Concept for power scaling by harmonic beam coaxial combination in an intra-cavity frequency doubling laser.

A new method of harmonic beam coaxial combination (HBCC) from two intra-cavity frequency doubling branches was demonstrated. Firstly, two identical nanosecond (ns) 532 nm green lasers with high power and good beam quality were created. Each green laser was constructed of an intra-cavity frequency doubling branch based on a laser diode (LD) end-pumped acousto-optical (AO) Q-switched 1064 nm Nd:YVO4 laser in a LiB3O5 (LBO) nonlinear crystal. Each branch generated about 45 W green output at a 50 kHz pulse repetition rate (PRR) with diffraction limited beam quality. The first green beam was injected into the LBO crystal in the second branch, and the pulses from the two branches did not exist simultaneously. Then, the HBCC was performed. Consequently, an 83 W combined green output power at 532 nm was obtained with a combination efficiency of 92.2%. The PRR of the HBCC pulse was doubled to be 100 kHz, with a pulse width of about 22 ns, corresponding to a single pulse energy of 0.83 mJ and a peak power of 37.73 kW. The combined beam quality factor was measured to be M x2 = 1.80 in the x direction and M y2 = 1.71 in the y direction, respectively. Moreover, many more beams could also be combined with this method for further scaling the green power.

Ixazomib-based frontline therapy followed by ixazomib maintenance in frail elderly newly diagnosed with multiple myeloma: a prospective multicenter study.

Background: Frail elderly patients with newly diagnosed multiple myeloma (NDMM) have inferior survival and less benefit from high-dose therapies. This prospective study aimed to investigate the efficacy, safety, and quality of life (QoL) of induction treatment of ixazomib/lenalidomide/dexamethasone (IRd) and ixazomib/pegylated liposomal doxorubicin/dexamethasone (IDd) followed by ixazomib/dexamethasone (Id) maintenance therapy in frail, elderly patients with NDMM. Methods: From July 2019 to December 2021, this non-randomized concurrent controlled clinical study enrolled 120 NDMM patients aged ≥65 years with frailty defined by the International Myeloma Working Group (IMWG) frailty score or Mayo geriatric scoring system. The enrolled patients received 6-8 cycles of IRd or IDd followed by Id maintenance therapy for a minimum of 2 years at the discretion of physicians based on patient's clinical characteristics (chiCTR1900024917). Findings: The median age was 71 years and 55% of the patients were males. The overall response rate (ORR) was 82% and 77%, complete response (CR) rate was 25% and 12% for IRd and IDd groups, respectively. The difference in ORR of the Idd group minus the IRd group was -5.36% (95% CI: -18.9% to 8.19%), indicating that the ORR of the IDd group was neither inferior nor non-inferior to the IRd group. After a median follow-up of 34.3 months, the median progression-free survival (PFS) was 21.6 and 13.9 months, OS was not reached and 29.2 months in IRd and IDd groups, respectively. 28 and 33 patients discontinued induction therapy, 20 and 19 discontinued maintenance therapy in IRd and IDd groups, respectively. Cumulative Grade 3 or higher hematological adverse events (AEs) occurred in 10 of the 60 patients (17%) and non-hematological AEs occurred in 15 of the 60 patients (25%) in the IRd group, while 13 of the 60 patients (22%) and 21 of the 60 patients (35%) in the IDd group. Patients were observed with clinically significant improvement in QoL when compared with that at baseline in both IRd and IDd groups by evaluation per cycle (P < 0.0001). Interpretation: The results demonstrated that compared with IRd regimen, IDd regimen showed no significant advantage, but the survival of the IDd group was shorter than that of the IRd group, indicating an all-oral outpatient triplet regimen with IRd, which has low toxicity and has improved QoL, could be the viable first-line treatment option for frail NDMM patients. Funding: The Young Elite Scientist sponsorship program by bast of Beijing Association for Science and Technology (No. BYESS2023116) and Beijing Medical Award Foundation (No. YXJL-2018-0539-0073).