maytansine and Thrombocytopenia

To evaluate the safety profile and preliminary antitumor activity of mirvetuximab soravtansine when administered in combination with carboplatin to relapsed ovarian cancer patients.. Patients with recurrent, platinum-sensitive epithelial ovarian or fallopian tube cancer were enrolled. Eligibility included a minimum requirement of tumor FRα positivity (≥25% of cells with ≥2+ staining intensity). Patients received escalating doses of mirvetuximab soravtansine and carboplatin on day 1 of a 21-day cycle (once every 3 weeks). Mirvetuximab soravtansine maintenance therapy was permitted, at the investigators discretion, following cessation of carboplatin treatment. Adverse events, tumor response, and progression-free survival (PFS) were determined.. Eighteen patients were enrolled and dosed with combination therapy; thirteen continued with mirvetuximab soravtansine maintenance following carboplatin discontinuation. Mirvetuximab soravtansine dosing was escalated from 5 to 6 mg/kg (adjusted ideal body weight) and carboplatin from AUC4 to AUC5. Adverse events were generally mild (≤ grade 2) with nausea, diarrhea, thrombocytopenia, blurred vision, and fatigue being the most common treatment-emergent toxicities. For all evaluable patients (n = 17), the confirmed objective response rate (ORR) was 71%, including three complete responses and nine partial responses, and the median PFS was 15 months. A median duration of response was not reached.. These data demonstrate that mirvetuximab soravtansine combined with carboplatin is a well-tolerated and highly active regimen in recurrent, platinum-sensitive ovarian cancer. Further evaluation of this combination in a randomized fashion is warranted.

Topics: Aged; Aged, 80 and over; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Carboplatin; Cohort Studies; Diarrhea; Disease-Free Survival; Drug Resistance, Neoplasm; Fallopian Tube Neoplasms; Fatigue; Female; Folate Receptor 1; Humans; Immunoconjugates; Incidence; Maximum Tolerated Dose; Maytansine; Middle Aged; Nausea; Neoplasm Recurrence, Local; Ovarian Neoplasms; Thrombocytopenia; Treatment Outcome

The antibody-drug conjugate trastuzumab emtansine is indicated for the treatment of patients with HER2-positive metastatic breast cancer previously treated with trastuzumab and a taxane. Approval of this drug was based on progression-free survival and interim overall survival data from the phase 3 EMILIA study. In this report, we present a descriptive analysis of the final overall survival data from that trial.. EMILIA was a randomised, international, open-label, phase 3 study of men and women aged 18 years or older with HER2-positive unresectable, locally advanced or metastatic breast cancer previously treated with trastuzumab and a taxane. Enrolled patients were randomly assigned (1:1) via a hierarchical, dynamic randomisation scheme and an interactive voice response system to trastuzumab emtansine (3·6 mg/kg intravenously every 3 weeks) or control (capecitabine 1000 mg/m. Between Feb 23, 2009, and Oct 13, 2011, 991 eligible patients were enrolled and randomly assigned to either trastuzumab emtansine (n=495) or capecitabine and lapatinib (control; n=496). In this final descriptive analysis, median overall survival was longer with trastuzumab emtansine than with control (29·9 months [95% CI 26·3-34·1] vs 25·9 months [95% CI 22·7-28·3]; hazard ratio 0·75 [95% CI 0·64-0·88]). 136 (27%) of 496 patients crossed over from control to trastuzumab emtansine after the second interim overall survival analysis (median follow-up duration 24·1 months [IQR 19·5-26·1]). Of those patients originally randomly assigned to trastuzumab emtansine, 254 (51%) of 495 received capecitabine and 241 [49%] of 495 received lapatinib (separately or in combination) after study drug discontinuation. In the safety population (488 patients treated with capecitabine plus lapatinib, 490 patients treated with trastuzumab emtansine), fewer grade 3 or worse adverse events occurred with trastuzumab emtansine (233 [48%] of 490) than with capecitabine plus lapatinib control treatment (291 [60%] of 488). In the control group, the most frequently reported grade 3 or worse adverse events were diarrhoea (103 [21%] of 488 patients) followed by palmar-plantar erythrodysaesthesia syndrome (87 [18%]), and vomiting (24 [5%]). The safety profile of trastuzumab emtansine was similar to that reported previously; the most frequently reported grade 3 or worse adverse events in the trastuzumab emtansine group were thrombocytopenia (70 [14%] of 490), increased aspartate aminotransferase levels (22 [5%]), and anaemia (19 [4%]). Nine patients died from adverse events; five of these deaths were judged to be related to treatment (two in the control group [coronary artery disease and multiorgan failure] and three in the trastuzumab emtansine group [metabolic encephalopathy, neutropenic sepsis, and acute myeloid leukaemia]).. This descriptive analysis of final overall survival in the EMILIA trial shows that trastuzumab emtansine improved overall survival in patients with previously treated HER2-positive metastatic breast cancer even in the presence of crossover treatment. The safety profile was similar to that reported in previous analyses, reaffirming trastuzumab emtansine as an efficacious and tolerable treatment in this patient population.. F Hoffmann-La Roche/Genentech.

Topics: Ado-Trastuzumab Emtansine; Adult; Aged; Aged, 80 and over; Anemia; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Aspartate Aminotransferases; Breast Neoplasms; Breast Neoplasms, Male; Bridged-Ring Compounds; Capecitabine; Diarrhea; Disease-Free Survival; Female; Hand-Foot Syndrome; Humans; Lapatinib; Male; Maytansine; Middle Aged; Quinazolines; Receptor, ErbB-2; Response Evaluation Criteria in Solid Tumors; Retreatment; Survival Rate; Taxoids; Thrombocytopenia; Trastuzumab; Vomiting; Young Adult

In the randomised, parallel assignment, open-label, phase 3 TH3RESA study, progression-free survival was significantly longer with trastuzumab emtansine versus treatment of physician's choice in previously treated patients with HER2-positive advanced breast cancer. We report results from the final overall survival analysis of the TH3RESA trial.. Eligible patients for the TH3RESA trial were men and women (aged ≥18 years) with centrally confirmed HER2-positive advanced breast cancer previously treated with both trastuzumab and lapatinib (advanced setting) and a taxane (any setting) and with progression on two or more HER2-directed regimens in the advanced setting. Patients had to have an Eastern Cooperative Oncology Group performance status of 0-2, left ventricular ejection fraction of at least 50%, and adequate organ function. Patients were randomly assigned (2:1) by an interactive voice and web response system with permuted block randomisation in blocks of six to receive trastuzumab emtansine (3·6 mg/kg intravenously every 21 days) or treatment of physician's choice administered per local practice. Randomisation was stratified by world region, number of previous regimens for advanced breast cancer, and presence of visceral disease. On Sept 12, 2012, the study protocol was amended to allow patients with disease progression to crossover from treatment of physician's choice to trastuzumab emtansine. The coprimary endpoints for TH3RESA were investigator-assessed progression-free survival and overall survival in the intention-to-treat population. We report results from a preplanned second interim analysis of overall survival, which was planned for when approximately 67% (n=330) of 492 expected deaths had occurred. This study is registered with ClinicalTrials.gov, number NCT01419197.. Between Sept 14, 2011, and Nov 19, 2012, 602 patients were enrolled from 146 centres in 22 countries and randomly assigned to trastuzumab emtansine (n=404) or treatment of physician's choice (n=198). At data cutoff (Feb 13, 2015), 93 (47%) of 198 patients in the physician's choice group had crossed over to trastuzumab emtansine. Overall survival was significantly longer with trastuzumab emtansine versus treatment of physician's choice (median 22·7 months [95% CI 19·4-27·5] vs 15·8 months [13·5-18·7]; hazard ratio 0·68 [95% CI 0·54-0·85]; p=0·0007). As the stopping boundary for overall survival was crossed, this overall survival analysis serves as the final and confirmatory analysis of overall survival and the study was terminated according to the protocol. The incidence of grade 3 or worse adverse events was 161 (40%) of 403 patients in the trastuzumab emtansine group and 87 (47%) of 184 patients in the treatment of physician's choice group. Of the most common grade 3 or worse adverse events (affecting ≥2% of patients in either group), those with a 3% or greater difference in incidence between groups that were more frequent with treatment of physician's choice than with trastuzumab emtansine were diarrhoea (three [1%] of 403 patients in the trastuzumab emtansine group vs eight [4%] of 184 patients in the treatment of physician's choice group), neutropenia (ten [3%] vs 29 [16%]), and febrile neutropenia (one [<1%] vs seven [4%]); whereas those that were more frequent with trastuzumab emtansine were thrombocytopenia (24 [6%] of 403 patients vs five [3%] of 184 patients) and haemorrhage of any type (17 [4%] of 403 vs one [<1%] of 184). Serious adverse events were reported in 102 (25%) of 403 patients in the trastuzumab emtansine group and 41 (22%) of 184 in the physician's choice group. Deaths from adverse events were reported in three patients (2%) in the physician's choice group (of which one was judged to be treatment related) and nine (2%) in the trastuzumab emtansine group (of which three were judged to be treatment related).. In patients who had progressed on two or more HER2-directed regimens, trastuzumab emtansine treatment resulted in a significant improvement in overall survival versus treatment of physician's choice. These data further solidify the role of trastuzumab emtansine in the management of patients with previously treated HER2-positive advanced breast cancer, and validate HER2 as a therapeutic target even after multiple lines of previous therapy.. F Hoffman-La Roche/Genentech.

Topics: Ado-Trastuzumab Emtansine; Adult; Aged; Aged, 80 and over; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Breast Neoplasms; Breast Neoplasms, Male; Bridged-Ring Compounds; Chemotherapy-Induced Febrile Neutropenia; Diarrhea; Early Termination of Clinical Trials; Female; Hemorrhage; Humans; Lapatinib; Male; Maytansine; Middle Aged; Neoplasm Metastasis; Neutropenia; Practice Patterns, Physicians'; Quinazolines; Receptor, ErbB-2; Retreatment; Survival Rate; Taxoids; Thrombocytopenia; Trastuzumab

Trastuzumab emtansine significantly improved progression-free survival and overall survival when compared with lapatinib-capecitabine in pretreated human epidermal growth factor receptor 2-positive advanced breast cancer. However, data in Japanese populations are limited.. In the single-arm Phase II JO22997 study, Japanese patients with human epidermal growth factor receptor 2-positive inoperable locally advanced/recurrent or metastatic breast cancer previously treated with at least one prior chemotherapy regimen for locally advanced/recurrent or metastatic breast cancer and trastuzumab in any setting received 3.6 mg/kg trastuzumab emtansine every 3 weeks until progression, unacceptable toxicity or consent withdrawal. The primary endpoint was Independent Review Committee-assessed objective response rate. Secondary endpoints included progression-free survival, overall survival, safety and pharmacokinetics.. The objective response rate in 73 treated patients was 38.4% (90% confidence interval, 28.8-48.6%), exceeding the prespecified boundary for an objective response rate > 20%. After 6.5 months' median follow-up, median progression-free survival was 5.6 months (95% confidence interval, 4.6-8.2). After 28.9 months' median follow-up, median overall survival was 30.5 months (95% confidence interval 25.2-not reached). There were no treatment-related deaths. The most common Grade 3/4 adverse events were thrombocytopenia (22%) and aspartate aminotransferase elevations (14%). Thrombocytopenia did not require platelet transfusion and typically recovered before the next cycle. There were no substantial differences in trastuzumab emtansine or trastuzumab pharmacokinetic parameters between this study and previous data from non-Japanese patients.. JO22997 results suggest high activity of trastuzumab emtansine in Japanese patients, a safety profile consistent with previous studies in non-Japanese patients, no new safety signals and no evidence of pharmacokinetic differences between Japanese and non-Japanese populations. These results support trastuzumab emtansine therapy for Japanese patients with chemotherapy- and trastuzumab-pretreated human epidermal growth factor receptor 2-positive locally advanced/recurrent or metastatic breast cancer.

Topics: Ado-Trastuzumab Emtansine; Adult; Aged; Aged, 80 and over; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Asian People; Breast Neoplasms; Disease-Free Survival; Female; Half-Life; Humans; Japan; Maytansine; Middle Aged; Neoplasm Metastasis; Neoplasm Recurrence, Local; Receptor, ErbB-2; Survival Rate; Thrombocytopenia; Trastuzumab; Treatment Outcome

Trastuzumab emtansine (T-DM1), an antibody-drug conjugate composed of the cytotoxic agent DM1 conjugated to trastuzumab via a stable thioether linker, has shown clinical activity in human epidermal growth factor receptor 2-positive metastatic breast cancer patients. This study evaluated the maximum tolerated dose, toxicity and pharmacokinetics of trastuzumab emtansine in Japanese breast cancer patients.. Inoperable advanced or recurrent human epidermal growth factor receptor 2-positive breast cancer patients were administered trastuzumab emtansine intravenously at a dose of 1.8, 2.4 or 3.6 mg/kg every 3 weeks. The maximum tolerated dose was estimated using the continual reassessment method.. This study enrolled 10 patients who were administered trastuzumab emtansine for a median of seven cycles. The dose-limiting toxicity was Grade 3 elevation of aspartate aminotransferase/alanine aminotransferase at the 2.4 mg/kg dose level. The maximum tolerated dose was estimated to be 3.6 mg/kg because at the point when dose-limiting toxicity was evaluable in 10 patients, the probability of dose-limiting toxicity estimated using the continual reassessment method was closest to 25% at a dose of 3.6 mg/kg and this was unchanged by the results for patients enrolled after that. The most frequent adverse events were nausea, arthralgia, fever, fatigue and decreased appetite. Adverse events were generally tolerable. The maximum concentration and area under the concentration-time curve increased linearly with the dose.. Trastuzumab emtansine up to 3.6 mg/kg was well tolerated by Japanese breast cancer patients. Although thrombocytopenia and hepatotoxicity tended to be more severe than was seen in Western patients in previous trastuzumab emtansine trials, those adverse events recovered without special supportive treatment.

Topics: Ado-Trastuzumab Emtansine; Adult; Aged; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Area Under Curve; Asian People; Biomarkers, Tumor; Breast Neoplasms; Chemical and Drug Induced Liver Injury; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Humans; Hypokalemia; Japan; Maximum Tolerated Dose; Maytansine; Middle Aged; Receptor, ErbB-2; Severity of Illness Index; Thrombocytopenia; Trastuzumab

Trastuzumab emtansine (T-DM1) is an antibody-drug conjugate in the development for the treatment of human epidermal growth factor receptor 2-positive cancers. Thrombocytopenia (TCP) is the dose-limiting toxicity of T-DM1. A semimechanistic population pharmacokinetic/pharmacodynamic (PK/PD) model was developed to characterize the effect of T-DM1 on patient platelet counts.. A PK/PD model with transit compartments that mimic platelet development and circulation was fit to concentration-platelet-time course data from two T-DM1 single-agent studies (TDM3569g; N = 52 and TDM4258g; N = 112). NONMEM(®) 7 software was used for model development. Data from a separate phase II study (TDM4374g; N = 110) were used for model evaluation. Patient baseline characteristics were evaluated as covariates of model PD parameters.. The model described the platelet data well and predicted the incidence of grade ≥3 TCP. The model predicted that with T-DM1 3.6 mg/kg given every 3 weeks (q3w), the lowest platelet nadir would occur after the first dose. Also predicted was a patient subgroup (46 %) having variable degrees of downward drifting platelet-time profiles, which were predicted to stabilize by the eighth treatment cycle to platelet counts above grade 3 TCP. Baseline characteristics were not significant covariates of PD parameters in the model.. This semimechanistic PK/PD model accurately captures the cycle 1 platelet nadir, the downward drift noted in some patient platelet-time profiles, and the ~8 % incidence of grade ≥3 TCP with T-DM1 3.6 mg/kg q3w. This model supports T-DM1 3.6 mg/kg q3w as a well-tolerated dose with minimal dose delays or reductions for TCP.

Topics: Ado-Trastuzumab Emtansine; Antibodies, Monoclonal, Humanized; Breast Neoplasms; Female; Humans; Immunotoxins; Maytansine; Models, Biological; Platelet Count; Receptor, ErbB-2; Thrombocytopenia; Trastuzumab

Trastuzumab-DM1 (T-DM1) is an antibody-drug conjugate that uses trastuzumab to specifically deliver the maytansinoid antimicrotubule agent DM1 to HER2-positive cells. This first-in-human study of T-DM1 evaluated safety, pharmacokinetics, and preliminary activity of T-DM1 in patients with advanced HER2-positive breast cancer.. Successive cohorts of patients who had progressed on trastuzumab-based therapy received escalating doses of T-DM1. Outcomes were assessed by standard solid-tumor phase I methods.. Twenty-four patients who had received a median of four prior chemotherapeutic agents for metastatic disease received T-DM1 at 0.3 mg/kg to 4.8 mg/kg on an every-3-weeks schedule. Transient thrombocytopenia was dose-limiting at 4.8 mg/kg; the maximum-tolerated dose (MTD) was 3.6 mg/kg. The half-life of T-DM1 at the MTD was 3.5 days, with peak DM1 levels < 10 ng/mL. Clearance at doses < 1.2 mg/kg was faster than at higher doses. Common drug-related adverse events (AEs) included grade < or = 2 thrombocytopenia, elevated transaminases, fatigue, nausea, and anemia. No grade > 1 nausea, vomiting, alopecia, or neuropathy events and no cardiac effects requiring dose modification were reported. The clinical benefit rate (objective response plus stable disease at 6 months) among 15 patients treated at the MTD was 73%, including five objective responses. The confirmed response rate in patients with measurable disease at the MTD (n = 9) was 44%.. At the MTD of 3.6 mg/kg every 3 weeks, T-DM1 was associated with mild, reversible toxicity and substantial clinical activity in a heavily pretreated population. Phase II and III trials in patients with advanced HER2-positive breast cancer are under way.

Topics: Ado-Trastuzumab Emtansine; Adult; Aged; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Biopsy, Needle; Bone Neoplasms; Breast Neoplasms; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Follow-Up Studies; Half-Life; Humans; Immunoconjugates; Immunohistochemistry; Liver Neoplasms; Lung Neoplasms; Maximum Tolerated Dose; Maytansine; Middle Aged; Neoplasm Staging; Patient Selection; Receptor, ErbB-2; Risk Assessment; Survival Analysis; Thrombocytopenia; Trastuzumab; Treatment Outcome

Thrombocytopenia is a common adverse event on HER2-targeted therapies, fam-trastuzumab deruxtecan (T-DXd) and ado-trastuzumab emtansine (T-DM1). A reported association of Asian ancestry with this event merits investigation to rule out potential confounding.. Subjects in this retrospective cohort were female patients with HER2 positive breast cancer, of Asian or non-Hispanic White ancestry, who initiated T-DM1 or T-DXd from January 2017 through October 2021. Follow-up closed in January 2022. Primary endpoint was dose adjustment for thrombocytopenia. Competing endpoints were discontinuation of drug for other toxicity, disease progression, or for completion of prescribed cycles. The association between Asian ancestry and thrombocytopenia-related dose adjustment was tested at p < 0.01 in a proportional hazards model for the sub-distributions of 4 (primary and competing) endpoints. Covariates examined as potential confounders were age, metastatic disease, specific HER2-targeted drug, and prior drug switching for toxicity.. Among 181 subjects, 48 reported Asian ancestry. Incidence of dose adjustment for thrombocytopenia was higher in patients with Asian ancestry and among patients switched to T-DXd after experiencing thrombocytopenia on T-DM1. Independent of specific drug and prior drug switching, Asian ancestry was associated with dose adjustment for thrombocytopenia (hazards ratio 2.95, 95% confidence interval 1.41-6.18) but not with competing endpoints. Among participants of Asian ancestry, the ancestral origin was usually China or the Philippines (where Chinese ancestry is common).. The association between Asian ancestry and thrombocytopenia on HER2-targeted therapy is independent of age, metastatic disease, drug, and history of similar toxicity. This association may have a genetic basis linked to Chinese ancestry.

Topics: Ado-Trastuzumab Emtansine; Breast Neoplasms; Female; Humans; Immunoconjugates; Male; Maytansine; Receptor, ErbB-2; Retrospective Studies; Thrombocytopenia; Trastuzumab

Ado-trastuzumab emtansine (T-DM1) treatment results in grade 3-4 thrombocytopenia in 8%-13% of patients. Prior in vitro studies reported T-DM1 inhibition of megakaryocyte maturation as the cause of decreased platelet production. The current observational study was initiated to evaluate causes of thrombocytopenia in patients with metastatic breast cancer.. Patients with human epidermal growth factor receptor 2-positive metastatic breast cancer (N = 11) were enrolled in this postmarket safety study. 111-Indium- radiolabeled autologous platelet recoveries and survivals as well as serial platelet counts, bleeding time assays, and platelet aggregation responses to a wide range of agonists were performed at baseline (BL) and during two consecutive cycles of the drug (3.6 mg/kg IV once every 3 weeks).. Platelet nadirs occurred earlier in cycle 2 than in cycle 1. Average nadir counts (% BL) in cycles 1 and 2 were 116,000/µL (53% ± 6%) and 115,000/µL (51% ± 9%), respectively, with return to BL by D15 in both cycles. BL platelet survival averaged 8.8 (± 0.3) days but progressively shortened to 5.5 (± 0.5) days during cycle 1 and to 4.6 (± 0.3) days during cycle 2 (. Following T-DM1 administration, we observed statistically significant progressive decreases in platelet survivals and decreased platelet function from BL values. In distinction to published in vitro studies, these unexpected results indicate a direct toxic effect of T-DM1 on patients' autologous circulating platelets.

Topics: Ado-Trastuzumab Emtansine; Antibodies, Monoclonal, Humanized; Blood Platelets; Breast Neoplasms; Female; Humans; Indium; Kinetics; Maytansine; Receptor, ErbB-2; Thrombocytopenia; Trastuzumab

Trastuzumab-emtansine (T-DM1) is an antibody-drug conjugate (ADC) comprising the cytotoxic agent DM1 conjugated to trastuzumab with a stable linker. Thrombocytopenia was the dose-limiting toxicity in the phase I study, and grade ≥3 thrombocytopenia occurred in up to 13% of patients receiving T-DM1 in phase III studies. We investigated the mechanism of T-DM1-induced thrombocytopenia.. The effect of T-DM1 on platelet function was measured by aggregometry, and by flow cytometry to detect the markers of activation. The effect of T-DM1 on differentiation and maturation of megakaryocytes (MK) from human hematopoietic stem cells was assessed by flow cytometry and microscopy. Binding, uptake, and catabolism of T-DM1 in MKs, were assessed by various techniques including fluorescence microscopy, scintigraphy to detect T-[H(3)]-DM1 and (125)I-T-DM1, and mass spectrometry. The role of FcγRIIa was assessed using blocking antibodies and mutant constructs of trastuzumab that do not bind FcγR.. T-DM1 had no direct effect on platelet activation and aggregation, but it did markedly inhibit MK differentiation via a cytotoxic effect. Inhibition occurred with DM1-containing ADCs but not with trastuzumab demonstrating a role for DM1. MKs internalized these ADCs in a HER2-independent, FcγRIIa-dependent manner, resulting in intracellular release of DM1. Binding and internalization of T-DM1 diminished as MKs matured; however, prolonged exposure of mature MKs to T-DM1 resulted in a disrupted cytoskeletal structure.. These data support the hypothesis that T-DM1-induced thrombocytopenia is mediated in large part by DM1-induced impairment of MK differentiation, with a less pronounced effect on mature MKs.

Topics: Ado-Trastuzumab Emtansine; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Breast Neoplasms; Cell Differentiation; Female; Humans; Immunoconjugates; Maytansine; Megakaryocytes; Platelet Activation; Platelet-Rich Plasma; Receptor, ErbB-2; Thrombocytopenia; Trastuzumab

Topics: Ado-Trastuzumab Emtansine; Antibodies, Monoclonal, Humanized; Antineoplastic Agents; Blood Platelet Disorders; Breast Neoplasms; Drug-Related Side Effects and Adverse Reactions; Female; Humans; Maytansine; Skin Diseases; Thrombocytopenia; Trastuzumab; Vasculitis

Proplatelet production represents a terminal stage of megakaryocyte development during which long, branching processes composed of platelet-sized swellings are extended and released into the surrounding culture. Whereas the cytoskeletal mechanics driving these transformations have been the focus of many studies, significant limitations in our ability to quantify the rate and extent of proplatelet production have restricted the field to qualitative analyses of a limited number of cells over short intervals. A novel high-content, quantitative, live-cell imaging assay using the IncuCyte system (Essen BioScience) was therefore developed to measure the rate and extent of megakaryocyte maturation and proplatelet production under live culture conditions for extended periods of time. As proof of concept, we used this system in the present study to establish a mechanism by which trastuzumab emtansine (T-DM1), an Ab-drug conjugate currently in clinical development for cancer, affects platelet production. High-content analysis of primary cell cultures revealed that T-DM1 is taken up by mouse megakaryocytes, inhibits megakaryocyte differentiation, and disrupts proplatelet formation by inducing abnormal tubulin organization and suppressing microtubule dynamic instability. Defining the pathways by which therapeutics such as T-DM1 affect megakaryocyte differentiation and proplatelet production may yield strategies to manage drug-induced thrombocytopenias.

Topics: Ado-Trastuzumab Emtansine; Animals; Antibodies, Monoclonal, Humanized; Biological Assay; Blood Platelets; Cell Differentiation; Fetus; Flow Cytometry; Humans; Liver; Maytansine; Megakaryocytes; Mice; Microscopy, Fluorescence; Microtubules; Molecular Imaging; Platelet Count; Primary Cell Culture; Thrombocytopenia; Thrombopoiesis; Trastuzumab; Tubulin

Topics: Ado-Trastuzumab Emtansine; Animals; Antibodies, Monoclonal, Humanized; Blood Platelets; Cell Differentiation; Humans; Maytansine; Megakaryocytes; Thrombocytopenia; Trastuzumab

Twenty-nine patients with advanced or recurrent adenocarcinoma of the ovary no longer responsive to standard treatment measures were given maytansine 1.2 mg/m2 I.V. every 3 weeks. None of the 29 patients demonstrated an objective regression of disease. Eighteen (62%) demonstrated stable disease for 1 or more months, while 11 (38%) developed rapid progression of disease. Adverse effects consisted primarily of leukopenia (7/29), thrombocytopenia (9/29), and nausea and vomiting (14/29). Only one patient developed life-threatening toxicity (platelets less than 25,000 microliters), and no drug-related deaths were observed. Maytansine thus appears inactive in the treatment of adenocarcinoma of the ovary at the dose and schedule tested.

Topics: Adenocarcinoma; Adult; Aged; Drug Evaluation; Female; Humans; Leukopenia; Maytansine; Middle Aged; Nausea; Neoplasm Recurrence, Local; Ovarian Neoplasms; Oxazines; Thrombocytopenia; Vomiting

Twenty-nine patients with advanced or recurrent squamous cell carcinoma of the cervix who had failed standard therapy were treated with maytansine 1.2 mg/m2 intravenously once every 3 weeks. Only one partial remission was observed among the 29 patients (3%). There were no complete remissions. Stable disease was observed in 18 (62%) and progressive disease in 10 (35%). Adverse effects were infrequent and mild to moderate and consisted primarily of myelosuppression, weakness, and nausea and vomiting. This study shows that maytansine at the dose and schedule tested is essentially inactive in the treatment of advanced or recurrent squamous cell carcinoma of the cervix.

Topics: Adult; Aged; Carcinoma, Squamous Cell; Drug Evaluation; Female; Humans; Leukocyte Count; Leukopenia; Maytansine; Middle Aged; Neoplasm Recurrence, Local; Oxazines; Thrombocytopenia; Uterine Cervical Neoplasms

Maytansine, an ansa macrolide, was evaluated in an early clinical trial in 40 adult patients with various solid tumors. Severe nausea and vomiting, sometimes associated with watery diarrhea and abdominal cramps, and liver function abnormalities, mainly elevation of serum glutamic--oxaloacetic transaminase levels, together constituted what we considered dose-limiting toxicity. Mild hematologic toxicity (mainly thrombocytopenia), neurotoxicity, and possibly cardiac toxicity were also noted. No antitumor effect was seen. An iv dose of 0.750 mg/m2 on days 1, 3, and 5 (total dose, 2.25 mg/m2) repeated every 4 weeks is recommended for Phase II trials.

Topics: Adult; Aged; Atrial Fibrillation; Child, Preschool; Diarrhea; Drug Administration Schedule; Drug Evaluation; Female; Humans; Liver; Male; Maytansine; Middle Aged; Nausea; Neoplasms; Nervous System; Oxazines; Thrombocytopenia; Vomiting