A Phase I study of LGD1069 in adults with advanced cancer.

LGD1069 [Targretin; 4-[1-(5,6,7,8-tetrahydro-3,5,5,8,8-pentamethyl-2-naphtalenyl) propenyl] benzoic acid] is a novel synthetic retinoid X receptor-selective retinoid that has been recently identified. The goals of this study were to determine the safety, toxicity, pharmacokinetics (PKs), and metabolic profile of LGD1069 in advanced cancer patients. Sixty patients received oral LGD1069 at doses ranging from 5-1000 mg/m2/day with PK sampling performed on days 1 and 15. No dose-limiting toxicities (DLTs) were observed up to the 500 mg/m2/day dose level. DLT observed at and above 650 mg/m2/day included skin desquamation, hyperbilirubinemia, transaminase elevation, leukopenia, and diarrhea. Asymptomatic, dose-related alterations in lipid and thyroid metabolism were also observed. DLTs frequently observed with retinoic acid receptor-selective retinoids and pan agonists, including headache, mucocutaneous toxicity, and hypercalcemia, were not dose-limiting with LGD1069. Day 1 LGD1069 Cmax and area under the curve values increased dose-proportionately up to 800 mg/m2/day. Repeat-dose (day 15) area under the curve values varied between 25 and 105% of day 1 values. Although no objective tumor responses were observed, tumor progression may have been substantially arrested or delayed in non-small cell lung cancer (5 of 16) and in head and neck cancer (1 of 5), as well as other tumor types. At the higher dose levels, the molar concentration of LGD1069 was up to 10-fold higher than observed with other retinoids, yet toxicity was minimal. LGD1069 is an retinoid X receptor-selective retinoid agonist with a more favorable PK and toxicity profile than previously studied retinoids and merits further investigation as a chemopreventive and anticancer agent. On the basis of this Phase I trial, the recommended Phase II dose is 500 mg/m2/day.

Phase I study of 9-cis-retinoic acid (ALRT1057 capsules) in adults with advanced cancer.

9-cis-Retinoic acid (9-cis-RA) and all-trans-RA (ATRA) are naturally occurring hormones. The nuclear receptors that mediate the effects of retinoids are the retinoic acid receptors (RARs) and the retinoid X receptors (RXRs). ATRA binds RAR with high affinity but does not bind to RXR, whereas 9-cis-RA, an isomer of ATRA, is a ligand that binds and transactivates both RARs and RXRs. The goals of this study were to determine the safety, tolerability, pharmacokinetics, and metabolic profile of 9-cis-RA in advanced cancer patients. Forty-one patients received oral 9-cis-RA (ALRT1057; Panretin capsules) at doses ranging from 5-140 mg/m2/day. Twenty-six patients were treated once daily with up to 140 mg/m2; a subsequent cohort of 15 patients were treated twice daily (b.i.d.) at 100-140 mg/m2/day (50, 60, and 70 mg/m2 b.i.d.) to evaluate a b.i.d. dosing regimen. Headache was the most frequent adverse event and was dose limiting in 3 of 41 patients. Skin toxicity was the next most common toxicity and was seen in 11 of 41 patients; it was typically mild and limited to skin dryness and erythema. Other toxicities included conjunctivitis, flushing, diarrhea, transaminitis, hypercalcemia, and asymptomatic hypertryglyceridemia. Toxicities were typically dose related, occurred primarily above 83 mg/m2/day, and were not ameliorated by b.i.d. dosing. No tumor responses were observed. The mean day 1 area under the plasma concentration-time curve and peak plasma concentration values were dose-proportional over all dose levels, whereas day 15 area under the plasma concentration-time curve and peak plasma concentration values were nonlinear above 83 mg/m2/day, suggesting that 9-cis-RA induced its own metabolism at doses equal to and above 140 mg/m2/day. 9-cis-RA is a retinoid receptor pan agonist with a more favorable pharmacokinetic and toxicity profile than that observed with previously studied retinoids and merits further investigation.

Initial clinical trial of the retinoid receptor pan agonist 9-cis retinoic acid.

The retinoid response is mediated by families of nuclear receptors, the retinoic acid receptors (RARs), and the retinoid X receptors. All-trans retinoic acid (RA) binds only RARs and induces its own metabolism. In contrast, 9-cis RA is a newly identified agonist for both RARs and retinoid X receptors. We undertook a dose-ranging study to examine the safety, clinical tolerance, and pharmacokinetics of 9-cis RA in patients with advanced cancer. Thirty-four patients received once daily p.o. doses of 9-cis RA (administered as LGD1057) ranging from 5 to 230 mg/m2 for 4 weeks. Pharmacokinetic studies were performed on 28 patients at seven dose levels. 9-cis RA was generally well tolerated. Headache was the most common dose-limiting adverse effect. Other prominent reactions included facial flushing, myalgia, dyspnea, hypertriglyceridemia, and hypercalcemia. Relative to other retinoids, mucocutaneous reactions were mild. No major antitumor responses were observed. Pharmacokinetic analysis revealed that the day 1 area under the plasma concentration x time curves (AUCs) were proportional to the dose. Up through doses of 140 mg/m2, the day 1 AUCs were similar to those on days 15 and 29. At higher doses, however, AUCs tended to decline with repeat dosing. 9-cis RA is a novel compound that exploits a newly identified pathway of retinoid receptor biology that may be relevant to tumor cell proliferation and differentiation. We recommend a dose of 140 mg/m2 for single-agent trials utilizing a once-daily schedule of administration.

9-cis retinoic acid induces complete remission but does not reverse clinically acquired retinoid resistance in acute promyelocytic leukemia.

9-cis retinoic acid (RA) is a high-affinity ligand for both retinoic acid receptors (RARs) and retinoid "X" receptors (RXRs). Although all-trans RA does not bind to RXRs, RAR/RXR heterodimers or RXR/RXR homodimers bind to specific DNA response elements and modulate proliferation and differentiation of normal and malignant cells. Because the development of clinical resistance to all-trans RA has been associated with a progressive decrease in plasma drug concentrations, we evaluated the ability of 9-cis RA to induce in vitro cytodifferentiation in subclones of a retinoid-sensitive and resistant APL cell line (NB4) and in short-term cultures of fresh leukemic cells aspirated from patients. We also evaluated the clinical activity and pharmacokinetics of 9-cis RA (LGD 1057) in patients with APL who were previously treated with all-trans RA. In vitro tests of both retinoid-sensitive NB4 cells, as well as samples of fresh cells from 11 patients with APL, showed relatively equivalent degrees of sensitivity to both 9-cis RA and all-trans RA at concentrations ranging from 10(-6) to 10(-8) mol/L; however, no substantial cytodifferentiation was observed using either drug alone or in combination (10(-6) mol/L of each) in retinoid-resistant NB4 cells. Seven patients with APL who had previously relapsed from a remission induced by all-trans RA were treated with 9-cis RA at daily oral doses ranging from 30 to 230 mg/m2. Pharmacokinetic studies showed that the mean terminal plasma half-life of 9-cis RA (1.3 hours) changed very little after several weeks of dosing, although the mean change per dose level in area under the plasma concentration x time curves and peak plasma concentrations showed a decrease by 49% and 45%, respectively. Peak plasma concentrations equaled or exceeded concentrations that were effective against retinoid-sensitive cells in vitro. Despite these favorable pharmacokinetic results, only one of the seven patients achieved complete remission, corroborating in vitro studies of blasts from three of the nonresponders that showed a relatively equivalent degree of resistance to both retinoids. Our results suggest that while 9-cis RA may not induce its own catabolism to the same degree as all-trans RA, this feature does not appear to overcome clinically acquired resistance to all-trans RA in APL. Nonetheless, the drug can induce complete remissions in patients with APL and may be useful for extended therapy in other diseases. Future studies should address the use of lower doses in patients who have not previously received retinoid therapy.(ABSTRACT TRUNCATED AT 400 WORDS)

Estramustine phosphate compared with diethylstilbestrol. A randomized, double-blind, crossover trial for stage D prostate cancer.

In a double-blind, crossover comparison, 236 patients with metastatic prostate cancer were randomized to receive estramustine phosphate (EMP) or diethylstilbestrol (DES). Previously castrated patients (66) were separately randomized. Patients kept taking their first drug until progression was proved by objective studies, at which time alternative treatment was begun. The primary determinant of efficacy was the duration between start of therapy and date of objective progression. Uncastrated patients treated with EMP had a significantly longer duration without progression than those treated with DES (p less than 0.01). The following subcategories of entry were further evaluated: little or no pain, moderate to severe pain, little reduction in activity, significant reduction in activity, presence or absence of cardiovascular disease, age above or below 70 years, and "good" or "bad" histology. For all but the last category, EMP was statistically superior to DES. Patients who underwent orchiectomy less than 3 months before randomization had nonprogression rates similar to those for noncastrated men in both groups. Secondary (crossover) therapy was less effective than first therapy in both groups: 46% of patients receiving EMP and 40% receiving DES had no progression at 6 months. Clinical and laboratory adverse experiences were similar for both drugs, except that gastrointestinal disturbances were more common in the EMP group.

Treatment of stage D hormone-resistant carcinoma of the prostate with estramustine phosphate.

We report on 51 patients with hormone-resistant, stage D prostatic carcinoma who were treated with estramustine phosphate and followed for at least 6 months. Of the 51 patients 5 (10 per cent) had a partial objective response, 30 (59 per cent) remained stable and 16 (31 per cent) had progression of the disease. All of those patients who had a partial response or remained stable also experienced subjective improvement as judged by relief of pain and performance status. Approximately 8 per cent of the patients will be unable to take estramustine phosphate because of intolerable gastrointestinal side effects.

Survey of general practitioners' views on postgraduate education in North-east Scotland.

A questionnaire was sent to all doctors in North-east Scotland enquiring about postgraduate education. The educational programme devised by the Education Committee of the North-east Scotland Faculty of the Royal College of General Practitioners was considered to be relevant, interesting, and well-planned. Suggestions made by the doctors have been taken account of by the Education Committee in their present programme.Journals considered to have the best educational content were Prescriber's Journal, Update and The Practitioner. Those doctors who read The Journal of the Royal College of General Practitioners thought it expressed up-to-date and helpful views about the development of general practice. However, it was ranked poorly alongside such journals as Update.The doctors rated contact with their partners and hospital colleagues as the most important sources of education. These links must be a growth point for postgraduate education within an integrated health service.One-week courses, covering several subjects with a variety of presentations, were most favoured by the replying doctors.