Background: Previously, we had shown the potent anti−tumor activity of dual anti-angiogenic therapy by combining bevacizumab (B) and thalidomide (T) with docetaxel (D) and prednisone (P) in mCRPC (Ning JCO 2010). We hypothesized that combining lenalidomide (L), an analogue of T, with B, D, and P would have a more favorable efficacy/toxicity profile. Methods: All patients (pts) had chemotherapy−naïve mCRPC. Among the first 52 pts, 3 received L 15 mg daily, 3 had 20 mg daily, and the rest had 25 mg daily for 14 days of every 21−day cycle (C). The protocol was recently amended to enroll 11 more pts at L 15 mg; 2 pts have now been enrolled in this expansion cohort. All pts received D 75 mg/m2 and B 15 mg/kg on day 1 with P 10 mg and enoxaparin daily throughout each C. Pegfilgrastim was given on day 2. PSA each C with imaging after C2 and after every 3C. Dental exams with mandible CT scan at baseline, after C5, and every 6C. Results: 54 of 62 pts have been enrolled. Median age 65.5 (51−82), Gleason score 8 (5−10), on−study PSA 85.2 ng/ml (0.15−3520), and pre−study PSA doubling time 1.49 months (0.52−6.73). Median number of Cs was 16 (3−38). PFS was 22 months and probability of survival at 12 months was 90%. Forty-six (85.2%) and 42 (77.8%) pts had PSA declines of ≥50% and ≥75%, respectively. Of 30 pts with measurable disease there were 1 CR and 25 PR (86.7% overall RR). 17/54 pts were off study for radiographic disease progression and 8/54 for other reasons. Grade ≥2 toxicities included neutropenia (34/54), anemia (23/54), thrombocytopenia (7/54), hypertension (12/54), perianal fistula (3/54), rectal fissure (1/54), myocardial infarction (1/54), and osteonecrosis of the jaw (ONJ) (12/54, 22.0%). At the time of diagnosis of ONJ, 7/12pts were on bisphosphonates (BP), 2/12 had used BP previously, and 3/12 never used BP. The incidence of ONJ was comparable to 18.3% reported by Ning et al. A recent study of carboplatin plus weekly docetaxel reported an incidence of 29.3%. Conclusions: Dual anti-angiogenic therapy with, B and L, plus D and P was associated with high PSA (85.2%) and tumor (86.7%) responses in mCRPC, with manageable toxicities. The incidence of ONJ is comparable to other studies.