In vitro PK/PD modeling of tyrosine kinase inhibitors in non-small cell lung cancer cell lines.

Tyrosine kinase inhibitors (TKIs) are routinely prescribed for the treatment of non-small cell lung cancer (NSCLC). As with all medications, patients can experience adverse events due to TKIs. Unfortunately, the relationship between many TKIs and the occurrence of certain adverse events remains unclear. There are limited in vivo studies which focus on TKIs and their effects on different regulation pathways. Many in vitro studies, however, that investigate the effects of TKIs observe additional changes, such as changes in gene activations or protein expressions. These studies could potentially help to gain greater understanding of the mechanisms for TKI induced adverse events. However, in order to utilize these pathways in a pharmacokinetic/pharmacodynamic (PK/PD) framework, an in vitro PK/PD model needs to be developed, in order to characterize the effects of TKIs in NSCLC cell lines. Through the use of ordinary differential equations, cell viability data and nonlinear mixed effects modeling, an in vitro TKI PK/PD model was developed with estimated PK and PD parameter values for the TKIs alectinib, crizotinib, erlotinib, and gefitinib. The relative standard errors for the population parameters are all less than 25%. The inclusion of random effects enabled the model to predict individual parameter values which provided a closer fit to the observed response. It is hoped that this model can be extended to include in vitro data of certain pathways that may potentially be linked with adverse events and provide a better understanding of TKI-induced adverse events.

Sendaway capillary NT-proBNP in pulmonary hypertension.

BACKGROUND: N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a biomarker of cardiac ventricular wall stress that is incorporated into pulmonary hypertension (PH) risk stratification models. Sendaway sampling may enable patients to perform NT-proBNP tests remotely. This UK-wide study aimed to assess the agreement of sendaway NT-proBNP with standard venous NT-proBNP and to assess the effect of delayed processing. METHODS: Reference venous NT-proBNP was collected from PH patients. Samples for capillary and venous sendaway tests were collected contemporaneously, mailed to a reference laboratory and processed at 3 and 7 days using a Roche Cobas e411 device. Differences in paired measurements were analysed with Passing-Bablok regression, percentage difference plots and the % difference in risk strata. RESULTS: 113 patients were included in the study. 13% of day 3 capillary samples were insufficient. Day 3 capillary samples were not equivalent to reference samples (Passing Bablok analysis slope of 0.91 (95% CI 0.88 to 0.93) and intercept of 6.0 (95% CI 0.2 to 15.9)). The relative median difference was -7% and there were acceptable limits of agreement. Day 3 capillary NT-proBNP accurately risk stratified patients in 93.5% of cases. By comparison, day 3 venous results accurately risk stratified patients in 90.1% of cases and were equivalent by Passing-Bablok regression. Delayed sampling of sendaway tests led to an unacceptable level of agreement and systematically underestimated NT-proBNP. CONCLUSIONS: Sendaway NT-proBNP sampling may provide an objective measure of right ventricular strain for virtual PH clinics. Results must be interpreted with caution in cases of delayed sampling.

Pulmonary Embolism (PE) to Chronic Thromboembolic Pulmonary Disease (CTEPD): Findings from a Survey of UK Physicians.

Chronic thromboembolic pulmonary disease (CTEPD) is a complication of pulmonary embolism (PE). We conducted an online survey of UK PE-treating physicians to understand practices in the follow-up of PE and awareness of CTEPD. The physicians surveyed (N = 175) included 50 each from cardiology, respiratory and internal medicine, plus 25 haematologists. Most (89%) participants had local guidelines for PE management, and 65% reported a PE follow-up clinic, of which 69% were joint clinics. Almost half (47%) had a protocol for the investigation of CTEPD. According to participants, 129 (74%) routinely consider a diagnosis of CTEPD and 97 (55%) routinely investigate for CTEPD, with 76% of those 97 participants investigating in patients who are symptomatic at 3 months and 22% investigating in all patients. This survey demonstrated variability in the follow-up of PE and the awareness of CTEPD and its investigation. The findings support the conduct of a national audit to understand the barriers to the timely detection of CTEPD.

Attitudes to Male Homosexuality Within the British Medical Association in the 1950s.

The British Government appointed a departmental committee to review anti-homosexuality laws in 1954 following a marked increase in the number of arrests for homosexuality after World War II. The committee invited the British Medical Association (BMA) and other institutions to provide scientific and medical evidence relating to homosexuality. In 1954, the BMA established the Committee on Homosexuality and Prostitution to present its view on how the law impacted upon homosexuals and society. This paper analyses the BMA's attitudes to homosexuality by examining its submission to the Departmental Committee. Whilst the BMA supported implicitly the decriminalization of certain homosexual acts, it remained strongly opposed to homosexuality from a moral perspective and insisted that it was an illness. It is concluded that the BMA's submission was driven primarily by a desire to control the "unnatural deviant" behavior of homosexuals and to protect society from that behavior rather than to protect homosexuals.

Longitudinal Circulating Tumor DNA Modeling to Predict Disease Progression in First-Line Mutant Epidermal Growth Factor Receptor Non-Small Cell Lung Cancer.

This exploratory, post hoc analysis aimed to model circulating tumor DNA (ctDNA) dynamics and predict disease progression in patients with treatment-naïve locally advanced/metastatic epidermal growth factor receptor mutation (EGFRm)-positive non-small cell lung cancer, from the FLAURA trial (NCT02296125). Patients were randomized 1:1 and received osimertinib 80 mg once daily (q.d.) or comparator EGFR-TKIs (gefitinib 250 mg q.d. or erlotinib 150 mg q.d.). Plasma was collected at baseline and multiple timepoints until treatment discontinuation. Patients with Response Evaluation Criteria in Solid Tumors (RECIST) imaging data and detectable EGFR mutations (Ex19del/L858R) at baseline and ≥ 3 additional timepoints were evaluable. Joint modeling was conducted to characterize the relationship between longitudinal changes in ctDNA and probability of progression-free survival (PFS). A Bayesian joint model of ctDNA and PFS was developed solving differential equations with the ctDNA dynamics and the PFS time-to-event probability. Of 556 patients, 353 had detectable ctDNA at baseline. Evaluable patients (with available imaging and ≥ 3 additional timepoints, n = 320; ctDNA set) were divided into training (n = 259) and validation (n = 61) sets. In the validation set, the model predicted a median PFS of 17.7 months (95% confidence interval (CI): 11.9-28.3) for osimertinib (n = 23) and 9.1 months (95% CI: 6.3-14.8) for comparator (n = 38), consistent with observed RECIST PFS (16.4 months and 9.7, respectively). The model demonstrates that EGFRm ctDNA dynamics can predict the risk of disease progression in this patient population and could be used to predict RECIST-defined disease progression.

Study of heart function in PRE-Eclampsia during and after PreGnancy (SHePREG): The pilot cohort.

BACKGROUND: Pre-eclampsia with severe features (severe PreE) is associated with heart dysfunction, yet the impact beyond pregnancy, including its association with cardiomyopathic genetic polymorphisms, remains poorly understood. OBJECTIVE: We aimed to characterize the temporal impact of severe PreE on heart function through the 4th trimester in women with and without deleterious cardiomyopathic genetic variants. METHODS: Pregnant women were enrolled to undergo transthoracic echocardiography (TTE) in late pregnancy and 3 months postpartum. In women with severe PreE a targeted approach to identify pathogenic cardiomyopathic genetic polymorphisms was undertaken, and heart function was compared in carriers and noncarriers. RESULTS: Pregnant women (32 ± 4 years old, severe PreE = 14, control = 8) were enrolled between 2019 - 2021. Women with severe PreE displayed attenuated myocardial relaxation (mitral e' = 11.0 ± 2.2 vs 13.2 ± 2.3 cm/sec, P < .05) in late pregnancy, and on in-silico analysis, deleterious cardiomyopathic variants were found in 58%. At 103 ± 33 days postpartum, control women showed stability in myocardial relaxation (Mitral e' Entry: 13.2 ± 2.3 vs Postpartum: 13.9 ± 1.7cm/sec, P = .464), and genetic negative severe PreE women (G-) demonstrated recovery of diastolic function to control level (Mitral e' Entry: 11.0 ± 3.0 vs Postpartum 13.7 ± 2.8cm/sec, P < .001), unlike their genetic positive (G+) counterparts (Mitral e' Entry: 10.5 ± 1.7 vs Postpartum 10.8 ± 2.4cm/sec, P = .853). CONCLUSIONS: Postpartum recovery of heart function after severe PreE is attenuated in women with deleterious cardiomyopathic genetic polymorphisms.

The History of Flow Chemistry at Eli Lilly and Company.

Flow chemistry was initially used for speed to early phase material delivery in the development laboratories, scaling up chemical transformations that we would not or could not scale up batch for safety reasons. Some early examples included a Newman Kwart Rearrangement, Claisen rearrangement, hydroformylation, and thermal imidazole cyclization. Next, flow chemistry was used to enable safe scale up of hazardous chemistries to manufacturing plants. Examples included high pressure hydrogenation, aerobic oxidation, and Grignard formation reactions. More recently, flow chemistry was used in Small Volume Continuous (SVC) processes, where highly potent oncolytic molecules were produced by fully continuous processes at about 10 kg/day including reaction, extraction, distillation, and crystallization, using disposable equipment contained in fume hoods.

Remote exercise testing in pulmonary hypertension (PHRET).

Remote exercise tests for patients with pulmonary hypertension (PH) would improve the telemedicine strategies in this disease. The PHRET study assessed the validity and feasibility of four remote exercise tests performed by PH patients at home. Participants undergoing diagnostic assessment for PH were included. At baseline, patients completed a 6MWT followed by a range of study tests including a Timed Up and Go (TUG) test, a Sit-to-Stand (STS), a Step Test (ST), and a tele-6MWT (T6MWT) performed outside using a GPS-enabled smartphone. Patients performed these tests at home following discharge and at first follow-up. Analysis focused on comparing the results of study tests to the standard 6MWT. The discontinuation rate was 15%. Ninety-seven percent of patients were able to complete a TUG, 92% a STS, 73% a ST, and 49% a T6MWT. At baseline, correlation between the standard 6MWT and study tests, respectively, was T6MWT 0.93, ST 0.78, STS 0.71, and TUG -0.76 (p < 0.001). Direction of change in the study test agreed with the standard 6MWT in 68% of the follow-up ST, 68% of the STS, 71% of the TUG, and 79% of the T6MWT. Patients were able to complete the tests at home, there were no adverse incidents and ≥92% of patients were happy to continue performing home tests. Remote exercise testing is feasible. The T6MWT was a valid remote measure of exercise capacity, but could only be performed by a limited number of patients. The high discontinuation rate may impact the utility of remote tests.

Management of trigeminal neuralgia: A multi-centre case study in general practice.

Background and aims: Patients often first present with symptoms of trigeminal neuralgia (TN) to primary care. However, there has been little research to determine whether the diagnosis and management of this condition is carried out according to current guidelines. Furthermore, there is little up-to-date information regarding the prevalence of TN in the UK. The aim is to estimate the prevalence of TN and to audit the diagnosis and management process of TN in primary care. Methods: Between 2019 and 2020 a search was made at five UK GP practices with a total patient population of 55,842 using EMIS and SystmOne patient record systems to review patient consultations to identify patients coded with TN or facial pain (FP). These records were reviewed to ascertain the basis for diagnosis, management in primary care and referral to secondary care. Results: 157 patients were identified; 54 coded with FP and 103 with TN. These results indicate a prevalence of 22.3 in 10,000. There was no difference in documented symptoms between the two groups. Seven patients had all ICDH3 criteria recorded, with two meeting the requirements for TN diagnosis. 58.8% of patients with TN were started on carbamazepine, the current gold standard treatment, compared with 16.7% in the FP group. 38.2% of TN patients were referred to a range of different specialities. Conclusion: The prevalence of TN may be higher than previously thought. Key diagnostic criteria are often omitted, leading to potential misdiagnosis or delays in diagnosis. Relatively few referrals are made, though all patients should be considered for imaging.

Loss of STIM2 in colorectal cancer drives growth and metastasis through metabolic reprogramming and PERK-ATF4 endoplasmic reticulum stress pathway.

The endoplasmic reticulum (ER) stores large amounts of calcium (Ca2+), and the controlled release of ER Ca2+ regulates a myriad of cellular functions. Although altered ER Ca2+ homeostasis is known to induce ER stress, the mechanisms by which ER Ca2+ imbalance activate ER stress pathways are poorly understood. Stromal-interacting molecules STIM1 and STIM2 are two structurally homologous ER-resident Ca2+ sensors that synergistically regulate Ca2+ influx into the cytosol through Orai Ca2+ channels for subsequent signaling to transcription and ER Ca2+ refilling. Here, we demonstrate that reduced STIM2, but not STIM1, in colorectal cancer (CRC) is associated with poor patient prognosis. Loss of STIM2 causes SERCA2-dependent increase in ER Ca2+, increased protein translation and transcriptional and metabolic rewiring supporting increased tumor size, invasion, and metastasis. Mechanistically, STIM2 loss activates cMyc and the PERK/ATF4 branch of ER stress in an Orai-independent manner. Therefore, STIM2 and PERK/ATF4 could be exploited for prognosis or in targeted therapies to inhibit CRC tumor growth and metastasis.

Retrospective Data Analysis of the Use of an Autologous Multilayered Leukocyte, Platelet, and Fibrin Patch for Diabetic Foot Ulcers Treatment in Daily Clinical Practice.

OBJECTIVE: To describe the healing outcome of chronic, hard-to-heal diabetic foot ulcers (DFUs) treated with an autologous multilayered leukocyte, platelet, and fibrin (MLPF) patch in addition to the best standard of care, in a real-world clinical setting of two US amputation preventive centers. METHODS: In this retrospective study of patients treated between September 2021 and October 2022, the authors analyzed DFU healing outcomes based on Wound, Ischemia, and foot Infection-derived amputation risk. RESULTS: All 36 patients had a diagnosis of type 2 diabetes and 29 (81%) were male. Their average age was 61.4 years, body mass index was 29.2 kg/m2, and glycated hemoglobin was 7.9. Twenty-seven patients (78%) were diagnosed with peripheral vascular disease, 20 (56%) underwent a peripheral vascular procedure, 15 (42%) had a prior amputation, and 6 (17%) were on hemodialysis. Average wound size was 4.9 cm2, and wound age was 9.5 months. Twelve patients (32%) were classified as low risk, 15 (39%) as moderate risk, and 11 (29%) as high risk for amputation. Within 12 weeks of the first MLPF patch application, nine wounds (24%) healed. After 20 weeks, 23 wounds (61%) were closed, and by follow-up, 30 wounds (79%) healed. No amputations were noted. Compared with published data, 40% fewer patients underwent readmission within 30 days, with 72% shorter admission duration. CONCLUSIONS: Real-world clinical experiences using the MLPF patch to treat hard-to-heal DFUs resulted in the majority of wounds healing. Few patients experienced a readmission within 30 days, and the average admission duration was short.

Predictors of outcomes in mild pulmonary hypertension according to 2022 ESC/ERS Guidelines: the EVIDENCE-PAH UK study.

BACKGROUND AND AIMS: Interventional studies in pulmonary arterial hypertension completed to date have shown to be effective in symptomatic patients with significantly elevated mean pulmonary artery pressure (mPAP) (≥25 mmHg) and pulmonary vascular resistance (PVR) > 3 Wood Unit (WU). However, in health the mPAP does not exceed 20 mmHg and PVR is 2 WU or lower, at rest. The ESC/ERS guidelines have recently been updated to reflect this. There is limited published data on the nature of these newly defined populations (mPAP 21-24 mmHg and PVR >2-≤3 WU) and the role of comorbidity in determining their natural history. With the change in guidelines, there is a need to understand this population and the impact of the ESC/ERS guidelines in greater detail. METHODS: A retrospective nationwide evaluation of the role of pulmonary haemodynamics and comorbidity in predicting survival among patients referred to the UK pulmonary hypertension (PH) centres between 2009 and 2017. In total, 2929 patients were included in the study. Patients were stratified by mPAP (<21 mmHg, 21-24 mmHg, and ≥25 mmHg) and PVR (≤2 WU, > 2-≤3 WU, and >3 WU), with 968 (33.0%) in the mPAP <21 mmHg group, 689 (23.5%) in the mPAP 21-24 mmHg group, and 1272 (43.4%) in the mPAP ≥25 mmHg group. RESULTS: Survival was negatively correlated with mPAP and PVR in the population as a whole. Survival in patients with mildly elevated mPAP (21-24 mmHg) or PVR (>2-≤3WU) was lower than among those with normal pressures (mPAP <21 mmHg) and normal PVR (PVR ≤ 2WU) independent of comorbid lung and heart disease [hazard ratio (HR) 1.36, 95% confidence interval (CI) 1.14-1.61, P = .0004 for mPAP vs. HR 1.28, 95% CI 1.10-1.49, P = .0012 for PVR]. Among patients with mildly elevated mPAP, a mildly elevated PVR remained an independent predictor of survival when adjusted for comorbid lung and heart disease (HR 1.33, 95% CI 1.01-1.75, P = .042 vs. HR 1.4, 95% CI 1.06-1.86, P = .019). 68.2% of patients with a mPAP 21-24 mmHg had evidence of underlying heart or lung disease. Patients with mildly abnormal haemodynamics were not more symptomatic than patients with normal haemodynamics. Excluding patients with heart and lung disease, connective tissue disease was associated with a poorer survival among those with PH. In this subpopulation evaluating those with a mPAP of 21-24 mmHg, survival curves only diverged after 5 years. CONCLUSIONS: This study supports the change in diagnostic category of the ESC/ERS guidelines in a PH population. The newly included patients have an increased mortality independent of significant lung or heart disease. The majority of patients in this new category have underlying heart or lung disease rather than an isolated pulmonary vasculopathy. Mortality is higher if comorbidity is present. Rigorous phenotyping will be pivotal to determine which patients are at risk of progressive vasculopathic disease and in whom surveillance and recruitment to studies may be of benefit. This study provides an insight into the population defined by the new guidelines.

The MRC Dyspnoea Scale and mortality risk prediction in pulmonary arterial hypertension: A retrospective longitudinal cohort study.

Risk stratification models in pulmonary arterial hypertension (PAH) rely on World Health Organisation Functional Class (WHO FC). A high proportion of patients are classified as WHO FC III, a heterogenous group which limits the stratification abilities of risk models. The Medical Research Council (MRC) Dyspnoea Scale may allow a more precise assessment of functional status and improve current risk models. We investigated the ability of the MRC Dyspnoea Scale to assess survival in PAH and compared performance to WHO FC and the COMPERA 2.0 models. Patients with Idiopathic, Hereditary or Drug-induced PAH who were diagnosed between 2010 and 2021 were included. The MRC Dyspnoea Scale was retrospectively applied as derived from a combination of patient notes, 6MWD tests results and WHO functional status using a purpose-designed algorithm. Survival was assessed using Kaplan-Meier analyses, log rank testing and Cox proportional hazard ratios. Model performance was compared with Harrell's C Statistic. Data from 216 patients were retrospectively analyzed. At baseline, of 120 patients classified as WHO FC III, 8% were MRC Dyspnoea Scale 2, 12% Scale 3, 71% Scale 4 and 10% Scale 5. The MRC Dyspnoea Scale performed well compared to the WHO FC and COMPERA models at follow up (respectively, C-statistic 0.74 vs. 0.69 vs. 0.75). It was possible to use the MRC Dyspnoea Scale to subdivide patients in WHO FC III into groups which had distinct survival estimates. We conclude that at follow-up, the MRC Dyspnoea Scale may be a valid tool for the assessment of risk stratification in pulmonary arterial hypertension.

Quantitative Global Survey Results of Acute Back Pain Sufferers Across Four Countries.

Background: Surveys of back pain sufferers in the United States, China, Russia, and Germany were performed to better understand self-reported causes of acute nonspecific back pain and acute lower back pain among individuals engaging in sports and their preferred treatments. Methods: In each country, 1000 participants were surveyed (Step 1) to identify a population of nonspecific acute back pain sufferers, understand pain and treatment characteristics, and generate profiles for individuals with long-lasting (≥7 days) acute lower back pain. Subsequently, 200 participants with acute lower back pain episodes (7-21 days) and sports participation were identified in each country and completed surveys (Step 2) about sociodemographic, pain, treatment characteristics, and causes/triggers of long-lasting acute lower back pain episodes. Results: In the United States, China, Russia, and Germany, respectively, 59%, 49%, 61%, and 63% of respondents reported ≥1 episode of nonspecific acute back pain in the previous 6 months. Average numbers of monthly nonspecific acute back pain episodes in the United States, Russia, Germany, and China were 2.5, 1.8, 1.3, and 0.8, respectively. Prevalence of acute lower back pain associated with sports/leisure activities ranged from 20% (Russia and Germany) to 46% (China). Onset of long-lasting acute lower back pain was between ages 30 and 33 years, limiting usual activities and reducing walking distance in 60% to 85% of respondents across all countries. Acute lower back pain started post-exercise within the first day for ≥75% of respondents. Most popular nonprescription and prescription treatments for acute lower back pain were creams/gels in Russia, creams/gels and oral painkillers in Germany, oral painkillers in the United States, and hot/cold patches in China. Conclusion: These results help to better understand acute back pain triggers, features, and treatment preferences among sports participants in different countries. Further research is warranted to develop preventative strategies. Trial Registration: Not applicable.

Orai3 and Orai1 mediate CRAC channel function and metabolic reprogramming in B cells.

The essential role of store-operated Ca2+ entry (SOCE) through Ca2+ release-activated Ca2+ (CRAC) channels in T cells is well established. In contrast, the contribution of individual Orai isoforms to SOCE and their downstream signaling functions in B cells are poorly understood. Here, we demonstrate changes in the expression of Orai isoforms in response to B cell activation. We show that both Orai3 and Orai1 mediate native CRAC channels in B cells. The combined loss of Orai1 and Orai3, but not Orai3 alone, impairs SOCE, proliferation and survival, nuclear factor of activated T cells (NFAT) activation, mitochondrial respiration, glycolysis, and the metabolic reprogramming of primary B cells in response to antigenic stimulation. Nevertheless, the combined deletion of Orai1 and Orai3 in B cells did not compromise humoral immunity to influenza A virus infection in mice, suggesting that other in vivo co-stimulatory signals can overcome the requirement of BCR-mediated CRAC channel function in B cells. Our results shed important new light on the physiological roles of Orai1 and Orai3 proteins in SOCE and the effector functions of B lymphocytes.

Development challenges in challenging contexts: A 3-stage curriculum framework design approach for Education in Emergencies.

There is a pressing need to develop processes to facilitate the organization of education responses in time-pressured emergency situations. As part of a joint Learning Passport (LP) partnership project with UNICEF, researchers along with curriculum and subject specialists at the University of Cambridge, UK, developed a curriculum framework that could be used as a resource for coordinating the actions of education specialists and practitioners in Education in Emergencies (EiE) situations. This article outlines the curriculum framework design approach they developed for the Maths and Science components of the LP framework. The article outlines a three-stage curriculum framework development model, which involves consideration of context, leading to descriptor generation, and attending to cohesion building elements.

Mechanistic Study of Diketopiperazine Formation during Solid-Phase Peptide Synthesis of Tirzepatide.

This study focused on investigating diketopiperazine (DKP) and the formation of associated double-amino-acid deletion impurities during linear solid-phase peptide synthesis (SPPS) of tirzepatide (TZP). We identified that the DKP formation primarily occurred during the Fmoc-deprotection reaction and post-coupling aging of the unstable Fmoc-Pro-Pro-Ser-resin active pharmaceutical ingredient (API) intermediate. Similar phenomena have also been observed for other TZP active pharmaceutical ingredient (API) intermediates that contain a penultimate proline amino acid, such as Fmoc-Ala-Pro-Pro-Pro-Ser-resin, Fmoc-Pro-Pro-Pro-Ser-resin, and Fmoc-Gly-Pro-Ser-Ser-Gly-Ala-Pro-Pro-Pro-Ser-resin, which are intermediates for both hybrid and linear synthesis approaches. During post-coupling aging, it is found that Fmoc deprotection can proceed in dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), and acetonitrile (ACN) solvents without any piperidine addition. Density functional theory (DFT) calculations showed that a peptide that has a penultimate proline stabilizes the transition state through the C-H···π interaction during Fmoc decomposition, which causes those peptides to be more prone to cascade-deprotection reactions. Pseudo-reaction pathways are then proposed, and a corresponding macrokinetics model is developed to allow accurate prediction of the TZP peptide intermediate self-deprotection and DKP formation rate. Based on those studies, control strategies for minimizing DKP formation were further investigated and an alternative to Fmoc protection was identified (Bsmoc-protected amino acids), which eliminated the formation of the DKP byproducts. In addition, the use of oxyma additives and lower storage temperature was demonstrated to markedly improve the peptide intermediate stability to DKP degradation pathways.