFBP2 cancer vaccine) showed an anti-tumor effect as mono treatment and would be potentially leading to a synergistic effect with a combination regimen of pembrolizumab. Phase 2 randomized-controlled study of AST-201 in ovarian cancer will be initiated under the MRCT strategy (CornerStone-004 study, NCT05794659). Citation Format: Jinback Lim, Jinho Kang, Hyo-Hyun Park, Jin Kyeong Choi, Jee Hyun Choi, Seong-Yong Jang, Min-Ah Kim, Myeong-Kyu Park, Mary L Disis, Eunkyo Joung, Ashley Yongmin Kim, Hun Jung. AST-201 (pUMVC3-hIGFBP2 N-terminus) demonstrates anti-tumor effect in an ovarian cancer mouse model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4114.

Efficacy and safety of pembrolizumab as first-line treatment for advanced non-small cell lung cancer complicated with chronic obstructive pulmonary disease: protocol for a prospective, single-arm, single-center, phase II clinical trial.

The first-line standard treatment option for patients with NSCLC complicated with Chronic obstructive pulmonary disease (COPD) is still unclear and relies on the treatment option of NSCLC alone. To date, a limited number of retrospective studies have explored the efficacy and safety of immunotherapy in patients with NSCLC complicated with COPD. We therefore designed this study to further explore the efficacy and safety of first-line immunotherapy in patients with NSCLC complicated with COPD. This study was designed as a single-armed, single-center, prospective, phase II clinical study. It will include 30 advanced (stage IV) NSCLC combined with COPD primary treatment subjects. Each subject's diagnosis will be confirmed by clinical, radiographic, pathologic, and pulmonary function evaluation. A fixed dose of 200 mg pembrolizumab will be administered by intravenous infusion on day1 every 3 weeks (Q3W). The management of stable and acute exacerbations of COPD include home oxygen therapy, and the use of conventional medications are also administered. Imaging evaluation will be performed every 6 weeks for 6 months from the first pembrolizumab dose and approximately every 12 weeks thereafter until disease progression or early withdrawal. COPD status will be evaluated every 3 months by pulmonary function, GOLD grading, mMRC score, CAT score, ABCD grouping, and AECOPD severity. The primary outcome is Progression-free survival. The secondary outcome measures include objective response rate, overall survival, rate of acute exacerbations of COPD (times/year), lung function, mMRC score, CAT score, impact of treatment on patient's health-related quality of life, antibiotic use (including duration and classes), and adverse events associated with immune checkpoint inhibitors. Exploratory endpoint is to explore the association between COPD grade and the degree of immune cell (CD4+ T lymphocytes and CD8+ T lymphocytes) infiltration, as well as the association between COPD grade and the efficacy of immune checkpoint inhibitors. ClinicalTrials.gov, identifier NCT05578222.

Anterior Uveitis Secondary to Avelumab and Pembrolizumab in a Patient with Metastatic Renal Cell Carcinoma—A Case Report

We present an unusual case of uveitis secondary to avelumab and pembrolizumab in a 39-year-old Taiwanese male with stage IV clear cell renal cell carcinoma (ccRCC) and lung metastasis, who initially received pembrolizumab as his primary treatment. However, the patient experienced skin and liver immune-related adverse events (irAEs) after the seventh dose of pembrolizumab, which prompted a switch to avelumab. The patient began to experience gradual blurring of vision after completing the fifth cycle of avelumab immunotherapy. Ophthalmic examinations revealed findings consistent with bilateral anterior uveitis. Despite an initial lack of significant improvement with steroid treatment, the patient’s vision and inflammation improved upon discontinuation of avelumab. Due to the occurrence of uveitis, avelumab was switched back to pembrolizumab. However, three months after initiating pembrolizumab, the patient developed foggy vision and bilateral anterior uveitis with cystoid macular edema (CME). The administration of topical, oral, and subconjunctival steroids resulted in an improvement in vision and the resolution of CME, without the need to discontinue pembrolizumab. Over the subsequent eighteen months, there has been no recurrence of uveitis, and there is no evidence of relapse or further metastasis in his ccRCC.

Novel uses of complement inhibitors in myasthenia gravis-Two case reports.

Myasthenia gravis (MG) is a rare, life-threatening immune-related adverse effect (irAE) of immune checkpoint inhibitor (ICI) treatment. C5-complement inhibitors are effective treatments for acetylcholine receptor antibody (AChR ab) positive generalized MG. We describe the use of eculizumab/ravulizumab in two patients with MGreceiving concomitant pembrolizumab. This was a retrospective review of two medical records. Patient 1: An 80-year-old male with recurrent, non-muscle invasive transitional cell carcinoma of the bladder developed ICI-induced AChR ab positive MG (ICI-MG), myositis, and myocarditis 2 weeks after the first dose of pembrolizumab. Myositis responded to corticosteroids. MG responded to eculizumab, followed by ravulizumab. He died of metastatic cancer 8 months later. Patient 2: A 58-year-old male had refractory thymoma-associated AChR ab-positive MG, which responded to eculizumab. He developed metastatic Merkel cell cancer necessitating pembrolizumab. MG remained stable on eculizumab. He had no irAEs for 22 months, with positron emission tomographic resolution of cancer. He then developed mild, indolent retinal vasculitis, which responded to prednisone. Discontinuation of pembrolizumab for 5 months resulted in cancer recurrence; pembrolizumab was resumed with peri-infusion pulse prednisone. MG remained stable and he continues eculizumab. In the first patient, eculizumab, followed by ravulizumab, improved ICI-MG. In the second patient, eculizumab treatment may have had a prophylactic effect on the development of ICI-induced irAEs. The effect of complement inhibition on cancer outcomes of ICI therapy is unknown. A possible biologic basis for complement inhibitors in reducing irAEs of ICI, especially in the presence of underlying autoimmune disease, merits evaluation.

High red blood cell distribution width attenuates the effectiveness of Immune checkpoint inhibitor therapy: An exploratory study using a clinical data warehouse.

Immune checkpoint inhibitors (ICIs) have improved outcomes in cancer treatment but are also associated with adverse events and financial burdens. Identifying accurate biomarkers is crucial for determining which patients are likely to benefit from ICIs. Current markers, such as PD-L1 expression and tumor mutation burden, exhibit limited predictive accuracy. This study utilizes a Clinical Data Warehouse (CDW) to explore the prognostic significance of novel blood-based factors, such as the neutrophil-to-lymphocyte ratio and red cell distribution width (RDW), to enhance the prediction of ICI therapy benefit. This retrospective study utilized an exploratory cohort from the CDW that included a variety of cancers to explore factors associated with pembrolizumab treatment duration, validated in a non-small cell lung cancer (NSCLC) patient cohort from electronic medical records (EMR) and CDW. The CDW contained anonymized data on demographics, diagnoses, medications, and tests for cancer patients treated with ICIs between 2017-2022. Logistic regression identified factors predicting ≤2 or ≥5 pembrolizumab doses as proxies for progression-free survival (PFS), and Receiver Operating Characteristic analysis was used to examine their predictive ability. These factors were validated by correlating doses with PFS in the EMR cohort and re-testing their significance in the CDW cohort with other ICIs. This dual approach utilized the CDW for discovery and EMR/CDW cohorts for validating prognostic biomarkers before ICI treatment. A total of 609 cases (428 in the exploratory cohort and 181 in the validation cohort) from CDW and 44 cases from EMR were selected for study. CDW analysis revealed that elevated red cell distribution width (RDW) correlated with receiving ≤2 pembrolizumab doses (p = 0.0008), with an AUC of 0.60 for predicting treatment duration. RDW's correlation with PFS (r = 0.80, p<0.0001) and its weak association with RDW (r = -0.30, p = 0.049) were confirmed in the EMR cohort. RDW also remained significant in predicting short treatment duration across various ICIs (p = 0.0081). This dual methodology verified pretreatment RDW elevation as a prognostic biomarker for shortened ICI therapy. This study suggests the utility of CDWs in identifying prognostic biomarkers for ICI therapy in cancer treatment. Elevated RDW before treatment initiation emerged as a potential biomarker of shorter therapy duration.

Early Experience With Pembrolizumab in Bacillus Calmette-Guérin Unresponsive Non–Muscle-Invasive Bladder Cancer

Purpose: Radical cystectomy (RC) is recommended for patients with non–muscle-invasive bladder cancer (NMIBC) who are unresponsive to intravesical bacillus Calmette-Guérin (BCG) instillation. However, RC is a very risky treatment, and some patients cannot undergo RC due to old age, patient preference, and comorbidities. In this study, we investigated the efficacy of pembrolizumab, a programmed cell death protein 1 inhibitor, in patients with NMIBC unresponsive to intravesical BCG instillation.Materials and Methods: Between December 2016 and February 2023, 24 patients who experienced recurrence after BCG treatment and subsequently received pembrolizumab were enrolled. We evaluated the patients’ response to pembrolizumab therapy using urine cytology, cystoscopic examination (with/without biopsy), and/or computed tomography imaging. The primary endpoint was the complete response (CR) rate 3 months after the first dose of pembrolizumab. Patients were followed up every 3 months for the first 2 years and every 6 months thereafter. Kaplan-Meier survival analysis was used to illustrate CR and the individual treatment course was demonstrated.Results: The median follow-up period was 16 months (range, 2–68 months) and the median number of pembrolizumab administrations was 5 times (range, 3–39 times). Thirteen of the 18 patients (54.2%) with BCG-unresponsive NMIBC achieved CR at 3 months. The median duration of CR maintenance was 15 months (range, 5–47 months). Five patients (20.8%) showed no recurrence for 12 months after pembrolizumab administration. Seven patients underwent RC, and pathological reports showed T2 stage in 3 patients. To date, 1 patient (4.2%) has died.Conclusions: Our early experience with pembrolizumab treatment for BCG-unresponsive NMIBC showed better results than those of the KEYNOTE-057 trial, which reported a CR rate of 40% at 3 months. However, long-term data and more cases are required to establish pembrolizumab therapy in patients with BCG-unresponsive NMIBC in a real-world setting.

Outcomes of weight-based vs. fixed dose of Pembrolizumab among patients with non-small cell lung cancer.

This study aims to assess outcomes among patients with non-small cell lung cancer (NSCLC) who received treatment with pembrolizumab on a weight-based dose (WBD) or fixed-dose (FD) regimen using a non-inferiority (NI) analysis. This retrospective cohort study included adult patients with NSCLC weighing under 100 kg who received pembrolizumab between 1 January 2015 and 31 December 2020. Patients were grouped into either WBD or FD cohort based on the initial pembrolizumab dose and dosing regimen. The primary effectiveness outcome was overall survival (OS), analyzed using NI analysis with a lower margin of 10% comparing WBD to FD. Safety outcomes were all-cause emergency room visits or hospitalizations and incidence of selected immune-related adverse events (irAEs) and analyzed using NI analysis with an upper margin of 10%. All patients were followed until the end of health plan membership, death, or 30 June 2022, whichever occurred first. A total of 1413 patients were evaluated. OS was observed in 36.6% of the FD group, and 37.7% in the WBD group (rate difference: 1%, 90% CI: -6%-8%, NI p-value < 0.01). NI was met in all three safety outcomes: proportion of all-cause emergency room visits (rate difference: 1.1%, NI p-value < 0.01); proportion of hospitalizations (rate difference: 2%, NI p-value < 0.01); and composite incidence of irAEs (rate difference: -2.2%, NI p-value = 0.03). These findings suggest that WBD of pembrolizumab may be as appropriate as FD for the treatment of lung cancer.

Progressive multifocal leukoencephalopathy secondary to idiopathic CD4 lymphocytopenia treated with pembrolizumab

BackgroundProgressive multifocal leukoencephalopathy (PML) is a rare demyelinating disease due to a lytic infection of oligodendrocytes caused by John Cunningham polyoma virus (JCV) infection. Idiopathic CD4+ T-cell lymphocytopenia (ICL) is a very rare cause of PML. MethodsWe present an individual with PML secondary to ICL treated with 3 doses of pembrolizumab, a Programmed-Death-1 Immune Checkpoint Inhibitor following with complete resolution of symptoms and conduct a review of the literature. ConclusionThis report illustrates the objective clinical and radiological improvement in a patient with PML due to ICL and suggests further study of immune checkpoint inhibitors as potential treatment for patients with PML.