Comparative effectiveness and cost-effectiveness of natalizumab and fingolimod in rapidly evolving severe relapsing-remitting multiple sclerosis in the United Kingdom.

AIM: To evaluate the real-world comparative effectiveness and the cost-effectiveness, from a UK National Health Service perspective, of natalizumab versus fingolimod in patients with rapidly evolving severe relapsing-remitting multiple sclerosis (RES-RRMS). METHODS: Real-world data from the MSBase Registry were obtained for patients with RES-RRMS who were previously either naive to disease-modifying therapies or had been treated with interferon-based therapies, glatiramer acetate, dimethyl fumarate, or teriflunomide (collectively known as BRACETD). Matched cohorts were selected by 3-way multinomial propensity score matching, and the annualized relapse rate (ARR) and 6-month-confirmed disability worsening (CDW6M) and improvement (CDI6M) were compared between treatment groups. Comparative effectiveness results were used in a cost-effectiveness model comparing natalizumab and fingolimod, using an established Markov structure over a lifetime horizon with health states based on the Expanded Disability Status Scale. Additional model data sources included the UK MS Survey 2015, published literature, and publicly available sources. RESULTS: In the comparative effectiveness analysis, we found a significantly lower ARR for patients starting natalizumab compared with fingolimod (rate ratio [RR] = 0.65; 95% confidence interval [CI], 0.57-0.73) or BRACETD (RR = 0.46; 95% CI, 0.42-0.53). Similarly, CDI6M was higher for patients starting natalizumab compared with fingolimod (hazard ratio [HR] = 1.25; 95% CI, 1.01-1.55) and BRACETD (HR = 1.46; 95% CI, 1.16-1.85). In patients starting fingolimod, we found a lower ARR (RR = 0.72; 95% CI, 0.65-0.80) compared with starting BRACETD, but no difference in CDI6M (HR = 1.17; 95% CI, 0.91-1.50). Differences in CDW6M were not found between the treatment groups. In the base-case cost-effectiveness analysis, natalizumab dominated fingolimod (0.302 higher quality-adjusted life-years [QALYs] and £17,141 lower predicted lifetime costs). Similar cost-effectiveness results were observed across sensitivity analyses. CONCLUSIONS: This MSBase Registry analysis suggests that natalizumab improves clinical outcomes when compared with fingolimod, which translates to higher QALYs and lower costs in UK patients with RES-RRMS.

There are several medications used to treat people with relapsing remitting multiple sclerosis, such as interferon-based therapies (Betaferon/Betaseron (US), Rebif, Avonex, Extavia), glatiramer acetate (Copaxone), teriflunomide (Aubagio), and dimethyl fumarate (Tecfidera), collectively named BRACETD. Other treatments for multiple sclerosis (MS) have a narrower use, such as natalizumab (Tysabri) or fingolimod (Gilenya), among others.This study objective was to assess how well natalizumab and fingolimod helped treating MS (clinical effectiveness) and subsequently estimate what the cost of these treatments is in comparison to the benefit they bring to people with rapidly evolving severe MS that use them in the United Kingdom (UK) (cost-effectiveness).We used an international disease registry (MSBase), which collects clinical data from people with MS in various centers around the world to compare the effectiveness of natalizumab, fingolimod and BRACETD treatments. We used a technique called propensity score matching to obtain results from comparable patient groups. People treated with natalizumab had better disease control, namely with fewer relapses and higher improvement on their disability level, than patients on fingolimod or BRACETD. Conversely, there were no differences between each group of people on a measure called disability worsening.Based on these clinical results, we built an economic model that simulates the lifetime costs and consequences of treating people with MS with natalizumab in comparison with fingolimod. We found that using natalizumab was less costly and was more effective compared to using fingolimod in UK patients.

The clinical and cost impact of switching to fingolimod versus other first line injectable disease-modifying therapies in patients with relapsing multiple sclerosis.

BACKGROUND: There is limited evidence on the effectiveness and healthcare costs of switching to fingolimod versus another first line injectable therapy (FLIT) in patients with relapsing multiple sclerosis (RMS) who have already been treated with FLIT. OBJECTIVE: The objectives of the study were to assess the annualized relapse rate (ARR), socio-demographic and clinical characteristics, persistence and adherence rates, healthcare resource utilization and cost among patients with RMS who either switch to fingolimod or another FLIT in routine clinical practice. METHODS: A multicenter, observational, retrospective chart review was conducted across eight clinics in Canada between 1 May 2011 and 30 June 2013. The data was collected from two cohorts: patients who switched to fingolimod and patients who switched to FLIT from a previous FLIT. RESULTS AND CONCLUSIONS: A total of 124 patients were included in the study: 82 and 42 switched to fingolimod and FLIT, respectively. There were no significant differences in the patient characteristics at the date of switch except for number of previous disease-modifying therapies (DMTs) which was higher in the fingolimod cohort (fingolimod: 1.52; FLIT: 1.10, p < .001). The ARR during the first year of switching was numerically higher in the FLIT cohort compared to the fingolimod cohort (FLIT: 0.9 [95% CI 0.3-1.6]; fingolimod: 0.3 [95% CI 0.1-0.5]). The negative binomial model adjusted for the number of previous DMTs confirmed a statistically significant difference in ARR between the fingolimod and FLIT cohorts at 12 months of follow-up (p = .012). In the fingolimod cohort, 20.7% of patients experienced at least one relapse compared to 38.1% in the FLIT cohort. In both groups, a high proportion of patients (>90%) showed good treatment adherence (≥80% of prescribed doses).

Anti-inflammatory disease-modifying treatment and disability progression in primary progressive multiple sclerosis: a cohort study.

BACKGROUND AND PURPOSE: Treatment options in primary progressive multiple sclerosis (PPMS) are scarce and, with the exception of ocrelizumab, anti-inflammatory agents have failed to show efficacy in ameliorating disability progression. The aim of this study was to investigate a potential effect of anti-inflammatory disease-modifying treatment on disability outcomes in PPMS. METHODS: Using MSBase, a large, international, observational database, we identified patients with PPMS who were either never treated or treated with a disease-modifying agent. Propensity score matching was used to select subpopulations with similar baseline characteristics. Expanded Disability Status Scale (EDSS) outcomes were compared with an intention-to-treat and an as-treated approach in paired, pairwise-censored analyses. RESULTS: Of the 1284 included patients, 533 were matched (treated, n = 195; untreated n = 338). Median on-study pairwise-censored follow-up was 3.4 years (quartiles 1.2-5.5). No difference in the hazard of experiencing 3-month confirmed EDSS progression events was observed between the groups [hazard ratio (HR), 1.0; 95% confidence interval (CI), 0.6-1.7, P = 0.87]. We did not find significant differences in the hazards of confirmed EDSS improvement (HR, 1.0; 95% CI, 0.6-1.6, P = 0.91) or reaching a confirmed EDSS step ≥7 (HR, 1.1; 95% CI, 0.7-1.6, P = 0.69). CONCLUSION: Our pooled analysis of disease-modifying agents suggests that these therapies have no substantial effect on short- to medium-term disability outcomes in PPMS.

Risk of early relapse following the switch from injectables to oral agents for multiple sclerosis.

BACKGROUND AND PURPOSE: Early relapse outcomes in long-term stable patients switching from interferon ß/glatiramer acetate (IFNß/GA) to oral therapy are unknown. OBJECTIVE: The objective of this study was to compare early relapse and progression in multiple sclerosis (MS) patients switching to oral therapy following a period of stable disease on IFNß/GA, relative to a propensity-matched comparator of patients remaining on IFNß/GA. METHODS: The MSBase cohort study is a global, longitudinal registry for MS. Time to first 6-month relapse in previously stable MS patients switching from platform injectables ('switchers') to oral agents were compared with propensity-matched patients remaining on IFNß/GA ('stayers') using a Cox marginal model. RESULTS: Three-hundred and ninety-six switchers were successfully matched to 396 stayers on a 1:1 basis. There was no difference in the proportion of patients recording at least one relapse in the first 1-6 months by treatment arm (7.3% switchers, 6.6% stayers; P = 0.675). The mean annualized relapse rate (P = 0.493) and the rate of first 6-month relapse by treatment arm (hazard ratio 1.22, 95% confidence interval 0.70, 2.11) were also comparable. There was no difference in the rate of disability progression by treatment arm (hazard ratio 1.43, 95% confidence interval 0.63, 3.26). CONCLUSION: This is the first study to compare early relapse switch probability in the period immediately following switch to oral treatment in a population previously stable on injectable therapy. There was no evidence of disease reactivation within the first 6 months of switching to oral therapy.

BREMSO: a simple score to predict early the natural course of multiple sclerosis.

BACKGROUND AND PURPOSE: Early prediction of long-term disease evolution is a major challenge in the management of multiple sclerosis (MS). Our aim was to predict the natural course of MS using the Bayesian Risk Estimate for MS at Onset (BREMSO), which gives an individual risk score calculated from demographic and clinical variables collected at disease onset. METHODS: An observational study was carried out collecting data from MS patients included in MSBase, an international registry. Disease impact was studied using the Multiple Sclerosis Severity Score (MSSS) and time to secondary progression (SP). To evaluate the natural history of the disease, patients were analysed only if they did not receive immune therapies or only up to the time of starting these therapies. RESULTS: Data from 14 211 patients were analysed. The median BREMSO score was significantly higher in the subgroups of patients whose disease had a major clinical impact (MSSS≥ third quartile vs. ≤ first quartile, P < 0.00001) and who reached SP (P < 0.00001). The BREMSO showed good specificity (79%) as a tool for predicting the clinical impact of MS. CONCLUSIONS: BREMSO is a simple tool which can be used in the early stages of MS to predict its evolution, supporting therapeutic decisions in an observational setting.

Fluctuations of MS births and UV-light exposure.

BACKGROUND: Patients with multiple sclerosis (MS) are more frequently born in spring when compared to autumn. Fluctuation of UV-light has been hypothesized to drive this phenomenon. AIM: To assess the correlation between fluctuation of sunlight and birth season in persons with MS. METHODS: For this record-linkage study, we collected from the international MSBase and the Italian MS iMed-web databases the dates of birth of 11,415 patients with MS from 36 centres from 15 countries worldwide and compared these to dates of live-births from national registries. From all participating sites, we collected data on UV-light fluctuation and assessed its correlation with seasonal fluctuation in MS births. RESULTS: Compared with the reference cohort, an increased proportion of persons with MS were born in spring and a decreased proportion in autumn (odds ratio (OR) to be born in spring versus autumn = 1.158, χ² = 36.347, P < 0.001). There was no significantly increased fluctuation of MS births with increased quartile of ambient UV-light fluctuation (Ptrend = 0.086). CONCLUSION: Seasonal fluctuation of MS births as found in this worldwide cohort of patients with MS did not correlate with variation in seasonal fluctuation of UV-light. Most likely, it results from a complex interplay between fluctuation of sunlight, behavioural factors, other environmental factors and (epi)genetic factors.

The frequency of CSF oligoclonal banding in multiple sclerosis increases with latitude.

BACKGROUND: With the advent of MRI scanning, the value of lumbar puncture to assess oligoclonal band (OCB) status-for the diagnosis of multiple sclerosis (MS) is increasingly uncertain. One major issue is that the reported frequency of cerebrospinal fluid (CSF)-restricted oligoclonal banding for the diagnosis of MS varies considerably in different studies. In addition, the relationship between OCB positivity and disease outcome remains uncertain, as reported studies are generally too small to assess comparative disability outcomes with sufficient power. METHODS: In order to further investigate variation of OCB positivity in patients with MS, we utilized MSBase, a longitudinal, Web-based collaborative MS outcomes registry following clinical cohorts in several continents and latitudes. We also assessed whether OCB positivity affects long-term disability outcome. RESULTS: A total of 13,242 patient records were obtained from 37 MS specialist centres in 19 different countries. OCB status was documented in 4481 (34%) patients and 80% of these were OCB positive. The presence of OCB was associated with degree of latitude (p = 0.02). Furthermore, the outcome of patients negative for CSF-specific OCB was significantly better in comparison to the OCB positive patients, as assessed by Expanded Disability Status Scale change (p < 0.001). CONCLUSIONS: The results of this study indicate that latitude could explain some of the inconsistencies in OCB status reported in different populations. The study confirms that OCB positivity in MS is associated with a worse long-term prognosis.

Impact of the cognitive status on the memory complaints in MS patients.

OBJECTIVE: Despite the evidence of cognitive deficits in Multiple Sclerosis (MS) patients, evaluation of their cognitive integrity is often limited to the use of clinical interviews and questionnaires. However, the consensus in the literature is that these patients under- or overestimate their deficits and repercussions. The objective of this study was to clarify why some patients overestimate while others underestimate their memory deficits. METHOD: Fifty-four participants (30 MS, 24 controls) completed the Prospective and Retrospective Memory Questionnaire (PRMQ) and were tested on a battery of neuropsychological tests. Based on the test results, MS patients were categorized as having either mild or moderate/severe cognitive deficits. RESULTS: The moderate/severe MS group differed from the two other groups on the Rey Auditory Verbal Learning Test (RAVLT) but did not differ from the control group on the PRMQ. Conversely, the mild MS group did not differ from the control group on the RAVLT but did report significantly more problems than this group on the PRMQ. There was no difference between the two clinical groups on the Depression Index (Beck) but there was a significant correlation (r=.409) between the depression scores and the overestimation of prospective memory problems (PRMQ). CONCLUSION: The results explain the contradiction in the literature. It is the mild group who overestimates, maybe because they are overly concerned by their deficits, whereas the cognitive impairments of the moderate/severe group lead them to underestimate and may make their self-assessment unreliable. Formal testing or information from a significant other would be advisable.

Glatiramer acetate in combination with minocycline in patients with relapsing--remitting multiple sclerosis: results of a Canadian, multicenter, double-blind, placebo-controlled trial.

Minocycline is proposed as an add-on therapy to improve the efficacy of glatiramer acetate in relapsing-remitting multiple sclerosis. The effect of minocycline plus glatiramer acetate was evaluated in this double-blind, placebo-controlled study by determining the total number of T1 gadolinium-enhanced lesions at months 8 and 9 in patients who were starting glatiramer acetate and had at least one T1 gadolinium-enhanced lesion on screening magnetic resonance imaging. Forty-four participants were randomized to either minocycline 100 mg twice daily or matching placebo for 9 months as add-on therapy. They were assessed at screening and months 1, 3, 6, 8 and 9. Forty participants completed the study. Compared with glatiramer acetate/placebo, glatiramer acetate/minocycline reduced the total number of T1 gadolinium-enhanced lesions by 63% (mean 1.47 versus 2.95; p = 0.08), the total number of new and enlarging T2 lesions by 65% (mean 1.84 versus 5.14; p = 0.06), and the total T2 disease burden (p = 0.10). A higher number of gadolinium-enhanced lesions were present in the glatiramer acetate/minocycline group at baseline; this was incorporated into the analysis of the primary endpoint but makes interpretation of the data more challenging. The risk of relapse tended to be lower in the combination group (0.19 versus 0.41; p = NS). Treatment was safe and well tolerated. We conclude that efficacy endpoints showed a consistent trend favoring combination treatment. As minocycline is a relatively safe oral therapy, further study of this combination is warranted in relapsing-remitting multiple sclerosis.

Social-behavioural functioning in paediatric chronic kidney disease.

Background The social-behavioural functioning of children and adolescents with chronic kidney disease (CKD) is not well studied and not fully understood, with available studies reflecting a mixed set of findings. The primary purpose of this paper is to compare the social-behavioural functioning of children with CKD with typical controls using multiple raters. A secondary analysis also examines the impact of disease severity on social-behavioural functioning. Methods Parental ratings and self-reports on the Behavior Assessment System for Children were obtained from a patient sample of 26 children and adolescents with CKD. This sample was comprised of those with end-stage renal disease (end-stage renal disease; n= 13) and those with chronic renal insufficiency (n= 13). For comparison, a typically developing control group (n= 33) also was ascertained. Results While behaviour ratings by parents and children fell within the average range, parent ratings showed an increased number of internalizing symptoms when compared with the CKD Group. Exploratory analyses revealed parental ratings showing more specific concerns on the Behavior Assessment System for Children individual clinical scales of Anxiety, Depression and Somatization. No differences were observed between the groups on the children's self-ratings, or in terms of numbers of children falling above the 90th percentile for both parent and child ratings. Secondary analyses did not produce any group differences between the chronic renal insufficiency and end-stage renal disease severity groupings. Conclusions These findings failed to show the presence of social-behavioural difficulties in children with CKD, although there may be specific concerns for the presence of internalizing symptoms as per parent ratings. These findings suggest the need for follow-up of the subtle affective symptoms that might be present in children with CKD as recognizing these subthreshold social-behavioural symptoms may be a critical part of their overall clinical care.

A timing-of-birth effect on multiple sclerosis clinical phenotype.

BACKGROUND: A month-of-birth (MOB) effect has been shown in multiple sclerosis (MS). METHODS: Our chi(2) analyses looked at whether this MOB effect differed by MS phenotype ("bout onset," "primary progressive"). RESULTS: The MOB effect was derived from "bout onset" MS patients (May/November ratio = 1.43; chi(2) = 17.32, df = 1, p = 0.000032). CONCLUSIONS: An unspecified environmental effect in early development can influence both multiple sclerosis susceptibility and phenotype.

Randomized study of once-weekly interferon beta-1la therapy in relapsing multiple sclerosis: three-year data from the OWIMS study.

BACKGROUND: Once weekly interferon beta-1a for multiple sclerosis (OWIMS) demonstrated modest, but significant, magnetic resonance imaging (MRI) benefit of once-weekly (qw) interferon (IFN) beta-1a at 48 weeks, but no significant effect on relapses. OBJECTIVE: An OWIMS extension permitted assessment of longer-term efficacy/safety of qw IFN beta-1a in relapsing-remitting multiple sclerosis (RRMS). METHODS: Placebo patients were rerandomized to IFN beta-1a, 22 or 44 mcg qw, for two additional 48-week intervals. Primary outcome was MRI lesion activity. Relapse rate and other MRI measures were secondary outcomes. RESULTS: After three years, median (mean) T2 lesion count/patient/scan was 1.3 (2.6) for 44 mcg, 1.7 (3.3) for 22 mcg, 1.7 (3.4) for placebo/22 mcg, 2.0 (3.6) for placebo/44 mcg (all differences not significant). Annualized relapse rates were lowest for 44 mcg (0.77) versus other groups (0.83-0.86, not significant). Persistent neutralizing antibodies did not affect relapse rates, but MRI active lesions were increased in antibody-positive patients receiving 44 mcg compared to antibody negative patients. CONCLUSIONS: In RRMS, once weekly IFN beta-1a, particularly 44 mcg, can induce a significant MRI, but not relapse, effect, compared with placebo. No significant dose effect was seen. In contrast to the significant effect observed with three-times-weekly dosing of subcutaneous IFN beta-1a compared with placebo, this study confirms the lack of meaningful clinical benefit with once-weekly dosing.

The interaction of MS and pregnancy: a critical review.

Previous research on the effects of pregnancy on multiple sclerosis (MS) is somewhat flawed, and well-controlled, well-designed studies are needed to validate trial findings. In general, pregnancy appears to have a protective effect on MS course, with fewer, less severe relapses, especially in the third trimester. The exacerbation rate is increased in the first 3 months after delivery, but the overall relapse rate is no different to that observed in non-pregnant MS patients. A woman's past history of relapses may be the best indicator of clinical course during and immediately after pregnancy. Pregnancy does not appear to affect the long-term course of MS.

The immune system and hormones: review and relevance to pregnancy and contraception in women with MS.

Two-thirds of multiple sclerosis (MS) patients are women, and the average age of onset overlaps the childbearing years. Clinicians are frequently asked, therefore, about the most appropriate form of contraception and the risk of an MS relapse/exacerbation during pregnancy and the post-partum period. This paper reviews the literature on the immune system and the effects of pregnancy, oral contraceptives and hormone replacement therapy on MS.

B-cell immunity in MS.

T-cell-mediated immunity has dominated studies of multiple sclerosis (MS) pathogenesis, mainly due to detection of activated T-cells in MS lesions, and analogies with the animal model experimental allergic encephalomyelitis. The prevailing aetiological hypothesis is that MS is a multifactorial disorder, affecting individuals predisposed by a combination of susceptibility genes and environmental factors. Plaque formation is attributed to immune mechanisms, triggered by an autoimmune attack directed against antigens in the myelin membrane. This article reviews the roles of components of the immune response in MS including B-cells, the complement cascade, antibodies and genes. Evidence suggests that B-cell clonal expansion in cerebrospinal fluid and plaques of MS patients indicate an ongoing, antigen-driven response in the central nervous system. That MS is an autoimmune disease remains inconclusive, but the assumption is that humoral immunity plays a role in lesion formation and perpetuation, or is involved in tissue-repair mechanisms. The paradigm of MS as a T-cell disease must be revisited, as B-cells are involved during the initial and later disease stages, and evidence is mounting for a 'degenerative process', in addition to (and possibly even preceding) inflammation.

Persistence of immune responses to altered and native myelin antigens in patients with multiple sclerosis treated with altered peptide ligand.

Altered peptide ligands (APLs) can modulate responses of T cells to native peptide antigens implicated in the pathogenesis of autoimmune diseases. An APL of the putative target antigen myelin basic protein (MBP) peptide 83-99 has been used in abbreviated clinical trials in patients with multiple sclerosis (MS). Our objective was to assess the long-term persistence, and characteristics, of the APL-induced immune response in such patients. We measured the ex vivo proliferative frequency to the APL and native MBP, the cross-reactivity, and the cytokine production by these lines. We found that a 4- to 16-week course of APL therapy could induce a persistent (2-4.5 year) increase in the frequency of T cells responsive to both the APL and the native MBP in a select number of patients. These T cells produced high levels of IL-5, contrasting with the pretreatment observation that the responses to either antigen were IFNgamma (Th1) dominant. Our results indicate that APL therapy can induce persistent Th2-directed immune deviation. Understanding the impact of such APL-induced immune responses on MS disease activity will require additional clinical trials that incorporate careful monitoring of both clinical and immunological parameters.

Genetic susceptibility to MS: a second stage analysis in Canadian MS families.

Four published genome screens have identified a number of markers with increased sharing in multiple sclerosis (MS) families, although none has reached statistical significance. One hundred and five markers previously identified as showing increased sharing in Canadian, British, Finnish, and American genome screens were genotyped in 219 sibling pairs ascertained from the database of the Canadian Collaborative Project on Genetic Susceptibility to MS (CCPGSMS). No markers examined met criteria for significant linkage. Markers located at 5p14 and 17q22 were analyzed in a total of 333 sibling pairs and attained mlod scores of 2.27 and 1.14, respectively. The known HLA Class II DRB1 association with MS was confirmed (P<0.0001). Significant transmission disequilibrium was also observed for D17S789 at 17q22 (P=0.0015). This study highlights the difficulty of searching for genes with only mild-to-moderate effects on susceptibility, although large effects of specific loci may still be present in individual families. Future progress in the genetics of this complex trait may be helped by (1) focussing on more ethnically homogeneous samples, (2) using an increased number of MS families, and (3) using transmission disequilibrium analysis in candidate regions rather than the affected relative pair linkage analysis.

Local osmotic gradients drive the water flux associated with Na(+)/glucose cotransport.

It recently was proposed [Loo, D. D. F., Zeuthen, T., Chandy, G. & Wright, E. M. (1996) Proc. Natl. Acad. Sci. USA 93, 13367--13370] that SGLT1, the high affinity intestinal and renal sodium/glucose cotransporter carries water molecules along with the cosubstrates with a strict stoichiometry of two Na(+), one glucose, and approximately 220 water molecules per transport cycle. Using electrophysiology together with sensitive volumetric measurements, we investigated the nature of the driving force behind the cotransporter-mediated water flux. The osmotic water permeability of oocytes expressing human SGLT1 (L(p) +/- SE) averaged 3.8 +/- 0.3 x 10(-4) cm x s(-1) (n = 15) and addition of 100 microM phlorizin (a specific SGLT1 inhibitor) reduced the permeability to 2.2 +/- 0.2 x 10(-4) cm x s(-1) (n = 15), confirming the presence of a significant water permeability closely associated with the cotransporter. Addition of 5 mM alpha-methyl-glucose (alpha MG) induced an average inward current of 800 +/- 10 nA at -50 mV and a water influx reaching 120 +/- 20 pL cm(-2) x s(-1) within 5-8 min. After rapidly inhibiting the Na(+)/glucose cotransport with phlorizin, the water flux remained significantly elevated, clearly indicating the presence of a local osmotic gradient (Delta pi) estimated at 16 +/- 2 mOsm. In short-term experiments, a rapid depolarization from -100 to 0 mV in the presence of alpha MG decreased the cotransport current by 94% but failed to produce a comparable reduction in the swelling rate. A mathematical model depicting the intracellular accumulation of transported osmolytes can accurately account for these observations. It is concluded that, in SGLT1-expressing oocytes, alpha MG-dependent water influx is induced by a local osmotic gradient by using both endogenous and SGLT1-dependent water permeability.