Good afternoon, and welcome to Spero Therapeutics' fourth quarter and year-end 2022 financial results conference call. At this time, all participants are in a listen-only mode. Following the company's formal remarks, we will open up the call for questions. Please be advised that this call is being recorded and the replay will be available. You can find information on the replay and further information related to today's announcement on the Spero Therapeutics website at www.sperotherapeutics.com. At this time, I would like to turn the call over to Ted Jenkins, Vice President, Investor Relations and Strategic Finance at Spero Therapeutics. Mr. Jenkins, please go ahead. Thank you, operator, and thank you all for participating in today's conference call. This afternoon, Spero Therapeutics released financial results and provided a pipeline update for the fourth quarter and full year 2022. Our press release is available on the investor page of the Spero Therapeutics website. Before we begin, I'd like to remind you that some of the information presented on this conference call contains forward-looking statements based on our current expectations, including statements about the future development and commercialization of SPR720, SPR206, and tebipenem HBr. The design, initiation, timing, progress, and results of the company's pre-clinical studies and clinical trials and its research and developmental programs. Management's assessment of the results of such pre-clinical studies and clinical trials, the company's cash forecast and anticipated expenses, and the sufficiency of its cash resources. Such forward-looking statements are not a guarantee of performance, and the company's actual results could differ materially from those contained in such statements. Several factors that could cause or contribute to such differences are described in detail in Spero Therapeutics' filings with the SEC, including in the Risk Factors section of our annual report on Form 10-K for the year ended December 31, 2022, filed with the SEC today. These forward-looking statements speak only as of the date of this conference call, the company undertakes no obligation to publicly update any forward-looking statements or supply new information regarding the company after the date of today's call. Participating in today's call are Dr. Ankit Mahadevia, Chief Executive Officer, Dr. Kamal Hamed, Chief Medical Officer, and Sath Shukla, Chief Financial Officer. With that, I'd like to turn the call over to Dr. Ankit Mahadevia. Please go ahead, Ankit. Thanks, Ted, and thanks to everyone listening. Spero's off to a strong 2023, thanks to recent achievements that have provided us with a strong balance sheet and world-class partners to support the advancement of our multi-program pipeline of differentiated medicines. We remain committed to developing a pipeline of medicines that marry unmet need with high commercial potential, and we continue to do so while placing a premium on capital efficiency and complementing our efforts with those of our partners in pharma and in public agencies. Kamal will be providing an update on SPR720 and SPR206. I'll focus my part of the call on tebipenem HBr, which we are developing as potentially the first oral carbapenem antibiotic for the treatment of complicated urinary tract infections, or cUTI. As a reminder, tebipenem HBr is the subject of an exclusive license agreement with GSK, which closed last quarter. This agreement came with a $66 million upfront payment to us, as well as a $9 million equity investment in our common stock, both of which have now been received. In addition, we are eligible for up to $525 million in development, sales, and milestone payments, as well as single-digit to low double-digit royalties on net product sales. In exchange for all this, GSK was granted an exclusive license for tebipenem HBr's development and commercialization in all territories except Japan and certain other Asian countries, where rights are being retained by our partner, Meiji Seika. Per the agreement, we hold responsibility for an upcoming Phase 3 trial of tebipenem HBr, while GSK will be responsible for additional development and commercialization activities outside of the Meiji Seika territory. We're engaged with the FDA on the planned protocol for tebipenem HBr's upcoming clinical trial. As you may recall, we had a Type A meeting with the agency in 2022, during which we aligned on high-level aspects of the trial design and received feedback indicating that positive results from the trial, together with confirmatory non-clinical evidence of efficacy, could be sufficient to support tebipenem's approval in cUTI, including pyelonephritis for a limited use indication. We still anticipate providing an update on our engagement with the FDA in the first half of this year. This update will include details of the clinical trial design as well as granularity on the specific regulatory and development activities over the coming months that'll trigger milestone payments from our GSK partnership. We'll continue to anticipate initiating the Phase 3 trial in the second half of 2023, if all goes well with the program, we believe tebipenem HBr could reach commercialization by 2026, as noted by GSK on their earnings call last month. I'd like to thank GSK for their role in what's been a very productive partnership to date. As we work to advance tebipenem HBr through the regulatory process and complete the phase II trial, it's the program's strong foundation that fuels our enthusiasm. This foundation consists of three key pillars. The first of these pillars is the extensive dataset supporting tebipenem's safety and efficacy. Between our work and that of Meiji Seika, tebipenem has been evaluated in 24 clinical trials that have been collectively enrolled over 2,500 subjects. These are highlighted by our double-blind, placebo-controlled phase III trial, ADAPT-PO. Moreover, post-marketing surveillance efforts on tebipenem in Japan, where it's approved for pneumonia, otitis media, and sinusitis, have demonstrated its efficacy while noting no safety issues in a review of more than 3,300 patients. The second key pillar of tebipenem's foundation is its potential to address a clear and pressing unmet need. There are currently no oral carbapenem antibiotics available for millions of cUTI patients in the U.S., many of whom have no other option other than to receive an IV therapy in a hospital setting. By successfully developing tebipenem, we believe we can provide these patients with an at-home oral treatment that could provide health and economic benefits for them while also improving costs for the healthcare system. The last key pillar making up tebipenem's foundation for success comes from the support of our partners. We believe GSK is the ideal partner to lead tebipenem's commercialization if approved, given its well-established commercial organization and commitment to serving patients with infection, including urinary tract infections. We're also grateful for the continued support of BARDA for the advancement of tebipenem. With that, I'll turn the call over to Kamal to discuss SPR720 and SPR206. Thanks, Ankit. I'll begin by providing a brief update on SPR720, our novel oral drug candidate being developed as a first-line treatment for the orphan-designated nontuberculous mycobacterial pulmonary disease, or NTM PD for short. An important aspect of our SPR720 program is its target patient population, which consists of patients who are treatment naive or those who've received treatment but have non-refractory disease. This is noteworthy because patients with NTM PD who progress to refractory disease often suffer irreversible lung damage, limiting the potential for pharmacotherapy to improve how they feel and function. Despite the inherent challenges of treating patients with refractory disease, there remain no FDA-approved first-line therapies for NTM PD. Instead, patients who early in their disease journey are frequently treated with combinations of off-label therapies with limitations related to tolerability and effectiveness. In fact, published estimates indicate that 75% of patients with NTM PD who receive standard of care treatment discontinue such treatment after about a year, mainly due to tolerability and effectiveness concerns. Even when they complete their course of therapy, a relatively large proportion of patients experience recurrent disease. Through SPR720's development, we hope to improve the first-line standard of care for patients with NTM PD. Towards this end, we initiated a phase II-A clinical trial designed to establish proof of concept. We recently completed a successful investigator meeting, and we are conducting the appropriate development activities for the program, working to eventually advance SPR720 into. I'll jump in for Kamal. I think he's having technical difficulties. These activities include ongoing toxicology work, CMC and quality initiatives, engagement with FDA, and activities to expand into Japan as there is a large prevalence of Japanese patients with NTM PD. Importantly, we are also actively progressing with the development and validation of relevant patient-reported outcomes for NTM PD as part of the clinical endpoint work for our follow-on clinical studies. The phase II trial is designed to enroll approximately 35 patients with NTM PD due to Mycobacterium avium complex, implicated in approximately 80% of NTM PD cases. Eligible participants are either treatment naive or have received prior treatment but have non-refractory disease. The study will compare two doses of oral SPR720 monotherapy, 500 and 1,000 milligrams versus placebo. The primary endpoint is slope change of weekly sputum bacterial burden from day one to the end of the trial's 56-day treatment period. We aim to see SPR720 treatment leading to a weekly sputum bacterial slope change, which is both negative and significantly better than placebo. Achieving this goal would make SPR720 the only agent in development that we're aware of with a demonstrated ability to drive early microbiological response against NTM as a standalone agent versus placebo. Pairing this result with safety data that are consistent with the favorable safety findings observed in SPR720's prior phase I trial would strongly support advancement of the program. More broadly speaking, the goal of our phase II-A proof of concept study is to inform the design of a later stage and longer-term trial evaluating SPR720 in combination with current standard of care agents. Although we do not expect to comment on enrollment as trial progresses, 10 U.S. sites are currently active and more sites are expected to come on board in the coming months. This progress is in line with our target timelines, and we remain on track to report top-line results from this phase II-A trial in the first half of 2024. On behalf of Kamal, I'll now briefly discuss SPR206, our investigational next generation polymyxin candidate being developed to treat multi-drug resistant gram-negative infections in the hospital setting. This program is supported by multiple collaborations including Pfizer, Everest Medicines, and the National Institute of Allergy and Infectious Diseases, and the U.S. Department of Defense. A major limitation of currently available polymyxins is the nephrotoxicity associated with these agents. With that as a premise, our team leveraged the understanding of the structure activity relationships to design 206 in a way that minimizes in vitro cytotoxicity and in vivo kidney exposure. In animal models, this led to a substantial reduction of the nephrotoxicity profile compared to currently available polymyxins. Subsequent phase I trials indicated that 206 was generally well tolerated at dose levels above predicted therapeutic exposures in key tissues such as the lungs. These data, together with in vitro data demonstrating its potent activity against multi-drug resistant pathogens, supports our belief that 206 has the potential to be a best in class polymyxin. Supported by encouraging clinical and preclinical results we've seen to date, we're now working to advance SPR206 into an externally funded phase II trial in patients with hospital-acquired or ventilator-associated bacterial pneumonia. We expect to submit an IND application to the FDA to support this phase II trial in the fourth quarter of this year. With that, we'll pass the call over now to Sath to review our financial results. Sath? Thank you, Ankit, and good afternoon to all listening. It is my pleasure to now provide an overview of Spero's financial results for the fourth quarter and full year ended December 31, 2022. Total revenues for the fourth quarter of 2022 were $47.4 million, compared with revenues of $2.7 million for the fourth quarter of 2021. The revenue increase for the fourth quarter of 2022 was primarily due to $46.1 million in collaboration revenue related to our agreements with GSK and Pfizer. Total revenue for the year ended December 31, 2022 was $53.5 million, compared to $18.3 million for the year ended December 31, 2021. The revenue increase for the year ended December 31, 2022 was primarily due to the aforementioned partnership collaboration revenue. Research and development expenses for the fourth quarter of 2022 were $15.1 million compared to $17.2 million of research and development expenses for the same period in 2021. This year-over-year decrease was primarily due to a reduction in personnel-related costs following the strategic restructuring announced in May 2022. Research and development expenses for the year ended December 31, 2022 were $47.6 million, compared to $64.5 million for the year ended December 31, 2021, with lower expenses in 2022 compared to 2021, primarily due to reduced program activity for tebipenem HBr as a result of the strategic restructuring last year. General and administrative expenses for the fourth quarter of 2022 were $6.5 million, compared to $13 million of G&A expenses for the same period in 2021. This year-over-year decrease was primarily due to reduced headcount costs in our commercial, general and administrative functions as a result of the strategic restructuring. General and administrative expenses for the year ended December 31, 2022 were $36.5 million, compared to $41.7 million for the year ended December 31, 2021, with lower expenses in 2022 compared to 2021, again, primarily as a result of the strategic restructuring. Restructuring expenses of $11.6 million were incurred during the year ended December 31, 2022. These expenses primarily comprised of $8.6 million of severance and other employee costs, $2.4 million of discontinuation costs such as contract termination fees, and $0.6 million of lease impairment expenses. Spero reported net income of $26.8 million for the fourth quarter and a full year net loss of $46.4 million for the year ended December 31, 2022, or net income of $0.55 and net loss of $1.23 per share of common stock, respectively. Net losses for the fourth quarter and year ended December 31, 2021 were $29.2 million and $89.8 million, or $0.90 and $2.91 per share of common stock, respectively. As of December 31, 2022, Spero had cash and cash equivalents of $109.1 million. Based on its current operating plan, Spero believes that its cash and cash equivalents, together with other non-dilutive funding commitments, will be sufficient to fund its operating expenses and capital expenditure requirements beyond 2024. For further details on our financials, please refer to our 10-K filed with the SEC today. We will now open the call for questions. Operator? Thank you. We will now be conducting our question and answer session. If you would like to ask a question, please press star one on your telephone keypad. A confirmation tone will indicate your line is in the question queue. You may press star two if you would like to remove yourself from the queue. For participants using speaker equipment, it may be necessary to pick up your headset before pressing the star keys. One moment please while we poll for questions. Our first question comes from Louise Chen with Cantor. Please go ahead. Hi. Congratulations on all the progress this quarter. Thanks for taking my question. I want to ask you a few questions. First, on your cash balance, will it take you to the SPR720 Phase II readout? The other question I wanted to ask you was, if your drug, the SPR720 is approved for NTM, where do you expect to fit into the treatment paradigm? The last question is just on OpEx, how we should think about that relative to 2022, and then with the potential increase in R&D expense, I guess, given the new programs that you're working on, you know, how we should phase that in. Thank you. Thanks, Louise, for the questions. Your first and third question relate to some of our financials, so I'll have Sath answer those, but perhaps I'll start with, you know, the treatment paradigm for SPR720. So just to zoom out to 100,000 feet, NTM is a debilitating chronic disease. It affects about a quarter of a million patients worldwide, half in the U.S., half in the rest of the world. It's a slow-growing, debilitating disease where patients you know, lose their quality of life slowly. The longer a patient has the disease, the more long-term and lasting damage the lungs have. We believe that the treatment paradigm for NTM drugs generally and also SPR720 is to be a solution for patients early in their disease journey. Certainly, the drug has the microbiological characteristics to be useful throughout a patient's disease journey. We're starting with first line because it's 75% of the current patient population, number one. Number two, you know, as we've looked at published literature suggests that 75% of patients that are on the current options they have discontinue within a year. Of the patients that actually stick with it, half of them don't find any relief. The major unmet need right now is first line treatment and something that patients can take throughout their disease journey to avoid becoming refractory patients. That's where we'll start, and then we'll explore how we expand the story from there as we continue to generate clinical data. That's perhaps the first part of your question. For the financial components of your question, I'll turn it to Sath. Great. Yeah, thanks for the questions, Louise. Your first question on whether the cash balance will take us through the top-line data readout for SPR720, that is indeed the case. Our expected top-line data readout is in the first half of next year. Our expected cash runway is to beyond 2024, meaning beyond the end of 2024. We expect to have this data readout with still a healthy balance of cash sitting on our books when it becomes available. Unless you had questions on the cash, I can move on to the operating expenses question. Yeah, that makes sense. Thank you. Great. On the operating expenses, Louise, if you look at our financials for this quarter, other than a one-time payment made to Meiji as disclosed in our 10-K, the run rate for OpEx is virtually the same as our burn on OpEx for 3Q of last year. For 3Q of last year, we were in the early teens in terms of dollars. If you extrapolate that early teens burn on non-Tebipenem expenses on a $109 million cash balance, that would give you the support for our disclosed cash runway to beyond 2024. For the in-between R&D, you are of course right that we expect to scale that up when we start phase III trials, those will be funded by the milestones we receive from GSK on development through that process. Indeed, R&D expenses will go up, but so will the cash and milestones coming in from our partners. Therefore, for GSK, we expect that to be a wash. Prior run rates will give you the calculations that would support our disclosed cash runway. Okay, thank you. Please wait. This concludes our question-and-answer session. I will now turn the call back to Dr. Mahadevia. Thank you, operator. Thanks to everyone who joined us on the call today to hear about our recent progress. We look forward to the continued advancement of our programs and wish everyone a nice evening. This concludes today's teleconference. You may disconnect your lines at this time. Thank you for your participation. Have a great day.