On September 1, 2017, the FDA granted approval for gemtuzumab ozogamicin (Mylotarg; Pfizer Inc.) in combination with daunorubicin and cytarabine and as a monotherapy for the treatment of adult patients with newly diagnosed CD33-positive acute myeloid leukemia (AML). Gemtuzumab ozogamicin is a CD33-targeted antibody-drug conjugate joined to calicheamicin. Approval of gemtuzumab ozogamicin combination treatment was based on a randomized trial of 271 patients with newly diagnosed AML treated with daunorubicin and cytarabine with or without 3 mg/m fractionated gemtuzumab ozogamicin, which resulted in an event-free survival (EFS) of 13.6 months for gemtuzumab ozogamicin + daunorubicin and cytarabine and 8.8 months for daunorubicin and cytarabine alone [HR = 0.68 (95% confidence interval (CI), 0.51-0.91)]. Hemorrhage, prolonged thrombocytopenia, and veno-occlusive disease were serious toxicities that were more common in patients treated with gemtuzumab ozogamicin + daunorubicin and cytarabine. Approval of gemtuzumab ozogamicin monotherapy was based on a randomized trial of 237 patients with newly diagnosed AML treated without curative intent. Median overall survival (OS) was 4.9 months with gemtuzumab ozogamicin versus 3.6 months on best supportive care [HR = 0.69 (95% CI, 0.53-0.90)]. Adverse events were similar on both arms. Postapproval, several studies are required including evaluation of fractionated gemtuzumab ozogamicin pharmacokinetics, safety of combination gemtuzumab ozogamicin in the pediatric population, immunogenicity, and the effects of gemtuzumab ozogamicin on platelet function. .
On March 29, 2018, the FDA granted accelerated approval for blinatumomab (Blincyto; Amgen, Inc.) for the treatment of adults and children with B-cell precursor acute lymphoblastic leukemia (BCP ALL) in first or second complete remission with minimal residual disease (MRD) greater than or equal to 0.1%. Blinatumomab is a CD3xCD19 bispecific antibody approved previously for the treatment of relapsed or refractory BCP ALL. The basis for this accelerated approval was a single-arm trial. For the 86 patients in first and second complete remission with MRD 0.1%, conversion to MRD < 0.01% was achieved after one cycle of blinatumomab by 85.2% [95% confidence interval (CI): 73.8%, 93.0%] and 72.0% (95% CI: 50.6%, 87.9%), respectively, and the estimated median hematologic relapse-free survivals (RFS) were 35.2 months (95% CI: 0.4-53.5) and 12.3 months (95% CI: 0.7-42.3), respectively. Hematologic RFS was considered substantial independent of whether patients underwent subsequent allogeneic stem cell transplantation. The safety profile for blinatumomab was established in prior studies, and no new safety signals were observed in the new population. Cytokine release syndrome and neurotoxicity remain significant risks. The FDA is requiring confirmation of clinical benefit in a randomized trial.
The deregulation of the sonic hedgehog (shh) signaling pathway in epidermal keratinocytes is a primary event leading to the formation of basal cell carcinoma (BCC). The mechanisms by which this pathway exerts this effect remain largely undefined. We demonstrate that overexpression of shh in HaCaT keratinocytes grown in organotypic cultures induced a basal cell phenotype, as evidenced by their morphology, trans-epithelial staining of cytokeratin 14, and suprabasalar proliferation. Shh also induced keratinocyte infiltration into the underlying collagen matrix. Constitutive shh expression was associated with increased phosphorylation of the epidermal growth factor receptor (EGFR) as well as jnk and raf. Additionally, levels of c-jun and matrix metalloproteinase-9 (MMP-9) protein were elevated in shh-expressing cells. Inhibition of EGFR activity with either the tyrphostin, AG1478, or blocking receptor-ligand interaction with the monoclonal antibody, C-225, blocked matrix infiltration. In contrast, exogenously supplied EGF significantly augmented the invasiveness of the HaCaT cells. These observations provide insight into the impact of deregulated shh on epidermal homeostasis. The findings further suggest that an intact EGF signaling axis cooperates with shh and is a critical mediator of matrix invasion in a tumor type characterized by disrupted shh.
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