ELUCIDATION OF THE CELLULAR AND MOLECULAR MECHANISMS OF MISSENSE MUTATIONS ASSOCIATED WITH FAMILIAL EXUDATIVE VITREORETINOPATHY AND CONGENITAL MYASTHENIC SYNDROME

The endoplasmic reticulum (ER), within eukaryotic cells, is a hub for protein folding and assembly. Misfolded proteins and unassembled subunits of protein complexes are retained in the ER and degraded by a process termed endoplasmic reticulum associated degradation (ERAD). Frizzled class receptor 4 (FZD4) and muscle, skeletal, receptor tyrosine kinase (MuSK) are Wnt receptors. These proteins contain the frizzled cysteine-rich domain (Fz-CRD) required for dimerization in the ER. Mutations in FZD4 and MuSK genes are known to cause familial exudative vitreoretinopathy (FEVR, an autosomal dominant disease) and congenital myasthenic syndrome (CMS, an autosomal recessive disease), respectively. It was hypothesized that missense mutations within Fz-CRD lead to misfolding of FZD4 and MuSK proteins and consequent ER-retention. Investigating the molecular mechanism of these mutations is important since misfolded protein and ER-targeted therapies are in development being developed. Wild-type and mutants of FZD4 and MuSK were expressed at 37 °C in HeLa, COS-7, and HEK293 cells and their subcellular localizations were investigated using confocal microscopy imaging and glycosidase treatments. Abnormal trafficking was demonstrated in 10 of 21 mutants studied; nine mutants were within Fz-CRD and one was distant from Fz-CRD. These ER-retained mutants were improperly N-glycosylated confirming ER-localization. They were tagged with polyubiquitin chains confirming targeting for proteasomal degradation. The half-lives of wild-type MuSK and P344R-MuSK were 45 and 37 minutes, respectively; the latter half-life improved on incubation with proteasomal inhibitor MG132. The P344R-MuSK kinase mutant showed around 50% of its in vivo autophosphorylation activity. Trafficking defects in three of the 10 mutants (M105T-FZD4, C204Y-FZD4, and P344R-MuSK) were rescued by expression at 27 °C and by chemical chaperones (2.5-7.5% glycerol, 0.1-1% dimethyl sulfoxide, 10 μM thapsigargin, or 1 μM curcumin). Trafficking of wild-type FZD4 was not affected by co-expression with any of the nine ER-retained mutants, suggesting haploinsufficiency as the mechanism of disease. Thus, all nine Fz-CRD mutants of FEVR and CMS studied resulted in misfolded proteins. In contrast, only one of the 12 mutants outside Fz-CRD resulted in ER-retention. These findings demonstrate a common mechanism for diseases associated with Fz-CRD missense mutations. Disorders of Fz-CRD may be receptive to novel therapies that alleviate protein misfolding

Non-conventional treatments for conventional chondrosarcoma

Chondrosarcomas are the most common malignant tumors of the cartilage, are seen predominantly in adults, and have varied clinical behavior. The majority of them affect the medullary canal of long bones and pelvic bones. The prognosis of chondrosarcoma is closely related to histological grading; however, the grading is subject to interobserver variability. Conventional chondrosarcomas are overall considered to be chemotherapy- and radiation-resistant, resulting in limited treatment options. The majority of advanced conventional chondrosarcomas are treated with chemotherapy without any survival benefit. Recent studies have evaluated molecular genetic findings which have improved the understanding of chondrosarcoma biology. Newer therapeutic targets are desperately needed. In this review article, we explore ongoing clinical trials evaluating novel ways of treating advanced conventional chondrosarcoma

Cutaneous head and neck melanoma in OPTiM, a randomized phase 3 trial of talimogene laherparepvec versus granulocyte-macrophage colony-stimulating factor for the treatment of unresected stage IIIB/IIIC/IV melanoma

BACKGROUND: Cutaneous head and neck melanoma has poor outcomes and limited treatment options. In OPTiM, a phase 3 study in patients with unresectable stage IIIB/IIIC/IV melanoma, intralesional administration of the oncolytic virus talimogene laherparepvec improved durable response rate (DRR; continuous response ≥6 months) compared with subcutaneous granulocyte-macrophage colony-stimulating factor (GM-CSF). METHODS: Retrospective review of OPTiM identified patients with cutaneous head and neck melanoma given talimogene laherparepvec (n = 61) or GM-CSF (n = 26). Outcomes were compared between talimogene laherparepvec and GM-CSF treated patients with cutaneous head and neck melanoma. RESULTS: DRR was higher for talimogene laherparepvec-treated patients than for GM-CSF treated patients (36.1% vs 3.8%; p = .001). A total of 29.5% of patients had a complete response with talimogene laherparepvec versus 0% with GM-CSF. Among talimogene laherparepvec-treated patients with a response, the probability of still being in response after 12 months was 73%. Median overall survival (OS) was 25.2 months for GM-CSF and had not been reached with talimogene laherparepvec. CONCLUSION: Treatment with talimogene laherparepvec was associated with improved response and survival compared with GM-CSF in patients with cutaneous head and neck melanoma. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1752-1758, 2016

Cutaneous head and neck melanoma in OPTiM, a randomized phase 3 trial of talimogene laherparepvec versus granulocyte-macrophage colony-stimulating factor for the treatment of unresected stage IIIB/IIIC/IV melanoma

BACKGROUND: Cutaneous head and neck melanoma has poor outcomes and limited treatment options. In OPTiM, a phase 3 study in patients with unresectable stage IIIB/IIIC/IV melanoma, intralesional administration of the oncolytic virus talimogene laherparepvec improved durable response rate (DRR; continuous response ≥6 months) compared with subcutaneous granulocyte-macrophage colony-stimulating factor (GM-CSF). METHODS: Retrospective review of OPTiM identified patients with cutaneous head and neck melanoma given talimogene laherparepvec (n = 61) or GM-CSF (n = 26). Outcomes were compared between talimogene laherparepvec and GM-CSF treated patients with cutaneous head and neck melanoma. RESULTS: DRR was higher for talimogene laherparepvec-treated patients than for GM-CSF treated patients (36.1% vs 3.8%; p = .001). A total of 29.5% of patients had a complete response with talimogene laherparepvec versus 0% with GM-CSF. Among talimogene laherparepvec-treated patients with a response, the probability of still being in response after 12 months was 73%. Median overall survival (OS) was 25.2 months for GM-CSF and had not been reached with talimogene laherparepvec. CONCLUSION: Treatment with talimogene laherparepvec was associated with improved response and survival compared with GM-CSF in patients with cutaneous head and neck melanoma. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1752-1758, 2016

Patterns of Clinical Response with Talimogene Laherparepvec (T-VEC) in Patients with Melanoma Treated in the OPTiM Phase III Clinical Trial

PURPOSE: Talimogene laherparepvec (T-VEC) is an oncolytic immunotherapy designed to induce tumor regression of injected lesions through direct lytic effects, and of uninjected lesions through induction of systemic antitumor immunity. In this study, we describe the patterns and time course of response to T-VEC from the phase III OPTiM trial of 436 patients with unresected stages IIIB-IV melanoma. METHODS: Lesion-level response analyses were performed based on the type of lesion (injected or uninjected cutaneous, subcutaneous, or nodal lesions; or visceral lesions [uninjected]), and the best percentage change from baseline of the sum of products of the longest diameters was calculated. Patients randomized to T-VEC (n = 295) who experienced a durable response (continuous partial or complete response for ≥6 months) were evaluated for progression prior to response (PPR), defined as the appearance of a new lesion or >25 % increase in total baseline tumor area. RESULTS: T-VEC resulted in a decrease in size by ≥50 % in 64 % of injected lesions (N = 2116), 34 % of uninjected non-visceral lesions (N = 981), and 15 % of visceral lesions (N = 177). Complete resolution of lesions occurred in 47 % of injected lesions, 22 % of uninjected non-visceral lesions, and 9 % of visceral lesions. Of 48 patients with durable responses, 23 (48 %) experienced PPR, including 14 who developed new lesions only. No difference in overall survival was observed, and median duration of response was not reached in patients with PPR versus those without PPR. CONCLUSIONS: Responses in uninjected lesions provide validation of T-VEC-induced systemic immunotherapeutic effects against melanoma. PPR did not negatively impact the clinical effectiveness of T-VEC

Open-label, randomized, multi-center study comparing the sequence of high dose Aldesleukin (Proleukin® (HD IL-2) and Ipilimumab Yervoy® ) in patients with metastatic melanoma (proclivity 02)

Purpose: To investigate whether the sequence of HD IL-2 and a checkpoint inhibitor, Ipilimumab, will have additive or synergistic efficacy or toxicity when used in rapid sequence. Schema: Adult patients with Stage IV or unresectable Stage III metastatic melanoma who are eligible to receive HD IL-2, treatment naïve or have received prior adjuvant therapy are randomized to a sequential administration of 4 doses of Ipilimumab or 4 cycles of HD IL-2 dosed according to their package inserts. Fifty of the patients will start with one drug and 50 the other. The second drug will begin as soon as practically possible, without waiting for relapse. Entry criteria have recently been amended to include prior treatment with anti-PD-1 or anti-PDL-1. Twelve US sites are currently enrolling patients. An independent Data and Safety Monitoring Committee oversees the study. The primary endpoint is the proportional one year survival in the ITT population and a protocol defined population of patients who have received at least half of the planned doses of both study drugs. Clinical response and progression free survival will also be assessed. The primary endpoint is the proportional one year survival in the ITT population and a protocol defined population of patients who have received at least half of the planned doses of both study drugs. Clinical response and progression free survival will also be assessed. Current status: Twelve US sites are currently enrolling patients. To date 16 patients have been enrolled, 9 on the Ipilimumab first and 7 on the HD IL-2 first arms. No synergistic toxicity has been observed, but one death occurred in the HD IL-2 arm and one colectomy on the Ipilimumab arm, both prior to administration of the other drug

A multi-center study of high dose Aldesleukin (Proleukin® (HD IL-2) + Vemurafenib Zelboraf® ) therapy in patients with BRAFV600 mutation positive metastatic melanoma (proclivity 01)

Purpose: To investigate whether the Vemurafenib-induced increased tumor antigen expression, T lymphocyte infiltration and tumor debulking improve the complete response rate induced by HD IL-2 in metastatic melanoma and if there is synergistic toxicity using the drugs in close approximation. Schema: Adult patients with measurable metastatic or unresectable Stage III melanoma with no prior therapy and a BRAFV600 mutation who are candidates for HD IL-2 are eligible for entry into the first cohort of 135 patients (figure 1). Six weeks of Vemurafenib therapy per package insert precedes up to 2 courses of HD IL-2. Vemurafenib is administered during the outpatient intervals between cycles of HD IL-2 and following completion. A second cohort of up to 50 similar patients already responding or stable with < 18 weeks of Vemurafenib therapy will also be accrued. The study was amended to permit prior anti-PD-1 therapy. The primary endpoint is Complete Response (CR) and near CR at 6 months of therapy. Current status: Sixteen sites have enrolled patients. 41 patients have been enrolled to date, 27 in Cohort 1 and 14 in cohort 2. The Data Safety and Monitoring Board performed an initial safety analysis after the initial 8 patients which demonstrated no unexpected safety signal. An analysis of the effect of the combination on Progression Free Survival in both cohorts will be performed after the first 20% of patients in Cohort 1 have received at least one course of HD IL-2. The results of this analysis should be available at the time of the SITC meeting. Figure 1 Treatment of metastatic melanoma with HD IL-2 immunotherapy and targeted agent vemurafenib Treatment of metastatic melanoma with HD IL-2 immunotherapy and targeted agent vemurafenib