Small molecules
Small molecules are the newest development. But here it becomes complicated.
I´ll try to explain it with languages. Inside the cell an other language is spoken than outside from cell to cell. And inside the cell there are various dialects to talk to the nucleus, which in return gives instructions in its own language.
Communicating between cells, there are the cytokines such as TNF-alpha or the interleukins. This message is translated by kinases in the cell wall. Then, an instruction is read out in the nucleus of the genetic information as from a book and goes out of the nucleus as messsenger RNA (mRNA). For us, the kinases are important now.
The complexity of the operations can be traced very well on this image: http://upload.wikimedia.org/wikipedia/commons/2/29/Signal_transduction_v1.png
This complexity also means, that failures may happen much later than in other drugs.
GLPG0259, a so-called MAPKAP kinase 5 inhibitor looked very well in the first trials. According to the studies of Vanhoutte and Andrews onecould hope for a new drug.
[eular 2011 / SAT0249] SAFETY AND PHARMACOKINETIC PROFILE IN HEALTHY VOLUNTEERS OF GLPG0259, A SMALL MOLECULE MAPKAPK5 INHIBITOR CURRENTLY IN A PHASE II RA STUDY
F. Vanhoutte
Conclusions: GLPG0259 showed good safety and a PK profile supporting once daily dosing. Based on these promising results, a randomized, placebo-controlled multi-center Phase II dose-finding study was initiated in October 2010, where three dose levels of GLPG0259 will be evaluated in 180 active RA patients with an inadequate response to MTX.
[eular 2011 / OP0292] IDENTIFICATION OF GLPG0259, AN ORALLY BIOAVAILABLE INHIBITOR OF MAPKAPK5, AS A CLINICAL CANDIDATE FOR THE TREATMENT OF RHEUMATOID ARTHRITIS
M. Andrews et al.
Conclusions: Compound screening and rational drug design were applied to generate a series of potent inhibitors of the novel RA target MAPKAPK5. Of these promising molecules, ... GLPG0259 is currently being evaluated in a Phase II trial in RA patients.
At his second lecture Andrews himself had to admit that the phase 2 study, after submission of the abstract, had to be canceled due to lack of efficacy.
[eular 2011 / OP0292] IDENTIFICATION OF GLPG0259, AN ORALLY BIOAVAILABLE INHIBITOR OF MAPKAPK5, AS A CLINICAL CANDIDATE FOR THE TREATMENT OF RHEUMATOID ARTHRITIS
M. Andrews et al.
Conclusions: Compound screening and rational drug design were applied to generate a series of potent inhibitors of the novel RA target MAPKAPK5. Of these promising molecules, ... GLPG0259 is currently being evaluated in a Phase II trial in RA patients.
Now we come to the Janus kinases. Here for example is one of these images to the Janus kinases: http://oncochat.typepad.com/.a/6a00d8342ae08153ef01348768e87e970c-popup
Tofacitinib is a Janus kinase inhibitor.
Y. Tanaka and colleagues compared efficacy, safety and tolerability of five doses of Tofacitinib as monotherapy against placebo in the treatment of rheumatoid arthritis in Japanese patients with inadequate DMARDS of response to. The primary endpoint was ACR20 response rate in the 12th week. All doses of Tofacitinib were superior when compared to placebo and a clear dose response function was observed. ACR50 and ACR70 response rates also showed this. The most common adverse effects were nasopharyngitis, Hyperlipidemia, and elevated LDL; these were considered mild in severity.
[ACR 2011 / TUE2192]
Tofacitinib (CP-690,550), An Oral Janus Kinase Inhibitor, As Monotherapy in Japanese Patients with Active Rheumatoid Arthritis: A 12-Week Phase 2b Study.
Y. Tanaka1, T. Takeuchi2, H. Yamanaka3, M. Suzuki4, H. Nakamura4, S. Toyoizumi4, J. D. Bradley5 and S. H. Zwillich5. 1University of Occupational & Environmental Health, Kitakyushu, Fukuoka, Japan, 2Keio University School of Medicine, Tokyo, Japan, 3Institute of Rheumatology, Tokyo Women’s Medical University, Tokyo, Japan, 4Pfizer Inc., Tokyo, Japan, 5Pfizer Inc., Groton, CT
Conclusion: When used as monotherapy, tofacitinib dosed 1 mg BID demonstrated superior ACR20 response rates compared with placebo at week 12. Doses of tofacitinib 5, 10, and 15 mg BID demonstrated superiority to placebo in DAS28-4(ESR) 2.6. The safety profile of tofacitinib monotherapy was manageable in Japanese patients with longstanding active rheumatoid arthritis.
Other studies show the following results: Tofacitinib significantly reduced the progression of structural damage compared to placebo in patients with active RA who were treated with methotrexate. A study showed a statistically significant and clinically relevant improvements in several "outcomes reported by patients". Tofacitinib showed a safety profile of good compatibility and sustainable, long-term efficacy over a period of 36 months.
[ACR 20111 / WED2592]
Tofacitinib (CP-690,550), An Oral Janus Kinase Inhibitor, in Combination with Methotrexate Reduced the Progression of Structural Damage in Patients with Rheumatoid Arthritis: a 24-Month Phase 3 Study.
Désirée van der Heijde1, Y. Tanaka2, Roy Fleischmann3, Edward C. Keystone4, et al.
1Department of Rheumatology, Leiden University Medical Center, Leiden, Netherlands, 2University of Occupational & Environmental Health, Kitakyushu, Fukuoka, Japan, 3University of Texas Southwestern Medical Center, etc.
Conclusion: In this P3 study, tofacitinib significantly reduced progression of structural damage vs PBO in pts with active RA on MTX. Consistent with other studies, tofacitinib demonstrated significant and clinically meaningful reductions in signs and symptoms of RA and physical function. No new safety signals were detected.
[ACR 2011 / TUE2627]
Tofacitinib (CP-690,550) in Combination with Traditional Disease-Modifying Anti-Rheumatic Drugs: Phase 3 Study Patient-Reported Outcomes in Patients with Active Rheumatoid Arthritis and An Inadequate Response to Disease-Modifying Anti-Rheumatic Drugs.
V. Strand1, J. M. Kremer2, Z. G. Li3, S. Hall4, Roy M. Fleischmann5, M. C. Genovese6, et al.
1Stanford University, Palo Alto, CA, 2Albany Medical College and The Center for Rheumatology, Albany, NY, 3Peking University People’s Hospital, etc.
Conclusion: In this Phase 3 study of tofacitinib in combination with traditional DMARDs, treatment with 5 and 10 mg BID resulted in consistent statistically significant and clinically meaningful improvements in multiple patient-reported outcomes vs placebo at month 3.
[ACR 2011 / SUN407]
Tofacitinib (CP-690,550), An Oral Janus Kinase Inhibitor, in the Treatment of Rheumatoid Arthritis: Open-Label, Long-Term Extension Studies up to 36 Months.
J. Wollenhaupt1, J. C Silverfield2, E. B. Lee3, S. Wood4, K. Soma5, L. Wang5, H. Nakamura6, Y. Komuro6, C. I. Nduaka5, D. Gruben5, S. H. Zwillich5 and J. D. Bradley5.
1Teaching Hospital of the University of Hamburg, Hamburg, Germany, 2Tampa Medical Group, P.A., Tampa, FL, 3Hanyang University Hospital, Seoul, 4Pfizer Inc., Groton, NJ, 5Pfizer Inc., Groton, CT, 6Pfizer Inc., Tokyo, Japan
Conclusion: Treatment with tofacitinib at doses of 5 or 10 mg BID in pts with RA demonstrated a well-tolerated safety profile and sustained long-term efficacy over a 36-mo period.
An another candidate who could be successful, is fostamatinib, a SYK inhibitor. At eular 2011 Baluom pointed out at the OSKIRA study.
[eular 2011 / SAT0247] PHARMACOKINETICS OF FOSTAMATINIB, A NOVEL SYK INHIBITOR, IN HEALTHY HUMAN SUBJECTS FOLLOWING SINGLE AND MULTIPLE ORAL DOSING
M. Baluom et al.
Conclusions: … and is currently being evaluated in phase 3 clinical studies (OSKIRA trials) in RA.
Further studies were presented at the ACR 2011. Also noteworthy is a short B cell depletion which was seen under fostamatinib.
[ACR 2011 / SUN420]
Effects of the Oral SYK Inhibitor, Fostamatinib (R788), on Health-related Quality of Life in a Phase II Study of Active Rheumatoid Arthritis.
Michael E. Weinblatt1, Arthur Kavanaugh2, Mark C. Genovese3, David A. Jones4, Theresa K. Musser5, Elliott B. Grossbard5 and Daniel B. Magilavy5.
1Brigham and Women’s Hospital, Boston, MA, 2University of California San Diego, San Diego, CA, 3Stanford University, Palo Alto, CA, 4AstraZeneca, Macclesfield, United Kingdom, 5Rigel Pharmaceuticals, SouthSan Francisco, CA
Conclusion: In this phase II study, 100 mg bid fostamatinib significantly improved HRQL outcomes including physical function, pain, fatigue, and overall physical health status. Phase III clinical trials of fostamatinib in RA are in progress.
[ACR 2011 / TUE1744]
Syk Inhibition with Fostamatinib Leads to Transitional B Lymphocyte Depletion.
Chungwen Wei, Paul M. Barr, Julia Schaefer-Cutillo, John Jung,
James Roger, Jennifer L. Kelly, Alex Rosenberg, Jonathan W. Friedberg and In˜aki Sanz. University of Rochester, Rochester, NY
[ACR 2011 / WED2594]
Longer-Term Safety of Fostamatinib (R788) in Patients with Rheumatoid Arthritis—Analysis of Clinical Trial Data From up to 2 Years of Exposure.
Arthur Kavanaugh1, Michael E. Weinblatt2, Mark C. Genovese3,Theresa K. Musser4, Elliott B. Grossbard4, Daniel B. Magilavy4, SallyHollis5, Eveline Wesby van-Sway5 and David Millson5.
1University of California San Diego, San Diego, CA, 2Brigham and Women’s Hospital, Boston, MA, 3Stanford University, Palo Alto, CA, 4Rigel Pharmaceuticals, South San Francisco, CA, 5AstraZeneca, Macclesfield, United Kingdom
Conclusion: No new significant safety signals were identified with longer-term dosing of fostamatinib. Biologic refractory pts on a background of mixed DMARDs had a higher incidence rate of AEs, SAEs, and SIEs compared to MTX inadequate responders on background MTX; further confounding factors may play a role.3 This will be explored in ongoing phase III studies.
Summary
To sum up, we can rely on a number of classic DMARDs, TNF-alpha inhibitors, biologics with other modes of action; soon, the range will be expanded by other biologics (without new modes of action), biosimilars, and the small molecules.
