E2809. Androgen receptor (AR) modulation by bicalutamide (Bic) and MK-2206 (MK) in prostate cancer (PC) patients (pts) with rising PSA at high risk of progression after local treatment (tx)

Background

Men with a PSA doubling time (PSADT)

Methods

108 PC pts with PSA >2 ng/mL, PSADT 

Results

A/B, accrued 54/54, started tx 50/53, Tx arm characteristics were balanced according to age, PS, Gleason score, local tx type, testosterone, mPSA and PSADT. Tox Grade (G: Arm, pts): G4: B, 2 (embolism, hyperglycemia). G3: A, 1 (LFTs); B, 32 (rash 20, hyperglycemia 5, low lymphs 5, hypertension, 4). At 30 mo follow-up 3 died, Arm A vs B pts: 14 (26%) vs 7 (13%) started Bic early; 8 (15%, none for AE's) vs 21 (39%; 14 for AE's) stopped tx before 11 cy; at 11 and 18 cy, 42 (78%) and 31 (57%) vs 32 (59%) and 24 (44%) initiated planned tx and 4 and 6 vs 5 and 6 ( %) discontinued tx due to progression. Intent to treat analysis showed no effect of MK on PSA decline after 11cy (p = 0.39). An exploratory analysis of pts who completed or progressed on the planned tx at 11 and 18 cy: A, 48 (89%) and 41 (71%) vs B, 36 (67%) and 31 (57%). Excluding the disproportionate number of B dropouts due to MK Tox while continuing Bic, B showed a trend towards a higher fraction of pts achieving PSA

Conclusions

In overall PC pts with a rapidly rising PSA at recurrence, adding MK for variable number of cy to ongoing Bic had no beneficial effect at 11mo. Considering only pts who received MK+ Bic as planned, however, some positively interactive effect was suggested, raising the possibility that a subset of genetically heterogeneous PC might be benefited by this combination.

Clinical trial identification

National Cancer Institute NCT01251861 Study first Received: 12/01/2010

Legal entity responsible for the study

N/A

Funding

National Cancer Institute, Cancer Treatment Evaluation Program

Disclosure

All authors have declared no conflicts of interest.