Macrocyclic Compounds from Ansamycin Antibiotic Class as Inhibitors of PD1-PDL1 Protein-Protein Interaction.

The ability of tumors to escape from immune destruction is attributed to the protein-protein interaction between programmed cell death protein 1 (PD1) and programmed cell death ligand 1 (PDL1) proteins expressed by immune T cells and cancer cells, respectively. Therefore, pharmacological inhibition of the PD1-PDL1 interaction presents an important therapeutic target against a variety of tumors expressing PDL1 on their cell surface. Recently, five antibodies have been approved and several are in clinical trials against the PD1-PDL1 protein-protein interaction target. In contrast, there are very few reports of small-molecule inhibitors of PD1-PDL1 interaction, and most of them have relatively modest or weak inhibition activities, emphasizing the difficulty in designing small-molecule inhibitors against this challenging target. Therefore, we focused our attention on macrocycles that are known to exhibit target activity comparable to large macromolecules despite having molecular weights closer to small, drug-like molecules. In this context, our present study led to the identification of several macrocyclic compounds from the ansamycin antibiotics class to be inhibitors of PD1-PDL1 interaction. Importantly, one of these macrocyclic antibiotics, Rifabutin, showed an IC50 value of ca. 25 µM. This is remarkable considering it has a relatively low molecular weight and still is capable of inhibiting PD1-PDL1 protein-protein interaction whose binding interface spans over ca. 1970 Å2. Thus, these macrocycles may serve as guiding points for discovery and optimization of more potent, selective small-molecule inhibitors of PD1-PDL1 interaction, one of the most promising therapeutic targets against cancer.

Pregnancy Outcomes in the Tofacitinib Safety Databases for Rheumatoid Arthritis and Psoriasis.

INTRODUCTION: Tofacitinib is an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis (RA), and is being investigated for the treatment of psoriasis. Both conditions can present in women of child-bearing potential, but pregnancy was an exclusion and discontinuation criterion in tofacitinib randomized controlled trials (RCTs) because of the unknown effects of tofacitinib on mother and child. Tofacitinib is a small molecule that has the potential to cross the placenta. OBJECTIVE: The objective was to report outcomes of pregnancy cases identified through April 2014 from tofacitinib RA/psoriasis RCTs, RA post-approval non-interventional studies, and spontaneous adverse-event reporting. METHODS: Pregnancy outcomes were categorized as follows: healthy newborn, medical termination, fetal death, congenital malformation, spontaneous abortion, or pending/lost to follow-up. RESULTS: Out of 9815 patients, 1821 female patients of child-bearing age were enrolled in the RA/psoriasis RCTs; 47 women became pregnant, including 33 who received tofacitinib monotherapy, 13 who received combination therapy with methotrexate (RA patients only), and one patient whose therapy was still blinded. No fetal deaths were reported. One congenital pulmonary valve stenosis (monotherapy, n = 1), seven spontaneous abortions (monotherapy, n = 4; combination therapy, n = 3), and eight medical terminations (monotherapy, n = 4; combination therapy, n = 3; blinded therapy, n = 1) were identified. Remaining cases reported healthy newborns (n = 25) or were pending/lost to follow-up (n = 6). Forty-four cases of paternal exposure to tofacitinib were reported (monotherapy, n = 43; combination therapy, n = 1), including five spontaneous abortions (monotherapy, n = 4; combination therapy, n = 1), 23 healthy newborns, and 16 pending/lost to follow-up. CONCLUSIONS: The pregnancy outcomes reported in this small number of RA/psoriasis patients appear similar to those observed in the general population and in patients treated with biologic therapies for inflammatory diseases. However, definitive conclusions cannot be drawn, and pregnancy outcomes in patients receiving tofacitinib will continue to be monitored.

Tofacitinib versus etanercept or placebo in moderate-to-severe chronic plaque psoriasis: a phase 3 randomised non-inferiority trial.

BACKGROUND: New therapeutic options are needed for patients with psoriasis. Tofacitinib, an oral Janus kinase inhibitor, is being investigated as a treatment for moderate-to-severe chronic plaque psoriasis. In this study, we aimed to compare two tofacitinib doses with high-dose etanercept or placebo in this patient population. METHODS: In this phase 3, randomised, multicentre, double-dummy, placebo-controlled, 12-week, non-inferiority trial, adult patients with chronic stable plaque psoriasis (for ≥12 months) who were candidates for systemic or phototherapy and had a Psoriasis Area and Severity Index (PASI) score of 12 or higher and a Physician's Global Assessment (PGA) of moderate or severe, and had failed to respond to, had a contraindication to, or were intolerant to at least one conventional systemic therapy, were enrolled from 122 investigational dermatology centres worldwide. Eligible patients were randomly assigned in a 3:3:3:1 ratio to receive tofacitinib 5 mg or 10 mg twice daily at about 12 h intervals, etanercept 50 mg subcutaneously twice weekly at about 3-4 day intervals, or placebo. Randomisation was done by a computer-generated randomisation schedule, and all patients and study personnel were masked to treatment assignment. The co-primary endpoints were the proportion of patients at week 12 with at least a 75% reduction in the PASI score from baseline (PASI75 response) and the proportion of patients achieving a PGA score of "clear" or "almost clear" (PGA response), analysed in the full analysis set (all patients who were randomised and received at least one dose of study drug). This study is registered with ClinicalTrials.gov, number NCT01241591. FINDINGS: Between Nov 29, 2010, and Sept 13, 2012, we enrolled 1106 eligible adult patients with chronic plaque psoriasis and randomly assigned them to the four treatment groups (330 to tofacitinib 5 mg twice daily, 332 to tofacitinib 10 mg twice daily, 336 to etanercept 50 mg twice weekly, and 108 to placebo). Of these patients, 1101 actually received their assigned study medication (329 in the tofactinib 5 mg group, 330 in the tofacitinib 10 mg group, 335 in the etanercept group, and 107 in the placebo group). At week 12, PASI75 responses were recorded in 130 (39·5%) of 329 patients in the tofacitinib 5 mg group, 210 (63·6%) of 330 in the tofacitinib 10 mg group, 197 (58·8%) of 335 in the etanercept group, and six (5·6%) of 107 in the placebo group. A PGA response was achieved by 155 (47·1%) of 329 patients in the tofacitinib 5 mg group, 225 (68·2%) of 330 in the tofacitinib 10 mg group, 222 (66·3%) of 335 in the etanercept group, and 16 (15·0%) of 107 in the placebo group. The rate of adverse events was similar across the four groups, with serious adverse events occurring in seven (2%) of 329 patients in the tofacitinib 5 mg group, five (2%) of 330 in the tofacitinib 10 mg group, seven (2%) of 335 in the etanercept group, and two (2%) of 107 in the placebo group. Three (1%) of 329 patients in the tofacitinib 5 mg group, ten (3%) of 330 in the tofacitinib 10 mg group, 11 (3%) of 335 in the etanercept group, and four (4%) of 107 patients in the placebo group discontinued their assigned treatment because of adverse events. INTERPRETATION: In patients with moderate-to-severe plaque psoriasis, the 10 mg twice daily dose of tofacitinib was non-inferior to etanercept 50 mg twice weekly and was superior to placebo, but the 5 mg twice daily dose did not show non-inferiority to etanercept 50 mg twice weekly. The adverse event rates over 12 weeks were similar for tofacitinib and etanercept. This study indicates that in the future tofacitinib could provide a convenient and well-tolerated therapeutic option for patients with moderate-to-severe plaque psoriasis. FUNDING: Pfizer Inc.

Postmenopausal Evaluation and Risk Reduction With Lasofoxifene (PEARL) trial: 5-year gynecological outcomes.

OBJECTIVE: The aim of this study was to establish the gynecological effects of 5 years of treatment with lasofoxifene versus placebo in postmenopausal osteoporotic women. METHODS: A total of 8,556 women aged 59 to 80 years with femoral neck or spine bone mineral density T scores of -2.5 or lower were randomized to receive lasofoxifene 0.25 mg/day, or lasofoxifene 0.5 mg/day, or placebo, for 5 years. RESULTS: Endometrial cancer was confirmed for two women in each lasofoxifene group and for three women in the placebo group. Endometrial hyperplasia occurred in three, two, and zero women in the lasofoxifene 0.25 mg/day, lasofoxifene 0.5 mg/day, and placebo groups, respectively. Vaginal bleeding occurred in 2.2% (P = 0.012 vs placebo), 2.6% (P = 0.001 vs placebo), and 1.3% of women treated with 0.25 mg/day lasofoxifene, 0.5 mg/day lasofoxifene, and placebo, respectively. Lasofoxifene treatment resulted in a small increase in endometrial thickness versus placebo (least-squares mean change from baseline 1.19 mm [P = 0.001], 1.43 mm [P < 0.001], and -0.72 mm for 0.25 mg/day lasofoxifene, 0.5 mg/day lasofoxifene, and placebo). Similar numbers of women required surgery for pelvic organ prolapse or urinary incontinence in the placebo and 0.5 mg/day lasofoxifene groups (1.2% vs 1.6%, P = 0.224; 0.25 mg/day group: 1.9%, P = 0.036). The absolute incidence rates of endometrial polyps were 8.8%, 5.5%, and 3.3% for lasofoxifene 0.25 mg/day (P = 0.003 vs placebo), lasofoxifene 0.5 mg/day (P = 0.163 vs placebo), and placebo groups, respectively. CONCLUSION: These findings indicate that 5 years of lasofoxifene treatment result in benign endometrial changes that do not increase the risk for endometrial cancer or hyperplasia in postmenopausal women.