ALBERT

Description: We have conducted a retrospective study of 82 patients (49 - male, 33 - female, median age 67 years (Male), 63 years (Female) ) of whom 72 were de novo and 10 had a previous diagnosis of MGUS/Smouldering myeloma/Plasmacytoma. The duration of symptoms prior to diagnosis was used to categorise patients into 4 groups [A - 0 - 3months, B - 3 -6 months, C - 6 - 12 months, D 〉 12 months]. The incidence of complications of myeloma (infection, renal failure, bone disease, neurological disease and anaemia) were assessed in each group. 25 of 72 patients (35%) were in group A, 47 (65%) were in group B,C and D and 30 of these (64%) had presented initially to a general practitioner. The commonest presenting symptom was bone pain (60%) and skeletal disease was the commonest complication seeing in 43% of group A but in 57% of groups B,C and D. All 18 patients in group D had 〉 1 complication (median 2, range 1–4) while 9 of 25 patients (35%) in group A had no complication. Four of 25 (16%) patients in group A were in remission or first phase of treatment and 7 of 25 (28%) had survived 5 years or more. In contrast, 9 of 18 (50%) patients in group D had relapsed disease and only 2 had survived 5 years or more. Our findings indicate that a delay in diagnosing multiple myeloma has a significant impact on the course of the disease.

Description: Pts with CML resistant to im have few therapeutic options. A growing body of evidence suggests that treatment outcomes can be improved with increased potency of BCR-ABL inhibition. Escalating the dose of im to 800mg/day (d) can overcome some cases of im-resistance, but tolerability and durability of response are significant issues. Dasatinib (SPRYCEL®, formerly BMS-354825) is a novel, oral, multi-targeted kinase inhibitor of BCR-ABL, SRC, and other kinases that is approximately 300 times more potent than im in vitro. Dasatinib has been shown to be effective and safe in pts with CML resistant or intolerant to im, leading to recent FDA approval. START-R is an international trial of dasatinib 70mg twice daily (BID) and im 800mg/d in pts with CP-CML resistant to prior im 400–600mg/d. Crossover was allowed upon confirmed progression or intolerance despite dose reduction (grade 3/4 non-hematologic toxicity). Dasatinib dose escalation to 90mg BID was allowed for inadequate response at 12 wks, and dose reduction to 50 or 40mg BID for toxicity. Dose reduction of im to 600mg/d was allowed for patients who had not previously received that dose. Major cytogenetic response (MCyR) rate at 12 weeks was the primary endpoint. From Feb–Nov 2005, 150 pts were randomized (2:1), 101 to dasatinib, 49 to im. MCyR to prior im had been seen in 28% of dasatinib and 29% of im pts. With a minimum follow-up of 10 mo, complete hematologic response (CHR) rate was 92% (93 dasatinib pts) vs 82% (40 im pts), and MCyR rate was 48% dasatinib vs 33% im. Of importance, the primary difference was the complete cytogenetic response (CCyR) rate of 35% (35/101) dasatinib vs 16% (8/49) im, suggesting that dasatinib can achieve deeper responses in this patient population. Of pts with no prior CyR to im, 44% (17/39) achieved a MCyR with dasatinib vs 7% (1/15) with higher dose im. MCyR rates of 40% to dasatinib and 20% to im were achieved in pts with baseline im-resistant BCR-ABL mutations, with 47% of dasatinib pts vs 0 im pts with difficult-to-treat P-loop mutations achieving a MCyR. Pts with no prior CyR to im were able to achieve MCyR with dasatinib, but dose escalation of im was not effective. 23% dasatinib pts vs 80% im pts had treatment failure (TF, defined as progression, lack of response, crossover for intolerance, or off treatment). Median time to TF was not reached for dasatinib, and was 3.5 mo (95% CI: 3.3-3.8) for im. 61 pts discontinued the initially assigned treatment, of whom 50 (12 dasatinib; 38 im) crossed over after progression, no response, or intolerance. Of 45 post-crossover pts (38 dasatinib; 7 im), 17 (45%) dasatinib pts achieved MCyR, but no (0%) im pts with 800mg/d achieved MCyR after crossover following dasatinib. Grade 3/4 non-hematologic toxicity was minimal in both arms. All grades of superficial edema and fluid retention were more common with im than dasatinib (41% im vs 15% dasatinib; and 43% im vs 28% dasatinib respectively), whereas pleural effusion was 13% (3% grade 3/4) dasatinib vs 0 im. Cytopenia was more frequent and severe with dasatinib. This is the first clinical trial in pts with CML to include both im and dasatinib arms. Based on nearly 1 year of follow-up, dasatinib clearly appears to be more effective in achieving MCyR than high-dose im in pts who fail 400–600mg/d im. An update with molecular response data and detailed mutational analysis will be presented.

Description: Interpatient variability in intracellular uptake and retention (IUR) of imatinib may be due to variable function of the OCT-1 influx pump. OCT-1 activity was measured in pretherapy blood from chronic myeloid leukemia (CML) patients by calculating the difference in IUR of [14C]-imatinib with and without OCT-1 inhibition. Of patients with higher than median (high) OCT-1 activity, 85% achieved major molecular response (MMR) by 24 months, versus 45% with no more than a median (low) OCT-1 activity. Assessing patients receiving 600 mg imatinib per day and those averaging fewer than 600 mg over 12 months of therapy revealed patients with high OCT-1 activity achieved excellent molecular response regardless of dose, whereas response of patients with low OCT-1 activity was highly dose dependent. Of patients with low OCT-1 activity who received fewer than 600 mg, 45% failed to achieve a 2-log reduction by 12 months, and 82% failed to achieve a MMR by 18 months, compared with 8% and 17% in the cohort with high OCT-1 activity and dose less than 600 mg/day (P = .017 and P = .022). OCT-1 activity is an important determinant of molecular response to imatinib, with predictive value closely linked to dose. This pretherapy assay identifies patients at greatest risk of suboptimal response where dose intensity is critical, and those likely to respond equally well to standard dose imatinib.

Description: Fusion genes derived from the platelet-derived growth factor receptor beta (PDGFRB) or alpha (PDGFRA) play an important role in the pathogenesis of BCR-ABL–negative chronic myeloproliferative disorders (CMPDs). These fusion genes encode constitutively activated receptor tyrosine kinases that can be inhibited by imatinib. Twelve patients with BCR-ABL–negative CMPDs and reciprocal translocations involving PDGFRB received imatinib for a median of 47 months (range, 0.1-60 months). Eleven had prompt responses with normalization of peripheral-blood cell counts and disappearance of eosinophilia; 10 had complete resolution of cytogenetic abnormalities and decrease or disappearance of fusion transcripts as measured by reverse transcriptase–polymerase chain reaction (RT-PCR). Updates were sought from 8 further patients previously described in the literature; prompt responses were described in 7 and persist in 6. Our data show that durable hematologic and cytogenetic responses are achieved with imatinib in patients with PDGFRB fusion–positive, BCR-ABL–negative CMPDs.