On August 8, 2022 Sutro Biopharma, Inc. (Sutro or the Company) (NASDAQ: STRO), a clinical-stage oncology company pioneering site-specific and novel-format antibody drug conjugates (ADCs), reported its financial results for the quarter ended June 30, 2022, its recent business highlights, and a preview of anticipated select milestones (Press release, Sutro Biopharma, AUG 8, 2022, View Source [SID1234617848]).
Schedule your 30 min Free 1stOncology Demo!
Discover why more than 1,500 members use 1stOncology™ to excel in:
Early/Late Stage Pipeline Development - Target Scouting - Clinical Biomarkers - Indication Selection & Expansion - BD&L Contacts - Conference Reports - Combinatorial Drug Settings - Companion Diagnostics - Drug Repositioning - First-in-class Analysis - Competitive Analysis - Deals & Licensing
Schedule Your 30 min Free Demo!
"This quarter, Sutro continued to execute on the promise of our platform, as marked by the recently announced collaboration with Astellas covering research and development of immunostimulatory ADCs, or iADCs—a novel modality with the potential to turn cold tumors hot," said Bill Newell, Sutro’s Chief Executive Officer. "Additionally, we are pleased to see Merck dosing patients in its Phase 1 study as part of our cytokine derivative collaboration. This represents the sixth clinical-stage product candidate enabled by Sutro’s platform. Looking ahead, we are optimistic about the potential of our pipeline of ADCs; this includes STRO-002 for patients with platinum-resistant ovarian cancer, as well as our newly unveiled STRO-003, an optimized ROR1 ADC, which we anticipate will be our next proprietary product candidate to move into clinical studies."
Recent Business Highlights and Anticipated Select Milestones
STRO-002, FolRα-Targeting ADC: STRO-002 is being studied in the clinic, in both the U.S. and Europe, for patients with ovarian and endometrial cancers.
The Phase 1 dose-expansion cohort for patients with advanced ovarian cancer has completed enrollment and is ongoing. Sutro expects to report additional data on efficacy, safety, and durability from the dose-expansion cohort, together with the design of a potential registrational study, in the second half of 2022.
Discussions with the FDA on a potential registrational study for patients with advanced ovarian cancer were held mid-year 2022, in which the agency signaled that an accelerated approval pathway could be available for STRO-002 in a platinum-resistant ovarian cancer patient population.
Additional ongoing clinical studies for STRO-002 include a combination study with bevacizumab for patients with advanced ovarian cancer and a dose-expansion study for patients with endometrial cancer.
STRO-001, CD74-Targeting ADC: The Phase 1 study for patients with B-cell malignancies, including patients with non-Hodgkin’s lymphoma (NHL) and multiple myeloma (MM), continues in dose escalation.
Dose escalation is ongoing to achieve a recommended Phase 2 dose (RP2D), with the last reported doses of 5.0 mg/kg in the MM cohort and 5.0 mg/kg in the NHL cohort.
Sutro is opening additional sites for STRO-001 outside of the U.S. and Greater China, to increase the rate of enrollment; and Sutro’s partner BioNova Pharma (BioNova) is advancing clinical development of BN301 (STRO-001) for patients with hematological malignancies in Greater China.
Additional Pipeline Programs: A Sutro Research Forum highlighted STRO-003 and its emerging research portfolio.
STRO-003 is an optimally designed ADC targeting ROR1, with precisely positioned β-Glucuronidase-cleavable linkers, attached to eight next-generation exatecan warheads, which inhibit topoisomerase-1 resulting in DNA disruption.
Patient-derived xenograft models (PDX) have shown potent cell killing by STRO-003 in low antigen expressing tumors; and STRO-003 has shown encouraging tolerability in preclinical rodent and non-human primate studies.
Sutro provided details on its product and process design, which enables its emerging portfolio including novel therapeutic modalities—for example, a single antibody which was conjugated to be site-specific, with two different payloads with synergistic mechanisms.
Collaboration Updates: Sutro continues to seek to maximize the value of its proprietary cell-free platform by working with partners on programs in multiple disease spaces and geographies and has generated from collaborators an aggregate of approximately $583 million, which includes payments and equity investments through June 30, 2022, in addition to the $90 million upfront payment from Astellas received in July 2022.
Sutro entered into a collaboration with Astellas on the discovery and development of iADCs for three targets, including an upfront payment to Sutro of $90 million, which was received in July 2022, and $422.5 million in potential milestones per product candidate. Sutro will also receive financial support for its research efforts and has an option to co-develop and co-commercialize product candidates in the U.S.
A $10 million milestone payment from Merck was triggered in July 2022 upon the first patient dosed in a Phase 1 study of MK-1484, a selective IL-2 agonist, under the existing cytokine derivative collaboration.
Sutro is manufacturing initial drug supply for the clinical development of Merck’s MK-1484, currently in a Phase 1 study; clinical trial materials for Bristol Myers Squibb’s (BMS) CC-99712, a BCMA-targeting ADC for treatment of multiple myeloma, in Phase 1 studies; and clinical trial materials for M1231, a MUC1-EGFR-targeting bispecific ADC, for Merck KGaA, Darmstadt, Germany, known as EMD Serono in the U.S. and Canada (EMD Serono), in Phase 1 studies.
Sutro supplies cell-free extract to Vaxcyte for the manufacture of clinical trial materials for VAX-24, which is designed to prevent invasive pneumococcal disease. Vaxcyte announced in July 2022 that it had completed enrollment of the Phase 1/2 clinical proof-of-concept study of VAX-24. Sutro is eligible to receive four percent (4%) royalties on worldwide net sales of VAX-24 and any licensed vaccine candidates.
BioNova announced in July 2022 that it had submitted its IND for BN301 (STRO-001) to the National Medical Products Administration for the treatment of hematologic malignancies. Sutro is providing clinical drug supply to BioNova for clinical studies in Greater China.
Sutro is currently supporting Tasly for initiation of clinical development activities and IND filing in Greater China for STRO-002 and will provide initial clinical drug supply.
Second Quarter 2022 Financial Highlights
Cash, Cash Equivalents and Marketable Securities
As of June 30, 2022, Sutro had cash, cash equivalents and marketable securities of $191.6 million, as compared to $192.1 million as of March 31, 2022, which, together with the $90 million upfront payment received from Astellas in July 2022, provides a projected cash runway into the first half of 2024, based on current business plans and assumptions. The above balances do not include the value associated with Sutro’s holdings of Vaxcyte common stock.
Unrealized Loss from Decrease in Value of Vaxcyte Common Stock
As of June 30, 2022, Sutro held approximately 1.6 million shares of Vaxcyte common stock, with a fair value of $34.0 million. The non-operating, unrealized loss of $3.7 million in the second quarter of 2022 was due to the decrease since March 31, 2022 in the estimated fair value of Sutro’s holdings of Vaxcyte common stock. Vaxcyte common stock held by Sutro will be remeasured at fair value based on the closing price of Vaxcyte’s common stock on the last trading day of each reporting period, with any non-operating, unrealized gains and losses recorded in Sutro’s statements of operations.
Revenue
Revenue was $28.1 million for the quarter ended June 30, 2022, as compared to $28.0 million for the same period in 2021, related principally to recognition of the upfront payment from Tasly in the second quarter of 2022 and the Merck, BMS, and EMD Serono collaborations in both years. Future collaboration revenue from Astellas, Tasly, Merck, BMS, and EMD Serono, and from any additional collaboration partners, will fluctuate as a result of the amount and timing of revenue recognition of upfront, milestones, and other collaboration agreement payments.
Operating Expenses
Total operating expenses for the quarter ended June 30, 2022 were $47.5 million, as compared to $37.9 million for the same period in 2021. The second quarter of 2022 includes non-cash expenses for stock-based compensation of $6.7 million and depreciation and amortization of $1.4 million, as compared to $5.9 million and $1.1 million, respectively, in the comparable 2021 period. Total operating expenses for the quarter ended June 30, 2022 were comprised of research and development expenses of $32.3 million and general and administrative expenses of $15.1 million, which are expected to increase in 2022 as Sutro’s internal product candidates advance in clinical development and additional general and administrative expenses are incurred as a public company.