Clinical trials responsibilities

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Clinical trials for r-IEN-y in RA indicated that the dmg is well tolerated (52). Consistent improvement in tender and swollen joint scores was observed, but a large number of patients were needed in the trial to show statistical significance for r-IEN-y treatment. In certain individuals, responses were remarkable. An additive effect between r-IEN-y and penicillamine was detected. Efficacy was lower when r-IEN-y was combined with gold therapy. Research is continuing. 

The first SRS-A antagonist, FPL-55712 (26) (149), was discovered before the stmctures of the leukotrienes were detemiined. Although this compound is relatively weak as an antagonist and suffers from a very short half-life in vivo, it played an important role both in leukotriene stmcture elucidation and as a model for later antagonists. In work stmcturaHy related to FPL-55712, LY-171883 was developed (27) (150). LY-171883 was evaluated in several clinical trials before development was stopped. Orally adrninistered, LY-171883 blocked slightly the response to aerosol LTD improved pulmonary function (FEV ) in mild asthmatics (151), decreased the sensitivity of asthmatics to cold air-induced bronchoconstriction (152), and significantly reduced the bronchoconstrictor response to inhaled antigen (153). However, in all these studies the beneficial effects were minimal. 

Adjuvants are substances which can modify the immune response of an antigen (139,140). With better understanding of the functions of different arms of the immune system, it is possible to explore the effects of an adjuvant, such that the protective efficacy of a vaccine can be improved. At present, aluminum salt is the only adjuvant approved for use in human vaccines. New adjuvants such as QS-21, 3D-MPL, MF-59, and other liposome preparations are being evaluated. Several of these adjuvants have been in clinical trial, but none have been approved for human use. IL-12 has been proposed as an adjuvant which can specifically promote T-helper 1 ceU response, and can be a very promising adjuvant for future vaccine development. 

Another dideoxypyrimidine nucleoside active against human immunodeficiency vims is 3 -azido-2/3 -dideoxyuridine [84472-85-5] (AZDU or CS-87, 64) C H N O. Since its synthesis, (167) CS-87 has been identified as a promising antiHIV agent (168) and is currentiy undergoing phase I clinical trials in patients with AIDS and AIDS-related complex. It appears to be less potent than AZT against HIV in a peripheral blood mononuclear (PBM) cell screening system and in MT-4 cell lines. This lower activity in PBM cells appears to be related to a lower affinity of CS-87 for the enzyme responsible for its initial phosphorylation (169). However, CS-87 has significantly lower toxicity on bone marrow cells than AZT (170) and penetration of the CNS as a 5 -dihydropyridine derivative. 

The novel agent sulofenur (69) has entered clinical trials based on its broad spectmm antitumor activity in tumor models, its unusual mechanism of action, and its lack of cross-resistance to other agents (33). In Phase I clinical trials, the dmg was well tolerated and some clinical responses were noted. 

The majority of promising drug candidates emerging from marine natural products research to date are potential cancer treatments. Six anti-cancer compounds that are either marine natural products or synthetic analogs of marine natural products have made it to clinical trials. The first of these compounds to enter clinical trials was didemnin B (43), one of a family of cyclic depsipetides isolated from the Caribbean tunicate Trididemnum solidum Didemnin B was advanced to Phase II clinical trials for treatment of small cell lung cancer, myeloma, prostate cancer, and melanoma. Unfortunately, no favorable responses were found so the compound has been withdrawn. Crude extracts of another Caribbean tunicate, Ecteinascidia turbinata, showed extremely... 

In humans, biomarker responses to PPAR agonists by and large support possible antiatherosclerotic benefits, although recent clinical trial results have not proven conclusive. Further large-scale trials should help define the role of PPAR agonist therapy on cardiovascular events in at-risk populations. 

This experimental drug is a derivative of myriocin. After phosphorylation FTY720 modulates chemotactic responses and lymphocyte trafficking, leading to reversible lymphocyte sequestration in secondary lymphoid tissues. It is in clinical trials for the treatment of multiple sclerosis. 

LTRAs are extremely safe for patient use. However, the present generation of LTRAs is only modestly efficacious. Many patients show no clinically meaningful response, and current recommendations suggest a 1 month trial period to determine if patients will benefit from these drugs. With the exception of aspirin-sensitive asthmatics, there is currently no means for predicting which patients or under what circumstances antileukotrine therapies will be effective. 

A number of rationally designed MMP inhibitors have shown some promise in the treatment of pathologies, which MMPs are suspected to be involved in. However, most of these, such as Marimastat (BB-2516), a broad spectrum MMP inhibitor, or trocade (Ro 32-3555), an MMP-1 selective inhibitor, have performed poorly in clinical trials. The failure of Marimastat was partially responsible for the folding of British Biotech, which developed it. The failure of... 

The antisense oligonucleotide LErafAON against the serine/threonine kinase c-Raf has been tested in phase I clinical trials. The antisense oligonucleotides ISIS-5132, which also inhibits c-Raf, and ISIS-3521, which inhibits PKC, went through different phase clinical trials with solid tumour patients. Unfortunately, no objective responses occurred with these PKI. GEM-231, an oligonucleotide targeting the RIa subunit of protein kinase A is currently undergoing phase I/II clinical trials alone or in combination with traditional therapy for the treatment of solid cancers [3]. 

PTKs have been implicated in the regulation of a variety of biological responses such as cell proliferation, migration, differentiation, and survival. They have been demonstrated to play significant roles in the development of many disease states, including immunodeficiency, atherosclerosis, psoriasis, osteoporosis, diabetes, and cancer. In recent clinical trials impressive antitumor effects of PTK inhibitors have been observed. In future, PTK inhibitors may therefore become important drugs for the treatment of specific cancers. 

Proteasomal inhibition represents a novel strategy in cancer treatment and the small molecule Bortezomid (PS-341, Velcade ) has been approved for the treatment of refractory and relapsed multiple myeloma, a proliferative disease of plasma cells. Bortezomid inhibits an active site in a proteasome subunit and remarkably shows selective cytotoxicity to cancer cells. Although the underlying mechanisms are not completely understood bortezomid apparently induces a cell stress response in these tumor cells followed by caspase-dependent apoptosis. Whether bortezomid is beneficial for the treatment of other proliferative disease is currently being tested in clinical trials. 

A key element in planning and conducting clinical trials is to ensure that they have scientific validity and objectivity. This is particularly relevant with respect to Phase II and III studies, where it is desired to demonstrate a positive benefit to risk outcome. Responses to a drug among a patient population are rarely homogeneous and clear-cut. Thus, sound statistical principles must be applied in order to be able to distinguish significant effects from random events. 

Clinical trials should be designed so as to mirtimise potential sources of bias. It is known that patients can demonstrate a positive response to treatments that they believe will benefit them, even if no pharmaceutical agent has been admrrtistered (the placebo effect ). Similarly, investigators may be biased in their observations by an expectation of particular results. To avoid such bias, blinded trial designs are used. 

The regulatory authorities must be informed of any planned recall actions (see Chapter 12). Procedures are also required for emergency un-blinding of materials undergoing clinical trial. The responsibility for complaints and the initiation of product recalls should be assigned to designated individuals. 

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