The Double Antibody Drug Conjugate (DAD) phase I trial: sacituzumab govitecan plus enfortumab vedotin for metastatic urothelial carcinoma

BACKGROUND

The antibody-drug conjugates sacituzumab govitecan (SG) and enfortumab vedotin (EV) are standard monotherapies for metastatic urothelial carcinoma (mUC). Given the different targets and payloads, we evaluated the safety and efficacy of SG + EV in a phase I trial in mUC (NCT04724018).

PATIENTS AND METHODS

Patients with mUC and Eastern Cooperative Oncology Group performance status ≤1 who had progressed on platinum and/or immunotherapy were enrolled. SG + EV were administered on days 1 + 8 of a 21-day cycle until progression or unacceptable toxicity. Primary endpoint was the incidence of dose-limiting toxicities during cycle 1. The number of patients treated at each of four pre-specified dose levels (DLs) and the maximum tolerated doses in combination (MTD) were determined using a Bayesian Optimal Interval design. Objective response, progression-free survival, and overall survival were secondary endpoints.

RESULTS

Between May 2021 and April 2023, 24 patients were enrolled; 1 patient never started therapy and was excluded from the analysis. Median age was 70 years (range 41-88 years); 11 patients received ≥3 lines of therapy. Seventy-eight percent (18/23) of patients experienced grade ≥3 adverse event (AE) regardless of attribution at any DL, with one grade 5 AE (pneumonitis possibly related to EV). The recommended phase II doses are SG 8 mg/kg with EV 1.25 mg/kg with granulocyte colony-stimulating factor support; MTDs are SG 10 mg/kg with EV 1.25 mg/kg. The objective response rate was 70% (16/23, 95% confidence interval 47% to 87%) with three complete responses; three patients had progressive disease as best response. With a median follow-up of 14 months, 9/23 patients have ongoing response including 6 responses lasting over 12 months.

CONCLUSIONS

The combination of SG + EV was assessed at different DLs and a safe dose for phase II was identified. The combination had encouraging activity in patients with mUC with high response rates, including clinically significant complete responses. Additional study of this combination is warranted.

Exploring ethical issues arising from a problem-solving intervention in the Swedish Primary Care

Background

Common mental disorders count for a large percentage of sick leave cases in Europe and in Sweden. Problem-solving with workplace involvement have shown promising results in reducing the number of sick leave days for employees on sick leave for these conditions. Engaging the workplace by for example including the first-line manager in the return-to-work process changes the usual role of the primary care. Hence, this study aims to explore ethical issues that potentially arise when introducing workplace involvement as part of a problem-solving intervention.

Methods

A qualitative study in the Swedish Primary Care using data from semi-structured interviews with rehabilitation coordinators (n = 6), employees on sick leave for common mental disorders (n = 13), and their first-line managers (n = 8). A theoretical framework for systematic identification of ethical aspects of healthcare technologies was used to guide the interviews and reporting of results. Content analysis was used to code the data, searching for latent content. Ethical issues related to the ethical values privacy, identity, autonomy, professional values, third party, equality and justice were identified and described. The analysis was concluded by a normative discussion.

Results

Ethical issues were identified such as difficulties for the employees to control personal information. A need to create an integrated role of a patient and an employee and for coordinators to act neutral instead of as a patient advocate. Managers needed to balance the needs of the organization with the needs of the employee. A pre-requisite for participation was agreeing to manager involvement which may affect the equality of the intervention.

Conclusions

A conversation about sharing of information, roles, responsibilities and expectations during the rehabilitation should be initiated early and be continuous. Managers need support in learning the “how to” when having an employee on sick leave due to a common mental disorder.

Key messages

Work-related stress assessed by a text message single-item stress question

Background

Given the prevalence of work stress-related ill-health in the Western world, it is important to find cost-effective, easy-to-use and valid measures which can be used both in research and in practice.

Aims

To examine the validity and reliability of the single-item stress question (SISQ), distributed weekly by short message service (SMS) and used for measurement of work-related stress.

Methods

The convergent validity was assessed through associations between the SISQ and subscales of the Job Demand–Control–Support model, the Effort–Reward Imbalance model and scales measuring depression, exhaustion and sleep. The predictive validity was assessed using SISQ data collected through SMS. The reliability was analysed by the test–retest procedure.

Results

Correlations between the SISQ and all the subscales except for job strain and esteem reward were significant, ranging from −0.186 to 0.627. The SISQ could also predict sick leave, depression and exhaustion at 12-month follow-up. The analysis on reliability revealed a satisfactory stability with a weighted kappa between 0.804 and 0.868.

Conclusions

The SISQ, administered through SMS, can be used for the screening of stress levels in a working population.

Preventing sickness absenteeism among employees with common mental disorders or stress-related symptoms at work: Design of a cluster randomized controlled trial of a problem-solving based intervention versus care-as-usual conducted at the Occupational Health Services

BACKGROUND

Common mental disorders (CMDs) are among the leading causes of sick leave in Sweden and other OECD countries. They result in suffering for the individual and considerable financial costs for the employer and for society at large. The occupational health service (OHS) can offer interventions in which both the individual and the work situation are taken into account. The aim of this paper is to describe the design of a study evaluating the effectiveness of an intervention given at the OHS to employees with CMDs or stress-related symptoms at work. In addition, intervention fidelity and its relation to the outcome will be assessed in a process analysis.

METHODS

The study is designed as a cluster randomized trial in which the participating OHS consultants are randomized into either delivering the intervention or performing care as usual. Employees with CMDs or stress-related symptoms at work are recruited consecutively by the OHS consultants. The intervention aims to improve the match between the employee and the job situation. Interviews are held individually with the employee and the nearest supervisor, after which a joint meeting with both the employee and the supervisor takes place. A participatory approach is applied by which the supervisor and the employee are guided by the OHS consultant and encouraged to actively take part in problem solving concerning the work situation. Outcomes will be assessed at baseline and at six and 12 months. A long-term follow-up at 3 years will also be performed. The primary outcome is registered sickness absence during a 1-year period after study inclusion. Secondary outcomes are mental health and work ability. The intervention's cost effectiveness, compared to treatment as usual, both for society and for the employer will be evaluated. A process evaluation by both the OHS consultants and the employee will be carried out.

DISCUSSION

The study includes analyses of the effectiveness of the intervention (clinical and economic) as well as an analysis of its implementation at the participating OHSs. Possible methodological challenges such as selection bias and risk of contamination between OHS consultants delivering the experimental condition and consultants giving usual care are discussed.

TRIAL REGISTRATION

ClinicalTrials NCT02563743 Sep 28 2015.

Role of socio-cultural factors on changes in fitness and adiposity in youth: a 6-year follow-up study

BACKGROUND AND AIMS

Optimal cardio-respiratory fitness and adiposity levels are tightly related to health in youth. We analysed changes in fitness and adiposity in young individuals from two countries, and examined the role of maternal education in these changes.

METHODS AND RESULTS

A 6-year follow-up study was conducted on 483 Estonian children (9 years) and 466 Swedish children (9-10 years) and adolescents (15 years). Fitness was assessed by a maximal bike test, and total and central adiposity were indirectly estimated by skinfolds (Slaughter's equation for fat mass) and waist circumference. At follow-up, fitness and adiposity had increased in the children cohort (P ≤ 0.001), while small or no change occurred in the adolescent cohort. In the children cohort, Estonian participants had a lower increase in fitness and a higher increase in adiposity (total and central) than Swedish participants. Higher maternal education increased the odds of remaining fit (top quartile) by half and reduced the risk of remaining fat (top quartile) by half; odds ratios = 1.56 (1.00-2.43), 0.50 (0.32-0.77) and 0.61 (0.39-0.94) for fitness, total and central adiposity, respectively.

CONCLUSIONS

Our data suggest that the socioeconomic situation of a country might influence key cardiovascular risk factors (fitness and adiposity), being at higher risk for a low-middle income country (Estonia) than a higher income country (Sweden). The findings stress the role of socioeconomic status, particularly maternal education, in the maintenance of healthy fitness and adiposity levels from childhood into later life. Preventive efforts have to be taken from early age.

PSGL-1/selectin and ICAM-1/CD18 interactions are involved in macrophage-induced drug resistance in myeloma

Chemoresistance is the major obstacle in multiple myeloma (MM) management. We previously showed that macrophages protect myeloma cells, on a cell contact basis, from melphalan or dexamethasone-induced apoptosis in vitro. In this study, we found that macrophage-mediated myeloma drug resistance was also seen with purified macrophages from myeloma patients' bone marrow (BM) in vitro and was confirmed in vivo using the human myeloma-SCID (severe combined immunodeficient) mouse model. By profiling differentially regulated and paired plasma membrane protein genes, we showed that PSGL-1 (P-selectin glycoprotein ligand-1)/selectins and ICAM-1/CD18 played an important role in macrophage-mediated myeloma cell drug resistance, as blocking antibodies against these molecules or genetic knockdown of PSGL-1 or ICAM-1 in myeloma cells repressed macrophages' ability to protect myeloma cells. Interaction of macrophages and myeloma cells via these molecules activated Src and Erk1/2 kinases and c-myc pathways and suppressed caspase activation induced by chemotherapy drugs. Thus, our study sheds new light on the mechanism of drug resistance in MM and provides novel targets for improving the efficacy of chemotherapy in patients.

Lenalidomide and rituximab for untreated indolent non-Hodgkin's lymphoma

8548

Background: Despite advances in therapy and a better understanding of the natural history of indolent non-Hodgkins lymphomas (NHL), the optimal treatment for newly diagnosed patients (pts) has not been determined. While several combination chemotherapy regimens have response rates approaching 90%, toxicity is common with genotoxic drugs and secondary malignancies is a concern. Lenalidomide has been shown to have single agent activity in indolent NHL, and is approved for the treatment of multiple myeloma and myelodysplastic syndrome. Rituximab is effective as a single agent and in combination with chemotherapy for indolent NHL. The aim of this phase II, single arm study is to evaluate the efficacy and safety of lenalidomide and rituximab in pts with untreated, stage III, or IV indolent NHL. Methods: Pts with indolent NHL who were previously untreated, with measurable disease (>1.5 cm), were eligible for enrollment. Pts received 20mg of lenalidomide orally once daily on days 1–21 and rituximab 375mg/m2 intravenously on day 1 of each 28 day cycle. Pts could receive up to 6 cycles of therapy. Response was assessed after 3 cycles and at the end of therapy using the International Working Group Response Criteria. Results: At time of this report 17 pts have been enrolled and 14 are eligible for safety evaluation. The median age was 55 (33–77) years and 53% were male. Therapy was well tolerated with the following grade 3 adverse events (AE) reported; myalgia (1 pt), rash (1 pt), peripheral neuropathy (1pt). There were no grade 4 AEs. There have been no reported grade 3/4 hematologic AEs. There has been no tumor flare observed. In the 5 pts eligible for response assessment, 4 pts (80%) attained a complete response (CR), 1 patient (20%) had stable disease (SD). After 3 cycles, one patient had unconfirmed stable disease who also was previously treated with combination chemotherapy for Hodgkin's lymphoma. Updates for response will be presented. Conclusions: The combination of lenalidomide and rituximab has activity and is well tolerated with minimal toxicity in patients with newly diagnosed indolent lymphoma.

[Table: see text]

A poster-based intervention to promote stair use in blue- and white-collar worksites

OBJECTIVE

Previous studies have generally shown the effectiveness of prompts to promote stair use in worksites that mainly consist of white-collar workers. The present study tested whether an intervention using prompts is effective in stimulating stair use in two types of worksites: one consisting mainly of white-collar workers and one mainly of blue-collar workers.

METHOD

In 2005, elevator and stair use (stair climbing and descent) was monitored in two types of worksites in the Netherlands, namely one office building (n=150 white-collar workers) and one paper factory (n=800 blue-collar workers). The study used a simple time-series design of collecting data in three waves: before, during and after implementation of posters containing prompts stimulating stair use.

RESULTS

A total of 6771 choices between stairs and elevator were observed. There was a significant difference between stair use at baseline and during the poster intervention in both types of worksites. There was no worksite-by-intervention interaction, implying that the prompts were equally effective in both types of worksites. After removal of the posters stair use decreased significantly to a level that was not significantly different from baseline.

CONCLUSION

Stair use can be positively influenced in both blue- and white-collar workers by a short-term low-cost intervention using prompts on posters.

The NHF-NRG In Balance-project: the application of Intervention Mapping in the development, implementation and evaluation of weight gain prevention at the worksite

Very few examples of theory-driven and systematically developed weight gain prevention interventions for adults have been described in the literature. The present paper systematically describes the development, implementation and evaluation framework of a weight gain prevention programme directed at young adults at the worksite, namely the NHF-NRG In Balance-project. It not only can be used as a guide to systematically develop weight gain prevention interventions, but also gives an overview of the current theoretical and empirical knowledge-base in the field of obesity prevention. The outline of the paper follows the Intervention Mapping protocol, which includes a systematic inventory of important health issues, their risk behaviours and determinants of these risk behaviours, and specification of the proximal objectives of the programme directed at both energy intake and energy expenditure. The objectives are translated into behaviour change methods and strategies, which are combined in a stepwise intervention programme, and used for a detailed evaluation plan (process and effect evaluation). The NHF-NRG In Balance-project combines mass media and individually tailored communications with worksite environmental changes to raise awareness, to motivate and to enable energy balance behaviour changes. A quasi-experimental pre-test-multiple post-test control group design was applied in 12 worksites (>500 employees).

A phase I/II study of lenalidomide (Len) in combination with rituximab (R) in relapsed/refractory mantle cell lymphoma (MCL) with early evidence of efficacy

8030

Background: MCL remains a therapeutic challenge. R targets CD20 antigen on MCL cells while Len may target the microenvironment of MCL cells and enhance the ADCC activity of R. To test this hypothesis, we initiated a single-center; open label, phase I/II study. We now report the completed phase I. Methods: Eligible patients (pts) had 1–4 lines of prior therapy including prior thalidomide or R, regardless of resistance. Each cycle of treatment consisted of Len given orally daily on days 1–21 of a 28-day cycle and R 375 mg/m2 by IV infusion weekly for 4 weeks. A standard 3+3 dose escalation was used to determine MTD with Len doses at 10 mg, 15 mg, 20 mg, and 25 mg. DLT was defined as grade (G) 3 or 4 non-hematologic or G4 hematologic toxicity during the first cycle. Results: The phase I portion completed enrollment with 15 pts (4 at 10 mg, 3 at 15 mg, 6 at 20 mg and 2 at 25 mg). Thirteen pts were evaluable. Median age was 73 (62–84); median prior lines of therapy were 3 (1–4); median cycles received to date were 2 (1–7). Two DLT's occurred at 25 mg. One pt had G3 hypercalcemia. The other had G4 neutropenic fever and died of sepsis (G5) during the first cycle. Three additional pts were therefore enrolled at 20 mg. Common non-hematologic toxic events included pruritis (21 G1–2), hypercalcemia (9 G1–2, 1 G3), fatigue (9 G1–2), constipation (8 G1), diarrhea (6 G1–2), fever (6 G1–2), myalgias (4 G1–2, 1 G3) and elevated LDH (4 G1–2, 1 G3). Hematologic events included neutropenia (20 G1–2, 4 G3), thrombocytopenia (6 G1–2, 2 G3) and anemia (6 G1). There were no responses at 10 mg or 15 mg. At 20 mg after 2 cycles, 5 out of 6 pts achieved responses including 1 CR, 1 PR, 3 minor responses (MRs) and only 1 pt progressed. The 1 pt with PR went on to achieve a CR after 6 cycles. The 3 pts with MRs had tumor reductions by 43%, 40% and 38% respectively. These 3 patients with MRs continue to receive Len and might later achieve PR or CR. Conclusions: The MTD for Len with R in relapsed/refractory MCL was 20 mg, orally daily on days 1–21 of a 28-day cycle. Responses observed at 20 mg are promising with a favorable toxicity profile and are being evaluated further in an ongoing phase II study.

[Table: see text]

Trend and geographic variations in the incidence of mantle cell lymphoma in the United States from 1975 to 2003

8091

Background: Mantle cell lymphoma (MCL) is an uncommon subtype of non-Hodgkin's lymphoma (NHL). To better understand the incidence and epidemiological features of MCL in the United States, we conducted a population-based study with 3943 patients (pts) of MCL identified from the Surveillance, Epidemiology, and End Results (SEER) tumor registries over 28 years. Methods: From SEER public database, we identified 157,035 pts of all ages diagnosed with NHL between 1975 and 2003 in 9 SEER areas. Of these pts, 3,943 (2.5%) had histologically confirmed MCL, acccounting for 2.51% of NHL. The incidence with 95% confidence intervals were generated from SEER*Stat Software. Incidence was age-adjusted to the U.S. 2000 standard population. Annual percent change (APC) for the incidence was calculated and considered to be statistically significant if P<0.05. The crude 1-year survival rate was calculated as the ratio of the number of pts who survived over 1 year and the number of pts diagnosed with MCL. Results: Of 3,943 pts with MCL, 69.4% were late-stages (stages III IV), 24.2% were early-stages (stages I-II), and 7.1% were unstaged. Median age at diagnosis for MCL was 68.0. Overall incidence was 0.380/100,000/year, which increased by age from 0.02 in pts aged <40 to 2.02 for 70–79 and 1.81 in pts aged 80 or older. The age-adjusted incidence increased from 0.077 in 1975 to 0.641 in 2003. APC was 4.71% (P<0.001). Incidence of MCL was higher in men (0.555) than in women (0.250) (P<0.001). Annual increase was greater in men (5.84%) than in women (2.82%). There were also substantial geographic variations (P<0.001) in the incidence of MCL. The age-adjusted incidence was highest in Seattle (0.455) and the lowest in Hawaii (0.314). The incidence appeared to be higher in Caucasians (0.405) than in African-Americans (0.235) and other races (0.238). Annual increase was 5.1% in Caucasians, and 1.1% in African-Americans and other races. The 1-year survival rate was 85.0% for pts diagnosed in 1975–84, and increased to 90.4% for pts diagnosed in 1985–1994 and 82.0% for pts diagnosed in 1995–2003. Conclusions: The incidence of MCL increased progressively from 1975 to 2003, and was significantly higher in males and in Caucasians. There were substantial geographical variations in the incidence of MCL.

No significant financial relationships to disclose.

R-HCVAD/R-MTX-ARAC is an effective regimen for untreated diffuse large B-cell lymphoma (DLBCL) with aggressive features: M. D. Anderson experience in 40 patients

8058

Background: R-HCVAD (rituximab-cyclphosphamide, vincristine, dexamethasone, doxorubicin) alternating with R-MTX-ARAC (rituximab, methotrexate-cytarabine) is a chemoimmunotherapy regimen with activity in ALL, mantle cell, and Burkitt’s lymphomas (BL). Histological differentiation between BL, atypical BL, and DLBCL with high-grade features can be difficult. We thus have treated patients with DLBCL with high-grade histological features and/or poor-risk IPI with R-HCVAD. Methods: Forty consecutive patients with information collected prospectively in the NCCN database, treated between 7/2002 and 10/05 at M.D Anderson Cancer Center, and who received at least one cycle are included in this cohort analysis. Characteristics: 18 (45%) male; 18 (45%) HI and High IPI; 25 (62.5%) ↑LDH; 26 (65%) with Stage III/IV; 2 (5%) with PS>1; 8 (20%) with >60 years; 25 (62%) a Ki-67 >90%. Four patients received less than 4 cycles of treatment. Results: ORR was of 100%, with 95% CR/CRu. With a median follow-up of 26 months, 6 patients failed: 1 died in CR of pulmonary embolism while on treatment; 1 patient who achieved CR, had PD before the end of treatment; 1 achieved a PR and was transplanted (is alive in remission); 1 achieved a PR and progressed died of disease; and 2 relapsed (one is in remission after an ASCT). Four patients have died: 3 of disease, 1 of pulmonary embolism. The 3-year OS is 88% (95% CI 77%-99%); 3-year FFS is 71% (95% CI 47%-95%). The 3-year FFS for patients with L/LI risk (3-failures of 22 pts) was 78% (95% CI 52%-100%); and for patients with HI/H IPI (3 failures of 18 pts) 65% (95% CI 27%-100%). Conclusions: R-HCVAD/R-MTC-ARAC is a very active regimen for DLBCL of high grade. Toxicity was mostly hematological. We are currently doing a prospective randomized phase II study comparing this regimen to standard R-CHOP in patients with poor-risk IPI scores.

No significant financial relationships to disclose.

A phase II study of HCVIDDOXIL alternated with methotrexate-cytarabine in patients with newly diagnosed T-cell lymphoma

7597

Background: T cell lymphomas (TCL) generally are more aggressive and have a poorer prognosis than the corresponding B cell lymphomas. A chemotherapeutic regimen that is effective in aggressive lymphoid malignancies is HCVAD alternating with methotrexate (MTX) and cytarabine (Ara-C). Pegylated liposomal doxorubicin (DOXIL) is associated with greater tumor penetration and less toxicity. We initiated a phase II study to evaluate the efficacy of the regimen HCVIDDOXIL, using DOXIL as a substitute for doxorubicin in the HCVAD regimen, alternated with MTX-Ara-C . Methods: Previously untreated patients (pts) with Zubrod performance status ≤3, age > 18 years, and adequate organ function were eligible. Pts with skin involvement alone, CD30+, ALK +, T-anaplastic large cell lymphoma (ALCL), HIV-1 positive serology, and evidence of CNS involvement were excluded. Pts received HCVIDDOXIL ( cyclophosphamide 300 mg/m2 iv Q 12 h × 6 doses d 1–3, mesna 600 mg/m2 iv daily over 24 hours by continuous infusion d 1–3, DOXIL 25 mg/m2/day iv on d 2, vincristine 1.4 mg/m2 (max. 2 mg) iv days 4 and 11, dexamethasone 40 mg iv or po daily × 4 d 1–4 and 11–14) alternated with MTX/Ara-C ( MTX 200 mg/m2 iv over 2 hours on d 1, then 800 mg/m2 iv over 22 hours on d1, Ara-C 3 g/m2 iv Q 12 hours × 4 doses on d 3–4) every 3 weeks for a maximum of 8 cycles. Endpoints were progression-free survival and response rate. Results: Between October 2003 and November 2005, 23 pts were enrolled. Median age 53 years (range, 23–68). Twelve pts had stage IV, 6 stage III, 3 stage I, and 2 stage II disease. Fourteen (60%) pts had extranodal disease, and 8 (36%) pts had an elevated LDH. In 21 evaluable pts, the ORR was 90% [CR n=12 (57%); PR n= 7 pts (33%)]. Common Grade 3–4 adverse events were thrombocytopenia in 17 pts (77%), neutropenia in 6 (27%), anemia in 5 (23%), and febrile neutropenia in 7 (32%). With a median follow-up of 13 months, the median progression-free survival is 8.3 months (95% CI: 6.5 to 14.2 months). Conclusions: In this high-risk population the regimen HCVIDDOXIL alternated with MTX-Ara-C induced a high response rate. As expected, the most common toxicity was myelosuppression. The efficacy of this regimen should be confirmed in a larger cohort of patients. Enrollment in this study continues.

No significant financial relationships to disclose.

Participation rates in worksite-based intervention studies: health promotion context as a crucial quality criterion

Recently, a set of specific quality evaluation criteria for health promotion research has been proposed in this journal. One of the quality criteria identified is the 'health promotion context'. With this paper we would like to contribute to the dialogue by specifying the importance of this criterion on the basis of our on experience with worksite-based obesity prevention interventions. We advocate the reporting of participation rates among approached worksites in publications on worksite intervention effects. Such information will help to draw conclusions on the practical relevance of the shown effectiveness of the intervention. Health promotion practice is advised to adopt and disseminate evidence-based interventions, accompanied by a diffusion study with a minimal research burden for participants.

Novel secondary Ig VH gene rearrangement and in-frame Ig heavy chain complementarity-determining region III insertion/deletion variants in de novo follicular lymphoma

Human germinal center B cell tumors retain the ability of their nontransformed counterparts to somatically hypermutate Ig V genes by nucleotide substitution. Among a survey of 60 primary previously untreated, clonal, follicular lymphomas we have identified a rare V(H) rearrangement variant and two other in-frame nucleotide insertion/deletion variants within complementarity-determining region III of the Ig heavy chain. The neoplastic origin of the V(H) rearrangement variant was directly demonstrated in cells isolated by microdissection from malignant follicles. In all three cases a common clonal origin for the variants was demonstrated by complementarity-determining region III nucleotide sequence homology and shared somatic mutations in germline encoded positions in framework region IV. The monoclonal nature of the tumors was independently confirmed by demonstrating a single t(14;18) translocation breakpoint in the two cases with a detectable translocation. All the variants occurred in functional V(H) rearrangements, which in two cases were directly shown to encode functional Ab molecules. Both recombination-activating genes 1 and 2 were expressed in lymph node tumor cells containing the V(H) rearrangement variant, although recombination-activating gene expression among a panel of lymphomas was not limited to this variant.

Thymidine kinase (TK) gene-transduced human lymphocytes can be highly purified, remain fully functional, and are killed efficiently with ganciclovir

A graft-versus-leukemia (GVL) effect has been considered a major factor responsible for cures in patients with hematologic malignancies undergoing allogeneic bone marrow transplantation; however, associated graft-versus-host disease (GVHD) results in significant morbidity and mortality. T-cell depletion reduces the incidence and severity of GVHD but eliminates, at least partially, the GVL effect. Reinfusion of donor T lymphocytes at relapse posttransplantation can induce a potent antitumor response, but GVHD still occurs in the majority of patients. Prior transduction of T lymphocytes with the suicide gene, the viral thymidine kinase (TK), permits specific cell kill on administration of ganciclovir (GCV). Therefore, infusion of TK-transduced T lymphocytes may induce GVL effect and allow for their subsequent selective elimination in case GVHD develops. To evaluate the efficacy and feasibility of this promising approach, anti-CD3-stimulated primary human lymphocytes cultured in interleukin-2 were TK-transduced by a retroviral vector carrying both TK and neomycin-resistance genes. After selection in G418, more than 90% of the cells contained the TK gene as shown by a semiquantitative polymerase chain reaction. In addition, 1 to 5 days of GCV exposure, at clinically achievable concentrations of 20 to 50 micromol/L, induced > or = 90% killing of G418-selected cells without affecting nontransduced cells. Correlation of the extent of T-cell kill and the proportion of TK-gene-transduced cells is consistent with the absence of a bystander effect. Transduced cells were CD3+ and either CD8+ or CD4+ and retained functional properties of untransduced cells. In vivo administration of GCV prevented tumor development after subcutaneous injection of TK-transduced murine myeloma cells (MOPC-11), whereas such an effect was not observed on injection of untransduced cells into the opposite flank. Our studies provide critical information that (1) adequate numbers of TK-transduced lymphocytes can be selected efficiently with > or = 90% purity, (2) selected cells remain functional, (3) 24 hours of exposure to GCV at clinically achievable concentration effects > or = 90% killing of selected cells, and (4) GCV is effective in vivo in killing TK-transduced cells. Based on these data, a clinical study has been initiated in patients with multiple myeloma with persistent or relapsing disease after T-cell-depleted allogeneic transplants.