Patent Publication Number: US-2005142104-A1

Title: Methods of using and compositions comprising PDE4 modulators for the treatment and management of asbestos-related diseases and disorders

Description:
This invention claims the benefit of U.S. Provisional Application No. 60/518,603, filed Nov. 6, 2003, which is incorporated herein in its entirety by reference. 
    
    
     1. FIELD OF THE INVENTION  
      This invention relates to methods of treating, preventing and managing an asbestos-related disease or disorder, which comprise the administration of a PDE4 modulator alone or in combination with known therapeutics. The invention also relates to pharmaceutical compositions and dosing regimens. In particular, the invention encompasses the use of a PDE4 modulator in conjunction with surgery or radiation therapy and/or other standard therapies for diseases associated with asbestos poisoning.  
     2. BACKGROUND OF THE INVENTION  
      2.1 Asbestos-Related Diseases or Disorders  
      Several million individuals worldwide were exposed to asbestos in the mining of ore or the manufacture and use of asbestos products. D. R. Aberle,  Seminars in Roentgenology,  24 (2): 118, 1991. Given the long latency for the development of many pathological consequences of asbestos, asbestos-related diseases will likely dominate the field of occupational and environmental diseases for some time. Benign asbestos-related diseases and disorders include asbestosis, pleural effusion, pleural plaques, diffuse pleural thickening, and rounded atelectasis. C. A. Staples,  Radiologic Clinics of North America,  30 (6): 1191, 1992. Malignant asbestos-related diseases include malignant pleural effusion, pleural or peritoneal mesothelioma, and bronchogenic carcinoma. Merck Index, 1999 (17 th  ed.), 645 and 651.  
      Asbestosis (interstitial fibrosis) is defined as diffuse lung fibrosis due to the inhalation of asbestos fibers. C. A. Staples,  Radiologic Clinics of North America,  30 (6): 1195, 1992. It is one of the major causes of occupationally related lung damage. Merck Index, 1999 (17 th  ed.), 622. Asbestosis characteristically occurs following a latent period of 15-20 years, with a progression of disease even after exposure has ceased, but rarely occurs in the absence of pleural plaques. C. Peacock,  Clinical Radiology,  55: 425, 2000. Fibrosis first arises in and around the respiratory bronchioles, predominating in the subpleural portions of the lung in the lower lobes, and then progresses centrally. C. A. Staples,  Radiologic Clinics of North America,  30 (6): 1195, 1992. Asbestosis may cause an insidious onset of progressive dyspnea in addition to a dry cough. The incidence of lung cancer is increased in smokers with asbestosis, and a dose-response relationship has been observed. Merck Index, 1999 (17 th  ed.), 623.  
      Another asbestos-related disorder is pleural effusion. Pleural effusions are often the earliest manifestation of asbestos-related disease. C. A. Staples,  Radiologic Clinics of North America,  30 (6): 1192, 1992. People exposed to asbestos can develop an exudative pleural effusion five to 20 years after exposure. Merck Index, 1999 (17 th  ed.), 645; C. A. Staples,  Radiologic Clinics of North America,  30 (6): 1192, 1992; and C. Peacock,  Clinical Radiology,  55: 427, 2000. Effusion may follow short exposure, but more often follows intermediate exposure of about 10 to 15 years. The clinical picture in benign asbestos-related pleural effusion varies from asymptomatic patients to patients with an acute episode of pleuritic chest pain and pyrexia. Id., 426. The mechanism is unknown, but it is assumed that the fibers migrate from the lungs to the pleura and induce an inflammatory response. In most people, effusions clear after three to four months, but can persist or recur over several years. Id. As the effusion resolves, many develop diffuse pleural thickening. Id.  
      Pleural plaques are a common manifestation of asbestos exposure, typically occurring after a latent period of approximately 20-30 years. C. A. Staples,  Radiologic Clinics of North America,  30 (6): 1191, 1992; and C. Peacock,  Clinical Radiology,  55: 423, 2000. Histologically, pleural plaques consist of acellular collagen bundles that form a basket-weave pattern, which almost exclusively involves the parietal pleura. C. A. Staples,  Radiologic Clinics of North America,  30 (6): 1191, 1992. The precise pathogenesis of pleural plaques remains undetermined, although some have assumed that they are caused by the mechanical effect of asbestos fibers piercing the visceral pleura. C. Peacock,  Clinical Radiology,  55: 425, 2000. Currently, however, the fibers are believed to be transported to the parietal pleura via lymphatic channels, where they incite an inflammatory response. Id. Plaques slowly grow over time, even after cessation of exposure, but they are not considered premalignant. Id. Calcification occurs later, often 30-40 years following exposure. Id., 424; and C. A. Staples,  Radiologic Clinics of North America,  30 (6): 1191, 1992. Although there is a significant correlation between the severity of the pleural disease and that of asbestosis, pleural plaques tend to occur in isolation without any other manifestations of asbestos-related diseases. C. Peacock,  Clinical Radiology,  55: 425, 2000.  
      Another common manifestation of asbestos exposure is diffuse pleural thickening. C. A. Staples,  Radiologic Clinics of North America,  30 (6): 1193, 1992. Usually, the latent period is approximately 15 years. Diffuse pleural thickening is less specific for asbestos exposure than the presence of pleural plaques, since thickening also may be seen following TB pleuritis, hemothorax and empyema. C. Peacock,  Clinical Radiology,  55: 427, 2000. The most common symptom is dyspnea. The pathogenesis is unclear, but it is believed to be due to inflammation and fibrosis of the visceral pleural lymphatics, and it has been considered an extension of parenchymal fibrosis. Id. Development of diffuse pleural thickening has a similar time-line as plaque formation. Thickening is a common concomitant finding to asbestosis, with a reported associated incidence of 10%. Id.  
      Another disease associated with asbestos exposure is round atelectasis, which refers to atelectatic lung adjacent to pleural thickening with characteristic in-drawing of bronchi and vessels. T. Wallace,  Diagnostic Cytopathology,  8 (6): 617, 1992; C. Peacock,  Clinical Radiology,  55: 429, 2000; and C. A. Staples,  Radiologic Clinics of North America,  30 (6): 1193, 1992. It is also known as folded lung, pulmonary pseudotumor, pleuroma or Blesovsky syndrome. Id. The presence of the effusion has been postulated to cause passive atelectasis, with infolding of the lung resulting in invagination of the adjacent pleura. Id. This process causes tethering, which prevents reexpansion of the lung upon resolution of the effusion and which causes round atelectasis. Id. An alternative explanation is that an insult to the pleura leads to localized inflammation and fibrosis, which results in volume loss and buckling of the underlying lung. Id. The lingula is the most common site, followed by the middle and then the lower lobes, although lesions may be multiple and bilateral. Id.  
      Mesothelioma is a malignant pleural or peritoneal neoplasm that is usually associated with occupational exposure to asbestos. Merck Index, 1999 (17 th  ed.), 645. The clinical latency period between asbestos exposure and mesothelioma development is typically 15-40 years. Id., 623; and C. Peacock,  Clinical Radiology,  55: 427, 2000. As a result, the number of mesothelioma patients has continued to rise despite decreased asbestos production. J M W van Haarst et al.,  British Journal of Cancer,  86: 342, 2002. The common symptoms are chest pain, dyspnea, cough, weight loss, weakness and increased sputum production. Merck Index, 1999 (17 th  ed.), 645. The tumor gradually encases the lungs, invades the chest wall, and produces pleural effusion in about 75% of patients. Id. The prognosis is dismal, with poor response to radial surgery, chemotherapy, or radiation therapy. Id.  
      The causal relationship between bronchogenic carcinoma and asbestos exposure is well accepted. Merck Index, 1999 (17 th  ed.), 651; and D. R. Aberle,  Seminars in Roentgenology,  24 (2): 124, 1991. It shows a dose response at occupational exposure levels. Id. The relative risk of lung cancer in asbestos workers increases multiplicatively with combined cigarette smoking, and asbestos-related interstitial disease is often associated with it. Id. Lung cancer has been also reported in individuals without interstitial lung disease who are exposed to asbestos. Id.  
      2.2 Conventional Treatments  
      The primary strategy for dealing with asbestos-related diseases or disorders is prevention, with the worldwide elimination of asbestos use and with the replacement of asbestos by safe synthetic products. No treatment for asbestosis is known to be effective. Mesothelioma is very difficult to treat, and no standard therapy for its treatment currently exists. Kaiser L R.,  Semin Thorac Cardiovasc Surg . October, 9 (4): 383-90, 1997. The methods of chemotherapy, radiation therapy, and surgery have all been used with little improvement in overall survival, although trimodality therapy that involves a combination of all three treatments has been shown to improve survival in selected patients. Id.  
      The two primary surgical interventions used to treat mesothelioma are pleurectomy and extrapleural pneumonectomy (EPP). Pleurectomy usually is a palliative procedure to relieve chest wall pain and prevent recurrent pleural effusions by stripping off the visceral and parietal pleura. C. Turton,  British Journal of Hospital Medicine,  23(3): 249, 1980. EPP is an en bloc resection of the parietal and mediastinal pleura, lung, hemi-diaphragm, and ipsilateral pericardium to remove all gross disease. Sugarbaker D J,  Ann Surg.,  224(3): 288-94, 1996. EPP is indicated for stage I tumors with no involvement of the mediastinal lymph nodes. EPP is a technically demanding surgery with significant morbidity. The surgical complications of pleurectomy and EPP include pneumonia, bronchopleural fistulae, bronchial leaks, empyema, chylothorax, respiratory insufficiency, myocardial infarction, congestive heart failure, hemorrhage, cardiac volvulus, subcutaneous emphysema, incomplete tumor removal, and vocal cord paralysis. Id.  
      Radiotherapy usually is palliative or adjunctive to surgery. C. Turton,  British Journal of Hospital Medicine,  23(3): 249, 1980. Brachytherapy, intrapleural implantation of radioactive isotopes, delivers high-dose radiation locally to the pleural space and is used for recurrent pleural effusions. Id. Postoperative radiation therapy can prevent recurrence within chest wall incision sites. Complications of radiotherapy include nausea and vomiting, radiation hepatitis, esophagitis, myelitis, myocarditis, and pneumonitis with deterioration of pulmonary function.  
      Photodynamic therapy is an adjuvant treatment in patients with surgically treated pleural malignancies. P. Baas,  Br. J. Cancer.,  76(6): 819-26, 1997. A light-activated photosensitizing drug is instilled intrapleurally and is excited by light of a certain wavelength to produce oxygen free radicals that cause tumor necrosis. Id.  
      Response to chemotherapy has been disappointing because comparison of chemotherapies has been difficult. Intrapleural instillations of antibiotics such as mepacrine, thiotepa, and tetracycline have been reported to be sometimes successful. C. Turton,  British Journal of Hospital Medicine  23(3): 247, 1980. Various cytotoxic drugs including mustine have been instilled into the pleural cavity. Id. Medications presently used during the treatment of mesothelioma include GM-CSF, doxorubicin, gemcitabine, cisplatin, vinblastine, adriamycin, bleomycin, hyaluronidase, methotrexate and mitomycin. J M W van Haarst et al.,  British Journal of Cancer,  86: 342-345, 2002. However, patients rarely obtain complete relief. Chemotherapy results in less than 20% response and has not yet been shown to improve survival in patients with mesothelioma. Id. Therefore, there remains a need for safe and effective methods of treating and managing mesothelioma and other diseases associated with exposure to asbestos.  
      2.3 PDE4 Modulators  
      Compounds referred to PDE4 modulators have been synthesized and tested. These compounds potently inhibit TNF-α production, and exhibit modest inhibitory effects on LPS induced IL  1 B and IL12. L. G. Corral, et al.,  Ann. Rheum. Dis.  58: (Suppl 1) 1107-1113 (1999).  
      Further characterization of the PDE4 modulators shows that they are potent PDE4 inhibitors. PDE4 is one of the major phosphodiesterase isoenzymes found in human myeloid and lymphoid lineage cells. The enzyme plays a crucial part in regulating cellular activity by degrading the ubiquitous second messenger cAMP and maintaining it at low intracellular levels. Id. Inhibition of PDE4 activity results in increased cAMP levels leading to the modulation of LPS induced cytokines including inhibition of TNF-α production in monocytes as well as in lymphocytes.  
     3. SUMMARY OF THE INVENTION  
      This invention encompasses methods of treating, preventing and managing asbestos-related diseases or disorders, which comprise administering to a patient in need thereof a therapeutically or prophylactically effective amount of a PDE4 modulator, or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof.  
      Another embodiment of the invention encompasses the use of one or more PDE4 modulators in combination with other therapeutics typically used to treat or prevent asbestos-related diseases or disorders such as, but not limited to, anti-cancer agents, antibiotics, anti-inflammatory agents, cytokines, steroids, immunomodulatory agents, immunosuppressive agents, and other known therapeutics.  
      Yet another embodiment of the invention encompasses the use of one or more PDE4 modulators in combination with conventional therapies used to treat, prevent or manage asbestos-related diseases or disorders including, but not limited to, chemotherapy, surgery, radiation therapy and photodynamic therapy.  
      The invention further encompasses pharmaceutical compositions, single unit dosage forms, and kits suitable for use in treating, preventing and/or managing asbestos-related diseases or disorders, which comprise one or more PDE4 modulators, or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof, and one or more additional active agents. 
    
    
     4. DETAILED DESCRIPTION OF THE INVENTION  
      A first embodiment of the invention encompasses methods of treating, preventing or managing asbestos-related diseases or disorders, which comprise administering to a patient in need thereof a therapeutically or prophylactically effective amount of a PDE4 modulator, or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof.  
      As used herein, the terms “asbestos-related disease, disorder or syndrome,” “disease or disorder associated with asbestos exposure,” and “disease or disorder associated with asbestos poisoning” mean any disease, disorder, syndrome or abnormality associated with, or related to, exposure to asbestos or poisoning by asbestos. The terms encompass benign and malignant diseases or disorders, and include, but are not limited to, mesothelioma, asbestosis, malignant pleural effusion, benign exudative effusion, pleural plaques, pleural calcification, diffuse pleural thickening, rounded atelectasis, fibrotic masses, and lung cancer. In a specific embodiment, the terms do not encompass lung cancer. In a certain embodiment, the asbestos-related disease, disorder or syndrome does not include malignant mesothelioma or malignant pleural effusion mesothelioma syndrome.  
      Another embodiment of the invention encompasses a pharmaceutical composition suitable for treatment, prevention or management of asbestos-related diseases or disorders comprising a PDE4 modulator, or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof, and an optional carrier.  
      Also encompassed by the invention are single unit dosage forms suitable for use in treating, preventing or managing asbestos-related diseases or disorders comprising a PDE4 modulator, or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof, and an optional carrier.  
      Another embodiment of the invention encompasses a kit suitable for use in treating, preventing or managing asbestos-related diseases or disorders comprising: a pharmaceutical composition comprising a PDE4 modulator, or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof. The invention further encompasses kits comprising single unit dosage forms.  
      Without being limited by theory, it is believed that a PDE4 modulator can act in complementary or synergistic ways with certain second active agents in the treatment, prevention or management of asbestos-related diseases or disorders. Therefore, one embodiment of the invention encompasses a method of treating, preventing and/or managing an asbestos-related disease or disorder, which comprises administering to a patient in need thereof a therapeutically or prophylactically effective amount of a PDE4 modulator, or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof, and a therapeutically or prophylactically effective amount of a second active agent.  
      Examples of second active agents include, but are not limited to, conventional therapeutics used to treat or prevent mesothelioma such as anti-cancer agents, antibiotics, anti-inflammatory agents, steroids, cytokines, immunomodulatory agents, immunosuppressive agents, and other therapeutics drug capable of relieving or alleviating a symptom of asbestos-related diseases or disorders which can be found, for example, in the  Physician&#39;s Desk Reference,  2003.  
      It is further believed that a PDE4 modulator can reduce or eliminate adverse effects associated with the administration of conventional therapeutic agents used to treat asbestos-related diseases or disorders, thereby allowing the administration of larger amounts of those conventional agents to patients and/or increasing patient compliance. Consequently, another embodiment of the invention encompasses a method of reversing, reducing or avoiding an adverse effect associated with the administration of a second active agent in a patient suffering from an asbestos-related disease or disorder, which comprises administering to a patient in need thereof a therapeutically or prophylactically effective amount of a PDE4 modulator, or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof.  
      The invention also encompasses pharmaceutical compositions, single unit dosage forms, and kits which comprise a PDE4 modulator, or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof, and a second active agent.  
      As discussed elsewhere herein, symptoms of asbestos-related diseases or disorders may be treated with chemotherapy, surgery, radiation therapy, photodynamic therapy, immunotherapy, and/or gene therapy. Without being limited by theory, it is believed that the combined use of such conventional therapies and a PDE4 modulator can provide a uniquely effective treatment of asbestos-related diseases or disorders. Therefore, this invention encompasses a method of treating, preventing and/or managing asbestos-related diseases or disorders, which comprises administering to a patient (e.g., a human) a PDE4 modulator, or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof, before, during, or after chemotherapy, surgery, radiation therapy, photodynamic therapy, immunotherapy, gene therapy and/or other conventional, non-drug based therapies.  
      4.1 PDE4 Modulators  
      Compounds used in the invention include racemic, stereomerically pure and stereomerically enriched PDE4 modulators, stereomerically and enantiomerically pure compounds that have selective cytokine inhibitory activities, and pharmaceutically acceptable salts, solvates, hydrates, stereoisomers, clathrates, and prodrugs thereof.  
      As used herein and unless otherwise indicated, the term “PDE4 modulators” encompasses small molecule drugs, e.g., small organic molecules which are not peptides, proteins, nucleic acids, oligosaccharides or other macromolecules. Preferred compounds inhibit TNF-α production. Compounds may also have a modest inhibitory effect on LPS induced IL1β and IL12. More preferably, the compounds of the invention are potent PDE4 inhibitors.  
      Specific examples of PDE4 modulators include, but are not limited to, the cyclic imides disclosed in U.S. Pat. Nos. 5,605,914 and 5,463,063; the cycloalkyl amides and cycloalkyl nitriles of U.S. Pat. Nos. 5,728,844, 5,728,845, 5,968,945, 6,180,644 and 6,518,281; the aryl amides (for example, an embodiment being N-benzoyl-3-amino-3-(3′,4′-dimethoxyphenyl)-propanamide) of U.S. Pat. Nos. 5,801,195, 5,736,570, 6,046,221 and 6,284,780; the imide/amide ethers and alcohols (for example, 3-phthalimido-3-(3′,4′-dimethoxyphenyl)propan-1-ol) disclosed in U.S. Pat. No. 5,703,098; the succinimides and maleimides (for example methyl 3-(3′,4′,5′6′-petrahydrophthalimdo)-3-(3″,4″-dimethoxyphenyl)propionate) disclosed in U.S. Pat. No. 5,658,940; imido and amido substituted alkanohydroxamic acids disclosed in U.S. Pat. No. 6,214,857 and WO 99/06041; substituted phenethylsulfones disclosed in U.S. Pat. Nos. 6,011,050 and 6,020,358; fluoroalkoxy-substituted 1,3-dihydro-isoindolyl compounds disclosed in U.S. patent application Ser. No. 10/748,085 filed on Dec. 29, 2003; substituted imides (for example, 2-phthalimido-3-(3′,4′-dimethoxyphenyl)propane) disclosed in U.S. Pat. No. 6,429,221; substituted 1,3,4-oxadiazoles (for example, 2-[1-(3-cyclopentyloxy-4-methoxyphenyl)-2-(1,3,4-oxadiazole-2-yl)ethyl]-5-methylisoindoline-1,3-dione) disclosed in U.S. Pat. No. 6,326,388; cyano and carboxy derivatives of substituted styrenes (for example, 3,3-bis-(3,4-dimethoxyphenyl)acrylonitrile) disclosed in U.S. Pat. Nos. 5,929,117, 6,130,226, 6,262,101 and 6,479,554; isoindoline-1-one and isoindoline-1,3-dione substituted in the 2-position with an α-(3,4-disubstituted phenyl)alkyl group and in the 4- and/or 5-position with a nitrogen-containing group disclosed in WO 01/34606 and U.S. Pat. No. 6,667,316; and imido and amido substituted acylhydroxamic acids (for example, (3-(1,3-dioxoisoindoline-2-yl)-3-(3-ethoxy-4-methoxyphenyl)propanoylamino) propanoate disclosed in WO 01/45702 and U.S. Pat. No. 6,699,899. Other PDE4 modulators include diphenylethylene compounds disclosed in U.S. patent application Ser. No. 10/934,974, filed on Sep. 3, 2004, as a CIP of U.S. patent application Ser. No. 10/794,931, filed Mar. 5, 2004, which claims priority to U.S. provisional patent application No. 60/452,460, filed Mar. 5, 2003. Other PDE4 modulators include isoindoline compounds disclosed in U.S. patent application Ser. Nos. 10/900,332 and 10/900,270, both filed on Jul. 28, 2004. Other PDE4 modulators include substituted heterocyclic compounds disclosed in U.S. provisional patent application No. 60/607,408, filed on Sep. 3, 2004. The entireties of each of the patents and patent applications identified herein are incorporated herein by reference.  
      Additional PDE4 modulators belong to a family of synthesized chemical compounds of which typical embodiments include 3-(1,3-dioxobenzo-[f]isoindol-2-yl)-3-(3-cyclopentyloxy-4-methoxyphenyl)propionamide and 3-(1,3-dioxo-4-azaisoindol-2-yl)-3-(3,4-dimethoxyphenyl)-propionamide.  
      Other specific PDE4 modulators belong to a class of non-polypeptide cyclic amides disclosed in U.S. Pat. Nos. 5,698,579, 5,877,200, 6,075,041 and 6,200,987, and WO 95/01348, each of which is incorporated herein by reference. Representative cyclic amides include compounds of the formula:  
                 
          wherein n has a value of 1, 2, or 3;     R 5  is o-phenylene, unsubstituted or substituted with 1 to 4 substituents each selected independently from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, alkylamino, dialkylamino, acylamino, alkyl of 1 to 10 carbon atoms, alkyl of 1 to 10 carbon atoms, and halo;     R 7  is (i) phenyl or phenyl substituted with one or more substituents each selected independently of the other from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, and halo, (ii) benzyl unsubstituted or substituted with 1 to 3 substituents selected from the group consisting of nitro, cyano, trifluoromethyl, carbothoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, and halo, (iii) naphthyl, and (iv) benzyloxy;     R 12  is —OH, alkoxy of 1 to 12 carbon atoms, or  
                 
    R 8  is hydrogen or alkyl of 1 to 10 carbon atoms; and     R 9  is hydrogen, alkyl of 1 to 10 carbon atoms, —COR 10 , or —SO 2 R 10 , wherein R 10  is hydrogen, alkyl of 1 to 10 carbon atoms, or phenyl.        

      Specific compounds of this class include, but are not limited to: 
      3-phenyl-2-(1-oxoisoindolin-2-yl)propionic acid;     3-phenyl-2-(1-oxoisoindolin-2-yl)propionamide;     3-phenyl-3-(1-oxoisoindolin-2-yl)propionic acid;     3-phenyl-3-(1-oxoisoindolin-2-yl)propionamide;     3-(4-methoxyphenyl)-3-(1-oxisoindolin-yl)propionic acid;     3-(4-methoxyphenyl)-3-(1-oxisoindolin-yl)propionamide;     3-(3,4-dimethoxyphenyl)-3-(1-oxisoindolin-2-yl)propionic acid;     3-(3,4-dimethoxy-phenyl)-3-(1-oxo-1,3-dihydroisoindol-2-yl)propionamide;     3-(3,4-dimethoxyphenyl)-3-(1-oxisoindolin-2-yl)propionamide;     3-(3,4-diethoxyphenyl)-3-(1-oxoisoindolin-yl)propionic acid;     methyl 3-(1-oxoisoindolin-2-yl)-3-(3-ethoxy-4-methoxyphenyl)propionate;     3-(1-oxoisoindolin-2-yl)-3-(3-ethoxy-4-methoxyphenyl)propionic acid;     3-(1-oxoisoindolin-2-yl)-3-(3-propoxy-4-methoxyphenyl)propionic acid;     3-(1-oxoisoindolin-2-yl)-3-(3-butoxy-4-methoxyphenyl)propionic acid;     3-(1-oxoisoindolin-2-yl)-3-(3-propoxy-4-methoxyphenyl)propionamide;     3-(1-oxoisoindolin-2-yl)-3-(3-butoxy-4-methoxyphenyl)propionamide;     methyl 3-(1-oxoisoindolin-2-yl)-3-(3-butoxy-4-methoxyphenyl)propionate; and     methyl 3-(1-oxoisoindolin-2-yl)-3-(3-propoxy-4-methoxyphenyl)propionate.    

      Other representative cyclic amides include compounds of the formula:  
                 
          in which Z is:  
                 
    in which:     R 1  is the divalent residue of (i) 3,4-pyridine, (ii) pyrrolidine, (iii) imidizole, (iv) naphthalene, (v) thiophene, or (vi) a straight or branched alkane of 2 to 6 carbon atoms, unsubstituted or substituted with phenyl or phenyl substituted with nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamyl, acetoxy, carboxy, hydroxy, amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, or halo, wherein the divalent bonds of said residue are on vicinal ring carbon atoms;     R 2  is —CO— or —SO 2 —;     R 3  is (i) phenyl substituted with 1 to 3 substituents each selected independently from nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, or halo, (ii) pyridyl, (iii) pyrrolyl, (iv) imidazolyl, (iv) naphthyl, (vi) thienyl, (vii) quinolyl, (viii) furyl, or (ix) indolyl;     R 4  is alanyl, arginyl, glycyl, phenylglycyl, histidyl, leucyl, isoleucyl, lysyl, methionyl, prolyl, sarcosyl, seryl, homoseryl, threonyl, thyronyl, tyrosyl, valyl, benzimidol-2-yl, benzoxazol-2-yl, phenylsulfonyl, methylphenylsulfonyl, or phenylcarbamoyl; and     n has a value of 1, 2, or 3. Other representative cyclic amides include compounds of the formula:  
                 
    in which R 5  is (i) o-phenylene, unsubstituted or substituted with 1 to 4 substituents each selected independently from nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, alkylamino, dialkylamino, acylamino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, or halo, or (ii) the divalent residue of pyridine, pyrrolidine, imidizole, naphthalene, or thiophene, wherein the divalent bonds are on vicinal ring carbon atoms;     R 6  is —CO—, —CH 2 —, or —SO 2 —;     R 7  is (i) hydrogen if R 6  is —SO 2 —, (ii) straight, branched, or cyclic alkyl of 1 to 12 carbon atoms, (iii) pyridyl, (iv) phenyl or phenyl substituted with one or more substituents each selected independently of the other from nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, or halo, (v) alkyl of 1 to 10 carbon atoms, (vi) benzyl unsubstituted or substituted with 1 to 3 substituents selected from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, or halo, (vii) naphthyl, (viii) benzyloxy, or (ix) imidazol-4-yl methyl;     R 12  is —OH, alkoxy of 1 to 12 carbon atoms, or  
                 
    n has a value of 0, 1, 2, or 3;     R 8′  is hydrogen or alkyl of 1 to 10 carbon atoms; and        

      R 9′  is hydrogen, alkyl of 1 to 10 carbon atoms, —COR 10 , or —SO 2 R 10  in which R 10  is hydrogen, alkyl of 1 to 10 carbon atoms, or phenyl.  
      Other representative imides include compounds of the formula:  
                 
          in which R 7  is (i) straight, branched, or cyclic alkyl of 1 to 12 carbon atoms, (ii) pyridyl, (iii) phenyl or phenyl substituted with one or more substituents each selected independently of the other from nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, or halo, (iv) benzyl unsubstituted or substituted with one to three substituents selected from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, or halo, (v) naphthyl, (vi) benzyloxy, or (vii) imidazol-4-ylmethyl;     R 12  is —OH, alkoxy of 1 to 12 carbon atoms, —O—CH 2 -pyridyl, —O-benzyl or  
                 
    where n has a value of 0, 1, 2, or 3;     R 8′  is hydrogen or alkyl of 1 to 10 carbon atoms; and        

      R 9′  is hydrogen, alkyl of 1 to 10 carbon atoms, —CH 2 -pyridyl, benzyl, —COR 10 , or —SO 2 R 10  in which R 10  is hydrogen, alkyl of 1 to 4 carbon atoms, or phenyl.  
      Other specific PDE4 modulators include the imido and amido substituted alkanohydroxamic acids disclosed in WO 99/06041 and U.S. Pat. No. 6,214,857, each of which is incorporated herein by reference. Examples of such compound include, but are not limited to:  
                 
          wherein each of R 1  and R 2 , when taken independently of each other, is hydrogen, lower alkyl, or R 1  and R 2 , when taken together with the depicted carbon atoms to which each is bound, is o-phenylene, o-naphthylene, or cyclohexene-1,2-diyl, unsubstituted or substituted with 1 to 4 substituents each selected independently from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, alkylamino, dialkylamino, acylamino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, and halo;     R 3  is phenyl substituted with from one to four substituents selected from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, alkylthio of 1 to 10 carbon atoms, benzyloxy, cycloalkoxy of 3 to 6 carbon atoms, C 4 -C 6 -cycloalkylidenemethyl, C 3 -C 10 -alkylidenemethyl, indanyloxy, and halo;     R 4  is hydrogen, alkyl of 1 to 6 carbon atoms, phenyl, or benzyl;     R 4 ′ is hydrogen or alkyl of 1 to 6 carbon atoms;     R 5  is —CH 2 —, —CH 2 —CO—, —SO 2 —, —S—, or —NHCO—; and     n has a value of 0, 1, or 2; and     the acid addition salts of said compounds which contain a nitrogen atom capable of being protonated.        

      Additional specific PDE4 modulators used in the invention include, but are not limited to: 
      3-(3-ethoxy-4-methoxyphenyl)-N-hydroxy-3-(1-oxoisoindolinyl)propionamide;     3-(3-ethoxy-4-methoxyphenyl)-N-methoxy-3-(1-oxoisoindolinyl)propionamide;     N-benzyloxy-3-(3-ethoxy-4-methoxyphenyl)-3-phthalimidopropionamide;     N-benzyloxy-3-(3-ethoxy-4-methoxyphenyl)-3-(3-nitrophthalimido)propionamide;     N-benzyloxy-3-(3-ethoxy-4-methoxyphenyl)-3-(1-oxoisoindolinyl)propionamide;     3-(3-ethoxy-4-methoxyphenyl)-N-hydroxy-3-phthalimidopropionamide;     N-hydroxy-3-(3,4-dimethoxyphenyl)-3-phthalimidopropionamide;     3-(3-ethoxy-4-methoxyphenyl)-N-hydroxy-3-(3-nitrophthalimido)propionamide;     N-hydroxy-3-(3,4-dimethoxyphenyl)-3-(1-oxoisoindolinyl)propionamide;     3-(3-ethoxy-4-methoxyphenyl)-N-hydroxy-3-(4-methyl-phthalimido)propionamide;     3-(3-cyclopentyloxy-4-methoxyphenyl)-N-hydroxy-3-phthalimidopropionamide;     3-(3-ethoxy-4-methoxyphenyl)-N-hydroxy-3-(1,3-dioxo-2,3-dihydro-1H-benzo[f]isoindol-2-yl)propionamide;     N-hydroxy-3-{3-(2-propoxy)-4-methoxyphenyl}-3-phthalimidopropionamide;     3-(3-ethoxy-4-methoxyphenyl)-3-(3,6-difluorophthalimido)-N-hydroxypropionamide;     3-(4-aminophthalimido)-3-(3-ethoxy-4-methoxyphenyl)-N-hydroxypropionamide;     3-(3-aminophthalimido)-3-(3-ethoxy-4-methoxyphenyl)-N-hydroxypropionamide;     N-hydroxy-3-(3,4-dimethoxyphenyl)-3-(1-oxoisoindolinyl)propionamide;     3-(3-cyclopentyloxy-4-methoxyphenyl)-N-hydroxy-3-(1-oxoisoindolinyl) propionamide; and     N-benzyloxy-3-(3-ethoxy-4-methoxyphenyl)-3-(3-nitrophthalimido)propionamide.    

      Additional PDE4 modulators used in the invention include the substituted phenethylsulfones substituted on the phenyl group with a oxoisoindine group. Examples of such compounds include, but are not limited to, those disclosed in U.S. Pat. No. 6,020,358, which is incorporated herein by reference, which include the following:  
                 
          wherein the carbon atom designated * constitutes a center of chirality;     Y is C═O, CH 2 , SO 2 , or CH 2 C═O; each of R 1 , R 2 , R 3 , and R 4 , independently of the others, is hydrogen, halo, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, nitro, cyano, hydroxy, or —NR 8 R 9 ; or any two of R 1 , R 2 , R 3 , and R 4  on adjacent carbon atoms, together with the depicted phenylene ring are naphthylidene;     each of R 5  and R 6 , independently of the other, is hydrogen, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, cyano, or cycloalkoxy of up to 18 carbon atoms;     R 7  is hydroxy, alkyl of 1 to 8 carbon atoms, phenyl, benzyl, or NR 8′  R 9′ ;     each of R 8  and R 9  taken independently of the other is hydrogen, alkyl of 1 to 8 carbon atoms, phenyl, or benzyl, or one of R 8  and R 9  is hydrogen and the other is —COR 10  or —SO 2 R 10 , or R 8  and R 9  taken together are tetramethylene, pentamethylene, hexamethylene, or —CH 2 CH 2 X 1 CH 2 CH 2 — in which X 1  is —O—, —S— or —NH—; and     each of R 8′  and R 9′  taken independently of the other is hydrogen, alkyl of 1 to 8 carbon atoms, phenyl, or benzyl, or one of R 8′  and R 9′  is hydrogen and the other is —COR 10′  or —SO 2 R 10′ , or R 8′  and R 9′  taken together are tetramethylene, pentamethylene, hexamethylene, or —CH 2 CH 2 X 2 CH 2 CH 2 — in which X 2  is —O—, —S—, or —NH—.        

      It will be appreciated that while for convenience the above compounds are identified as phenethylsulfones, they include sulfonamides when R 7  is NR 8′  R 9′ .  
      Specific groups of such compounds are those in which Y is C═O or CH 2 .  
      A further specific group of such compounds are those in which each of R 1 , R 2 , R 3 , and R 4  independently of the others, is hydrogen, halo, methyl, ethyl, methoxy, ethoxy, nitro, cyano, hydroxy, or —NR 8 R 9  in which each of R 5  and R 9  taken independently of the other is hydrogen or methyl or one of R 8  and R 9  is hydrogen and the other is —COCH 3 .  
      Particular compounds are those in which one of R 1 , R 2 , R 3 , and R 4  is —NH 2  and the remaining of R 1 , R 2 , R 3 , and R 4  are hydrogen.  
      Particular compounds are those in which one of R 1 , R 2 , R 3 , and R 4  is —NHCOCH 3  and the remaining of R 1 , R 2 , R 3 , and R 4  are hydrogen.  
      Particular compounds are those in which one of R 1 , R 2 , R 3 , and R 4  is —N(CH 3 ) 2  and the remaining of R 1 , R 2 , R 3 , and R 4  are hydrogen.  
      A further preferred group of such compounds are those in which one of R 1 , R 2 , R 3 , and R 4  is methyl and the remaining of R 1 , R 2 , R 3 , and R 4  are hydrogen.  
      Particular compounds are those in which one of R 1 , R 2 , R 3 , and R 4  is fluoro and the remaining of R 11 , R 2 , R 3 , and R 4  are hydrogen.  
      Particular compounds are those in which each of R 5  and R 6 , independently of the other, is hydrogen, methyl, ethyl, propyl, methoxy, ethoxy, propoxy, cyclopentoxy, or cyclohexoxy.  
      Particular compounds are those in which R 5  is methoxy and R 6  is monocycloalkoxy, polycycloalkoxy, and benzocycloalkoxy.  
      Particular compounds are those in which R 5  is methoxy and R 6  is ethoxy.  
      Particular compounds are those in which R 7  is hydroxy, methyl, ethyl, phenyl, benzyl, or NR 8′  R 9′  in which each of R 8′  and R 9′  taken independently of the other is hydrogen or methyl.  
      Particular compounds are those in which R 7  is methyl, ethyl, phenyl, benzyl or NR 8′  R 9′  in which each of R 8′  and R 9′  taken independently of the other is hydrogen or methyl.  
      Particular compounds are those in which R 7  is methyl.  
      Particular compounds are those in which R 7  is NR 8 R 9′  in which each of R 8′  and R 9′  taken independently of the other is hydrogen or methyl.  
      Additional PDE4 modulators include fluoroalkoxy-substituted 1,3-dihydro-isoindolyl compounds disclosed in U.S. patent application Ser. No. 10/748,085 filed on Dec. 29, 2003, which is incorporated herein by reference. Representative compounds are of formula:  
                 
          wherein:     Y is —C(O)—, —CH 2 , —CH 2 C(O)—, —C(O)CH 2 —, or SO 2 ;     Z is —H, —C(O)R 3 , —(C 0-1 -alkyl)-SO 2 —(C 1-4 -alkyl), —C 1-8 -alkyl, —CH 2 OH, CH 2 (O)(C 1-8 -alkyl) or —CN;     R 1  and R 2  are each independently —CHF 2 , —C 1-8 -alkyl, —C 3-18 -cycloalkyl, or —(C 1-10 -alkyl)(C 3-18 -cycloalkyl), and at least one of R 1  and R 2  is CHF 2 ;     R 3  is —NR 4 R 5 , -alkyl, —OH, —O-alkyl, phenyl, benzyl, substituted phenyl, or substituted benzyl;     R 4  and R 5  are each independently —H, —C 1-8 -alkyl, —OH, —OC(O)R 6 ;     R 6  is —C 1-8 -alkyl, -amino(C 1-8 -alkyl), -phenyl, -benzyl, or -aryl;     X 1 , X 2 , X 3 , and X 4  are each independently —H, -halogen, -nitro, —NH 2 , —CF 3 , —C 1-6 -alkyl, —(C 0-4 -alkyl)-(C 3-6 -cycloalkyl), (C 0-4 -alkyl)-NR 7 R 8 , (C 0-4 -alkyl)-N(H)C(O)—(R 8 ), (C 0-4 -alkyl)-N(H)C(O)N(R 7 R 8 ), (C 0-4 -alkyl)-N(H)C(O)O(R 7 R 8 ), (C 0-4 -alkyl)-OR 8 , (C 0-4 -alkyl)-imidazolyl, (C 0-4 -alkyl)-pyrrolyl, (C 0-4 -alkyl)-oxadiazolyl, or (C 0-4 -alkyl)-triazolyl, or two of X 1 , X 2 , X 3 , and X 4  may be joined together to form a cycloalkyl or heterocycloalkyl ring, (e.g., X 1  and X 2 , X 2  and X 3 , X 3  and X 4 , X 1  and X 3 , X 2  and X 4 , or X 1  and X 4  may form a 3, 4, 5, 6, or 7 membered ring which may be aromatic, thereby forming a bicyclic system with the isoindolyl ring); and     R 7  and R 8  are each independently H, C 1-9 -alkyl, C 3-6 -cycloalkyl, (C 1-6 -alkyl)-(C 3-6 -cycloalkyl), (C 1-6 -alkyl)-N(R 7 R 8 ), (C 1-6 -alkyl)-OR 8 , phenyl, benzyl, or aryl; or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof.        

      Additional PDE4 modulators include the enantiomerically pure compounds disclosed in U.S. patent application Ser. No. 10/392,195 filed on Mar. 19, 2003; international patent application nos. PCT/US03/08737 and PCT/US03/08738, filed on Mar. 20, 2003; U.S. provisional patent application Nos. 60/438,450 and 60/438,448 to G. Muller et al., both of which were filed on Jan. 7, 2003; U.S. provisional patent application No. 60/452,460 to G. Muller et al. filed on Mar. 5, 2003; and U.S. patent application Ser. No. 10/715,184 filed on Nov. 17, 2003, all of which are incorporated herein by reference. Preferred compounds include an enantiomer of 2-[1-(3-ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-4-acetylaminoisoindoline-1,3-dione and an enantiomer of 3-(3,4-dimethoxy-phenyl)-3-(1-oxo-1,3-dihydro-isoindol-2-yl)-propionamide.  
      Preferred PDE4 modulators used in the invention are 3-(3,4-dimethoxy-phenyl)-3-(1-oxo-1,3-dihydro-isoindol-2-yl)-propionamide and cyclopropanecarboxylic acid {2-[1-(3-ethoxy-4-methoxy-phenyl)-2-methanesulfonyl-ethyl]-3-oxo-2,3-dihydro-1H-isoindol-4-yl}-amide, which are available from Celgene Corp., Warren, N.J. 3-(3,4-Dimethoxy-phenyl)-3-(1-oxo-1,3-dihydro-isoindol-2-yl)-propionamide has the following chemical structure:  
                 
 
      Other specific PDE4 modulators include, but are not limited to, the cycloalkyl amides and cycloalkyl nitriles of U.S. Pat. Nos. 5,728,844, 5,728,845, 5,968,945, 6,180,644 and 6,518,281, and WO 97/08143 and WO 97/23457, each of which is incorporated herein by reference. Representative compounds are of formula:  
                 
          wherein:     one of R 1  and R 2  is R 3 —X— and the other is hydrogen, nitro, cyano, trifluoromethyl, carbo(lower)alkoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, lower alkyl, lower alkoxy, halo, or R 3 —X—;     R 3  is monocycloalkyl, bicycloalkyl, or benzocycloalkyl of up to 18 carbon atoms;     X is a carbon-carbon bond, —CH 2 —, or —O—;     R 5  is (i) o-phenylene, unsubstituted or substituted with 1 to 3 substituents each selected independently from nitro, cyano, halo, trifluoromethyl, carbo(lower)alkoxy, acetyl, or carbamoyl, unsubstituted or substituted with lower alkyl, acetoxy, carboxy, hydroxy, amino, lower alkylamino, lower acylamino, or lower alkoxy; (ii) a vicinally divalent residue of pyridine, pyrrolidine, imidazole, naphthalene, or thiophene, wherein the divalent bonds are on vicinal ring carbon atoms; (iii) a vicinally divalent cycloalkyl or cycloalkenyl of 4-10 carbon atoms, unsubstituted or substituted with 1 to 3 substituents each selected independently from the group consisting of nitro, cyano, halo, trifluoromethyl, carbo(lower)alkoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, lower alkylamino, lower alkyl, lower alkoxy, or phenyl; (iv) vinylene di-substituted with lower alkyl; or (v) ethylene, unsubstituted or monosubstituted or disubstituted with lower alkyl;     R 6  is —CO—, —CH 2 —, or —CH 2 CO—;     Y is —COZ, —C—N, —OR 8 , lower alkyl, or aryl;     Z is —NH 2 , —OH, —NHR, —R 9 , or —OR 9       R 8  is hydrogen or lower alkyl;     R 9  is lower alkyl or benzyl; and,     n has a value of 0, 1, 2, or 3.        

      In another embodiment, one of R 1  and R 2  is R 3 —X— and the other is hydrogen, nitro, cyano, trifluoromethyl, carbo(lower)alkoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, lower alkyl, lower alkoxy, halo, or R 3 —X—; 
          R 3  is monocycloalkyl of up to 10 carbon atoms, polycycloalkyl of up to 10 carbon atoms, or benzocyclic alkyl of up to 10 carbon atoms;     X is —CH 2 —, or —O—;     R 5  is (i) the vicinally divalent residue of pyridine, pyrrolidine, imidazole, naphthalene, or thiophene, wherein the two bonds of the divalent residue are on vicinal ring carbon atoms;     (ii) a vicinally divalent cycloalkyl of 4-10 carbon atoms, unsubstituted or substituted with 1 to 3 substituents each selected independently from the group consisting of nitro, cyano, halo, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, substituted amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, or phenyl;     (iii) di-substituted vinylene, substituted with nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, carbamoyl substituted with and alkyl of 1 to 3 carbon atoms, acetoxy, carboxy, hydroxy, amino, amino substituted with an alkyl of 1 to 3 carbon atoms, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, or halo;     (iv) ethylene, unsubstituted or substituted with 1 to 2 substituents each selected independently from nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, carbamoyl substituted with and alkyl of 1 to 3 carbon atoms, acetoxy, carboxy, hydroxy, amino, amino substituted with an alkyl of 1 to 3 carbon atoms, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, or halo;     R 6  is —CO—, —CH 2 —, or —CH 2 CO—;     Y is —COX, —C—N, —OR 8 , alkyl of 1 to 5 carbon atoms, or aryl;     X is —NH 2 , —OH, —NHR, —R 9 , —OR 9 , or alkyl of 1 to 5 carbon atoms;     R 8  is hydrogen or lower alkyl;     R 9  is alkyl or benzyl; and,     n has a value of 0, 1, 2, or 3.        

      In another embodiment, one of R 1  and R 2  is R 3 —X— and the other is hydrogen, nitro, cyano, trifluoromethyl, carbo(lower)alkoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, lower alkyl, lower alkoxy, halo, HF 2 CO, F 3 CO, or R 3 —X—; 
          R 3  is monocycloalkyl, bicycloalkyl, benzocyclo alkyl of up to 18 carbon atoms, tetrahydropyran, or tetrahydrofuran;     X is a carbon-carbon bond, —CH 2 —, —O—, or —N═;     R 5  is (i) o-phenylene, unsubstituted or substituted with 1 to 3 substituents each selected independently from nitro, cyano, halo, trifluoromethyl, carbo(lower)alkoxy, acetyl, or carbamoyl, unsubstituted or substituted with lower alkyl, acetoxy, carboxy, hydroxy, amino, lower alkylamino, lower acylamino, or lower alkoxy; (ii) a vicinally divalent residue of pyridine, pyrrolidine, imidazole, naphthalene, or thiophene, wherein the divalent bonds are on vicinal ring carbon atoms; (iii) a vicinally divalent cycloalkyl or cycloalkenyl of 4-10 carbon atoms, unsubstituted or substituted with 1 or more substituents each selected independently from the group consisting of nitro, cyano, halo, trifluoromethyl, carbo(lower)alkoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, lower alkylamino, lower alkyl, lower alkoxy, or phenyl; (iv) vinylene di-substituted with lower alkyl; or (v) ethylene, unsubstituted or monosubstituted or disubstituted with lower alkyl;     R 6  is —CO—, —CH 2 —, or —CH 2 CO—;     Y is —COX, —C—N, —OR 8 , alkyl of 1 to 5 carbon atoms, or aryl;     X is —NH 2 , —OH, —NHR, —R 9 , —OR 9 , or alkyl of 1 to 5 carbon atoms;     R 8  is hydrogen or lower alkyl;     R 9  is alkyl or benzyl; and,     n has a value of 0, 1, 2, or 3.        

      Other representative compounds are of formula:  
                 
          wherein:     Y is —C—N or CO(CH 2 ) m CH 3 ;     m is 0, 1, 2, or 3;     R 5  is (i) o-phenylene, unsubstituted or substituted with 1 to 3 substituents each selected independently from nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, carbamoyl substituted with and alkyl of 1 to 3 carbon atoms, acetoxy, carboxy, hydroxy, amino, amino substituted with an alkyl of 1 to 3 carbon atoms, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, or halo; (ii) the divalent residue of pyridine, pyrrolidine, imidizole, naphthalene, or thiophene, wherein the divalent bonds are on vicinal ring carbon atoms; (iii) a divalent cycloalkyl of 4-10 carbon atoms, unsubstituted or substituted with one or more substituents each selected independently of the other from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, substituted amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, phenyl or halo; (iv) di-substituted vinylene, substituted with nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, carbamoyl substituted with and alkyl of 1 to 3 carbon atoms, acetoxy, carboxy, hydroxy, amino, amino substituted with an alkyl of 1 to 3 carbon atoms, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, or halo; or (v) ethylene, unsubstituted or substituted with 1 to 2 substituents each selected independently from nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, carbamoyl substituted with and alkyl of 1 to 3 carbon atoms, acetoxy, carboxy, hydroxy, amino, amino substituted with an alkyl of 1 to 3 carbon atoms, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, or halo;     R 6  is —CO—, —CH 2 —, —CH 2 CO—, or —SO 2 —;     R 7  is (i) straight or branched alkyl of 1 to 12 carbon atoms; (ii) cyclic or bicyclic alkyl of 1 to 12 carbon atoms; (iii) pyridyl; (iv) phenyl substituted with one or more substituents each selected independently of the other from nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, straight, branched, cyclic, or bicyclic alkyl of 1 to 10 carbon atoms, straight, branched, cyclic, or bicyclic alkoxy of 1 to 10 carbon atoms, CH 2 R where R is a cyclic or bicyclic alkyl of 1 to 10 carbon atoms, or halo; (v) benzyl substituted with one to three substituents each selected independently from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 10 carbon atoms, or halo; (vi) naphthyl; or (vii) benzyloxy; and     n has a value of 0, 1, 2, or 3.        

      In another embodiment, specific PDE4 modulators are of formula:  
                 
          wherein:        

      R 5  is (i) the divalent residue of pyridine, pyrrolidine, imidizole, naphthalene, or thiophene, wherein the divalent bonds are on vicinal ring carbon atoms; (ii) a divalent cycloalkyl of 4-10 carbon atoms, unsubstituted or substituted with one or more substituents each selected independently of the other from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, substituted amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, phenyl or halo; (iii) di-substituted vinylene, substituted with nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, carbamoyl substituted with and alkyl of 1 to 3 carbon atoms, acetoxy, carboxy, hydroxy, amino, amino substituted with an alkyl of 1 to 3 carbon atoms, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, or halo; or (iv) ethylene, unsubstituted or substituted with 1 to 2 substituents each selected independently from nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, carbamoyl substituted with and alkyl of 1 to 3 carbon atoms, acetoxy, carboxy, hydroxy, amino, amino substituted with an alkyl of 1 to 3 carbon atoms, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, or halo; 
          R 6  is —CO—, —CH 2 —, —CH 2 CO—, or —SO 2 —;     R 7  is (i) cyclic or bicyclic alkyl of 4 to 12 carbon atoms; (ii) pyridyl; (iii) phenyl substituted with one or more substituents each selected independently of the other from nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, straight, branched, cyclic, or bicyclic alkyl of 1 to 10 carbon atoms, straight, branched, cyclic, or bicyclic alkoxy of 1 to 10 carbon atoms, CH 2 R where R is a cyclic or bicyclic alkyl of 1 to 10 carbon atoms, or halo; (iv) benzyl substituted with one to three substituents each selected independently from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 10 carbon atoms, or halo; (v) naphthyl; or (vi) benzyloxy; and     Y is COX, —C—N, OR 8 , alkyl of 1 to 5 carbon atoms, or aryl;     X is —NH 2 , —OH, —NHR, —R 9 , —OR 9 , or alkyl of 1 to 5 carbon atoms;     R 8  is hydrogen or lower alkyl;     R 9  is alkyl or benzyl; and     n has a value of 0, 1, 2, or 3.        

      Other specific PDE4 modulators include, but are not limited to, the aryl amides (for example, an embodiment being N-benzoyl-3-amino-3-(3′,4′-dimethoxyphenyl)-propanamide) of U.S. Pat. Nos. 5,801,195, 5,736,570, 6,046,221 and 6,284,780, each of which is incorporated herein by reference. Representative compounds are of formula:  
                 
          wherein:     Ar is (i) straight, branched, or cyclic, unsubstituted alkyl of 1 to 12 carbon atoms; (ii) straight, branched, or cyclic, substituted alkyl of 1 to 12 carbon atoms; (iii) phenyl; (iv) phenyl substituted with one or more substituents each selected independently of the other from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, substituted amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, or halo; (v) heterocycle; or (vi) heterocycle substituted with one or more substituents each selected independently of the other from nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, or halo;     R is —H, alkyl of 1 to 10 carbon atoms, CH 2 OH, CH 2 CH 2 OH, or CH 2 COZ where Z is alkoxy of 1 to 10 carbon atoms, benzyloxy, or NHR 1  where R 1  is H or alkyl of 1 to 10 carbon atoms; and     Y is i) a phenyl or heterocyclic ring, unsubstituted or substituted one or more substituents each selected independently one from the other from nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, or halo or ii) naphthyl. Specific examples of the compounds are of formula:  
                 
    wherein:     Ar is 3,4-disubstituted phenyl where each substituent is selected independently of the other from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, and halo;     Z is alkoxy of 1 to 10 carbon atoms, benzyloxy, amino, or alkylamino of 1 to 10 carbon atoms; and     Y is (i) a phenyl, unsubstituted or substituted with one or more substituents each selected, independently one from the other, from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, and halo, or (ii) naphthyl.        

      Other specific PDE4 modulators include, but are not limited to, the imide/amide ethers and alcohols (for example, 3-phthalimido-3-(3′,4′-dimethoxyphenyl) propan-1-ol) disclosed in U.S. Pat. No. 5,703,098, which is incorporated herein by reference. Representative compounds have the formula:  
                 
          wherein:     R 1  is (i) straight, branched, or cyclic, unsubstituted alkyl of 1 to 12 carbon atoms; (ii) straight, branched, or cyclic, substituted alkyl of 1 to 12 carbon atoms; (iii) phenyl; or (iv) phenyl substituted with one or more substituents each selected independently of the other from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, acylamino, alkylamino, di(alkyl)amino, alkyl of 1 to 10 carbon atoms, cycloalkyl of 3 to 10 carbon atoms, bicycloalkyl of 5 to 12 carbon atoms, alkoxy of 1 to 10 carbon atoms, cycloalkoxy of 3 to 10 carbon atoms, bicycloalkoxy of 5 to 12 carbon atoms, and halo;     R 2  is hydrogen, alkyl of 1 to 8 carbon atoms, benzyl, pyridylmethyl, or alkoxymethyl;     R 3  is (i) ethylene, (ii) vinylene, (iii) a branched alkylene of 3 to 10 carbon atoms, (iv) a branched alkenylene of 3 to 10 carbon atoms, (v) cycloalkylene of 4 to 9 carbon atoms unsubstituted or substituted with one or more substituents each selected independently from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, amino substituted with alkyl of 1 to 6 carbon atoms, amino substituted with acyl of 1 to 6 carbon atoms, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 12 carbon atoms, and halo, (vi) cycloalkenylene of 4 to 9 carbon atoms unsubstituted or substituted with one or more substituents each selected independently from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, amino substituted with alkyl of 1 to 6 carbon atoms, amino substituted with acyl of 1 to 6 carbon atoms, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 12 carbon atoms, and halo, (vii) o-phenylene unsubstituted or substituted with one or more substituents each selected independently from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, amino substituted with alkyl of 1 to 6 carbon atoms, amino substituted with acyl of 1 to 6 carbon atoms, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 12 carbon atoms, and halo, (viii) naphthyl, or (ix) pyridyl;     R 4  is —CX—, —CH 2 — or —CH 2 CX—;     X is O or S; and     n is 0, 1, 2, or 3.        

      Other specific PDE4 modulators include, but are not limited to, the succinimides and maleimides (for example methyl 3-(3′,4′,5′6′-petrahydrophthalimdo)-3-(3″,4″-dimethoxyphenyl)propionate) disclosed in U.S. Pat. No. 5,658,940, which is incorporated herein by reference. Representative compounds are of formula:  
                 
          wherein:     R 1  is —CH 2 —, —CH 2 CO—, or —CO—;     R 2  and R 3  taken together are (i) ethylene unsubstituted or substituted with alkyl of 1-10 carbon atoms or phenyl, (ii) vinylene substituted with two substituents each selected, independently of the other, from the group consisting of alkyl of 1-10 carbon atoms and phenyl, or (iii) a divalent cycloalkyl of 5-10 carbon atoms, unsubstituted or substituted with one or more substituents each selected independently of the other from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl unsubstituted or substituted with alkyl of 1-3 carbon atoms, acetoxy, carboxy, hydroxy, amino, substituted amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, norbornyl, phenyl or halo;     R 4  is (i) straight or branched unsubstituted alkyl of 4 to 8 carbon atoms, (ii) cycloalkyl or bicycloalkyl of 5-10 carbon atoms, unsubstituted or substituted with one or more substituents each selected independently of the other from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, substituted amino, branched, straight or cyclic alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, phenyl or halo, (iii) phenyl substituted with one or more substituents each selected independently of the other from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, substituted amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, cycloalkyl or bicyctoalkyl of 3 to 10 carbon atoms, cycloalkoxy or bicycloalkoxy of 3 to 10 carbon atoms, phenyl or halo, (iv) pyridine or pyrrolidine, unsubstituted or substituted with one or more substituents each selected independently of the other from the group consisting of nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, substituted amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, phenyl or halo; and,     R 5  is —COX, —CN, —CH 2 COX, alkyl of 1 to 5 carbon atoms, aryl, —CH 2 OR, —CH 2  aryl, or —CH 2 OH,     where X is NH 2 , OH, NHR, or OR 6 ,     where R is lower alkyl; and     where R 6  is alkyl or benzyl.        

      Other specific PDE4 modulators include, but are not limited to, substituted imides (for example, 2-phthalimido-3-(3′,4′-dimethoxyphenyl)propane) disclosed in U.S. Pat. No. 6,429,221, which is incorporated herein by reference. Representative compounds have the formula:  
                 
          wherein:        

      R 1  is (i) straight, branched, or cyclic alkyl of 1 to 12 carbon atoms, (ii) phenyl or phenyl substituted with one or more substituents each selected independently of the other from nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, straight or branched alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, or halo, (iii) benzyl or benzyl substituted with one or more substituents each selected independently of the other from nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, or halo, or (iv)-Y-Ph where Y is a straight, branched, or cyclic alkyl of 1 to 12 carbon atoms and Ph is phenyl or phenyl substituted with one or more substituents each selected independently of the other from nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, or halo; 
          R 2  is —H, a branched or unbranched alkyl of 1 to 10 carbon atoms, phenyl, pyridyl, heterocycle, —CH 2 -aryl, or —CH 2 -heterocycle;     R 3  is i) ethylene, ii) vinylene, iii) a branched alkylene of 3 to 10 carbon atoms, iv) a branched alkenylene of 3 to 10 carbon atoms, v) cycloalkylene of 4 to 9 carbon atoms unsubstituted or substituted with 1 to 2 substituents each selected independently from nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, substituted amino, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, or halo, vi) cycloalkenylene of 4 to 9 carbon atoms unsubstituted or substituted with 1 to 2 substituents each selected independently from nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, substituted amino, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, or halo, or vii) o-phenylene unsubstituted or substituted with 1 to 2 substituents each selected independently from nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, substituted amino, alkyl of 1 to 4 carbon atoms, alkoxy 1 to 4 carbon atoms, or halo; and,     R 4  is —CX, or —CH 2 —;     X is O or S.        

      Other specific PDE4 modulators include, but are not limited to, substituted 1,3,4-oxadiazoles (for example, 2-[1-(3-cyclopentyloxy-4-methoxyphenyl)-2-(1,3,4-oxadiazole-2-yl)ethyl]-5-methylisoindoline-1,3-dione) disclosed in U.S. Pat. No. 6,326,388, which is incorporated herein by reference. Representative compounds are of formula:  
                 
          wherein:     the carbon atom designated constitutes a center of chirality;     Y is C═O, CH 2 , SO 2  or CH 2 C═O;     X is hydrogen, or alkyl of 1 to 4 carbon atoms;     each of R 1 , R 2 , R 3 , and R 4 , independently of the others, is hydrogen, halo, trifluoromethyl, acetyl, alkyl of 1 to 8 carbon atoms, alkoxy of 1 to 4 carbon atoms, nitro, cyano, hydroxy, —CH 2 NR 8 R 9 , —(CH 2 ) 2 NR 8 R 9 , or —NR 8 R 9  or     any two of R 1 , R 2 , R 3 , and R 4  on adjacent carbon atoms, together with the depicted benzene ring are naphthylidene, quinoline, quinoxaline, benzimidazole, benzodioxole or 2-hydroxybenzimidazole;     each of R 5  and R 6 , independently of the other, is hydrogen, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 6 carbon atoms, cyano, benzocycloalkoxy, cycloalkoxy of up to 18 carbon atoms, bicyloalkoxy of up to 18 carbon atoms, tricylcoalkoxy of up to 18 carbon atoms, or cycloalkylalkoxy of up to 18 carbon atoms;     each of R 8  and R 9 , taken independently of the other is hydrogen, straight or branched alkyl of 1 to 8 carbon atoms, phenyl, benzyl, pyridyl, pyridylmethyl, or one of R 8  and R 9  is hydrogen and the other is —COR 10 , or —SO 2 R 10 , or R 8  and R 9  taken together are tetramethylene, pentamethylene, hexamethylene, —CH═NCH═CH—, or —CH 2 CH 2 X 1 CH 2 CH 2 -in which X 1  is —O—, —S—, or —NH—,     R 10  is hydrogen, alkyl of 1 to 8 carbon atoms, cycloalkyl, cycloalkylmethyl of up to 6 carbon atoms, phenyl, pyridyl, benzyl, imidazolylmethyl, pyridylmethyl, NR 11 R 12  CH 2 R 14 R 15 , or NR 11 R 12 ,     wherein R 14  and R 15 , independently of each other, are hydrogen, methyl, ethyl, or propyl, and     wherein R 11  and R 12 , independently of each other, are hydrogen, alkyl of 1 to 8 carbon atoms, phenyl, or benzyl; and     the acid addition salts of said compounds which contain a nitrogen atom susceptible of protonation.        

      Specific examples of the compounds are of formula:  
                 
          wherein:     the carbon atom designated* constitutes a center of chirality;     Y is C═O, CH 2 , SO 2  or CH 2 C═O;     X is hydrogen, or alkyl of 1 to 4 carbon atoms;     (i) each of R 1 , R 2 , R 3 , and R 4 , independently of the others, is hydrogen, halo, trifluoromethyl, acetyl, alkyl of 1 to 8 carbon atoms, alkoxy of 1 to 4 carbon atoms, nitro, cyano, hydroxy, —CH 2 NR 8 R 9 , —(CH 2 ) 2 NR 8 R 9 , or —NR 8 R 9  or     (ii) any two of R 1 , R 2 , R 3 , and R 4  on adjacent carbon atoms, together with the depicted benzene ring to which they are bound are naphthylidene, quinoline, quinoxaline, benzimidazole, benzodioxole or 2-hydroxybenzimidazole;     each of R 5  and R 6 , independently of the other, is hydrogen, alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 6 carbon atoms, cyano, benzocycloalkoxy, cycloalkoxy of up to 18 carbon atoms, bicyloalkoxy of up to 18 carbon atoms, tricylcoalkoxy of up to 18 carbon atoms, or cycloalkylalkoxy of up to 18 carbon atoms;     (i) each of R 8  and R 9 , independently of the other, is hydrogen, alkyl of 1 to 8 carbon atoms, phenyl, benzyl, pyridyl, pyridylmethyl, or     (ii) one of R 8  and R 9  is hydrogen and the other is —COR 10 , or —SO 2 R 10 , in which R 10  is hydrogen, alkyl of 1 to 8 carbon atoms, cycloalkyl, cycloalkylmethyl of up to 6 carbon atoms, phenyl, pyridyl, benzyl, imidazolylmethyl, pyridylmethyl, NR 11 R 12 , or CH 2 NR 14 R 15 , wherein R 11  and R 12 , independently of each other, are hydrogen, alkyl of 1 to 8 carbon atoms, phenyl, or benzyl and R 14  and R 15 , independently of each other, are hydrogen, methyl, ethyl, or propyl; or     (iii) R 8  and R 9  taken together are tetramethylene, pentamethylene, hexamethylene, —CH═NCH═CH—, or —CH 2 CH 2 X 1 CH 2 CH 2 — in which X 1  is —O—, —S—, or —NH—.        

      Other specific PDE4 modulators include, but are not limited to, cyano and carboxy derivatives of substituted styrenes (for example, 3,3-bis-(3,4-dimethoxyphenyl) acrylonitrile) disclosed in U.S. Pat. Nos. 5,929,117, 6,130,226, 6,262,101 and 6,479,554, each of which is incorporated herein by reference. Representative compounds are of formula:  
                 
          wherein:     (a) X is —O— or —(C n H 2n )— in which n has a value of 0, 1, 2, or 3, and R 1  is alkyl of one to 10 carbon atoms, monocycloalkyl of up to 10 carbon atoms, polycycloalkyl of up to 10 carbon atoms, or benzocyclic alkyl of up to 10 carbon atoms, or     (b) X is —CH═ and R 1  is alkylidene of up to 10 carbon atoms, monocycloalkylidene of up to 10 carbon atoms, or bicycloalkylidene of up to 10 carbon atoms;     R 2  is hydrogen, nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, lower alkyl, lower alkylidenemethyl, lower alkoxy, or halo;     R 3  is (i) phenyl, unsubstituted or substituted with 1 or more substituents each selected independently from nitro, cyano, halo, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, carbamoyl substituted with alkyl of 1 to 3 carbon atoms, acetoxy, carboxy, hydroxy, amino, amino substituted with an alkyl of 1 to 5 carbon atoms, alkyl of up to 10 carbon atoms, cycloalkyl of up to 10 carbon atoms, alkoxy of up to 10 carbon atoms, cycloalkoxy of up to 10 carbon atoms, alkylidenemethyl of up to 10 carbon atoms, cycloalkylidenemethyl of up to 10 carbon atoms, phenyl, or methylenedioxy; (ii) pyridine, substituted pyridine, pyrrolidine, imidizole, naphthalene, or thiophene; (iii) cycloalkyl of 4-10 carbon atoms, unsubstituted or substituted with 1 or more substituents each selected independently from the group consisting of nitro, cyano, halo, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, substituted amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, phenyl;     each of R 4  and R 5  taken individually is hydrogen or R 4  and R 5  taken together are a carbon-carbon bond;     Y is —COZ, —C≡N, or lower alkyl of 1 to 5 carbon atoms;     Z is —OH, —NR 6 R 6 , —R 7 , or —OR 7 ; R 6  is hydrogen or lower alkyl; and R 7  is alkyl or benzyl. Specific examples of the compounds are of formula:  
                 
    wherein:     (a) X is —O— or —(C n H 2n )— in which n has a value of 0, 1, 2, or 3, and R 1  is alkyl of one to 10 carbon atoms, monocycloalkyl of up to 10 carbon atoms, polycycloalkyl of up to 10 carbon atoms, or benzocyclic alkyl of up to 10 carbon atoms, or     (b) X is —CH═ and R 1  is alkylidene of up to 10 carbon atoms, monocycloalkylidene of up to 10 carbon atoms, or bicycloalkylidene of up to 10 carbon atoms;     R 2  is hydrogen, nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, lower alkyl, lower alkylidenemethyl, lower alkoxy, or halo;     R 3  is pyrrolidine, imidazole or thiophene unsubstituted or substituted with 1 or more substituents each selected independently from the group consisting of nitro, cyano, halo, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, substituted amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, or phenyl;     each of R 4  and R 5  taken individually is hydrogen or R 4  and R 5  taken together are a carbon-carbon bond;     Y is —COZ, —C—N, or lower alkyl of 1 to 5 carbon atoms;     Z is —OH, —NR 6 R 6 , —R 7 , or —OR 7 ; R 6  is hydrogen or lower alkyl; and R 7  is alkyl or benzyl.        

      Particularly preferred nitriles are compounds of the formula:  
                 
          wherein:     (a) X is —O— or —(C n H 2n )— in which n has a value of 0, 1, 2, or 3, and R 1  is alkyl of up to 10 carbon atoms, monocycloalkyl of up to 10 carbon atoms, polycycloalkyl of up to 10 carbon atoms, or benzocyclic alkyl of up to 10 carbon atoms, or     (b) X is —CH═, and R 1  is alkylidene of up to 10 carbon atoms or monocycloalkylidene of up to 10 carbon atoms;     R 2  is hydrogen, nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, lower alkyl, lower alkoxy, or halo; and     R 3  is (i) phenyl or naphthyl, unsubstituted or substituted with 1 or more substituents each selected independently from nitro, cyano, halo, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, or carbamoyl substituted with alkyl of 1 to 3 carbon atoms, acetoxy, carboxy, hydroxy, amino, amino substituted with an alkyl of 1 to 5 carbon atoms, alkoxy or cycloalkoxy of 1 to 10 carbon atoms; or (ii) cycloalkyl of 4 to 10 carbon atoms, unsubstituted or substituted with one or more substituents each selected independently from the group consisting of nitro, cyano, halo, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, substituted amino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, or phenyl.        

      Particularly preferred nitrile is of formula:  
                 
 
      Other specific PDE4 modulators include, but are not limited to, isoindoline-1-one and isoindoline-1,3-dione substituted in the 2-position with an α-(3,4-disubstituted phenyl)alkyl group and in the 4- and/or 5-position with a nitrogen-containing group disclosed in WO 01/34606 and U.S. Pat. No. 6,667,316, which are incorporated herein by reference. Representative compounds are of formula:  
                 
          and include pharmaceutically acceptable salts and stereoisomers thereof,     wherein:     one of X and X′ is ═C═O or ═SO 2 , and the other of X and X′ is ═C═O, ═CH 2 , ═SO 2  or ═CH 2 C═O;     n is 1, 2 or 3;     R 1  and R 2  are each independently (C 1 -C 4 )alkyl, (C 1 -C 4 )alkoxy, cyano, (C 3 -C 18 )cycloalkyl, (C 3 -C 18 )cycloalkoxy or (C 3 -C 18 )cycloalkyl-methoxy;     R 3  is SO 2 —Y, COZ, CN or (C 1 -C 6 )hydroxyalkyl, wherein:     Y is (C 1 -C 6 )alkyl, benzyl or phenyl;     Z is —NR 6 R 7 , (C 1 -C 6 )alkyl, benzyl or phenyl;     R 6  is H, (C 1 -C 4 )alkyl, (C 3 -C 18 )cycloalkyl, (C 2 -C 5 )alkanoyl, benzyl or phenyl, each of which can be optionally substituted with halo, amino or (C 1 -C 4 )alkyl-amino;     R 7  is H or (C 1 -C 4 )alkyl;     R 4  and R 5  are taken together to provide —NH—CH 2 —R 8 —, NH—CO—R 8 —, or —N═CH—R 8 —, wherein:     R 8  is CH 2 , O, NH, CH═CH, CH═N, or N═CH; or     one of R 4  and R 5  is H, and the other of R 4  and R 5  is imidazoyl, pyrrolyl, oxadiazolyl, triazolyl, or a structure of formula (A),  
                 
    wherein:     z is 0 or 1;     R 9  is: H; (C 1 -C 4 )alkyl, (C 3 -C 18 )cycloalkyl, (C 2 -C 5 )alkanoyl, or (C 4 -C 6 )cycloalkanoyl, optionally substituted with halo, amino, (C 1 -C 4 )alkyl-amino, or (C 1 -C 4 )dialkyl-amino; phenyl; benzyl; benzoyl; (C 2 -C 5 )alkoxycarbonyl; (C 3 -C 5 )alkoxyalkylcarbonyl; N-morpholinocarbonyl; carbamoyl; N-substituted carbamoyl substituted with (C 1 -C 4 )alkyl; or methylsulfonyl; and     R 10  is H, (C 1 -C 4 )alkyl, methylsulfonyl, or (C 3 -C 5 )alkoxyalkylcarbonyl; or     R 9  and R 10  are taken together to provide —CH═CH—CH═CH—, —CH═CH—N═CH—, or (C 1 -C 2 )alkylidene, optionally substituted with amino, (C 1 -C 4 )alkyl-amino, or (C 1 -C 4 )dialkyl-amino; or     R 4  and R 5  are both structures of formula (A).        

      In one embodiment, z is not 0 when (i) R 3  is —SO 2 —Y, —COZ, or —CN and (ii) one of R 4  or R 5  is hydrogen. In another embodiment, R 9  and R 10 , taken together, is —CH═CH—CH═CH—, —CH═CH—N═CH—, or (C 1 -C 2 )alkylidene substituted by amino, (C 1 -C 4 )alkyl-amino, or (C 1 -C 4 )dialkyl-amino. In another embodiment, R 4  and R 5  are both structures of formula (A).  
      Specific compounds are of formula:  
                 
          and the enantiomers thereof. Further specific compounds are of formulas:  
                 
       

      Further examples include, but are not limited to: 2-[1-(3-Ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-4,5-dinitroisoindoline-1,3-dione; 2-[1-(3-Ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-4,5-diaminoisoindoline-1,3-dione; 7-[1-(3-Ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-3-pyrrolino[3,4-e]benzimidazole-6,8-dione; 7-[1-(3-Ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]hydro-3-pyrrolino[3,4-e]benzimidazole-2,6,8-trione; 2-[1-(3-Ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-3-pyrrolino[3,4-f]quinoxaline-1,3-dione; Cyclopropyl-N-{2-[1-(3-ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-1,3-dioxoisoindolin-4-yl}carboxamide; 2-Chloro-N-{2-[1-(3-ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-1,3-dioxoisoindolin-4-yl}acetamide; 2-Amino-N-{2-[1-(3-ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-1,3-dioxoisoindolin-4-yl}acetamide; 2-N,N-Dimethylamino-N-{2-[-(3-ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-1,3-dioxoisoindolin-4-yl}acetamide; N-{2-[1-(3-ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-1,3-dioxoisoindolin-4-yl}-2,2,2-trifluoroacetamide; N-{2-[1-(3-Ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-1,3-dioxoisoindolin-4-yl}methoxycarboxamide; 4-[1-Aza-2-(dimethylamino)vinyl]-2-[1-(3-ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]isoindoline-1,3-dione; 4-[1-Aza-2-(dimethylamino)prop-1-enyl]-2-[1-(3-ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]isoindoline-1,3-dione; 2-[1-(3-Ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-4-(5-methyl-1,3,4-oxadiazol-2-yl)isoindoline-1,3-dione; 2-[1-(3-Ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-4-pyrrolylisoindoline-1,3-dione; 4-(Aminomethyl)-2-[1-(3-ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-isoindoline-1,3-dione; 2-[1-(3-Ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-4-(pyrrolylmethyl)isoindoline-1,3-dione; N-{2-[1-(3-ethoxy-4-methoxyphenyl)-3-hydroxybutyl]-1,3-dioxoisoindolin-4-yl}acetamide; N-{2-[1-(3-Ethoxy-4-methoxyphenyl)-3-oxobutyl]-1,3-dioxoisoindolin-4-yl}acetamide; N-{2-[1R-(3-ethoxy-4-methoxyphenyl)-3-hydroxybutyl]-1,3-dioxoisoindolin-4-yl}acetamide; N-{2-[1R-(3-ethoxy-4-methoxyphenyl)-3-oxobutyl]-1,3-dioxoisoindolin-4-yl}acetamide; N-{2-[1 S-(3-Ethoxy-4-methoxyphenyl)-3-hydroxybutyl]-1,3-dioxoisoindolin-4-yl}acetamide; N-{2-[1S-(3-ethoxy-4-methoxyphenyl)-3-oxobutyl]-1,3-dioxoisoindolin-4-yl}acetamide; 4-Amino-2-[1-(3-ethoxy-4-methoxyphenyl)-3-hydroxybutylisoindoline-1,3-dione; 4-Amino-2-[1-(3-ethoxy-4-methoxyphenyl)-3-oxobutyl]isoindoline-1,3-dione; 2-[1-(3-Ethoxy-4-methoxyphenyl)-3-oxobutyl]-4-pyrrolylisoindoline-1,3-dione; 2-Chloro-N-{2-[1-(3-ethoxy-4-methoxyphenyl)-3-oxobutyl]-1,3-dioxoisoindol-4-yl}acetamide; 2-(Dimethylamino)-N-{2-[1-(3-ethoxy-4-methoxyphenyl)-3-oxobutyl]-1,3-dioxoisoindolin-4-yl}acetamide; 4-Amino-2-[1R-(3-ethoxy-4-methoxyphenyl)-3-hydroxybutyl]isoindoline-1,3-dione; 4-Amino-2-[1R-(3-ethoxy-4-methoxyphenyl)-3-oxobutyl]isoindoline-1,3-dione; 2-[1R-(3-ethoxy-4-methoxyphenyl)-3-oxobutyl]-4-pyrrolylisoindoline-1,3-dione; 2-(Dimethylamino)-N-{2-[1R-(3-ethoxy-4-methoxyphenyl)-3-oxobutyl]-1,3-dioxoisoindolin-4-yl}acetamide; Cyclopentyl-N-{2-[1-(3-ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethyl]-1,3-dioxoisoindolin-4-yl}carboxamide; 3-(Dimethylamino)-N-{2-[1-(3-ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethyl]-1,3-dioxoisoindolin-4-yl}propanamide; 2-(Dimethylamino)-N-{2-[1-(3-ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethyl]-1,3-dioxoisoindolin-4-yl}propanamide; N-{2-[(1R)-1-(3-ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethyl]-1,3-dioxoisoindolin-4-yl}-2-(dimethylamino)acetamide; N-{2-[(1S)-1-(3-ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethyl]-1,3-dioxoisoindolin-4-yl}-2-(dimethylamino)acetamide; 4-{3-[(Dimethylamino)methyl]pyrrolyl}-2-[1-(3-ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethyl]isoindoline-1,3-dione; Cyclopropyl-N-{2-[(1S)-1-(3-ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethyl]-1,3-dioxoisoindolin-4-yl}carboxamide; 2-[1-(3,4-dimethoxyphenyl)-2-(methylsulfonyl)ethyl]-4-pyrrolylisoindoline-1,3-dione; N-{2-[1-(3,4-dimethoxyphenyl)-2-(methylsulfonyl)ethyl]-1,3-dioxoisoindolin-4-yl}-2-(dimethylamino)acetamide; Cyclopropyl-N-{2-[1-(3,4-dimethoxyphenyl)-2-(methylsulfonyl)ethyl]-1,3-dioxoisoindolin-4-yl}carboxamide; Cyclopropyl-N-{2-[1-(3-ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethyl]-3-oxoisoindolin-4-yl}carboxamide; 2-(Dimethylamino)-N-{2-[1-(3-ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethyl]-3-oxoisoindolin-4-yl}acetamide; Cyclopropyl-N-{2-[(1S)-1-(3-ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethyl]-3-oxoisoindolin-4-yl}carboxamide; Cyclopropyl-N-{2-[(1R)-1-(3-ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethyl]-3-oxoisoindolin-4-yl}carboxamide; (3R)-3-[7-(Acetylamino)-1-oxoisoindolin-2-yl]-3-(3-ethoxy-4-methoxyphenyl)-N,N-dimethylpropanamide; (3R)-3-[7-(Cyclopropylcarbonylamino)-1-oxoisoindolin-2-yl]-3-(3-ethoxy-4-methoxyphenyl)-N,N-dimethylpropanamide; 3-{4-[2-(Dimethylamino)acetylamino]-1,3-dioxoisoindolin-2-yl}-3-(3-ethoxy-4-methoxyphenyl)-N,N-dimethylpropanamide; (3R)-3-[7-(2-Chloroacetylamino)-1-oxoisoindolin-2-yl]-3-(3-ethoxy-4-methoxy-phenyl)-N,N-dimethylpropanamide; (3R)-3-{4-[2-(dimethylamino)acetylamino]-1,3-dioxoisoindolin-2-yl}-3-(3-ethoxy-4-methoxyphenyl)-N,N-dimethylpropanamide; 3-(1,3-Dioxo-4-pyrrolylisoindolin-2-yl)-3-(3-ethoxy-4-methoxyphenyl)-N,N-dimethylpropanamide; 2-[1-(3-Ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethyl]-4-(imidazolyl-methyl)isoindoline-1,3-dione; N-({2-[1-(3-Ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethyl]-1,3-dioxoisoindolin-4-yl}methyl)acetamide; 2-Chloro-N-({2-[1-(3-ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethyl]-1,3-dioxoisoindolin-4-yl}methyl)acetamide; 2-(Dimethylamino)-N-({2-[1-(3-ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethyl]-1,3-dioxoisoindolin-4-yl}methyl)acetamide; 4-[Bis(methylsulfonyl)amino]-2-[1-(3-ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethyl]isoindoline-1,3-dione; 2-[1-(3-Ethoxy-4-methoxyphenyl)-2-(methylsulfonyl)ethyl]-4-[(methylsulfonyl)amino]isoindoline-1,3-dione; N-{2-[1-(3-Ethoxy-4-methoxyphenyl)-3-hydroxypentyl]-1,3-dioxoisoindolin-4-yl}acetamide; N-{2-[1-(3-Ethoxy-4-methoxyphenyl)-3-oxopentyl]1,3-dioxoisoindolin-4-yl}acetamide; 2-[(1R)-1-(3-Ethoxy-4-methoxyphenyl)-3-hydroxybutyl]-4-(pyrrolylmethyl)isoindoline-1,3-dione; 2-[(1R)-1-(3-Ethoxy-4-methoxyphenyl)-3-oxobutyl]-4-(pyrrolylmethyl)isoindoline-1,3-dione; N-{2-[1-(3-Cyclopentyloxy-4-methoxyphenyl)-3-hydroxybutyl]-1,3-dioxoisoindolin-4-yl}acetamide; N-{2-[1-(3-Cyclopentyloxy-4-methoxyphenyl)-3-oxobutyl]-1,3-dioxoisoindolin-4-yl}acetamide; 2-[1-(3-Cyclopentyloxy-4-methoxyphenyl)-3-oxobutyl]-4-pyrrolylisoindoline-1,3-dione; 2-[1-(3,4-Dimethoxyphenyl)-3-oxobutyl]-4-[bis(methylsulfonyl)amino]isoindoline-1,3-dione; and pharmaceutically acceptable salts, solvates, and stereoisomers thereof.  
      Still other specific PDE4 modulators include, but are not limited to, imido and amido substituted acylhydroxamic acids (for example, (3-(1,3-dioxoisoindoline-2-yl)-3-(3-ethoxy-4-methoxyphenyl)propanoylamino)propanoate disclosed in WO 01/45702 and U.S. Pat. No. 6,699,899, which are incorporated herein by reference. Representative compounds are of formula:  
                 
          wherein:     the carbon atom designated * constitutes a center of chirality,     R 4  is hydrogen or —(C═O)—R 12 ,     each of R 1  and R 12 , independently of each other, is alkyl of 1 to 6 carbon atoms, phenyl, benzyl, pyridyl methyl, pyridyl, imidazoyl, imidazolyl methyl, or     CHR*(CH 2 ) n NR*R 0 ,     wherein R* and R 0 , independently of the other, are hydrogen, alkyl of 1 to 6 carbon atoms, phenyl, benzyl, pyridyl methyl, pyridyl, imidazoyl or imidazolylmethyl, and n=0, 1, or 2;     R 5  is C═O, CH 2 , CH 2 —CO—, or SO 2 ;     each of R 6  and R 7 , independently of the other, is nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 6 carbon atoms, cycloalkoxy of 3 to 8 carbon atoms, halo, bicycloalkyl of up to 18 carbon atoms, tricycloalkoxy of up to 18 carbon atoms, 1-indanyloxy, 2-indanyloxy, C 4 -C 8 -cycloalkylidenemethyl, or C 3 -C 10 -alkylidenemethyl;     each of R 8 , R 9 , R 10 , and R 11 , independently of the others, is     (i) hydrogen, nitro, cyano, trifluoromethyl, carbethoxy, carbomethoxy, carbopropoxy, acetyl, carbamoyl, acetoxy, carboxy, hydroxy, amino, alkylamino, dialkylamino, acylamino, alkyl of 1 to 10 carbon atoms, alkoxy of 1 to 10 carbon atoms, halo, or     (ii) one of R 8 , R 9 , R 10 , and R 11  is acylamino comprising a lower alkyl, and the remaining of R 8 , R 9 , R 10 , and R 11  are hydrogen, or     (iii) hydrogen if R 8  and R 9  taken together are benzo, quinoline, quinoxaline, benzimidazole, benzodioxole, 2-hydroxybenzimidazole, methylenedioxy, dialkoxy, or dialkyl, or     (iv) hydrogen if R 10  and R 9 , taken together are benzo, quinoline, quinoxaline, benzimidazole, benzodioxole, 2-hydroxybenzimidazole, methylenedioxy, dialkoxy, or dialkyl, or     (v) hydrogen if R 9  and R 10  taken together are benzo.        

      Still specific PDE4 modulators include, but are not limited to, 7-amido-isoindolyl compounds disclosed in U.S. patent application Ser. No. 10/798,317 filed on Mar. 12, 2004, which is incorporated herein by reference. Representative compounds are of formula:  
                 
          wherein:     Y is —C(O)—, —CH 2 , —CH 2 C(O)— or SO 2 ;     X is H;     Z is (C 0-4 -alkyl)-C(O)R 3 , C 1-4 -alkyl, (C 0-4 -alkyl)-OH, (C 1-4 -alkyl)-O(C 1-4 -alkyl), (C 1-4 -alkyl)-SO 2 (C 1-4 -alkyl), (C 0-4 -alkyl)-SO(C 1-4 -alkyl), (C 0-4 -alkyl)-NH 2 , (C 0-4 -alkyl)-N(C 1-8 -akyl) 2 , (C 0-4 -alkyl)-N(H)(OH), or CH 2 NSO 2 (C 1-4 -alkyl);     R 1  and R 2  are independently C 1-8 -alkyl, cycloalkyl, or (C 1-4 -alkyl)cycloalkyl;     R 3  is, NR 4 R 5 , OH, or O—(C 1-8 -alkyl);     R 4  is H;     R 5  is —OH, or —OC(O)R 6 ;     R 6  is C 1-8 -alkyl, amino-(C 1-8 -alkyl), (C 1-8 -alkyl)-(C 3-6 -cycloalkyl), C 3-6 -cycloalkyl, phenyl, benzyl, or aryl;     or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof; or formula:  
                 
    wherein:     Y is —C(O)—, —CH 2 , —CH 2 C(O)—, or SO 2 ;     X is halogen, —CN, —NR 7 R 8 , —NO 2 , or —CF 3 ;     Z is (C 0-4 alkyl)-SO 2 (C 1-4 -alkyl), —(C 0-4 -alkyl)-CN, —(C 0-4 -alkyl)-C(O)R 3 , C 1-4 -alkyl, (C 0-4 -alkyl)OH, (C 0-4 -alkyl)O(C 1-4 -alkyl), (C 0-4 -alkyl)SO(C 1-4 -alkyl), (C 0-4 -alkyl)NH 2 , (C 0-4 -alkyl)N(C 1-8 -alkyl) 2 , (C 0-4 -alkyl) N(H)(OH), (C 0-4 -alkyl)-dichloropyridine or (C 0-4 -alkyl)NSO 2 (C 1-4 -alkyl);     W is —C 3-6 -cycloalkyl, —(C 1-8 -alkyl)-(C 3-6 -cycloalkyl), —(C 0-8 -alkyl)-(C 3-6 -cycloalkyl)-NR 7 R 8 , (C 0-8 -alkyl)-NR 7 R 8 , (C 0-4 alkyl)-CHR 9 —(C 0-4 alkyl)-NR 7 R 8 ;     R 1  and R 2  are independently C 1-8 -alkyl, cycloalkyl, or (C 1-4 -alkyl)cycloalkyl;     R 3  is C 1-8 -alkyl, NR 4 R 5 , OH, or O—(C 1-8 -alkyl);     R 4  and R 5  are independently H, C 1-8 -alkyl, (C 0-8 -alkyl)-(C 3-6 -cycloalkyl), OH, or —OC(O)R 6 ;     R 6  is C 1-8 -alkyl, (C 0-8 -alkyl)-(C 3-6 -cycloalkyl), amino-(C 1-8 -alkyl), phenyl, benzyl, or aryl;     R 7  and R 8  are each independently H, C 1-8 -alkyl, (C 0-8 -alkyl)-(C 3-6 -cycloalkyl), phenyl, benzyl, aryl, or can be taken together with the atom connecting them to form a 3 to 7 membered heterocycloalkyl or heteroaryl ring;     R 9  is C 1-4  alkyl, (C 0-4 alkyl)aryl, (C 0-4 alkyl)-(C 3-6 -cycloalkyl), (C 0-4 alkyl)-heterocylcle; or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof. In another embodiment, W is  
                 
       

      In another embodiment, representative compounds are of formula:  
                 
          wherein:     R 1 , R 2  and R 3  are independently H or C 1-8 -alkyl, with the proviso that at least one of R 1 , R 2  and R 3  is not H;     and pharmaceutically acceptable salts, solvates, hydrates, stereoisomers, clathrates, or prodrugs thereof.        

      Still specific PDE4 modulators include, but are not limited to, isoindoline compounds disclosed in U.S. patent application Ser. No. 10/900,332 filed on Jul. 28, 2004, which is incorporated herein by reference. Representative compounds are listed in Table 1 below, and pharmaceutically acceptable prodrugs, salts, solvates, and stereoisomers thereof:  
                   TABLE 1                       No.   Structure                                                    1                                     2                                     3                                     4                                     5                                     6                                     7                                     8                                     9                                     10                                     11                                     12                                     13                                     14                                     15                                     16                                        
 
      In another embodiment, this invention also encompasses 2-[1-(3-ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-4,5-dinitroisoindoline-1,3-dione and its acid addition salts. In a particular embodiment, this invention encompasses a hydrochloride salt of 2-[1-(3-ethoxy-4-methoxyphenyl)-2-methylsulfonylethyl]-4,5-dinitroisoindoline-1,3-dione.  
      Still specific PDE4 modulators include, but are not limited to, isoindoline compounds disclosed in U.S. patent application Ser. No. 10/900,270 filed on Jul. 28, 2004, which is incorporated herein by reference. Representative compounds are cyclopropanecarboxylic acid {2-[1-(3-ethoxy-4-methoxy-phenyl)-2-[1,3,4]oxadiazol-2-yl-ethyl]-3-oxo-2,3-dihydro-1H-isoindol-4-yl}-amide, which has the following chemical structure, and pharmaceutically acceptable salts, solvates, prodrugs, and stereoisomers thereof:  
                 
 
      Still specific PDE4 modulators include, but are not limited to, N-alkyl-hydroxamic acid-isoindolyl compounds disclosed in U.S. provisional application No. 60/454,149 filed on Mar. 12, 2003, and its U.S. non-provisional application entitled “N-alkyl-hydroxamic acid-isoindolyl compounds and their pharmaceutical uses” which was filed on Mar. 12, 2004 by Man et al. under U.S. Ser. No. 10/798,372, each of which is incorporated herein by reference. Representative compounds are of formula:  
                 
          wherein:     Y is —C(O)—, —CH 2 , —CH 2 C(O)— or SO 2 ;     R 1  and R 2  are independently C 1-8 -alkyl, CF 2 H, CF 3 , CH 2 CHF 2 , cycloalkyl, or (C 1-8 -alkyl)cycloalkyl;     Z 1 , is H, C 1-6 -alkyl, —NH 2 —NR 3 R 4  or OR 5 ;     Z 2  is H or C(O)R 5 ;     X 1 , X 2 , X 3  and X 4  are each independent H, halogen, NO 2 , OR 3 , CF 3 , C 1-6 -alkyl, (C 0-4  alkyl)-(C 3-6 -cycloalkyl), (C 0-4 -alkyl)-N—(R 8 R 9 ), (C 0-4 -alkyl)-NHC(O)—(R 8 ), (C 0-4 -alkyl)-NHC(O)CH(R 8 )(R 9 ), (C 0-4 -alkyl)-NHC(O)N(R 8 R 9 ), (C 0-4 -alkyl)-NHC(O)O(R 8 ), (C 0-4 -alkyl)-O—R 8 , (C 0-4 -alkyl)-imidazolyl, (C 0-4 -alkyl)-pyrrolyl, (C 0-4 -alkyl) oxadiazolyl, (C 0-4 -alkyl)-triazolyl or (C 0-4 -alkyl)-heterocycle;     R 3 , R 4 , and R 5  are each independently H, C 1-6 -alkyl, O—C 1-6 -alkyl, phenyl, benzyl, or aryl;     R 6  and R 7  are independently H or C 1-6 -alkyl;     R 8  and R 9  are each independently H, C 1-9 -alkyl, C 3-6 -cycloalkyl, (C 1-6 -alkyl)-(C 3-6 -cycloalkyl), (C 0-6 -alkyl)-N(R 4 R 5 ), (C 1-6 -alkyl)-OR 5 , phenyl, benzyl, aryl, piperidinyl, piperizinyl, pyrolidinyl, morpholino, or C 3-7 -heterocycloalkyl; and     or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof.        

      Still specific PDE4 modulators include, but are not limited to, diphenylethylene compounds disclosed in U.S. patent application Ser. No. 10/934,974, filed on Sep. 3, 2004, as a CIP of U.S. patent application Ser. No. 10/794,931, filed Mar. 5, 2004, which claims priority to U.S. provisional patent application No. 60/452,460, filed Mar. 5, 2003, which is incorporated herein by reference. Representative compounds are of formula:  
                 
          and pharmaceutically acceptable salts, solvates or hydrates thereof,     wherein:     R 1  is halogen, —CN, lower alkyl, —COOH, —C(O)—N(R 9 ) 2 , —C(O)-lower alkyl, —C(O)-benzyl, —C(O)O-lower alkyl, —C(O)O-benzyl;     R 4  is —H, —NO 2 , cyano, substituted or unsubstituted lower alkyl, substituted or unsubstituted alkoxy, halogen, —OH, —C(O)(R 10 ) 2 , —COOH, —NH 2 , —OC(O)—N(R 10 ) 2 ;     R 5  is substituted or unsubstituted lower alkyl, substituted or unsubstituted alkoxy, or substituted or unsubstituted alkenyl;     X is substituted or unsubstituted phenyl, substituted or unsubstituted pyridine, substituted or unsubstituted pyrrolidine, substituted or unsubstituted imidizole, substituted or unsubstituted naphthalene, substituted or unsubstituted thiophene, or substituted or unsubstituted cycloalkyl;     each occurrence of R 9  is independently —H or substituted or unsubstituted lower alkyl; and     each occurrence of R 10  is independently —H or substituted or unsubstituted lower alkyl.        

      In another embodiment, representative compounds are of formula:  
                 
          and pharmaceutically acceptable salts, solvates or hydrates thereof,     wherein:     R 1  and R 2  are independently —H, —CN, halogen, substituted or unsubstituted lower alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, —NHC(O)OR 9 , —COOH, —C(O)-lower alkyl, —C(O)O-lower alkyl, —C(O)—N(R 9 ) 2 , substituted or unsubstituted aryl, or substituted or unsubstituted heterocycle;     each occurrence of R a , R b , R c , and R d  is independently —H, substituted or unsubstituted lower alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heterocycle, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, halogen, cyano, —NO 2 , —OH, —OPO(OH) 2 , —N(R 9 ) 2 , —OC(O)—R 10 , —OC(O)—R 10 —N(R 10 ) 2 , —C(O)N(R 10 ) 2 , —NHC(O)—R 10 , —NHS(O) 2 —R 10 , —S(O) 2 —R 10 , —NHC(O)NH—R 10 , —NHC(O)N(R 10 ) 2 , —NHC(O)NHSO 2 —R 10 , —NHC(O)—R 10 —N(R 10 ) 2 , —NHC(O)CH(R 10 )(N(R 9 ) 2 ) or —NHC(O)—R 10 —NH 2 ;     R 3  is —H, substituted or unsubstituted lower alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heterocycle, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, halogen, cyano, —NO 2 , —OH, —OPO(OH) 2 , —N(R 9 ) 2 , —OC(O)—R 10 , —OC(O)—R 10 —N(R 10 ) 2 , —OC(O)—R 10 —NH 2 , —C(O)N(R 10 ) 2 , —NHC(O)—R 10 , —NHS(O) 2 —R 10 , —S(O) 2 —R 10 , —OS(O) 2 —R 10 , —OS(O) 2 —NH 2 , —OS(O) 2 —N(R 10 ) 2 , —SO 2 NH 2 , —SO 2 —N(R 10 ) 2 , —NHC(O)O—R 10 , —NHC(O)NH—R 10 , —NHC(O)N(R 10 ) 2 , —NHC(O)NHSO 2 —R 10 , —NHC(O)—R 10 —N(R 10 ) 2 , —NHC(O)CH(R 10 )(N(R 9 ) 2 ) or —NHC(O)—R 10 —NH 2 , or R 3  with either R a  or with R 4 , together form —O—C(R 16 R 17 )—O— or —O—(C(R 16 R 17 )) 2 —O—;     R 4  is —H, substituted or unsubstituted lower alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heterocycle, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, halogen, cyano, —NO 2 , —OH, —OPO(OH) 2 , —N(R 9 ) 2 , —OC(O)—R 10 , —OC(O)—R 10 —N(R 10 ) 2 , —OC(O)—R 10 —NH 2 , —C(O)N(R 10 ) 2 , —NHC(O)—R 10 , —NHS(O) 2 —R 10 , —S(O) 2 —R 10 , —OS(O) 2 —R 10 , —OS(O) 2 —NH 2 , —OS(O) 2 —N(R 10 ) 2 , —SO 2 NH 2 , —SO 2 —N(R 10 ) 2 , —NHC(O)O—R 10 , —NHC(O)NH—R 10 , —NHC(O)N(R 10 ) 2 , —NHC(O)NHSO 2 —R 10 , —NHC(O)—R 10 —N(R 10 ) 2 , —NHC(O)CH(R 10 )(N(R 9 ) 2 ) or —NHC(O)—R 10 —NH 2 ;     R 5  is —H, substituted or unsubstituted lower alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heterocycle, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, halogen, cyano, —NO 2 , —OH, —OPO(OH) 2 , —N(R 9 ) 2 , —OC(O)—R 10 , —OC(O)—R 10 —N(R 10 ) 2 , —OC(O)—R 10 —NH 2 , —C(O)N(R 10 ) 2 , —NHC(O)—R 10 , —NHS(O) 2 —R 10 , —S(O) 2 —R 10 , —OS(O) 2 —R 10 , —OS(O) 2 —NH 2 , —OS(O) 2 —N(R 10 ) 2 , —SO 2 NH 2 , —SO 2 —N(R 10 ) 2 , —NHC(O)O—R 10 , —NHC(O)NH—R 10 , —NHC(O)N(R 10 ) 2 , —NHC(O)NHSO 2 —R 10 , —NHC(O)—R 10 —N(R 10 ) 2 , —NHC(O)CH(R 10 )(N(R 9 ) 2 ) or —NHC(O)—R 10 —NH 2 ;     R 6  is —H, substituted or unsubstituted lower alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heterocycle, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, halogen, cyano, —NO 2 , —OH, —OPO(OH) 2 , —N(R 9 ) 2 , —OC(O)—R 10 , —OC(O)—R 10 —N(R 10 ) 2 , —OC(O)—R 10 —NH 2 , —C(O)N(R 10 ) 2 , —NHC(O)—R 10 , —NHS(O) 2 —R 10 , —S(O) 2 —R 10 , —OS(O) 2 —R 10 , —OS(O) 2 —NH 2 , —OS(O) 2 —N(R 10 ) 2 , —SO 2 NH 2 , —SO 2 —N(R 10 ) 2 , —NHC(O)O—R 10 , —NHC(O)NH—R 10 , —NHC(O)N(R 10 ) 2 , —NHC(O)NHSO 2 —R 10 , —NHC(O)—R 10 -N(R 10 ) 2 , —NHC(O)CH(R 10 )(N(R 9 ) 2 ) or —NHC(O)—R 10 —NH 2 ;     R 7  is —H, substituted or unsubstituted lower alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heterocycle, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, halogen, cyano, —NO 2 , —OH, —OPO(OH) 2 , —N(R 9 ) 2 , —OC(O)—R 10 , —OC(O)—R 10 -N(R 10 ) 2 , —OC(O)—R 10 —NH 2 , —C(O)N(R 10 ) 2 , —NHC(O)—R 10 , —NHS(O) 2 —R 10 , —S(O) 2 —R 10 , —OS(O) 2 —R 10 , —OS(O) 2 —NH 2 , —OS(O) 2 —N(R 10 ) 2 , —SO 2 NH 2 , —SO 2 —N(R 10 ) 2 , —NHC(O)O—R 10 , —NHC(O)NH—R 10 , —NHC(O)N(R 10 ) 2 , —NHC(O)NHSO 2 —R 10 , —NHC(O)—R 10 -N(R 10 ) 2 , —NHC(O)CH(R 10 )(N(R 9 ) 2 ) or —NHC(O)—R 10 —NH 2 ;     R 8  is —H, substituted or unsubstituted lower alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heterocycle, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, halogen, cyano, —NO 2 , —OH, —OPO(OH) 2 , —N(R 9 ) 2 , —OC(O)—R 10 , —OC(O)—R 10 -N(R 10 ) 2 , —OC(O)—R 10 —NH 2 , —C(O)N(R 10 ) 2 , —NHC(O)—R 10 , —NHS(O) 2 —R 10 , —S(O) 2 —R 10 , —OS(O) 2 —R 10 , —OS(O) 2 —NH 2 , —OS(O) 2 —N(R 10 ) 2 , —SO 2 NH 2 , —SO 2 —N(R 10 ) 2 , —NHC(O)O—R 10 , —NHC(O)NH—R 10 , —NHC(O)N(R 10 ) 2 , —NHC(O)NHSO 2 —R 10 , —NHC(O)—R 10 -N(R 10 ) 2 , —NHC(O)CH(R 10 )(N(R 9 ) 2 ) or —NHC(O)—R 10 —NH 2 , or R 5  with either R c , or with R 7 , together form —O—C(R 16 R 17 )—O— or —O—(C(R 16 R 17 )) 2 —O—;     each occurrence of R 9  is independently —H, substituted or unsubstituted lower alkyl, or substituted or unsubstituted cycloalkyl;     each occurrence of R 10  is independently substituted or unsubstituted lower alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, substituted or unsubstituted lower hydroxyalkyl, or R 10  and a nitrogen to which it is attached form a substituted or unsubstituted heterocycle, or R 10  is —H where appropriate; and     each occurrence of R 16  and R 17  is independently —H or halogen.        

      Still specific PDE4 modulators include, but are not limited to, substituted heterocyclic compounds disclosed in U.S. Provisional Patent Application No. 60/607,408, filed on Sep. 3, 2004, which is incorporated herein by reference. Representative compounds are of formula:  
                 
          and pharmaceutically acceptable salts, solvates or hydrates thereof,     wherein:     X is substituted or unsubstituted imidazole, substituted or unsubstituted pyridine, substituted or unsubstituted pyrrolidine, substituted or unsubstituted thiophene, substituted or unsubstituted indole, substituted or unsubstituted 2,3-dihydrobenzofuran, substituted or unsubstituted 3,4-dihydro-2H-benzo(b)(1,4)oxazine, substituted or unsubstituted 1H-benzo(d)(1,2,3)triazole, substituted or unsubstituted quinoline, substituted or unsubstituted benzofuran, substituted or unsubstituted benzo(d)oxazol-2(3H)one or substituted or unsubstituted pyrimidine;     each occurrence of R 1  and R 2  is independently —H, —CN, halogen, substituted or unsubstituted lower alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, —NHC(O)R 9 , —NHC(O)OR 9 , —COOH, —C(O)-lower alkyl, —C(O)O-lower alkyl, —C(O)—N(R 9 ) 2 , substituted or unsubstituted aryl, or substituted or unsubstituted heterocycle;     each occurrence of R a  and R b  is independently —H, substituted or unsubstituted lower alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heterocycle, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, halogen, cyano, —NO 2 , —OH, —OPO(OH) 2 , —N(R 9 ) 2 , —OC(O)—R 10 , —OC(O)—R 10 -N(R 10 ) 2 , —C(O)N(R 10 ) 2 , —NHC(O)—R 10 , —NHS(O) 2 —R 10 , —S(O) 2 —R 10 , —S(O) 2 —NH 2 , —S(O) 2 —N(R 10 ) 2 , —NHC(O)NH—R 10 , —NHC(O)N(R 10 ) 2 , —NHC(O)NHSO 2 —R 10 , —NHC(O)—R 10 -N(R 10 ) 2 , —NHC(O)CH(R 10 )(N(R 9 ) 2 ) or —NHC(O)—R 10 —NH 2 ;     R 3  is —H, substituted or unsubstituted lower alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heterocycle, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, halogen, cyano, —NO 2 , —OH, —OPO(OH) 2 , —N(R 9 ) 2 , —OC(O)—R 10 , —OC(O)—R 10 -N(R 10 ) 2 , —OC(O)—R 10 —NH 2 , —C(O)N(R 10 ) 2 , —NHC(O)—R 10 , —NHS(O) 2 —R 10 , —S(O) 2 —R 10 , —OS(O) 2 —R 10 , —S(O) 2 —NH 2 , —S(O) 2 —N(R 10 ) 2 , —OS(O) 2 —NH 2 , —OS(O) 2 —N(R 10 ) 2 , —NHC(O)O—R 10 , —NHC(O)NH—R 10 , —NHC(O)N(R 10 ) 2 , —NHC(O)NHSO 2 —R 10 , —NHC(O)—R 10 -N(R 10 ) 2 , —NHC(O)CH(R 10 )(N(R 9 ) 2 ) or —NHC(O)—R 10 —NH 2 , or R 3  with either R a  or with R 4 , together form —O—C(R 16 R 17 )—O—, —O—(C(R 16 R 17 )) 2 —O— or —O—(C(R 16 R 17 )) 3 —O—;     R 4  is —H, substituted or unsubstituted lower alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heterocycle, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, halogen, cyano, —NO 2 , —OH, —OPO(OH) 2 , —N(R 9 ) 2 , —OC(O)—R 10 , —OC(O)—R 10 -N(R 10 ) 2 , —OC(O)—R 10 —NH 2 , —C(O)N(R 10 ) 2 , —NHC(O)—R 10 , —NHS(O) 2 —R 10 , —S(O) 2 —R 10 , —OS(O) 2 —R 10 , —S(O) 2 —NH 2 , —S(O) 2 —N(R 10 ) 2 , —OS(O) 2 —NH 2 , —OS(O) 2 —N(R 10 ) 2 , —NHC(O)O—R 10 , —NHC(O)NH—R 10 , —NHC(O)N(R 10 ) 2 , —NHC(O)NHSO 2 —R 10 , —NHC(O)—R 10 -N(R 10 ) 2 , —NHC(O)CH(R 10 )(N(R 9 ) 2 ) or —NHC(O)—R 10 —NH 2 ;     R 5  is —H, substituted or unsubstituted lower alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heterocycle, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, halogen, cyano, —NO 2 , —OH, —OPO(OH) 2 , —N(R 9 ) 2 , —OC(O)—R 10 , —OC(O)—R 10 -N(R 10 ) 2 , —OC(O)—R 10 —NH 2 , —C(O)N(R 10 ) 2 , —NHC(O)—R 10 , —NHS(O) 2 —R 10 , —S(O) 2 —R 10 , —OS(O) 2 —R 10 , —S(O) 2 —NH 2 , —S(O) 2 —N(R 10 ) 2 , —OS(O) 2 —NH 2 , —OS(O) 2 —N(R 10 ) 2 , —NHC(O)O—R 10 , —NHC(O)NH—R 10 , —NHC(O)N(R 10 ) 2 , —NHC(O)NHSO 2 —R 10 , —NHC(O)—R 10 -N(R 10 ) 2 , —NHC(O)CH(R 10 )(N(R 9 ) 2 ) or —NHC(O)—R 10 —NH 2 ;     each occurrence of R 9  is independently —H, substituted or unsubstituted lower alkyl, or substituted or unsubstituted cycloalkyl;     each occurrence of R 10  is independently substituted or unsubstituted lower alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, substituted or unsubstituted lower hydroxyalkyl, or R 10  and a nitrogen to which it is attached form a substituted or unsubstituted heterocycle, or R 10  is —H where appropriate; and     each occurrence of R 16  and R 17  is independently —H or halogen.        

      Compounds of the invention can either be commercially purchased or prepared according to the methods described in the patents or patent publications disclosed herein. Further, optically pure compositions can be asymmetrically synthesized or resolved using known resolving agents or chiral columns as well as other standard synthetic organic chemistry techniques.  
      As used herein and unless otherwise indicated, the term “pharmaceutically acceptable salt” encompasses non-toxic acid and base addition salts of the compound to which the term refers. Acceptable non-toxic acid addition salts include those derived from organic and inorganic acids or bases known in the art, which include, for example, hydrochloric acid, hydrobromic acid, phosphoric acid, sulfuric acid, methanesulphonic acid, acetic acid, tartaric acid, lactic acid, succinic acid, citric acid, malic acid, maleic acid, sorbic acid, aconitic acid, salicylic acid, phthalic acid, embolic acid, enanthic acid, and the like.  
      Compounds that are acidic in nature are capable of forming salts with various pharmaceutically acceptable bases. The bases that can be used to prepare pharmaceutically acceptable base addition salts of such acidic compounds are those that form non-toxic base addition salts, i.e., salts containing pharmacologically acceptable cations such as, but not limited to, alkali metal or alkaline earth metal salts and the calcium, magnesium, sodium or potassium salts in particular. Suitable organic bases include, but are not limited to, N,N-dibenzylethylenediamine, chloroprocaine, choline, diethanolamine, ethylenediamine, meglumaine (N-methylglucamine), lysine, and procaine.  
      As used herein and unless otherwise indicated, the term “prodrug” means a derivative of a compound that can hydrolyze, oxidize, or otherwise react under biological conditions (in vitro or in vivo) to provide the compound. Examples of prodrugs include, but are not limited to, derivatives of PDE4 modulators that comprise biohydrolyzable moieties such as biohydrolyzable amides, biohydrolyzable esters, biohydrolyzable carbamates, biohydrolyzable carbonates, biohydrolyzable ureides, and biohydrolyzable phosphate analogues. Other examples of prodrugs include derivatives of a PDE4 modulator that comprise —NO, —NO 2 , —ONO, or —ONO 2  moieties. Prodrugs can typically be prepared using well-known methods, such as those described in 1  Burger&#39;s Medicinal Chemistry and Drug Discovery,  172-178, 949-982 (Manfred E. Wolff ed., 5th ed. 1995), and  Design of Prodrugs  (H. Bundgaard ed., Elselvier, N.Y. 1985).  
      As used herein and unless otherwise indicated, the terms “biohydrolyzable amide,” “biohydrolyzable ester,” “biohydrolyzable carbamate,” “biohydrolyzable carbonate,” “biohydrolyzable ureide,” and “biohydrolyzable phosphate” mean an amide, ester, carbamate, carbonate, ureide, or phosphate, respectively, of a compound that either: 1) does not interfere with the biological activity of the compound but can confer upon that compound advantageous properties in vivo, such as uptake, duration of action, or onset of action; or 2) is biologically inactive but is converted in vivo to the biologically active compound. Examples of biohydrolyzable esters include, but are not limited to, lower alkyl esters, lower acyloxyalkyl esters (such as acetoxylmethyl, acetoxyethyl, aminocarbonyloxymethyl, pivaloyloxymethyl, and pivaloyloxyethyl esters), lactonyl esters (such as phthalidyl and thiophthalidyl esters), lower alkoxyacyloxyalkyl esters (such as methoxycarbonyloxymethyl, ethoxycarbonyloxyethyl and isopropoxycarbonyloxyethyl esters), alkoxyalkyl esters, choline esters, and acylamino alkyl esters (such as acetamidomethyl esters). Examples of biohydrolyzable amides include, but are not limited to, lower alkyl amides, α-amino acid amides, alkoxyacyl amides, and alkylaminoalkylcarbonyl amides. Examples of biohydrolyzable carbamates include, but are not limited to, lower alkylamines, substituted ethylenediamines, aminoacids, hydroxyalkylamines, heterocyclic and heteroaromatic amines, and polyether amines.  
      Various PDE4 modulators contain one or more chiral centers, and can exist as racemic mixtures of enantiomers or mixtures of diastereomers. This invention encompasses the use of stereomerically pure forms of such compounds, as well as the use of mixtures of those forms. For example, mixtures comprising equal or unequal amounts of the enantiomers of PDE4 modulators may be used in methods and compositions of the invention. The purified (R) or (S) enantiomers of the specific compounds disclosed herein may be used substantially free of its other enantiomer.  
      As used herein and unless otherwise indicated, the term “stereomerically pure” means a composition that comprises one stereoisomer of a compound and is substantially free of other stereoisomers of that compound. For example, a stereomerically pure composition of a compound having one chiral center will be substantially free of the opposite enantiomer of the compound. A stereomerically pure composition of a compound having two chiral centers will be substantially free of other diastereomers of the compound. A typical stereomerically pure compound comprises greater than about 80% by weight of one stereoisomer of the compound and less than about 20% by weight of other stereoisomers of the compound, more preferably greater than about 90% by weight of one stereoisomer of the compound and less than about 10% by weight of the other stereoisomers of the compound, even more preferably greater than about 95% by weight of one stereoisomer of the compound and less than about 5% by weight of the other stereoisomers of the compound, and most preferably greater than about 97% by weight of one stereoisomer of the compound and less than about 3% by weight of the other stereoisomers of the compound.  
      As used herein and unless otherwise indicated, the term “stereomerically enriched” means a composition that comprises greater than about 60% by weight of one stereoisomer of a compound, preferably greater than about 70% by weight, more preferably greater than about 80% by weight of one stereoisomer of a compound.  
      As used herein and unless otherwise indicated, the term “enantiomerically pure” means a stereomerically pure composition of a compound having one chiral center. Similarly, the term “enantiomerically enriched” means a stereomerically enriched composition of a compound having one chiral center.  
      It should be noted that if there is a discrepancy between a depicted structure and a name given that structure, the depicted structure is to be accorded more weight. In addition, if the stereochemistry of a structure or a portion of a structure is not indicated with, for example, bold or dashed lines, the structure or portion of the structure is to be interpreted as encompassing all stereoisomers of it.  
      4.2 Second Active Agents  
      A second active agent can be used in the methods and compositions of the invention together with a PDE4 modulator. It is believed that certain combinations work synergistically in the treatment of asbestos-related diseases or disorders. A PDE4 modulator can also work to alleviate adverse effects associated with certain second active agents, and some second active agents can be used to alleviate adverse effects associated with a PDE4 modulator.  
      One or more second active agents can be used in the methods and compositions of the invention together with a PDE4 modulator, or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof. Second active agents can be large molecules (e.g., proteins) or small molecules (e.g., synthetic inorganic, organometallic, or organic molecules).  
      Examples of large molecule active agents are biological molecules, such as naturally occurring or artificially made proteins. Particular proteins include, but are not limited to: cytokines such as GM-CSF, interleukins such as IL-2 (including recombinant IL-II (“rIL2”) and canarypox IL-2), IL-10, IL-12, and IL-18; and interferons, such as interferon alfa-2a, interferon alfa-2b, interferon alfa-n1, interferon alfa-n3, interferon beta-Ia, and interferon gamma-Ib.  
      In one embodiment of the invention, the large molecule active agent reduces, eliminates, or prevents an adverse effect associated with the administration of a PDE4 modulator. Depending on the disease or disorder begin treated, adverse effects can include, but are not limited to, drowsiness, somnolence, nausea, emesis, gastrointestinal discomfort, diarrhea, and vasculitis.  
      Second active agents that are small molecules can also be used to alleviate adverse effects associated with the administration of a PDE4 modulator. Like some large molecules, many are believed to be capable of providing a synergistic effect when administered with (e.g., before, after or simultaneously) a PDE4 modulator. Examples of small molecule second active agents include, but are not limited to, anti-cancer agents, antibiotics, anti-inflammatory agents, and steroids.  
      Examples of anti-cancer agents include, but are not limited to: acivicin; aclarubicin; acodazole hydrochloride; acronine; 4-(amino)-2-(2,6-dioxo(3-piperidyl))-isoindoline-1,3-dione (Actimid™); adozelesin; aldesleukin; altretamine; ambomycin; ametantrone acetate; amsacrine; anastrozole; anthramycin; asparaginase; asperlin; azacitidine; azetepa; azotomycin; batimastat; benzodepa; bicalutamide; bisantrene hydrochloride; bisnafide dimesylate; bizelesin; bleomycin sulfate; brequinar sodium; bropirimine; busulfan; cactinomycin; calusterone; caracemide; carbetimer; carboplatin; carmustine; carubicin hydrochloride; carzelesin; cedefingol; celecoxib (COX-2 inhibitor); chlorambucil; cirolemycin; cisplatin; cladribine; crisnatol mesylate; cyclophosphamide; cytarabine; dacarbazine; dactinomycin; daunorubicin hydrochloride; decitabine; dexormaplatin; dezaguanine; dezaguanine mesylate; diaziquone; docetaxel; doxorubicin; doxorubicin hydrochloride; droloxifene; droloxifene citrate; dromostanolone propionate; duazomycin; edatrexate; eflomithine hydrochloride; elsamitrucin; enloplatin; enpromate; epipropidine; epirubicin hydrochloride; erbulozole; esorubicin hydrochloride; estramustine; estramustine phosphate sodium; etanidazole; etoposide; etoposide phosphate; etoprine; fadrozole hydrochloride; fazarabine; fenretinide; floxuridine; fludarabine phosphate; fluorouracil; flurocitabine; fosquidone; fostriecin sodium; gemcitabine; gemcitabine hydrochloride; hydroxyurea; idarubicin hydrochloride; ifosfamide; ilmofosine; iproplatin; irinotecan; irinotecan hydrochloride; lanreotide acetate; letrozole; leuprolide acetate; liarozole hydrochloride; lometrexol sodium; lomustine; losoxantrone hydrochloride; masoprocol; maytansine; mechlorethamine hydrochloride; megestrol acetate; melengestrol acetate; melphalan; menogaril; mercaptopurine; methotrexate; methotrexate sodium; metoprine; meturedepa; mitindomide; mitocarcin; mitocromin; mitogillin; mitomalcin; mitomycin; mitosper; mitotane; mitoxantrone hydrochloride; mycophenolic acid; nocodazole; nogalamycin; ormaplatin; oxisuran; paclitaxel; pegaspargase; peliomycin; pentamustine; peplomycin sulfate; perfosfamide; pipobroman; piposulfan; piroxantrone hydrochloride; plicamycin; plomestane; porfimer sodium; porfiromycin; prednimustine; procarbazine hydrochloride; puromycin; puromycin hydrochloride; pyrazofurin; 3-(4-amino-1-oxo-1,3-dihydro-isoindol-2-yl)-piperidine-2,6-dione (Revimid™); riboprine; safingol; safingol hydrochloride; semustine; simtrazene; sparfosate sodium; sparsomycin; spirogermanium hydrochloride; spiromustine; spiroplatin; streptonigrin; streptozocin; sulofenur; talisomycin; tecogalan sodium; taxotere; tegafur; teloxantrone hydrochloride; temoporfin; teniposide; teroxirone; testolactone; thiamiprine; thioguanine; thiotepa; tiazofurin; tirapazamine; toremifene citrate; trestolone acetate; triciribine phosphate; trimetrexate; trimetrexate glucuronate; triptorelin; tubulozole hydrochloride; uracil mustard; uredepa; vapreotide; verteporfin; vinblastine sulfate; vincristine sulfate; vindesine; vindesine sulfate; vinepidine sulfate; vinglycinate sulfate; vinleurosine sulfate; vinorelbine tartrate; vinrosidine sulfate; vinzolidine sulfate; vorozole; zeniplatin; zinostatin; and zorubicin hydrochloride.  
      Other anti-cancer drugs include, but are not limited to: 20-epi-1,25 dihydroxyvitamin D3; 5-ethynyluracil; abiraterone; aclarubicin; acylfulvene; adecypenol; adozelesin; aldesleukin; ALL-TK antagonists; altretamine; ambamustine; amidox; amifostine; aminolevulinic acid; amrubicin; amsacrine; anagrelide; anastrozole; andrographolide; angiogenesis inhibitors; antagonist D; antagonist G; antarelix; anti-dorsalizing morphogenetic protein-1; antiandrogen, prostatic carcinoma; antiestrogen; antineoplaston; antisense oligonucleotides; aphidicolin glycinate; apoptosis gene modulators; apoptosis regulators; apurinic acid; ara-CDP-DL-PTBA; arginine deaminase; asulacrine; atamestane; atrimustine; axinastatin 1; axinastatin 2; axinastatin 3; azasetron; azatoxin; azatyrosine; baccatin III derivatives; balanol; batimastat; BCR/ABL antagonists; benzochlorins; benzoylstaurosporine; beta lactam derivatives; beta-alethine; betaclamycin B; betulinic acid; bFGF inhibitor; bicalutamide; bisantrene; bisaziridinylspermine; bisnafide; bistratene A; bizelesin; breflate; bropirimine; budotitane; buthionine sulfoximine; calcipotriol; calphostin C; camptothecin derivatives; capecitabine; carboxamide-amino-triazole; carboxyamidotriazole; CaRest M3; CARN 700; cartilage derived inhibitor; carzelesin; casein kinase inhibitors (ICOS); castanospermine; cecropin B; cetrorelix; chlorlns; chloroquinoxaline sulfonamide; cicaprost; cis-porphyrin; cladribine; clomifene analogues; clotrimazole; collismycin A; collismycin B; combretastatin A4; combretastatin analogue; conagenin; crambescidin 816; crisnatol; cryptophycin 8; cryptophycin A derivatives; curacin A; cyclopentanthraquinones; cycloplatam; cypemycin; cytarabine ocfosfate; cytolytic factor; cytostatin; dacliximab; decitabine; dehydrodidemnin B; deslorelin; dexamethasone; dexifosfamide; dexrazoxane; dexverapamil; diaziquone; didemnin B; didox; diethylnorspermine; dihydro-5-azacytidine; dihydrotaxol, 9-; dioxamycin; diphenyl spiromustine; docetaxel; docosanol; dolasetron; doxifluridine; doxorubicin; droloxifene; dronabinol; duocarmycin SA; ebselen; ecomustine; edelfosine; edrecolomab; eflomithine; elemene; emitefur; epirubicin; epristeride; estramustine analogue; estrogen agonists; estrogen antagonists; etanidazole; etoposide phosphate; exemestane; fadrozole; fazarabine; fenretinide; filgrastim; finasteride; flavopiridol; flezelastine; fluasterone; fludarabine; fluorodaunorunicin hydrochloride; forfenimex; formestane; fostriecin; fotemustine; gadolinium texaphyrin; gallium nitrate; galocitabine; ganirelix; gelatinase inhibitors; gemcitabine; glutathione inhibitors; hepsulfam; heregulin; hexamethylene bisacetamide; hypericin; ibandronic acid; idarubicin; idoxifene; idramantone; ilmofosine; ilomastat; imatinib (e.g., Gleevec®), imiquimod; immunostimulant peptides; insulin-like growth factor-1 receptor inhibitor; interferon agonists; interferons; interleukins; iobenguane; iododoxorubicin; ipomeanol, 4-; iroplact; irsogladine; isobengazole; isohomohalicondrin B; itasetron; jasplakinolide; kahalalide F; lamellarin-N triacetate; lanreotide; leinamycin; lenograstim; lentinan sulfate; leptolstatin; letrozole; leukemia inhibiting factor; leukocyte alpha interferon; leuprolide+estrogen+progesterone; leuprorelin; levamisole; liarozole; linear polyamine analogue; lipophilic disaccharide peptide; lipophilic platinum compounds; lissoclinamide 7; lobaplatin; lombricine; lometrexol; lonidamine; losoxantrone; loxoribine; lurtotecan; lutetium texaphyrin; lysofylline; lytic peptides; maitansine; mannostatin A; marimastat; masoprocol; maspin; matrilysin inhibitors; matrix metalloproteinase inhibitors; menogaril; merbarone; meterelin; methioninase; metoclopramide; MIF inhibitor; mifepristone; miltefosine; mirimostim; mitoguazone; mitolactol; mitomycin analogues; mitonafide; mitotoxin fibroblast growth factor-saporin; mitoxantrone; mofarotene; molgramostim; Erbitux, human chorionic gonadotrophin; monophosphoryl lipid A+myobacterium cell wall sk; mopidamol; mustard anticancer agent; mycaperoxide B; mycobacterial cell wall extract; myriaporone; N-acetyldinaline; N-substituted benzamides; nafarelin; nagrestip; naloxone+pentazocine; napavin; naphterpin; nartograstim; nedaplatin; nemorubicin; neridronic acid; nilutamide; nisamycin; nitric oxide modulators; nitroxide antioxidant; nitrullyn; oblimersen (Genasense®); O 6 -benzylguanine; octreotide; okicenone; oligonucleotides; onapristone; ondansetron; ondansetron; oracin; oral cytokine inducer; ormaplatin; osaterone; oxaliplatin; oxaunomycin; paclitaxel; paclitaxel analogues; paclitaxel derivatives; palauamine; palmitoylrhizoxin; pamidronic acid; panaxytriol; panomifene; parabactin; pazelliptine; pegaspargase; peldesine; pentosan polysulfate sodium; pentostatin; pentrozole; perflubron; perfosfamide; perillyl alcohol; phenazinomycin; phenylacetate; phosphatase inhibitors; picibanil; pilocarpine hydrochloride; pirarubicin; piritrexim; placetin A; placetin B; plasminogen activator inhibitor; platinum complex; platinum compounds; platinum-triamine complex; porfimer sodium; porfiromycin; prednisone; propyl bis-acridone; prostaglandin J2; proteasome inhibitors; protein A-based immune modulator; protein kinase C inhibitor; protein kinase C inhibitors; microalgal; protein tyrosine phosphatase inhibitors; purine nucleoside phosphorylase inhibitors; purpurins; pyrazoloacridine; pyridoxylated hemoglobin polyoxyethylene conjugate; raf antagonists; raltitrexed; ramosetron; ras farnesyl protein transferase inhibitors; ras inhibitors; ras-GAP inhibitor; retelliptine demethylated; rhenium Re 186 etidronate; rhizoxin; ribozymes; RII retinamide; rohitukine; romurtide; roquinimex; rubiginone B1; ruboxyl; safingol; saintopin; SarCNU; sarcophytol A; sargramostim; Sdi 1 mimetics; semustine; senescence derived inhibitor 1; sense oligonucleotides; signal transduction inhibitors; sizofiran; sobuzoxane; sodium borocaptate; sodium phenylacetate; solverol; somatomedin binding protein; sonermin; sparfosic acid; spicamycin D; spiromustine; splenopentin; spongistatin 1; squalamine; stipiamide; stromelysin inhibitors; sulfinosine; superactive vasoactive intestinal peptide antagonist; suradista; suramin; swainsonine; tallimustine; tamoxifen methiodide; tauromustine; tazarotene; tecogalan sodium; tegafur; tellurapyrylium; telomerase inhibitors; temoporfin; teniposide; tetrachlorodecaoxide; tetrazomine; thaliblastine; thiocoraline; thrombopoietin; thrombopoietin mimetic; thymalfasin; thymopoietin receptor agonist; thymotrinan; thyroid stimulating hormone; tin ethyl etiopurpurin; tirapazamine; titanocene bichloride; topsentin; toremifene; translation inhibitors; tretinoin; triacetyluridine; triciribine; trimetrexate; triptorelin; tropisetron; turosteride; tyrosine kinase inhibitors; tyrphostins; UBC inhibitors; ubenimex; urogenital sinus-derived growth inhibitory factor; urokinase receptor antagonists; vapreotide; variolin B; velaresol; veramine; verdins; verteporfin; vinorelbine; vinxaltine; vitaxin; vorozole; zanoterone; zeniplatin; zilascorb; and zinostatin stimalamer.  
      Specific second active agents include, but are not limited to, anthracycline, platinum, alkylating agent, oblimersen (Genasense®), gemcitabine, cisplatinum, cyclophosphamide, temodar, carboplatin, procarbazine, gliadel, tamoxifen, methotrexate, taxotere, irinotecan, topotecan, temozolomide, capecitabine, cisplatin, thiotepa, fludarabine, liposomal daunorubicin, cytarabine, doxetaxol, pacilitaxel, vinblastine, IL-2, GM-CSF, dacarbazine, vinorelbine, zoledronic acid, palmitronate, biaxin, busulphan, prednisone, bisphosphonate, arsenic trioxide, vincristine, doxorubicin (Doxil®), paclitaxel, ganciclovir, adriamycin, bleomycin, hyaluronidase, mepacrine, thiotepa, tetracycline and mitomycin C.  
      4.3 Methods of Treatment and Management  
      Methods of this invention encompass methods of treating, preventing and/or managing various types of asbestos-related diseases or disorders. As used herein, unless otherwise specified, the term “treating” refers to the administration of a PDE4 modulator or other additional active agent after the onset of symptoms of asbestos-related diseases or disorders, whereas “preventing” refers to the administration prior to the onset of symptoms, particularly to patients at risk of mesothelioma or other asbestos-related disorders. The term “preventing” includes inhibiting or averting a symptom of the particular disease or disorder. Symptoms of asbestos-related diseases or disorders include, but are not limited to, dyspnea, obliteration of the diaphragm, radiolucent sheet-like encasement of the pleura, pleural effusion, pleural thickening, decreased size of the chest, chest discomfort, chest pain, easy fatigability, fever, sweats and weight loss. Examples of patients at risk of asbestos-related diseases or disorders include, but are not limited to, those who have been exposed to asbestos in the workplace and their family members who have been exposed to asbestos embedded in the worker&#39;s clothing. Patients having familial history of asbestos-related diseases or disorders are also preferred candidates for preventive regimens.  
      As used herein and unless otherwise indicated, the term “managing asbestos-related diseases or disorders” encompasses preventing the recurrence of the diseases or disorders in a patient who had suffered from the diseases or disorders, and/or lengthening the time that a patient who had suffered from those remains in remission.  
      Methods encompassed by this invention comprise administering a PDE4 modulator, or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof to a patient (e.g., a human) suffering, or likely to suffer, from asbestos-related diseases or disorders.  
      Without being limited by theory, it is believed that compounds of the invention can be prophylactically administered to prevent people who have been previously exposed to asbestos from developing asbestos-related diseases or disorders. This prophylactic method can actually prevent asbestos-related diseases or disorders from developing in the first place. Therefore, the invention encompasses a method of preventing asbestos-related diseases or disorders in people who are at risk of asbestos-related diseases or disorders, comprising administering an effective amount of a PDE4 modulator, or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof, to those in need thereof.  
      Without being limited by theory, it is also believed that compounds of the invention can inhibit spread of asbestos-related diseases or disorders after diagnosis, because the compounds can affect the production of cytokines (e.g., TNF-α, IL-1β, and IL12).  
      The invention encompasses methods of treating, preventing and managing asbestos-related diseases or disorders in patients with various stages and specific types of the diseases, including, but not limited to, malignant mesothelioma, asbestosis, malignant pleural effusion, benign pleural effusion, pleural plaque, pleural calcification, diffuse pleural thickening, round atelectasis, and bronchogenic carcinoma. It further encompasses methods of treating patients who have been previously treated for asbestos-related diseases or disorders but were not sufficiently responsive or were non-responsive, as well as those who have not previously been treated for the diseases or disorders. Because patients have heterogenous clinical manifestations and varying clinical outcomes, the treatment given to a patient may vary, depending on his/her prognosis. The skilled clinician will be able to readily determine without undue experimentation specific secondary agents and types of physical therapy that can be effectively used to treat an individual patient.  
      In one embodiment of the invention, a PDE4 modulator is administered orally and daily in an amount of from about 1 mg to about 10,000 mg. More specifically, the daily dose is administered twice daily in equally divided doses. Specifically, a daily dose range can be from about 1 mg to about 5,000 mg per day, from about 10 mg to about 2,500 mg per day, from about 100 mg to about 800 mg per day, from about 100 mg to about 1,200 mg per day, or from about 25 mg to about 2,500 mg per day. In managing the patient, the therapy should be initiated at a lower dose, perhaps about 1 mg to about 2,500 mg, and increased if necessary up to about 200 mg to about 5,000 mg per day as either a single dose or divided doses, depending on the patient&#39;s global response. In a particular embodiment, 3-(3,4-dimethoxy-phenyl)-3-(1-oxo-1,3-dihydro-isoindol-2-yl)-propionamide can be preferably administered in an amount of about 400, 800, 1,200, 2,500, 5,000 or 10,000 mg a day as two divided doses. In a particular embodiment, 3-(3,4-dimethoxy-phenyl)-3-(1-oxo-1,3-dihydro-isoindol-2-yl)-propionamide is administered in an amount of from about 400 to about 1,200 mg/d daily, or every other day.  
      In a particular embodiment, a method of preventing asbestos-related diseases comprises administering 3-(3,4-dimethoxy-phenyl)-3-(1-oxo-1,3-dihydro-isoindol-2-yl)-propionamide in an amount of about 400, 800, or 1,200 mg a day as two divided doses in people who have recognized that they have been exposed to asbestos. In a particular embodiment of the prophylactic regimen, 3-(3,4-dimethoxy-phenyl)-3-(1-oxo-1,3-dihydro-isoindol-2-yl)-propionamide is administered in an amount of about 400 mg a day.  
      4.3.1 Combination Therapy with a Second Active Agent  
      Specific methods of the invention comprise administering a PDE4 modulator, or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof, in combination with a second active agent. Examples of second active agents are disclosed herein (see, e.g., section 4.2).  
      Administration of a PDE4 modulator and the second active agents to a patient can occur simultaneously or sequentially by the same or different routes of administration. The suitability of a particular route of administration employed for a particular active agent will depend on the active agent itself (e.g., whether it can be administered orally without decomposing prior to entering the blood stream) and the disease being treated. A preferred route of administration for a PDE4 modulator is oral. Preferred routes of administration for the second active agents of the invention are known to those of ordinary skill in the art, for example, in  Physicians&#39; Desk Reference,  2003.  
      The specific amount of the second active agent will depend on the specific agent used, the type, severity and stage of the diseases or disorders being treated or managed, and the amount(s) of PDE4 modulators and any optional additional active agents concurrently administered to the patient.  
      In one embodiment, the second active agent is anthracycline, platinum, alkylating agent, oblimersen (Genasense®), cisplatinum, cyclophosphamide, temodar, carboplatin, procarbazine, gliadel, tamoxifen, topotecan, methotrexate, taxotere, irinotecan, capecitabine, cisplatin, thiotepa, fludarabine, carboplatin, liposomal daunorubicin, cytarabine, doxetaxol, pacilitaxel, vinblastine, IL-2, GM-CSF, dacarbazine, vinorelbine, zoledronic acid, palmitronate, biaxin, busulphan, prednisone, bisphosphonate, arsenic trioxide, vincristine, doxorubicin (Doxil®), paclitaxel, ganciclovir, adriamycin, bleomycin, hyaluronidase, mitomycin C, mepacrine, thiotepa, tetracycline and gemcitabine.  
      In a specific embodiment, a PDE4 modulator is administered in combination with vinorelbine to patients with malignant mesothelioma or malignant pleural effusion mesothelioma syndrome.  
      In another embodiment, a PDE4 modulator is administered in combination with cyclophosphamide/adriamycin/cisplatin, cisplatin/methotrexate/vinblastine, cisplatin/gemcitabine, cisplatin/adriamycin/mitomycin C, bleomycin/intrapleural hyaluronidase, cisplatin/adriamycin, cisplatin/vinblastine/mitomycin C, gemcitabine/irinotecan, carboplatin/taxotere, or carboplatin/pacilitaxel.  
      4.3.2 Use with Conventional Therapy  
      The standard methods of chemotherapy, radiation therapy, photodynamic therapy, and surgery are used for treating or managing mesothelioma. Kaiser L R.,  Semin Thorac Cardiovasc Surg . October; 9(4): 383-90, 1997. Intracavitary approaches using targeted cytokines and gene therapy have been tried in patients with mesothelioma using intratumoral gene transfer of recombinant adenovirus (rAd) containing herpes simplex virus thymidine kinase (HSVtk) gene into the pleural space of patients. Id. and Sterman D H,  Hematol Oncol Clin North Am . June; 12(3): 553-68, 1998.  
      Certain embodiments of this invention encompass methods of treating and managing asbestos-related diseases or disorders, which comprise administering a PDE4 modulator, or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof, in conjunction with (e.g. before, during, or after) conventional therapy including, but not limited to, chemotherapy, surgery, photodynamic therapy, radiation therapy, gene therapy, immunotherapy or other non-drug based therapy presently used to treat or manage the diseases or disorders. The combined use of a PDE4 modulator and conventional therapy can provide a unique treatment regimen that is unexpectedly effective in certain patients.  
      As discussed elsewhere herein, the invention encompasses a method of reducing, treating and/or preventing adverse or undesired effects associated with conventional therapy including, but not limited to, chemotherapy, photodynamic therapy, surgery, radiation therapy, gene therapy, and immunotherapy. A PDE4 modulator and other active agent can be administered to a patient prior to, during, or after the occurrence of the adverse effect associated with conventional therapy. Examples of adverse effects associated with chemotherapy and radiation therapy that can be treated or prevented by this method include, but are not limited to: gastrointestinal toxicity such as, but not limited to, early and late-forming diarrhea and flatulence; nausea; vomiting; anorexia; leukopenia; anemia; neutropenia; asthenia; abdominal cramping; fever; pain; loss of body weight; dehydration; alopecia; dyspnea; insomnia; dizziness, mucositis, xerostomia, and kidney failure.  
      In one embodiment, a PDE4 modulator is administered in an amount of from about 1 mg to about 5,000 mg per day, from about 10 mg to about 2,500 mg per day, from about 100 mg to about 800 mg per day, from about 100 mg to about 1,200 mg per day, or from about 25 mg to about 2,500 mg per day orally and daily alone, or in combination with a second active agent disclosed herein (see, e.g., section 4.2), prior to, during, or after the use of conventional therapy. In a specific embodiment of this method, a PDE4 modulator and doxetaxol are administered to patients with mesothelioma who were previously treated with radiotherapy.  
      In one embodiment of this method, a PDE4 modulator is administered to patients with asbestos-related diseases or disorders in combination with trimodality therapy. Trimodality therapy involves a combination of three standard strategies of surgery, chemotherapy, and radiation therapy. In one embodiment of this method, extrapleural pneumonectomy is followed by a combination of chemotherapy using a PDE4 modulator and radiotherapy. In another embodiment of the trimodality treatment, a PDE4 modulator is administered in combination with different chemotherapeutic regimens including a combination of cyclophosphamide/adriamycin/cisplatin, carboplatin/paclitaxel, or cisplatin/methotrexate/vinblastine.  
      4.3.3 Cycling Therapy  
      In certain embodiments, a PDE4 modulator is cyclically administered to a patient. Cycling therapy involves the administration of a PDE4 modulator for a period of time, followed by a rest for a period of time, and repeating this sequential administration. Cycling therapy can reduce the development of resistance to one or more of the therapies, avoid or reduce the side effects of one of the therapies, and/or improves the efficacy of the treatment. Consequently, in one specific embodiment of the invention, a PDE4 modulator is administered daily in a single or divided doses in a four to six week cycle with a rest period of about a week or two weeks. Typically, the number of cycles during which the combinatorial treatment is administered to a patient will be from about one to about 24 cycles, more typically from about two to about 16 cycles, and even more typically from about four to about six cycles. The invention further allows the frequency, number, and length of dosing cycles to be increased. Thus, a specific embodiment of the invention encompasses the administration of a PDE4 modulator for more cycles than are typical when it is administered alone. In another specific embodiment of the invention, a PDE4 modulator is administered for a greater number of cycles that would typically cause dose-limiting toxicity in a patient to whom a second active agent is not also being administered.  
      In one embodiment, a PDE4 modulator is administered daily and continuously for three or four weeks at a dose of from about 400 to about 1,200 mg/d followed by a break of one or two weeks in a four or six week cycle.  
      In another embodiment of the invention, a PDE4 modulator and a second active agent are administered orally, with administration of a PDE4 modulator occurring 30 to 60 minutes prior to a second active agent, during a cycle of four to six weeks.  
      In another embodiment, a PDE4 modulator is administered with cisplatin in an amount of 100 mg/m 2  on day 1 and gemcitabine in an amount of 1000 mg/m 2  intravenously on days 1, 8, and day 15 of a 28-day cycle for 6 cycles.  
      4.4 Pharmaceutical Compositions and Single Unit Dosage Forms  
      Pharmaceutical compositions can be used in the preparation of individual, single unit dosage forms. Pharmaceutical compositions and dosage forms of the invention comprise PDE4 modulators, or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof. Pharmaceutical compositions and dosage forms of the invention can further comprise one or more excipients.  
      Pharmaceutical compositions and dosage forms of the invention can also comprise one or more additional active ingredients. Consequently, pharmaceutical compositions and dosage forms of the invention comprise the active agents disclosed herein (e.g., PDE4 modulators, or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof, and a second active agent). Examples of optional additional active agents are disclosed herein (see, e.g., section 4.2).  
      Single unit dosage forms of the invention are suitable for oral, mucosal (e.g., nasal, sublingual, vaginal, buccal, or rectal), or parenteral (e.g., subcutaneous, intravenous, bolus injection, intramuscular, or intraarterial), transdermal or transcutaneous administration to a patient. Examples of dosage forms include, but are not limited to: tablets; caplets; capsules, such as soft elastic gelatin capsules; cachets; troches; lozenges; dispersions; suppositories; powders; aerosols (e.g., nasal sprays or inhalers); gels; liquid dosage forms suitable for oral or mucosal administration to a patient, including suspensions (e.g., aqueous or non-aqueous liquid suspensions, oil-in-water emulsions, or a water-in-oil liquid emulsions), solutions, and elixirs; liquid dosage forms suitable for parenteral administration to a patient; and sterile solids (e.g., crystalline or amorphous solids) that can be reconstituted to provide liquid dosage forms suitable for parenteral administration to a patient.  
      The composition, shape, and type of dosage forms of the invention will typically vary depending on their use. For example, a dosage form used in the acute treatment of a disease may contain larger amounts of one or more of the active agents it comprises than a dosage form used in the chronic treatment of the same disease. Similarly, a parenteral dosage form may contain smaller amounts of one or more of the active agents it comprises than an oral dosage form used to treat the same disease. These and other ways in which specific dosage forms encompassed by this invention will vary from one another will be readily apparent to those skilled in the art. See, e.g.,  Remington&#39;s Pharmaceutical Sciences,  18th ed., Mack Publishing, Easton Pa. (1990).  
      Typical pharmaceutical compositions and dosage forms comprise one or more excipients. Suitable excipients are well known to those skilled in the art of pharmacy, and non-limiting examples of suitable excipients are provided herein. Whether a particular excipient is suitable for incorporation into a pharmaceutical composition or dosage form depends on a variety of factors well known in the art including, but not limited to, the way in which the dosage form will be administered to a patient. For example, oral dosage forms such as tablets may contain excipients not suited for use in parenteral dosage forms. The suitability of a particular excipient may also depend on the specific active ingredients in the dosage form. For example, the decomposition of some active ingredients may be accelerated by some excipients such as lactose, or when exposed to water. Active ingredients that comprise primary or secondary amines are particularly susceptible to such accelerated decomposition. Consequently, this invention encompasses pharmaceutical compositions and dosage forms that contain little, if any, lactose other mono- or di-saccharides. As used herein, the term “lactose-free” means that the amount of lactose present, if any, is insufficient to substantially increase the degradation rate of an active ingredient.  
      Lactose-free compositions of the invention can comprise excipients that are well known in the art and are listed, for example, in the  U.S. Pharmacopeia  (USP) 25-NF20 (2002). In general, lactose-free compositions comprise active ingredients, a binder/filler, and a lubricant in pharmaceutically compatible and pharmaceutically acceptable amounts. Preferred lactose-free dosage forms comprise active ingredients, microcrystalline cellulose, pre-gelatinized starch, and magnesium stearate.  
      This invention further encompasses anhydrous pharmaceutical compositions and dosage forms comprising active ingredients, since water can facilitate the degradation of some compounds. For example, the addition of water (e.g., 5%) is widely accepted in the pharmaceutical arts as a means of simulating long-term storage in order to determine characteristics such as shelf-life or the stability of formulations over time. See, e.g., Jens T. Carstensen,  Drug Stability: Principles  &amp;  Practice,  2d. Ed., Marcel Dekker, NY, N.Y., 1995, pp. 379-80. In effect, water and heat accelerate the decomposition of some compounds. Thus, the effect of water on a formulation can be of great significance since moisture and/or humidity are commonly encountered during manufacture, handling, packaging, storage, shipment, and use of formulations.  
      Anhydrous pharmaceutical compositions and dosage forms of the invention can be prepared using anhydrous or low moisture containing ingredients and low moisture or low humidity conditions. Pharmaceutical compositions and dosage forms that comprise lactose and at least one active ingredient that comprises a primary or secondary amine are preferably anhydrous if substantial contact with moisture and/or humidity during manufacturing, packaging, and/or storage is expected.  
      An anhydrous pharmaceutical composition should be prepared and stored such that its anhydrous nature is maintained. Accordingly, anhydrous compositions are preferably packaged using materials known to prevent exposure to water such that they can be included in suitable formulary kits. Examples of suitable packaging include, but are not limited to, hermetically sealed foils, plastics, unit dose containers (e.g., vials), blister packs, and strip packs.  
      The invention further encompasses pharmaceutical compositions and dosage forms that comprise one or more compounds that reduce the rate by which an active ingredient will decompose. Such compounds, which are referred to herein as “stabilizers,” include, but are not limited to, antioxidants such as ascorbic acid, pH buffers, or salt buffers.  
      Like the amounts and types of excipients, the amounts and specific types of active ingredients in a dosage form may differ depending on factors such as, but not limited to, the route by which it is to be administered to patients. However, typical dosage forms of the invention comprise a PDE4 modulator, or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof, in an amount of from about 1 to about 10,000 mg. Typical dosage forms comprise a PDE4 modulator, or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, clathrate, or prodrug thereof, in an amount of about 1, 2, 5, 10, 25, 50, 100, 200, 400, 800, 1,200, 2,500, 5,000 or 10,000 mg. In a particular embodiment, a preferred dosage form comprises 3-(3,4-dimethoxy-phenyl)-3-(1-oxo-1,3-dihydro-isoindol-2-yl)-propionamide in an amount of about 400, 800 or 1,200 mg. Typical dosage forms comprise the second active agent in an amount of form about 1 to about 3,500 mg, from about 5 to about 2,500 mg, from about 10 to about 500 mg, or from about 25 to about 250 mg. Of course, the specific amount of the second active agent will depend on the specific agent used, the type of disease of disorder being treated or managed, and the amount(s) of PDE4 modulators and any optional additional active agents concurrently administered to the patient.  
      4.4.1 Oral Dosage Forms  
      Pharmaceutical compositions of the invention that are suitable for oral administration can be presented as discrete dosage forms, such as, but are not limited to, tablets (e.g., chewable tablets), caplets, capsules, and liquids (e.g., flavored syrups). Such dosage forms contain predetermined amounts of active agents, and may be prepared by methods of pharmacy well known to those skilled in the art. See generally,  Remington&#39;s Pharmaceutical Sciences,  18th ed., Mack Publishing, Easton Pa. (1990).  
      Typical oral dosage forms of the invention are prepared by combining the active ingredients in an intimate admixture with at least one excipient according to conventional pharmaceutical compounding techniques. Excipients can take a wide variety of forms depending on the form of preparation desired for administration. For example, excipients suitable for use in oral liquid or aerosol dosage forms include, but are not limited to, water, glycols, oils, alcohols, flavoring agents, preservatives, and coloring agents. Examples of excipients suitable for use in solid oral dosage forms (e.g., powders, tablets, capsules, and caplets) include, but are not limited to, starches, sugars, micro-crystalline cellulose, diluents, granulating agents, lubricants, binders, and disintegrating agents.  
      Because of their ease of administration, tablets and capsules represent the most advantageous oral dosage unit forms, in which case solid excipients are employed. If desired, tablets can be coated by standard aqueous or nonaqueous techniques. Such dosage forms can be prepared by any of the methods of pharmacy. In general, pharmaceutical compositions and dosage forms are prepared by uniformly and intimately admixing the active ingredients with liquid carriers, finely divided solid carriers, or both, and then shaping the product into the desired presentation if necessary.  
      For example, a tablet can be prepared by compression or molding. Compressed tablets can be prepared by compressing in a suitable machine the active ingredients in a free-flowing form such as powder or granules, optionally mixed with an excipient. Molded tablets can be made by molding in a suitable machine a mixture of the powdered compound moistened with an inert liquid diluent.  
      Examples of excipients that can be used in oral dosage forms of the invention include, but are not limited to, binders, fillers, disintegrants, and lubricants. Binders suitable for use in pharmaceutical compositions and dosage forms include, but are not limited to, corn starch, potato starch, or other starches, gelatin, natural and synthetic gums such as acacia, sodium alginate, alginic acid, other alginates, powdered tragacanth, guar gum, cellulose and its derivatives (e.g., ethyl cellulose, cellulose acetate, carboxymethyl cellulose calcium, sodium carboxymethyl cellulose), polyvinyl pyrrolidone, methyl cellulose, pre-gelatinized starch, hydroxypropyl methyl cellulose, (e.g., nos. 2208, 2906, 2910), microcrystalline cellulose, and mixtures thereof.  
      Suitable forms of microcrystalline cellulose include, but are not limited to, the materials sold as AVICEL-PH-101, AVICEL-PH-103 AVICEL RC-581, AVICEL-PH-105 (available from FMC Corporation, American Viscose Division, Avicel Sales, Marcus Hook, Pa.), and mixtures thereof. An specific binder is a mixture of microcrystalline cellulose and sodium carboxymethyl cellulose sold as AVICEL RC-581. Suitable anhydrous or low moisture excipients or additives include AVICEL-PH-103™ and Starch 1500 LM.  
      Examples of fillers suitable for use in the pharmaceutical compositions and dosage forms disclosed herein include, but are not limited to, talc, calcium carbonate (e.g., granules or powder), microcrystalline cellulose, powdered cellulose, dextrates, kaolin, mannitol, silicic acid, sorbitol, starch, pre-gelatinized starch, and mixtures thereof. The binder or filler in pharmaceutical compositions of the invention is typically present in from about 50 to about 99 weight percent of the pharmaceutical composition or dosage form.  
      Disintegrants are used in the compositions of the invention to provide tablets that disintegrate when exposed to an aqueous environment. Tablets that contain too much disintegrant may disintegrate in storage, while those that contain too little may not disintegrate at a desired rate or under the desired conditions. Thus, a sufficient amount of disintegrant that is neither too much nor too little to detrimentally alter the release of the active ingredients should be used to form solid oral dosage forms of the invention. The amount of disintegrant used varies based upon the type of formulation, and is readily discernible to those of ordinary skill in the art. Typical pharmaceutical compositions comprise from about 0.5 to about 15 weight percent of disintegrant, preferably from about 1 to about 5 weight percent of disintegrant.  
      Disintegrants that can be used in pharmaceutical compositions and dosage forms of the invention include, but are not limited to, agar-agar, alginic acid, calcium carbonate, microcrystalline cellulose, croscarmellose sodium, crospovidone, polacrilin potassium, sodium starch glycolate, potato or tapioca starch, other starches, pre-gelatinized starch, other starches, clays, other algins, other celluloses, gums, and mixtures thereof.  
      Lubricants that can be used in pharmaceutical compositions and dosage forms of the invention include, but are not limited to, calcium stearate, magnesium stearate, mineral oil, light mineral oil, glycerin, sorbitol, mannitol, polyethylene glycol, other glycols, stearic acid, sodium lauryl sulfate, talc, hydrogenated vegetable oil (e.g., peanut oil, cottonseed oil, sunflower oil, sesame oil, olive oil, corn oil, and soybean oil), zinc stearate, ethyl oleate, ethyl laureate, agar, and mixtures thereof. Additional lubricants include, for example, a syloid silica gel (AEROSIL200, manufactured by W.R. Grace Co. of Baltimore, Md.), a coagulated aerosol of synthetic silica (marketed by Degussa Co. of Plano, Tex.), CAB-O-SIL (a pyrogenic silicon dioxide product sold by Cabot Co. of Boston, Mass.), and mixtures thereof. If used at all, lubricants are typically used in an amount of less than about 1 weight percent of the pharmaceutical compositions or dosage forms into which they are incorporated.  
      A preferred solid oral dosage form of the invention comprises PDE4 modulators, anhydrous lactose, microcrystalline cellulose, polyvinylpyrrolidone, stearic acid, colloidal anhydrous silica, and gelatin.  
      4.4.2 Delayed Release Dosage Forms  
      Active agents of the invention can be administered by controlled release means or by delivery devices that are well known to those of ordinary skill in the art. Examples include, but are not limited to, those described in U.S. Pat. Nos. 3,845,770; 3,916,899; 3,536,809; 3,598,123; and 4,008,719, 5,674,533, 5,059,595, 5,591,767, 5,120,548, 5,073,543, 5,639,476, 5,354,556, and 5,733,566, each of which is incorporated herein by reference. Such dosage forms can be used to provide slow or controlled-release of one or more active ingredients using, for example, hydropropylmethyl cellulose, other polymer matrices, gels, permeable membranes, osmotic systems, multilayer coatings, microparticles, liposomes, microspheres, or a combination thereof to provide the desired release profile in varying proportions. Suitable controlled-release formulations known to those of ordinary skill in the art, including those described herein, can be readily selected for use with the active ingredients of the invention. The invention thus encompasses single unit dosage forms suitable for oral administration such as, but not limited to, tablets, capsules, gelcaps, and caplets that are adapted for controlled-release.  
      All controlled-release pharmaceutical products have a common goal of improving drug therapy over that achieved by their non-controlled counterparts. Ideally, the use of an optimally designed controlled-release preparation in medical treatment is characterized by a minimum of drug substance being employed to cure or control the condition in a minimum amount of time. Advantages of controlled-release formulations include extended activity of the drug, reduced dosage frequency, and increased patient compliance. In addition, controlled-release formulations can be used to affect the time of onset of action or other characteristics, such as blood levels of the drug, and can thus affect the occurrence of side (e.g., adverse) effects.  
      Most controlled-release formulations are designed to initially release an amount of drug (active ingredient) that promptly produces the desired therapeutic effect, and gradually and continually release of other amounts of drug to maintain this level of therapeutic or prophylactic effect over an extended period of time. In order to maintain this constant level of drug in the body, the drug must be released from the dosage form at a rate that will replace the amount of drug being metabolized and excreted from the body. Controlled-release of an active ingredient can be stimulated by various conditions including, but not limited to, pH, temperature, enzymes, water, or other physiological conditions or compounds.  
      4.4.3 Parenteral Dosage Forms  
      Parenteral dosage forms can be administered to patients by various routes including, but not limited to, subcutaneous, intravenous (including bolus injection), intramuscular, and intraarterial. Because their administration typically bypasses patients&#39; natural defenses against contaminants, parenteral dosage forms are preferably sterile or capable of being sterilized prior to administration to a patient. Examples of parenteral dosage forms include, but are not limited to, solutions ready for injection, dry products ready to be dissolved or suspended in a pharmaceutically acceptable vehicle for injection, suspensions ready for injection, and emulsions.  
      Suitable vehicles that can be used to provide parenteral dosage forms of the invention are well known to those skilled in the art. Examples include, but are not limited to: Water for Injection USP; aqueous vehicles such as, but not limited to, Sodium Chloride Injection, Ringer&#39;s Injection, Dextrose Injection, Dextrose and Sodium Chloride Injection, and Lactated Ringer&#39;s Injection; water-miscible vehicles such as, but not limited to, ethyl alcohol, polyethylene glycol, and polypropylene glycol; and non-aqueous vehicles such as, but not limited to, corn oil, cottonseed oil, peanut oil, sesame oil, ethyl oleate, isopropyl myristate, and benzyl benzoate.  
      Compounds that increase the solubility of one or more of the active ingredients disclosed herein can also be incorporated into the parenteral dosage forms of the invention. For example, cyclodextrin and its derivatives can be used to increase the solubility of PDE4 modulators and its derivatives. See, e.g., U.S. Pat. No. 5,134,127, which is incorporated herein by reference.  
      4.4.4 Topical and Mucosal Dosage Forms  
      Topical and mucosal dosage forms of the invention include, but are not limited to, sprays, aerosols, solutions, emulsions, suspensions, or other forms known to one of skill in the art. See, e.g.,  Remington&#39;s Pharmaceutical Sciences,  16 th  and 18 th  eds., Mack Publishing, Easton Pa. (1980 &amp; 1990); and  Introduction to Pharmaceutical Dosage Forms,  4th ed., Lea &amp; Febiger, Philadelphia (1985). Dosage forms suitable for treating mucosal tissues within the oral cavity can be formulated as mouthwashes or as oral gels.  
      Suitable excipients (e.g., carriers and diluents) and other materials that can be used to provide topical and mucosal dosage forms encompassed by this invention are well known to those skilled in the pharmaceutical arts, and depend on the particular tissue to which a given pharmaceutical composition or dosage form will be applied. With that fact in mind, typical excipients include, but are not limited to, water, acetone, ethanol, ethylene glycol, propylene glycol, butane-1,3-diol, isopropyl myristate, isopropyl palmitate, mineral oil, and mixtures thereof to form solutions, emulsions or gels, which are non-toxic and pharmaceutically acceptable. Moisturizers or humectants can also be added to pharmaceutical compositions and dosage forms if desired. Examples of such additional ingredients are well known in the art. See, e.g.,  Remington&#39;s Pharmaceutical Sciences,  16 th  and 18 th  eds., Mack Publishing, Easton Pa. (1980 &amp; 1990).  
      The pH of a pharmaceutical composition or dosage form may also be adjusted to improve delivery of one or more active ingredients. Similarly, the polarity of a solvent carrier, its ionic strength, or tonicity can be adjusted to improve delivery. Compounds such as stearates can also be added to pharmaceutical compositions or dosage forms to advantageously alter the hydrophilicity or lipophilicity of one or more active ingredients so as to improve delivery. In this regard, stearates can serve as a lipid vehicle for the formulation, as an emulsifying agent or surfactant, and as a delivery-enhancing or penetration-enhancing agent. Different salts, hydrates or solvates of the active ingredients can be used to further adjust the properties of the resulting composition.  
      4.5 Kits  
      Typically, active ingredients of the invention are preferably not administered to a patient at the same time or by the same route of administration. This invention therefore encompasses kits which, when used by the medical practitioner, can simplify the administration of appropriate amounts of active ingredients to a patient.  
      A typical kit of the invention comprises a dosage form of PDE4 modulators, or a pharmaceutically acceptable salt, solvate, hydrate, stereoisomer, prodrug, or clathrate thereof. Kits encompassed by this invention can further comprise additional active agents or a combination thereof. Examples of the additional active agents include, but are not limited to, anti-cancer agents, antibiotics, anti-inflammatory agents, steroids, immunomodulatory agents, cytokines, immunosuppressive agents, or other therapeutics discussed herein (see, e.g., section 4.2).  
      Kits of the invention can further comprise devices that are used to administer the active agents. Examples of such devices include, but are not limited to, syringes, drip bags, patches, and inhalers.  
      Kits of the invention can further comprise pharmaceutically acceptable vehicles that can be used to administer one or more active ingredients. For example, if an active ingredient is provided in a solid form that must be reconstituted for parenteral administration, the kit can comprise a sealed container of a suitable vehicle in which the active ingredient can be dissolved to form a particulate-free sterile solution that is suitable for parenteral administration. Examples of pharmaceutically acceptable vehicles include, but are not limited to: Water for Injection USP; aqueous vehicles such as, but not limited to, Sodium Chloride Injection, Ringer&#39;s Injection, Dextrose Injection, Dextrose and Sodium Chloride Injection, and Lactated Ringer&#39;s Injection; water-miscible vehicles such as, but not limited to, ethyl alcohol, polyethylene glycol, and polypropylene glycol; and non-aqueous vehicles such as, but not limited to, corn oil, cottonseed oil, peanut oil, sesame oil, ethyl oleate, isopropyl myristate, and benzyl benzoate.  
     5. EXAMPLES  
      The following studies are intended to further illustrate the invention without limiting its scope.  
      5.1 Pharmacology Studies  
      One of the biological effects typically exerted by PDE4 modulators is the reduction of synthesis of TNF-α. Specific PDE4 modulators enhance the degradation of TNF-α mRNA. Further, the compounds may also have a modest inhibitory effect on LPS induced IL1β and IL12.  
      Preferred compounds of the invention are potent PDE4 inhibitors. PDE4 is one of the major phosphodiesterase isoenzymes found in human myeloid and lymphoid lineage cells. The enzyme plays a crucial part in regulating cellular activity by degrading the ubiquitous second messenger cAMP and maintaining it at low intracellular levels. Inhibition of PDE4 activity results in increased cAMP levels leading to the modulation of LPS induced cytokines, including inhibition of TNF-α production in monocytes as well as in lymphocytes.  
      In a specific embodiment, the pharmacological properties of 3-(3,4-dimethoxy-phenyl)-3-(1-oxo-1,3-dihydro-isoindol-2-yl)-propionamide are characterized in in vitro studies. Studies examine the effects of the compound on the production of various cytokines. Inhibition of TNF-α production following LPS-stimulation of human PBMC and human whole blood by the compound is investigated in vitro. The IC 50 &#39;s of the compound for inhibiting production of TNF-α are measured. In vitro studies suggest a pharmacological activity profile for 3-(3,4-dimethoxy-phenyl)-3-(1-oxo-1,3-dihydro-isoindol-2-yl)-propionamide is five to fifty times more potent than thalidomide. The pharmacological effects of 3-(3,4-dimethoxy-phenyl)-3-(1-oxo-1,3-dihydro-isoindol-2-yl)-propionamide may derive from its action as an inhibitor of the generation of inflammatory cytokines.  
      5.2 Clinical Studies in Mesothelioma Patients  
      Clinical trials with the administration of a PDE4 modulator in an amount of from about 1 mg to about 1,000 mg, from about 1 mg to about 500 mg, or from about 1 mg to about 250 mg per day are conducted in patients with asbestosis, malignant mesothelioma, or malignant pleural effusion mesothelioma syndrome. In a specific embodiment, patients receive about 1 mg to about 1000 mg/day of 3-(3,4-dimethoxy-phenyl)-3-(1-oxo-1,3-dihydro-isoindol-2-yl)-propionamide alone or in combination with vinorelbine. Patients who experience clinical benefit are permitted to continue on treatment.  
      Other clinical studies are performed using 3-(3,4-dimethoxy-phenyl)-3-(1-oxo-1,3-dihydro-isoindol-2-yl)-propionamide in unresectable or relapsed mesothelioma patients that have not responded to conventional therapy. In one embodiment, 3-(3,4-dimethoxy-phenyl)-3-(1-oxo-1,3-dihydro-isoindol-2-yl)-propionamide is administered in an amount of about 1 mg to about 1,000 mg/day to the patients. Treatment with 400 mg as a continuous oral daily dose is well-tolerated. The studies in mesothelioma or asbestosis patients treated with a PDE4 modulator suggests that the drug has therapeutic benefit in this disease.  
      Embodiments of the invention described herein are only a sampling of the scope of the invention. The full scope of the invention is better understood with reference to the attached claims.