Autologous stem-cell transplantation after second-line brentuximab vedotin in relapsed or refractory Hodgkin lymphoma.

Background: We previously demonstrated that brentuximab vedotin (BV) used as second-line therapy in patients with Hodgkin lymphoma is a tolerable and effective bridge to autologous hematopoietic cell transplantation (AHCT). Here, we report the post-AHCT outcomes of patients treated with second-line standard/fixed-dose BV and an additional cohort of patients where positron-emission tomography adapted dose-escalation of second-line BV was utilized. Patients and methods: Patients on the dose-escalation cohort received 1.8 mg/kg of BV intravenously every 3 weeks for two cycles. Patients in complete remission (CR) after two cycles received two additional cycles of BV at 1.8 mg/kg, while patients with stable disease or partial response were escalated to 2.4 mg/kg for two cycles. All patients, regardless of treatment cohort, proceeded directly to AHCT or received additional pre-AHCT therapy at the discretion of the treating physician based on remission status after second-line BV. Results: Of the 20 patients enrolled to the BV dose-escalation cohort, 8 patients underwent BV dose-escalation. BV escalation was well-tolerated, but no patients who were escalated converted to CR. Of 56 evaluable patients treated across cohorts, the overall response rate (ORR) to second-line BV was 75% with 43% CR. Twenty-eight (50%) patients proceeded directly to AHCT without post-BV chemotherapy, and a total of 50 patients proceeded to AHCT. Thirteen patients received consolidative post-AHCT therapy with either radiation, BV, or a PD-1 inhibitor. After AHCT, the 2-year progression-free survival (PFS) and overall survival were 67% and 93%, respectively. The 2-year PFS among patients in CR at the time of AHCT (n = 37) was 71% compared with 54% in patients not in CR (p = 0.12). The 2-year PFS in patients who proceeded to AHCT directly after receiving BV alone was 77%. Conclusions: Second-line BV is an effective bridge to AHCT that produces responses of sufficient depth to provide durable remission in conjunction with AHCT (clinicaltrials.gov: NCT01393717).

Conditional survival and cause-specific mortality after autologous hematopoietic cell transplantation for hematological malignancies.

The probability of survival is conventionally calculated from autologous hematopoietic cell transplantation (aHCT). Conditional survival takes into account the changing probability of survival with time survived, but this is not known for aHCT populations. We determined disease- and cause-specific conditional survival for 2388 patients treated with aHCT over a period of 20 years at a single institution. A total of 1054 deaths (44% of the cohort) were observed: 78% attributed to recurrent disease; 9% to subsequent malignancies and 6% to cardiopulmonary disease. Estimated probability of relative survival was 62% at 5 years and 50% at 10 years from aHCT. On the other hand, the 5-year relative survival was 70, 75, 81 and 88% after having survived 1, 2, 5 and 10 years after aHCT, respectively. The cohort was at a 13.9-fold increased risk of death compared with the general population (95% confidence interval (CI)=13.1-14.8). The risk of death approached that of the general population for 10-year survivors (standardized mortality ratio (SMR)=1.4, 95% CI=0.9-1.9), with the exception of female Hodgkin's lymphoma patients transplanted before 1995 at age 40 years (SMR=6.0, 95% CI=1.9-14.0). Among those who had survived 10 years, nonrelapse-related mortality rates exceeded relapse-related mortality rates. This study provides clinically relevant survival estimates after aHCT, and helps inform interventional strategies.

Inhibition of Ostwald ripening in model beverage emulsions by addition of poorly water soluble triglyceride oils.

Beverage emulsions containing flavor oils that have a relatively high water-solubility are unstable to droplet growth due to Ostwald ripening. The aim of this study was to improve the stability of model beverage emulsions to this kind of droplet growth by incorporating poorly water-soluble triglyceride oils. High pressure homogenization was used to prepare a series of 5 wt% oil-in-water emulsions stabilized by modified starch that had different lipid phase compositions (orange oil : corn oil). Emulsions prepared using only orange oil as the lipid phase were highly unstable to droplet growth during storage, which was attributed to Ostwald ripening resulting from the relatively high water-solubility of orange oil. Droplet growth could be effectively inhibited by incorporating ≥ 10% corn oil into the lipid phase prior to homogenization. In addition, creaming was also retarded because the lipid phase density was closer to that of the aqueous phase density. These results illustrate a simple method of improving the physical stability of orange oil emulsions for utilization in the food, beverage, and fragrance industries.

A phase 1 trial dose-escalation study of tipifarnib on a week-on, week-off schedule in relapsed, refractory or high-risk myeloid leukemia.

Inhibition of farnesyltransferase (FT) activity has been associated with in vitro and in vivo anti-leukemia activity. We report the results of a phase 1 dose-escalation study of tipifarnib, an oral FT inhibitor, in patients with relapsed, refractory or newly diagnosed (if over age 70) acute myelogenous leukemia (AML), on a week-on, week-off schedule. Forty-four patients were enrolled, two patients were newly diagnosed, and the rest were relapsed or refractory to previous treatment, with a median age of 61 (range 33-79). The maximum tolerated dose was determined to be 1200 mg given orally twice daily (b.i.d.) on this schedule. Cycle 1 dose-limiting toxicities were hepatic and renal. There were three complete remissions seen, two at the 1200 mg b.i.d. dose and one at the 1000 mg b.i.d. dose, with minor responses seen at the 1400 mg b.i.d. dose level. Pharmacokinetic studies performed at doses of 1400 mg b.i.d. showed linear behavior with minimal accumulation between days 1-5. Tipifarnib administered on a week-on, week-off schedule shows activity at higher doses, and represents an option for future clinical trials in AML.

The novel JAK inhibitor AZD1480 blocks STAT3 and FGFR3 signaling, resulting in suppression of human myeloma cell growth and survival.

IL-6 and downstream JAK-dependent signaling pathways have critical roles in the pathophysiology of multiple myeloma (MM). We investigated the effects of a novel small-molecule JAK inhibitor (AZD1480) on IL-6/JAK signal transduction and its biological consequences on the human myeloma-derived cell lines U266 and Kms.11. At low micromolar concentrations, AZD1480 blocks cell proliferation and induces apoptosis of myeloma cell lines. These biological responses to AZD1480 are associated with concomitant inhibition of phosphorylation of JAK2, STAT3 and MAPK signaling proteins. In addition, there is inhibition of expression of STAT3 target genes, particularly Cyclin D2. Examination of a wider variety of myeloma cells (RPMI 8226, OPM-2, NCI-H929, Kms.18, MM1.S and IM-9), as well as primary myeloma cells, showed that AZD1480 has broad efficacy. In contrast, viability of normal peripheral blood (PB) mononuclear cells and CD138(+) cells derived from healthy controls was not significantly inhibited. Importantly, AZD1480 induces cell death of Kms.11 cells grown in the presence of HS-5 bone marrow (BM)-derived stromal cells and inhibits tumor growth in a Kms.11 xenograft mouse model, accompanied with inhibition of phospho-FGFR3, phospho-JAK2, phospho-STAT3 and Cyclin D2 levels. In sum, AZD1480 blocks proliferation, survival, FGFR3 and JAK/STAT3 signaling in myeloma cells cultured alone or cocultured with BM stromal cells, and in vivo. Thus, AZD1480 represents a potential new therapeutic agent for patients with MM.

Influence of droplet charge on the chemical stability of citral in oil-in-water emulsions.

The chemical stability of citral, a flavor component widely used in beverage, food, and fragrance products, in oil-in-water emulsions stabilized by surfactants with different charge characteristics was investigated. Emulsions were prepared using cationic (lauryl alginate, LAE), non-ionic (polyoxyethylene (23) lauryl ether, Brij 35), and anionic (sodium dodecyl sulfate, SDS) surfactants at pH 3.5. The citral concentration decreased over time in all the emulsions, but the rate of decrease depended on surfactant type. After 7 d storage, the citral concentrations remaining in the emulsions were around 60% for LAE- or Brij 35-stabilized emulsions and 10% for SDS-stabilized emulsions. An increase in the local proton (H(+)) concentration around negatively charged droplet surfaces may account for the more rapid citral degradation observed in SDS-stabilized emulsions. A strong metal ion chelator (EDTA), which has previously been shown to be effective at increasing the oxidative stability of labile components, had no effect on citral stability in LAE- or Brij 35-stabilized emulsions, but it slightly decreased the initial rate of citral degradation in SDS-stabilized emulsions. These results suggest the surfactant type used to prepare emulsions should be controlled to improve the chemical stability of citral in emulsion systems.

Stability of citral in oil-in-water emulsions prepared with medium-chain triacylglycerols and triacetin.

Citral is widely used in the beverage, food, and fragrance industries for its characteristic flavor profile. However, it chemically degrades over time in aqueous solutions due to an acid-catalyzed reaction, which leads to loss of desirable flavor notes and formation of off-flavor notes. The objective of this research was to examine the impact of organic phase composition [triacetin and medium-chain triacylglycerols (MCT)] on the oil-water partitioning and chemical degradation of citral in oil-in-water emulsions. MCT was present as emulsion droplets (d approximately 900 nm), whereas triacetin was present as microemulsion droplets (d approximately 10 nm). In the absence of organic phase, the rate of citral degradation increased as the aqueous phase pH was reduced from 7 to 3. The percentage of citral within the aqueous phase increased with increasing triacetin concentration at both pH 3 and 7, which was attributed to a reduction in MCT droplet concentration. There was no significant change in the particle size distribution of the emulsions during storage, independent of triacetin concentration and pH, which indicated that they were physically stable. Both 5 wt % MCT as emulsion droplets and 5 wt % triacetin as microemulsion droplets were able to appreciably slow citral degradation at pH 3. These results may have important implications for understanding and improving the chemical stability of citral in beverage emulsions.

Comparative analysis of antisense oligonucleotide sequences for targeted skipping of exon 51 during dystrophin pre-mRNA splicing in human muscle.

Duchenne muscular dystrophy (DMD) is caused by mutations in the dystrophin gene that result in the absence of functional protein. In the majority of cases these are out-of-frame deletions that disrupt the reading frame. Several attempts have been made to restore the dystrophin mRNA reading frame by modulation of pre-mRNA splicing with antisense oligonucleotides (AOs), demonstrating success in cultured cells, muscle explants, and animal models. We are preparing for a phase I/IIa clinical trial aimed at assessing the safety and effect of locally administered AOs designed to inhibit inclusion of exon 51 into the mature mRNA by the splicing machinery, a process known as exon skipping. Here, we describe a series of systematic experiments to validate the sequence and chemistry of the exon 51 AO reagent selected to go forward into the clinical trial planned in the United Kingdom. Eight specific AO sequences targeting exon 51 were tested in two different chemical forms and in three different preclinical models: cultured human muscle cells and explants (wild type and DMD), and local in vivo administration in transgenic mice harboring the entire human DMD locus. Data have been validated independently in the different model systems used, and the studies describe a rational collaborative path for the preclinical selection of AOs for evaluation in future clinical trials.

Maintenance thalidomide following single cycle autologous peripheral blood stem cell transplant in patients with multiple myeloma.

Although autologous stem cell transplant is an effective therapy for patients with multiple myeloma and extends progression-free survival (PFS) and overall survival (OS), patients show a continued pattern of recurrent disease. Twenty-nine patients were enrolled in a phase II study investigating the tolerability and efficacy of maintenance thalidomide following single autologous peripheral blood stem cell transplant. Six to eight weeks after transplant, patients were started on maintenance thalidomide at 50 mg a day. The dose was gradually escalated to a target dose of 400 mg a day and continued until disease progression or 6 months after achieving complete remission (CR) for a maximum total duration of 18 months. At 6 months, 13 patients (45%) achieved CR or near complete remission (positive immunofixation without any evidence of disease). The estimated 2-year OS was 83% and PFS was 49%. Median tolerated dose of thalidomide was 200 mg a day. In conclusion, thalidomide as maintenance therapy is feasible and may improve outcome after single autologous stem cell transplant.

Cyclosporine and mycophenolate mofetil prophylaxis with fludarabine and melphalan conditioning for unrelated donor transplantation: a prospective study of 22 patients with hematologic malignancies.

In an attempt to decrease toxicity in high-risk patients undergoing unrelated donor hematopoietic stem cell transplantation (URD HSCT), we tested a combination of cyclosporine (CSP) and mycophenolate mofetil (MMF) as graft-versus-host disease (GVHD) prophylaxis with the reduced-intensity conditioning regimen fludarabine/melphalan (Flu/Mel). A total of 22 adult patients with advanced myeloid (n=15) and lymphoid (n=7) malignancies were treated. All patients received Flu 25 mg/m2 for 5 days and Mel 140 mg/m2, with CSP 3 mg/kg daily and MMF 15 mg/kg three times a day. The median age was 49 years (range 18-66). Durable engraftment was seen in all but one patient with myelofibrosis. The 1-year nonrelapse mortality was 32%, 27% from GVHD. The cumulative incidence of acute GVHD grade 2-4 and 3-4 was 63 and 41%, respectively. With a median follow-up of 18 months, the disease-free survival (DFS) and overall survival (OS) are 55 and 59%, respectively. For patients with AML and MDS (n=14), the DFS and OS is 71%. For patients undergoing a second transplant (n=14), the DFS and OS is 57%. In conclusion, this regimen is associated with acceptable toxicity but high rates of GVHD in high-risk patients undergoing URD HSCT. Encouraging disease control for patients with advanced myeloid malignancies was observed.

A long-term follow-up report on allogeneic stem cell transplantation for patients with primary refractory acute myelogenous leukemia: impact of cytogenetic characteristics on transplantation outcome.

The prognosis of patients with primary refractory acute myelogenous leukemia (AML) is poor. Our initial report suggested that some patients could achieve durable remission after allogeneic stem cell transplantation (SCT). Herein, we update our initial experience and report further analysis of this group of patients to determine whether there are pre-SCT prognostic factors predictive of posttransplantation relapse and survival. We reviewed the records of 68 patients who consecutively underwent transplantation at the City of Hope Cancer Center with allogeneic SCT for primary refractory AML between July 1978 and August 2000. Potential factors associated with overall survival and disease-free survival were examined. With a median follow-up of 3 years, the 3-year cumulative probabilities of disease-free survival (DFS), overall survival (OS), and relapse rate for all 68 patients were 31% (95% confidence interval [CI], 20%-42%), 30% (95% CI, 18%-41%), and 51% (95% CI, 38%-65%), respectively. In multivariate analysis, the only variables associated with shortened OS and DFS included the use of an unrelated donor as the stem cell source (relative risk, 2.23 [OS] and 2.05 [DFS]; P =.0005 and.0014, respectively) and unfavorable cytogenetics before SCT (relative risk: 1.68 [OS] and 1.58 [DFS]; P =.0107 and.0038, respectively). Allogeneic SCT can cure approximately one third of patients with primary refractory AML. Cytogenetic characteristics before SCT correlate with transplantation outcome and posttransplantation relapse.

Reduced-intensity allogeneic stem cell transplantation for patients whose prior autologous stem cell transplantation for hematologic malignancy failed.

Autologous hematopoietic stem cell transplantation (autoSCT) is an effective treatment for patients with various hematologic malignancies. Despite the significant improvement in the overall outcome, disease progression after transplantation remains the major cause of treatment failure. With longer follow-up, therapy-related myelodysplasia/acute myelogenous leukemia is becoming an important cause of treatment failure. The prognosis for these 2 groups of patients is very poor. Allogeneic hematopoietic stem cell transplantation (alloSCT) is a potential curative treatment for these patients. However, the outcome with conventional myeloablative alloSCT after failed autoSCT is typically poor because of high transplant-related mortality. In an attempt to reduce the treatment-related toxicity, we studied a reduced-intensity conditioning regimen followed by alloSCT for patients with progressive disease or therapy-related myelodysplasia/acute myelogenous leukemia after autoSCT. This report describes the outcomes of 28 patients with hematologic malignancies who received a reduced-intensity alloSCT after having treatment failure with a conventional autoSCT. Fourteen patients received a hematopoietic stem cell transplant from a related donor and 14 from an unrelated donor. The conditioning regimen consisted of low-dose (2 Gy) total body irradiation with or without fludarabine in 4 patients and the combination of melphalan (140 mg/m(2)) and fludarabine in 24. Cyclosporine and mycophenolate mofetil were used for posttransplantation immunosuppressive therapy, as well as graft-versus-host disease (GVHD) prophylaxis, in all patients. All patients engrafted and had >90% donor chimerism on day 100 after SCT. Currently, 13 patients (46%) are alive and disease free, 7 patients (25%) developed disease progression after alloSCT, and 8 (32%) died of nonrelapse causes. Day 100 mortality and nonrelapse mortality were 25% and 21%, respectively. With a median follow-up of 24 months for surviving patients, the 2-year probabilities of overall survival, event-free survival, and relapse rates were 56.5%, 41%, and 41.9%, respectively. Six patients (21%) developed grade III to IV acute GVHD. Among 21 evaluable patients, 15 (67%) developed chronic GVHD. We conclude that (1) reduced-intensity alloSCT is feasible and has an acceptable toxicity profile in patients who have previously received autoSCT and that (2) although follow-up was short, a durable remission may be achieved in some patients who would otherwise be expected to have a poor outcome.

High frequency of pro-B acute lymphoblastic leukemia in adults with secondary leukemia with 11q23 abnormalities.

To evaluate the frequency and cytogenetic and immunophenotypic features of therapy-related, precursor B-cell acute lymphoblastic leukemia (ALL), 152 cases of immature B-cell ALL were reviewed. These were compared to the frequency of therapy-related acute myeloid leukemia (t-AML) during the same time period. Eight ALL cases with a prior diagnosis of malignancy were identified, including six (4.0%) with prior therapy considered to be therapy-related ALL (t-ALL). The t-ALL cases followed treatment for breast carcinoma (two cases), lung carcinoma (two cases), lymphocyte predominance Hodgkin's disease and follicular lymphoma with a latency period of 13 months to 8 years. All t-ALL cases had a pro-B (CD10-negative) immunophenotype with significantly higher expression of CD15 and CD65, compared to the de novo CD10-positive ALL cases. All six t-ALL cases had MLL abnormalities by fluorescence in situ hybridization, and four showed t(4;11)(q21;q23). These represented half of all 11q23-positive adult ALL cases. During the same time period, 4.9% of all AML cases were considered t-AML. There was a 16.7% frequency of 11q23 abnormalities in the t-AML group. Despite the similar frequency in therapy-related disease among ALL and AML cases, there were differences in the frequency of the diseases and t-ALL represented 12% of all therapy-related leukemias. However, t-ALL represented 46% of all 11q23-positive therapy-related leukemias. The immunogenetic features of t-ALL appear distinct and may aid in identifying more cases of this disease type in the future.

Analysis of mismatch repair defects in the familial occurrence of lymphoma and colorectal cancer.

Hereditary non-polyposis colon cancer (HNPCC) is an autosomal dominant disorder featuring familial clustering of colorectal and/or endometrial cancer, and other malignancies. Except for a rare case report, Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL) have not been considered part of HNPCC. Recent murine models for HNPCC have shown an increased incidence of B- and T-cell lymphoma, as well as tumors of the gastrointestinal tract and other organ systems, involving defects in genes resulting in faulty mismatch repair (MMR) of DNA. These MMR genes include MLH1, MSH2, MSH3, MSH6, PMS1 and PMS2. We sought to analyze the occurrence of NHL and HD in families with clusters of colorectal cancers (CRC). Probands from 21 kindreds were classified as HNPCC (3), HNPCC-like (5), and HNPCC-variant (13); seen and followed by Clinical Genetics at Memorial Hospital the kindreds were assessed for the occurrence of NHL or HD. Of the 21 pedigrees, a total of 37 patients were identified who were diagnosed with leukemia, lymphoma, or HD. Fourteen of the 37 patients with a diagnosis of NHL or HD were further classified and showed varying histologies ranging from chronic lymphocytic leukemia/small lymphocytic lymphoma (2), mycosis fungoides (1), follicular lymphoma (1), extranodal marginal zone lymphoma of MALT type (2), diffuse large B-cell lymphoma (4), nodular sclerosis HD (3), and mixed cellularity HD (1). Microsatellite instability studies were performed on 6 cases but none showed evidence of replication error repair defects. Immunohistochemical stains performed on paraffin sections from these 6 representative cases showed differential protein expression of MLH1, MSH2, MSH6, and PMS2 when compared to normal reactive tissues from the same patient but showed no significant differences when compared to controls of non-familial, sporadic lymphomas. These results suggest that lymphomas arising in the setting of familial CRC do not bear the molecular hallmarks of HNPCC. Further studies are needed to explain the differential patterns of expression of RER-associated proteins in lymphomas, as well as the association of lymphomas and possibly renal cell cancers in a subset of kindreds in which CRC clustering is evident.

Is there an upper age limit for bone marrow transplantation?

Advances in hematopoietic cell transplantation have reduced the toxicity of both allogeneic and autologous transplantation. Decisions regarding the feasibility of transplantation should be individualized, and based upon physiological rather than chronological age.

NUP98 gene rearrangements and the clonal evolution of chronic myelogenous leukemia.

The role of the BCR-ABL fusion gene in the pathogenesis of the chronic phase of chronic myelogenous leukemia (CML) has been well established. Several additional genetic changes have been reported to occur, at varying frequencies, during disease progression to "accelerated" and "blast crisis" phases. The NUP98 gene localized to chromosome band 11p15 has been found at the breakpoints of several distinct chromosomal translocations in patients with both de novo and therapy-related myelodysplastic syndromes (MDS) and acute myelogenous leukemia (AML). Using combined cytogenetic and molecular analyses, we have found rearrangements of the NUP98 gene in the leukemic cells of two patients with Philadelphia chromosome-positive CML, during disease evolution. As expected, analysis of the t(7;11)(p15;p15) from one of the patients showed an in-frame NUP98-HOXA9 fusion. The fusion points were similar to previously reported NUP98-HOXA9 fusion points from patients with MDS/AML. Our results indicate that the NUP98 gene is an additional, albeit infrequent, genetic target during clonal evolution of CML.

Hematopoietic stem cell transplantation in the new millennium: report from City of Hope National Medical Center.

Progress in the in the field of human stem cell transplantation (HSCT) has led to a reduction in transplant-related toxicities and an improvement in survival rates. In the allogeneic setting, conditioning regimens containing FTBI and high dose VP-16 produce high rates of long-term progression-free survival in patients with AML and ALL. Because of more rapid engraftment, peripheral blood stem cells are increasingly being used for allogeneic HSCT, however, longer follow-up will be required to determine whether there are differences in overall survival and long-term complications such as chronic graft-versus host disease (GVHD). Results of autologous transplantation for acute leukemias are improving as new strategies are used to decrease the risk of relapse. For diffuse aggressive NHL, high-dose therapy and autologous HSCT has been established as a potentially curative therapy when performed at the time of relapse or as part of the frontline treatment in selected patients with poor prognostic features at presentation. Patients with HIV-associated NHL may also benefit from autologous HSCT. In other subtypes of NHL such as mantle cell lymphoma and low-grade lymphoma, the curative potential of autologous transplantation is less certain and the graft-versus-lymphoma effect which can be seen in allogeneic HSCT may be required for cure of these histologic subtypes. Our current research efforts focus on reducing the risk of relapse as well as acute and long-term complications.

Allogeneic hematopoietic stem cell transplantation for acute leukemia, chronic leukemia, and myelodysplasia.

More than 20,000 patients have survived 5 or more years after allogeneic transplantation, and the number of allogeneic transplantations performed each year continues to increase rapidly. The indications for allogeneic bone marrow transplantation are beginning to change as research continues on the use of transplantation to treat genetic diseases. This article focuses on the use of allogeneic bone marrow transplantation for the treatment of hematologic malignancies, including acute myelogenous leukemia, chronic myelogenous leukemia, acute lymphoblastic leukemia, myelodysplastic syndrome, and chronic lymphocytic leukemia.

Dystrophic phenotype induced in vitro by antibody blockade of muscle alpha-dystroglycan-laminin interaction.

alpha-dystroglycan is a glycoprotein expressed on the surface of skeletal muscle fibres and other cell types. In muscle, alpha-dystroglycan provides a link between the myofibre cytoskeleton through its indirect binding to dystrophin, and the basal lamina through its binding to laminin-2, a protein of the extracellular matrix. The disruption of this linkage between the myofibre cytoskeleton and the extracellular matrix is a common feature of Duchenne and other muscular dystrophies, though the pathogenic mechanisms leading to muscle wasting remain unknown. By treating primary mouse muscle cultures with a monoclonal antibody which blocks alpha-dystroglycan binding to laminin, we show here the induction of a dystrophic phenotype in vitro. The phenotype is inducible in differentiated cultures only, is characterised by reduced myotube size, myofibril disorganisation, loss of contractile activity, reduced spontaneous clustering of acetylcholine receptors and is reversed by addition of excess exogenous laminin-2. Thus, alpha-dystroglycan may be part of a signalling pathway for the maturation and maintenance of skeletal myofibres. Detailed knowledge of this signalling pathway may provide insights into the molecular pathology of the various inherited muscular dystrophies, and identify valuable pharmacological targets and new therapeutic strategies.