Alto Neuroscience, Inc.

Previous wording

We are a clinical-stage biopharmaceutical company with a mission to redefine psychiatry by leveraging neurobiology to develop personalized and highly effective treatment options. Through insights derived from our scalable and proprietary Precision Psychiatry Platform, or our Platform, we aim to discover brain-based biomarkers to better identify which patients are more likely to respond to our novel product candidates. Our current pipeline consists of seven clinical-stage assets addressing high-need therapeutic areas, focusing on major depressive disorder, or MDD, bipolar depression, or BPD, treatment resistant depression, or TRD, and schizophrenia.

Current wording

We are a clinical-stage biopharmaceutical company with a mission to redefine psychiatry by leveraging neurobiology to develop personalized and highly effective treatment options. Through insights derived from our scalable and proprietary Precision Psychiatry Platform, or our Platform, we aim to develop novel medicines that are more targeted based on a deep understanding of patient biology and the activity of our product candidates on brain processes. Our current pipeline consists of seven clinical-stage assets addressing high-need therapeutic areas, focusing on major depressive disorder, or MDD, bipolar depression, or BPD, treatment resistant depression, or TRD, schizophrenia, and Parkinson’s disease.

Previous wording

In October 2025, we entered into a Securities Purchase Agreement, or the Purchase Agreement, with certain institutional and other accredited investors, or the Purchasers, pursuant to which we agreed to sell and issue to the Purchasers in a private placement transaction, or Private Placement: (i) 3,832,263 shares of our common stock and (ii) with respect to certain Purchasers, pre-funded warrants to purchase 4,622,251 shares of common stock, or Pre-Funded Warrants, in lieu of shares of common stock. The purchase price per share of common stock was $5.9140 per share, or the Purchase Price, and the purchase price for the Pre-Funded Warrants was $5.9139 per Pre-Funded Warrant. The closing of the Private Placement occurred on October 21, 2025. The total gross proceeds to us at the Closing were approximately $50.0 million, and, after deducting offering expenses payable by us, net proceeds were approximately $49.9 million.

Current wording

In October 2025, we entered into a Securities Purchase Agreement, or the 2025 PIPE Purchase Agreement, with certain institutional and other accredited investors, or the 2025 PIPE Purchasers, pursuant to which we sold and issued to the 2025 PIPE Purchasers in a private placement transaction, or the 2025 Private Placement: (i) 3,832,263 shares of our common stock, or the 2025 PIPE Shares and (ii) with respect to certain 2025 PIPE Purchasers, pre-funded warrants to purchase 4,622,251 shares of our common stock, or the 2025 Pre-Funded Warrants, in lieu of shares of common stock. The purchase price per share of common stock was $5.9140 per share, or the 2025 PIPE Purchase Price, and the purchase price for the 2025 Pre-Funded Warrants was $5.9139 per 2025 Pre-Funded Warrant. The closing occurred on October 21, 2025. The total gross proceeds to us were approximately $50.0 million, and, after deducting offering expenses payable by us, net proceeds were approximately $49.7 million.

Previous wording

In May 2025, we acquired ALTO-207 (formerly known as CTC-501) from Chase Therapeutics Corporation, or Chase. ALTO-207 is afixed-dose combination of pramipexole, a dopamine D3-preferring D3/D2 agonist, approved for the treatment of Parkinson’s disease with demonstrated antidepressant effect, and ondansetron, an antiemetic, selective 5-HT3 receptor antagonist. As a fixed-dose combination, ALTO-207 is designed to enable rapid titration and higher dosing by mitigating the dose-limiting adverse events typically experienced with pramipexole. ALTO-207 is being developed to address the significant unmet need for patients with TRD. The planned Phase 2b trial of ALTO-207, which has the potential to serve as a pivotal trial subject to U.S. Food and Drug Administration, or FDA, feedback and review of data, is expected to initiate in the first half of-2026. Following a recent FDA meeting, we also expect to initiate a Phase 3 trial by early 2027 following Phase 3 readiness work and alignment with the FDA on the planned trial design.

Current wording

ALTO-207 is a fixed-dose combination of pramipexole, a dopamine D3-preferring D3/D2 agonist, approved for the treatment of Parkinson’s disease with demonstrated antidepressant effect through multiple robust randomized, placebo-controlled clinical trials, and ondansetron, an antiemetic, selective 5-HT3 receptor antagonist. As a fixed-dose combination, ALTO-207 is designed to enable rapid titration and higher dosing by mitigating the dose-limiting adverse events typically experienced with pramipexole. ALTO-207 is being developed to address the significant unmet need for patients with TRD. The Phase 2b trial of ALTO-207, which has the potential to serve as a pivotal trial subject to U.S. Food and Drug Administration, or FDA, feedback and review of data, was initiated in April 2026. The Phase 2b trial is a randomized, double-blind, placebo-controlled study evaluating ALTO-207 as an adjunctive treatment in approximately 178 adults with TRD. Eligible participants will have experienced two to five prior treatment failures and have moderate to severe depression symptoms, and will remain on their baseline antidepressant medication. Participants will be randomized 1:1 to receive ALTO-207 or placebo during an eight-week double-blind treatment period, which includes a 12-day dose titration period to reach a target total daily dose of 3.2mg pramipexole/15mg ondansetron. The study will be conducted across clinical sites in the U.S. and U.K. The primary endpoint is change from baseline in MADRS. The Company expects to report topline data from the trial in the second half of 2027. Following an FDA meeting in October 2025, we also expect to initiate a Phase 3 trial by early 2027 following Phase 3 readiness work and alignment with the FDA on the planned trial design.

Previous wording

Prior to the acquisition, Chase completed a randomized, placebo-controlled Phase 2a clinical trial evaluating CTC-501 in 32 patients with depression. CTC-501 met the primary and secondary endpoints in this trial, demonstrating statistically significant and clinically meaningful improvements on MADRS compared to placebo. Patients randomized to receive CTC-501 reached a mean dose of 4.1mg per day. CTC-501 was generally well tolerated in the maintenance period of the study with an adverse event rate similar to placebo.

Current wording

In May 2025, we acquired ALTO-207 (formerly known as CTC-501) from Chase Therapeutics Corporation, or Chase. Prior to the acquisition, Chase completed a randomized, placebo-controlled Phase 2a clinical trial evaluating CTC-501 in 32 patients with depression. CTC-501 met the primary and secondary endpoints in this trial, demonstrating statistically significant and clinically meaningful improvements on the Montgomery Åsberg Depression Rating Scale, or MADRS, compared to placebo. Patients randomized to receive CTC-501 reached a mean dose of 4.1mg per day. Real-world data demonstrate that it is challenging to achieve doses above 1mg per day of pramipexole. CTC-501 was generally well tolerated in the maintenance period of the study with an adverse event rate similar to placebo.

Previous wording

Our acquisition of ALTO-207 was motivated by the results from the PAX-D study conducted by the University of Oxford. Results, which were recently published in The Lancet Psychiatry, showed pramipexole augmentation of antidepressant treatment, at a target dose of 2.5mg, demonstrated a large (Cohen’s d=0.87) reduction in symptoms relative to placebo at 12 weeks, but was associated with a high rate of adverse effects. We believe the profile of ALTO-207 will enable higher dosing of pramipexole while mitigating the significant rates of nausea and vomiting that have limited its use for depression.

Current wording

Our acquisition of ALTO-207 was motivated by the results from the PAX-D study conducted by the University of Oxford. Results, which were published in The Lancet Psychiatry, showed pramipexole augmentation of antidepressant treatment, at a target dose of 2.5mg, demonstrated a large (Cohen’s d=0.87) reduction in symptoms relative to placebo at 12 weeks (and continuing through 48 weeks), but was associated with a high rate of adverse effects. We believe the profile of ALTO-207 will enable higher dosing of pramipexole while mitigating the significant rates of nausea and vomiting that have limited its use for depression.

Previous wording

ALTO-300, also known as agomelatine, is an oral, small molecule designed to act as a melatonin agonist and 5-HT2C antagonist, and is being developed at 25mg as an adjunctive treatment in the United States for patients with MDD, characterized by an EEG biomarker. Agomelatine is an approved antidepressant medication in Europe and Australia, at both 25mg and 50mg, but has not been approved in the United States. In comparison to the 50mg dose of agomelatine, the 25mg dose has been shown to have equivalent antidepressant efficacy and has not been associated with reversible, low liver enzyme elevations observed with the 50mg dose.

Current wording

ALTO-300, also known as agomelatine, is an investigational oral, small molecule melatonergic (MT1 and MT2) agonist and serotonergic (5-HT2C) antagonist with antidepressant properties, and is being developed at 25mg as an adjunctive treatment in the United States for patients with MDD, characterized by an electroencephalography, or EEG, biomarker. Agomelatine has been approved as an antidepressant in Europe and Australia at both 25mg and 50mg, but has not been approved in the United States. In comparison to the 50mg dose of agomelatine, the 25mg dose has been shown to have equivalent antidepressant efficacy and has not been associated with reversible, low liver enzyme elevations observed with the 50mg dose. A published meta analysis including more than 58,000 patients demonstrated that agomelatine is not associated with elevated aspartate transferase, or AST, or alanine transaminase, or ALT, unlike certain other commonly used antidepressants. In our development program, including our completed Phase 2a and ongoing Phase 2b study, we have observed low rates of liver function test, or LFT, elevations (greater than 3 times the upper limit of normal, or ULN) with the 25mg dose which supports our strategy of developing only the 25mg dosage strength.

Previous wording

We are currently evaluating ALTO-300 in a double-blind, placebo-controlled, randomized Phase 2b clinical trial in patients with MDD characterized by an EEG biomarker signature. We expect to enroll approximately 200 biomarker positive patients in the final analysis sample, which is therefore expected to result in approximately 320 patients enrolled in the study in total (inclusive of biomarker negative patients and patients not included in the final analysis sample as a result of the completed blinded site and patient case review). Patients are randomized to receive either 25mg of ALTO-300 once daily before bedtime, or QHS, or placebo in addition to a background antidepressant, to which they have had inadequate response, over a six-week treatment period. Patients are then enrolled into an eight-week open-label extension in which they receive 25mg QHS of ALTO-300. We selected the 25mg dose of ALTO-300 with the aim to optimize clinical efficacy while balancing safety and tolerability. The primary endpoint in the trial is the change in MADRS score from baseline to week six in the EEG biomarker positive group. We expect to report topline data from this trial in mid-2026.

Current wording

We are currently evaluating ALTO-300 in a double-blind, placebo-controlled, randomized Phase 2b clinical trial in patients with MDD characterized by an EEG biomarker signature. We expect to enroll approximately 200 biomarker positive patients in the final analysis sample, which is therefore expected to result in approximately 320 patients enrolled in the study in total (inclusive of biomarker negative patients and patients not included in the final analysis sample as a result of the completed blinded site and patient case review). Patients are randomized to receive either 25mg of ALTO-300 once daily before bedtime, or QHS, or placebo in addition to a background antidepressant, to which they have had inadequate response, over a six-week treatment period. Patients are then enrolled into an eight-week open-label extension in which they receive 25mg QHS of ALTO-300. We selected the 25mg dose of ALTO-300 with the aim to optimize clinical efficacy while balancing safety and tolerability. The primary endpoint in the trial is the change in MADRS score from baseline to week six in the EEG biomarker positive group. We expect to report topline data from this trial in the first half of 2027.

Previous wording

In October 2025, we announced that a blinded pharmacokinetic, or PK, analysis from the first cohort of patients in our ongoing Phase 2b study evaluating ALTO-100 as a treatment for BPD demonstrated that 96% of samples for ALTO-100 qualified as PK positive. A sample was considered PK positive if observed drug levels were above a pre-specified minimum threshold. We believe these results underscore the effectiveness of the operational adjustments made to trial design and execution following the completion of the ALTO-100 MDD Phase 2b trial. Enrollment in this trial is ongoing, with a target of approximately 200 patients, and we expect to report topline data from the study in the second half of 2026.

Current wording

A blinded pharmacokinetic, or PK, analysis from the first cohort of patients in this trial demonstrated that 96% of samples for ALTO-100 qualified as PK positive. A sample was considered PK positive if observed drug levels were above a pre-specified minimum threshold. We believe these results underscore the effectiveness of the operational adjustments made to trial design and execution following the completion of the ALTO-100 MDD Phase 2b trial. Enrollment in this trial is ongoing, with a target of approximately 200 patients, and we expect to report topline data from the study in mid-2027.

Previous wording

The exploratory Phase 2 POC trial, which enrolled 69 patients, was conducted in two sequential, double-blind, placebo-controlled periods. The trial was designed to characterize the pharmacodynamic, pharmacokinetic, safety, and tolerability profile of ALTO-203 across two dose levels compared to placebo in a crossover design and was not powered to detect statistical significance on traditional depression outcome scales (e.g., MADRS).

Current wording

In June 2025, we announced the completion of our exploratory Phase 2 POC trial of ALTO-203 in MDD with elevated levels of anhedonia and the resulting identification of a patient selection biomarker and positive pharmacodynamic results. The exploratory Phase 2 POC trial, which enrolled 69 patients, was conducted in two sequential, double-blind, placebo-controlled periods. The trial was designed to characterize the pharmacodynamic, pharmacokinetic, safety, and tolerability profile of ALTO-203 across two dose levels compared to placebo in a crossover design and was not powered to detect statistical significance on traditional depression outcome scales (e.g., MADRS).

Previous wording

In May 2025, we acquired ALTO-208 (formerly known as CTC-413) from Chase. ALTO-208 isa fixed-dose combination of pramipexole and aprepitant, an antiemetic, neurokinin-1 (NK-1) receptor antagonist. We plan to develop ALTO-208 for patients with Parkinson’s disease (PD).

Current wording

ALTO-208 is a fixed-dose combination of pramipexole and aprepitant, an antiemetic, neurokinin-1 (NK-1) receptor antagonist. We plan to develop ALTO-208 for patients with Parkinson’s disease (PD). In May 2025, we acquired ALTO-208 (formerly known as CTC-413) from Chase.

Previous wording

Since our inception in 2019, we have devoted substantially all of our resources to the research and development of our product candidates by conducting clinical trials and preclinical studies, building our Platform, and recruiting management and technical staff to support these operations. To date, we have funded our operations primarily through the aggregate net proceeds from equity financings (including from our initial public offering, or IPO, the Private Placement, and pre-IPO sales of our convertible preferred stock) and borrowings under our loan and security agreement.

Current wording

Since our inception in 2019, we have devoted substantially all of our resources to the research and development of our product candidates by conducting clinical trials and preclinical studies, building our Platform, and recruiting management and technical staff to support these operations. To date, we have funded our operations primarily through the aggregate net proceeds from equity financings (including from our initial public offering, or IPO, private placement transactions, and pre-IPO sales of our convertible preferred stock) and borrowings under our loan and security agreement.

Previous wording

We have not generated any revenue from product sales and we have incurred recurring losses since our inception. Our net losses were $14.2 million and $47.1 million for the three and nine months ended September 30, 2025, respectively. Our net losses were $16.8 million and $46.2 million for the three and nine months ended September 30, 2024, respectively. As of September 30, 2025, we had an accumulated deficit of $185.5 million. We expect to continue to generate operating losses and negative operating cash flows for the foreseeable future. We anticipate that our operating expenses and capital expenditures will increase substantially with our ongoing activities, particularly as we:

Current wording

We have not generated any revenue from product sales and we have incurred recurring losses since our inception. Our net losses were $26.2 million and $15.2 million for the three months ended March 31, 2026 and 2025, respectively. As of March 31, 2026, we had an accumulated deficit of $227.9 million. We expect to continue to generate operating losses and negative operating cash flows for the foreseeable future. We anticipate that our operating expenses and capital expenditures will increase substantially with our ongoing activities, particularly as we:

Previous wording

•continue to progress the clinical development of our product candidates, including ALTO-100 and ALTO-300 in ongoing Phase 2b clinical trials, ALTO-101 in ongoing Phase 2 POC trials, as well as ALTO-203, ALTO-207, and ALTO-208;

Current wording

•continue to progress the clinical development of our product candidates, including ALTO-207 in our Phase 2b clinical trial and planned Phase 3 clinical trial, and ALTO-100 and ALTO-300 in ongoing Phase 2b clinical trials, as well as ALTO-203, and ALTO-208;

Previous wording

As of September 30, 2025, we had cash, cash equivalents and restricted cash of$138.3 million, and in October 2025, we raised approximately$49.9 millionin net proceeds from the Private Placement. We believe that our existing cash and cash equivalents, including the Private Placement proceeds will be sufficient to fund our operating expenses and capital expenditure requirements into 2028, including enhanced development of ALTO-207. See “—Liquidity and Capital Resources.”

Current wording

As of March 31, 2026, we had cash, cash equivalents and restricted cash of$264.3 million. We believe that our existing cash and cash equivalents, together with the anticipated proceeds under our Convertible Grant Agreement with Wellcome, will be sufficient to fund our operating expenses and capital expenditure requirements for at least the next 12 months. See “—Liquidity and Capital Resources.”

Previous wording

Other income (expense) consists primarily of interest income on our cash and cash equivalents, interest expense on borrowings under our loan and security agreement, loss on debt extinguishment, and non-cash changes in the fair value of our Convertible Grant Agreement with Wellcome (See “— Liquidity and Capital Resources”) and our preferred stock warrant liability. In February 2024, in connection with the IPO, the Series A Preferred Stock Warrants were net exercised and settled in common stock and the K2 Warrant was converted into a common stock warrant (see Note 10 to our unaudited condensed consolidated financial statements included elsewhere in this Quarterly Report); as a result, both of these warrants are treated as equity instruments prospectively. Therefore, there will be no incremental changes to the fair value of the warrants in future periods.

Current wording

Other income (expense) consists primarily of interest income on our cash and cash equivalents, interest expense on borrowings under our loan and security agreement, loss on debt extinguishment, and non-cash changes in the fair value of our Convertible Grant Agreement with Wellcome (See “— Liquidity and Capital Resources”).

Previous wording

•an increase of approximately $0.5 million in expenses related to our Phase 2 POC trial of ALTO-101, which began in 2024; and

Current wording

•an increase of approximately $4.4 million in expenses related to the development of our ALTO-101 program, including our Phase 2 POC trial of ALTO-101 for which we announced top line data on April 1, 2026.

Previous wording

•an increase of approximately $0.3 million in expenses related to development of our ALTO-207 program ; and

Current wording

•an increase of approximately $4.1 million in expenses related to development of our ALTO-207 program, which we acquired in May 2025. The costs primarily related to clinical and manufacturing activities required to launch the Phase 2b clinical trial, which we announced the initiation of in April 2026.

Previous wording

•an increase of approximately $0.5 million in salary and personnel related costs.

Current wording

•an increase of $1.2 million in salary and personnel related costs, which includes $0.5 million of non-cash stock-based compensation.

Previous wording

General and administrative expenses were $4.4 million for the three months ended September 30, 2025, compared to $5.8 million for the three months ended September 30, 2024. The decrease of $1.4 million was primarily due to decreases in payroll related expenses and a decrease in professional fees.

Current wording

General and administrative expenses were $6.8 million for the three months ended March 31, 2026, compared to $5.7 million for the three months ended March 31, 2025. The increase of $1.1 million was primarily due to increases in professional fees.

Previous wording

We have incurred net losses and negative cash flows from operations since our inception and anticipate we will continue to incur net losses for the foreseeable future. We have not yet commercialized any of our product candidates, which are in various phases of development, and we do not expect to generate revenue from sales of any of our product candidates for several years, if at all. As we progress through the phases of development, we anticipate that we will incur increasing losses in future quarters and years compared to historical periods. To date, we have funded our operations primarily through the aggregate net proceeds from equity financings (including from our IPO, the Private Placement, and pre-IPO sales of our convertible preferred stock) and borrowings under our loan and security agreement.

Current wording

We have incurred net losses and negative cash flows from operations since our inception and anticipate we will continue to incur net losses for the foreseeable future. We have not yet commercialized any of our product candidates, which are in various phases of development, and we do not expect to generate revenue from sales of any of our product candidates for several years, if at all. As we progress through the phases of development, we anticipate that we will incur increasing losses in future quarters and years compared to historical periods. To date, we have funded our operations primarily through the aggregate net proceeds from equity financings (including from our IPO, our October 2025 and March 2026 private placement transactions, and pre-IPO sales of our convertible preferred stock) and borrowings under our loan and security agreement.

Previous wording

As of September 30, 2025 and December 31, 2024, we had cash, cash equivalents and restricted cash of $138.3 million and $168.7 million, respectively.

Current wording

As of March 31, 2026 and December 31, 2025, we had cash, cash equivalents and restricted cash of $264.3 million and $177.0 million, respectively.

Previous wording

In October 2025, we entered into the Purchase Agreement with the Purchasers pursuant to which we agreed to sell and issue to the Purchasers in the Private Placement: (i) 3,832,263 shares of our common stock and (ii) with respect to certain Purchasers, Pre-Funded Warrants to purchase 4,622,251 shares of common stock in lieu of shares of common stock. The Purchase Price was $5.9140 per share and the purchase price for the Pre-Funded Warrants was $5.9139 per Pre-Funded Warrant. . The Private Placement closed on October 21, 2025. The total gross proceeds to us at the Closing were approximately $50.0 million, and, after deducting offering expenses payable by us, net proceeds were approximately $49.9 million.

Current wording

In October 2025, we entered into the 2025 PIPE Purchase Agreement with the 2025 PIPE Purchasers pursuant to which we sold and issued to the 2025 PIPE Purchasers: (i) 3,832,263 shares of our common stock and (ii) with respect to certain 2025 PIPE Purchasers, 2025 Pre-Funded Warrants to purchase 4,622,251 shares of common stock in lieu of shares of common stock. The purchase price per share of common stock was $5.9140 per share and the purchase price for the 2025 Pre-Funded Warrants was $5.9139 per 2025 Pre-Funded Warrant. The closing occurred on October 21, 2025. The total gross proceeds to us were approximately $50.0 million, and, after deducting offering expenses payable by us, net proceeds were approximately $49.7 million.

Previous wording

We drew $20.0 million upon entry into the Amendment(approximately $10.0 million of which was used to refinance obligations under the Original Loan Agreement and pay fees and expenses incurred in connection with the Amendment). A portion of the second tranche term loans is tied to the timing of data from our Phase 2b study of ALTO-300; based on expected timing of top line data for this study, we anticipate that $20.0 million of the second tranche term loans will expire without being drawn.

Current wording

We drew $20.0 million upon entry into the Amendment(approximately $10.0 million of which was used to refinance obligations under the Original Loan Agreement and pay fees and expenses incurred in connection with the Amendment). The second tranche term loans, which were tied to the timing of clinical milestones, expired without being drawn.

Previous wording

As of December 31, 2024, we had an outstanding principal balance of $10.0 million under the Original Loan Agreement. As of September 30, 2025, we had an outstanding principal balance of $20.0 million under the Amended Loan Agreement.

Current wording

As of March 31, 2026 and December 31, 2025, we had an outstanding principal balance of $15.0 million and $16.0 million under the Amended Loan Agreement, respectively.

Previous wording

Following an initial period with no financial covenants, beginning January 1, 2026, we must maintain, at all times, a cash runway of at least five months, provided that this covenant will be waived during any period in which our market capitalization exceeds $700.0 million. The Term Loan is secured by substantially all of our assets, excluding intellectual property.

Current wording

Beginning January 1, 2026, we must maintain, at all times, a cash runway of at least five months based upon a trailing three month cash consumption calculation, provided that this covenant will be waived during any period in which our market capitalization exceeds $700.0 million. The Term Loan is secured by substantially all of our assets, excluding intellectual property.

Previous wording

Additionally, under the terms of the Amended Loan Agreement, the Lender may, at its option, elect to convert up to $9.0 million of the then outstanding Term Loan ($4.0 million of which was reflected in the Original Loan Agreement and $5.0 million of which is reflected in the Amendment) into shares of our common stock.

Current wording

Additionally, under the terms of the Amended Loan Agreement, the Lender may, at its option, elect to convert up to $9.0 million of the then outstanding Term Loan ($4.0 million of which was reflected in the Original Loan Agreement and $5.0 million of which is reflected in the Amendment) into shares of our common stock. On November 17, 2025 and March 19, 2026, the Lender elected to convert $4.0 million and $1.0 million, respectively, of its outstanding loan balance into the Company’s common stock. Pursuant to the terms of the Amended Loan Agreement, the conversion price was $4.83 per share, resulting in the issuance of 828,860 and 207,215 shares, respectively. The Lender has the option to convert a remaining $4.0 million into shares of common stock; the conversion price per share for the remaining option is $10.49.

Previous wording

In July 2024, we entered into a convertible loan agreement, or the Convertible Grant Agreement, with Wellcome. The Convertible Grant Agreement provides for an unsecured convertible loan, or the Convertible Loan, from Wellcome of up to approximately $11.7 million, payable in six tranches. As of September 30, 2025, we had drawn $2.0 million under the Convertible Grant Agreement, and the remainder will be funded upon draw down of payments following the completion of certain milestones as set forth in the Convertible Grant Agreement, subject to certain conditions described therein, which may or may not be achieved. In addition to the funds that we have drawn down as of September 30, 2025, we have achieved clinical milestones that allow us to draw down an incremental $3.0 million under the Convertible Grant Agreement.

Current wording

In July 2024, we entered into a convertible loan agreement, or the Convertible Grant Agreement, with Wellcome. The Convertible Grant Agreement provides for an unsecured convertible loan, or the Convertible Loan, from Wellcome of up to approximately $11.7 million, payable in six tranches. As of March 31, 2026, we had drawn down $2.0 million under the Convertible Grant Agreement, and the remainder will be funded upon draw down of payments following the completion of certain milestones as set forth in the Convertible Grant Agreement, subject to certain conditions described therein, which may or may not be achieved. In addition to the funds that we have drawn down as of March 31, 2026, we have achieved clinical milestones that allow us to draw down an incremental $3.0 million under the Convertible Grant Agreement.

Previous wording

Net cash used in operating activities was$40.3 million for the nine months ended September 30, 2025, as compared to$34.4 million for thenine months ended September 30, 2024. The increase in cash used was the result of an increase in net losses of $0.8 million and a change in accrued liabilities and other liabilities of $5.7 million primarily due to the timing of bonus and payroll payments. The increase in cash used in operating activities was partially offset by recognition of a non-cash loss on debt extinguishment related to the Amended Loan Agreement.

Current wording

Net cash used in operating activities was$27.1 million for the three months ended March 31, 2026, as compared to $16.6 million for the three months ended March 31, 2025. The increase in cash used was the result of an increase in net losses of $11.1 million which was partially offset by increased non-cash stock-based compensation expenses of $0.9 million.

Previous wording

The net cash used in investing activities for the nine months ended September 30, 2025 was negligible.

Current wording

The net cash used in investing activities for the three months ended March 31, 2025 was negligible.

Previous wording

Net cash provided by financing activities was$9.9 million for thenine months ended September 30, 2025, primarily related to the net increase in borrowings under our Amended Loan Agreement, the drawdown of $0.8 million under our Convertible Grant Agreement and $0.4 million of cash provided from the exercise of stock options.

Current wording

Net cash provided by financing activities was $114.9 million for the three months ended March 31, 2026, primarily related to the proceeds from our 2026 PIPE Purchase Agreement.

Previous wording

We believe that our existing cash and cash equivalents of $137.8 million as of September 30, 2025, together with both the net proceeds from the Private Placement and anticipated proceeds under our Convertible Grant Agreement with Wellcome Trust, will be sufficient to fund our operating expenses and capital expenditure requirements into 2028, including enhanced development of ALTO-207. This estimate reflects both our prioritization efforts to improve operating efficiency, including reducing headcount in May 2025 which resulted in short-term severance costs, and our re-deployment of long-term savings toward new programs such as ALTO-207 and ALTO-208. However, our forecast of the period of time through which our financial resources will be adequate to support our soperations is a forward-looking statement that involves risks and uncertainties, and actual results could vary materially. We have based this estimate on assumptions that may prove to be wrong, and we could expend our capital resources sooner than we currently expect.

Current wording

We believe that our existing cash and cash equivalents of $263.8 million as of March 31, 2026, together with the anticipated proceeds under our Convertible Grant Agreement with Wellcome, will be sufficient to fund our operating expenses and capital expenditure requirements for at least the next 12 months. However, our forecast of the period of time through which our financial resources will be adequate to support our operations is a forward-looking statement that involves risks and uncertainties, and actual results could vary materially. We have based this estimate on assumptions that may prove to be wrong, and we could expend our capital resources sooner than we currently expect.

Previous wording

In addition to ongoing needs to fund our operations, our material cash requirements as of September 30, 2025 consist primarily of obligations under both our Amended Loan Agreement (see Note 4 to our unaudited condensed consolidated financial statements included elsewhere in this Quarterly Report) and our lease commitment for our headquarters office space located in Mountain View, California with an initial lease term of 65 months that terminates in March 2030 for which we currently have a $6.4 million commitment remaining. If the Company elects to terminate the lease after the third lease year, including payments already made, the Company will make payments of approximately $4.0 million over the term of the lease.

Current wording

In addition to ongoing needs to fund our operations, our material cash requirements as of March 31, 2026 consist primarily of obligations under both our Amended Loan Agreement (see Note 4 to our unaudited condensed consolidated financial statements included elsewhere in this Quarterly Report) and our lease commitment for our headquarters office space located in Mountain View, California with an initial lease term of 65 months that terminates in March 2030 for which we currently have a $5.9 million commitment remaining. If the Company elects to terminate the lease after the third lease year, including payments already made, the Company will make payments of approximately $4.0 million over the term of the lease.

Previous wording

In October 2021, we entered into an asset purchase agreement, or the Teva Agreement, with Teva Pharmaceutical Industries, Ltd. and its affiliate Cephalon, Inc., or together Teva, pursuant to which we acquired patents, know-how and other rights to ALTO-203 and a specified related compound, or Teva Acquired Compounds, and we assumed all post-acquisition liabilities related thereto. In April 2024, we achieved a clinical milestone under the Teva Agreement related to the initiation of our Phase 2 POC trial evaluating ALTO-203 and paid Teva $0.5 million in cash during thenine months ended September 30, 2024.

Current wording

In October 2021, we entered into an asset purchase agreement, or the Teva Agreement, with Teva Pharmaceutical Industries, Ltd. and its affiliate Cephalon, Inc., or together Teva, pursuant to which we acquired patents, know-how and other rights to ALTO-203 and a specified related compound, or Teva Acquired Compounds, and we assumed all post-acquisition liabilities related thereto.

Previous wording

In September 2023, we entered into a joint development and license agreement, or the MedRx Agreement, with MedRx Co., Ltd., or MedRx, pursuant to which we obtained an exclusive, sublicensable, worldwide license, with the right to sublicense, under certain patent rights and know-how of MedRx relating to transdermal drug delivery to develop (excluding any pre-clinical development), manufacture, and commercialize transdermally delivered pharmaceutical products comprising MedRx’s transdermal patch technology and our ALTO-101, or MedRx Licensed Product, for all therapeutic, prophylactic, and diagnostic uses. We granted MedRx an exclusive, sublicensable, worldwide license under certain patent rights and know-how relating to ALTO-101 owned or controlled by us, including certain patents and know how licensed to us pursuant to the Sanofi Agreement, solely to conduct pre-clinical development and manufacturing of the MedRx Licensed Products for us in accordance with the MedRx Agreement and a separate manufacturing and supply agreement to be entered into between us and MedRx. In April 2024 we achieved a milestone under the MedRx Agreement and paid MedRx $0.8 million in cash and issued 46,875 shares of our common stock, recognizing expense of $1.5 million during the nine months ended September 30, 2024.

Current wording

In September 2023, we entered into a joint development and license agreement, or the MedRx Agreement, with MedRx Co., Ltd., or MedRx, pursuant to which we obtained an exclusive, sublicensable, worldwide license, with the right to sublicense, under certain patent rights and know-how of MedRx relating to transdermal drug delivery to develop (excluding any pre-clinical development), manufacture, and commercialize transdermally delivered pharmaceutical products comprising MedRx’s transdermal patch technology and our ALTO-101, or MedRx Licensed Product, for all therapeutic, prophylactic, and diagnostic uses. We granted MedRx an exclusive, sublicensable, worldwide license under certain patent rights and know-how relating to ALTO-101 owned or controlled by us, including certain patents and know how licensed to us pursuant to the Sanofi Agreement, solely to conduct pre-clinical development and manufacturing of the MedRx Licensed Products for us in accordance with the MedRx Agreement and a separate manufacturing and supply agreement to be entered into between us and MedRx.

Previous wording

On May 31, 2025, we entered into an asset purchase agreement, or Chase Agreement, with Chase Therapeutics Corporation, or Chase, to acquire all patent, know-how and other rights to ALTO-207, ALTO-208, and certain related assets. For a detailed description of the financial terms of the Chase Agreement, see Note 6 to our unaudited condensed consolidated financial statements included elsewhere in this Quarterly Report.

Current wording

On May 31, 2025, we entered into an asset purchase agreement, or Chase Agreement, with Chase Therapeutics Corporation, or Chase, to acquire all patent, know-how and other rights to ALTO-207, ALTO-208, and certain related assets.

Previous wording

Other than as described above, we could not estimate when milestones, royalties, and/or other payments due to third parties under our existing license agreements will be due, and none of these events were probable to occur as of September 30, 2025.

Current wording

We could not estimate when milestones, royalties, and/or other payments due to third parties under our existing license agreements will be due, and none of these events were probable to occur as of March 31, 2026.